Gulf Research Reports Volume 1, Number 5 Ocean Springs, Mississippi August, 1963 Gulf Research Reports Volume 1 Issue 5 January 1963 Biological Investigations of the St. Lucie Estuary (Florida) in Connection with Lake Okeechobee Discharges Through the St. Lucie Canal Gordon Gunter Gulf Coast Research Laboratory Gordon E. Hall Jacksonville District , Corps of Engineers DOI: 10.18785/grr.0105.01 Follow this and additional works at: http:/ / aquila.usm.edu/ gcr O Part of the Marine Biology Commons Recommended Citation Gunter, G. and G. E. Hall. 1963. Biological Investigations of the St. Lucie Estuary (Florida) in Connection with Lake Okeechobee Discharges Through the St. Lucie Canal. Gulf Research Reports 1 (5): 189-307. Retrieved from http:// aquila.usm.edu/gcr/voll/iss5/ 1 This Article is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Gulf and Caribbean Research by an authorized administrator of The Aquila Digital Community. For more information, please contact Joshua.Cromwell(o)usm.edu. Gulf Research Reports Volume 1, Number 5 Ocean Springs, Mississippi August, 1963 A JOURNAL DEVOTED PRIMARILY TO PUBLICATION OF THE DATA OF THE MARINE SCIENCES, CHIEFLY OF THE GULF OF MEXICO AND ADJACENT WATERS. GORDON GUNTER, Editor Published by the GULF COAST RESEARCH LABORATORY Ocean Springs, Mississippi BIOLOGICAL INVESTIGATIONS OF THE ST. LUCIE ESTUARY (FLORIDA) IN CONNECTION WITH LAKE OKEECHOBEE DISCHARGES THROUGH THE ST. LUCIE CANAL BY Gordon Gunter Gulf Coast Research Laboratory Ocean Springs, Mississippi AND Gordon E. Hall* Jacksonville District, Corps of Engineers THE OFFICE SUPPLY COMPANY PASCAGOULA. MISSISSIPPI ♦ PRESENT ADDRESS: TENNESSEE VALLEY AUTHORITY. NORRIS, TENNESSEE — 189 — TABLE OF CONTENTS A. Introduction 192 B. Basic Considerations 192 1 . Purpose and history of St, Lucie Canal 192 2 , Location and description - 193 a, St. Lucie Canal 193 b. St. Lucie Estuary 193 (1) General location 193 (2) St. Lucie Inlet 193 (3) Description and physical characteristics 193 3. Discharges into St. Lucie Estuary a. Through St. Lucie Canal b. From other areas __ C. Discussion of the Problem 1. Effects of fresh-water discharge _ 2. The sediment problem a. Available sediment data b. St. Lucie Canal 199 c. Other sources — * 200 D. Present Investigations « — 20 I 1. Other agencies — -= 201 a. United States Fish and Wildlife Service 201 b. Florida State Board of Conservation 201 2. Corps of Engineers 201 a. General plan of investigation 201 b. Collection of basic data 203 (1) Sampling gear and methods 203 (2) Location and description of sampling stations 203 (3) Extent of sampling during period of investigation 205 E. Physical Conditions During Study Period 208 1. Fresh- water discharge into St. Lucie Estuary 208 a. From Lake Okeechobee 208 b. From other areas 211 2. Salinity conditions 211 3. Turbidities 213 4. Temperatures 216 a. Water 216 b. Air - - — 216 5. Summary of physical conditions in the estuary during the study period _ - 216 F. Results of Biological Sampling 218 L The fish catch 218 2. Species account. Fishes 220 3. Invertebrate catch 281 4. Species account. Invertebrates , 284 5. Cold kill of fishes. January -February 1958 296 G. Summary and Conclusions 297 H. Literature Cited — 190 — LIST OF PLATES Plate 1. General location of the St. Lucie Estuary 194 Plate 2. A map of the St. Lucie Estuary showing trawl and seine stations and depths in feet 194 Plate 3. Discharge through the St. L.ucie Lock and Dam for the years shown 195 Plate 4. Total annual discharges into the St. Lucie Estuary from all sources (1945-58) 196 Plate 5. The Lake Okeechobee regulation schedule in operation during the study period 206 Plates 6 to 15. Bottom and surface salinity characteristics of the St. Lucie Estuary at times of biological sampling 207 Plate 1 6. The numbers of fishes caught during the investigations and the discharge through the St. Lucie Canal at the same periods 220 LIST OF FIGURES Figure 1. Trawl catches from the Estuary 202 Figure 2. Seining in the Estuary 20 d Figure 3. Cold killed fishes along the shores 260 Figure 4. Temperate zone fishes which survived the cold 261 — 191 — A. INTRODUCTION A survey of the turbidity, salinity and sediment effects of St. Lucie Canal discharge into the St. Lucie Estuary was authorized by the Chief of Engineers on May 9, 1955. Expansion of that program to include the work of the present biological investigation was authorized by the Chief of Engineers on June 12, 1956, The scope and purpose of this biological work was to: (a) review the history of the St. Lucie Canal and analyze the problems concerned with discharges of fresh water into the St, Lucie Estuary: ( b ) present biological data from a 2-year investigation of estuarine conditions, Jan- uary 1957 to January 1959: (c; determine the biological effects of op- eration of St. Lucie Lock and Dam with reference to important indicator species and evaluate the wide range of claimed damages relative thereto: and (d) determine operational procedures, practicable within the specific operational requirements of the project, which would cither be beneficial or of the least damage to estuarine fishes and fishing conditions. A report (Gunter, 1959) covering all sections of the work, but with particular reference to (c) and (d ) was submitted to the Jackson- ville District of the Corps of Engineers The present paper covers enough of (a) to give a background for exposition of the biological work and gives an expanded presentation of the biological data. Mr. Chester Adams, boat operator, Clewiston Area Office, and Messrs, Robert Highsmith and Paul Berry, Survey Branch, Jacksonville District, ably assisted in the field collections. B. BASIC CONSIDERATIONS 1. Purpose and history of St. Lucie Canal — ■ St. Lucie Canal was built originally by the Everglades Drainage District to provide an im- proved outlet to tidewater for control of floodwaters in Lake Okee- chobee. Construction along the shortest and cheapest route to tidewater was oegun in 1916 and practically completed in 1924. At that time the canal, with a capacity of 5,000 cubic feet a second with Lake Okeechobee at elevation 15.6 feet, was controlled by two dams, one near the lake and the other near the lower end. (All stages and elevations throughout this report refer to mean sea level datum) . Serious shoaling of eroded material and reduction of channel capacity occurred as a result of storms in 1924. 1926, and 1928. The deposited material was excavated by the Drainage District in 1927 and 1928 but channel capacity was again re- duced during the storm of 1930, In 1930 the United States Government accepted control of Lake Okeechobee as an authorized project, and sinco that date the canal has been maintained and operated by the Corps of Engineers. Construction of fixed spillways at 16 inflow' points along the banks of St. Lucie Canal was initiated in 1933 in order to prevent sedi ment from entering the canal. In 1937, the w-aterway was improved to provide a navigable channel 6 feet deep. The River and Harbor Act of 1937 authorized replacement of obsolete structures at the two locks with a new lock and spillway at the site of the lower dam. The main spillway was completed in 1944, except for tainter gates which were installed in 1950. The canal was enlarged in 1949 to provide a navigable depth of 8 feet and a discharge capacity of about 9,000 cubic feet a second with the lake stage at 15.6 feet. — 192 — 2. Location and description. — a. St. Lucie Canal leaves Lake Okee- chobee at Port Mayaca and extends northeast about 25,6 miles to the South Fork of St. Lucie River. 7 miles south of the confluence of the North and South Forks of that river at Stuart. St. Lucie Lock and Dam are located about 1.9 miles from the lower end of the canal, or about 23.7 miles from the entrance of Lake Okeechobee. The local watershed of the canal between the lake and the lock and dam. 79 percent of which is on the north side, covers 185 square miles. The area is imperfectly drained, with flat slopes, many swamps, and small lakes, and is often wet. Ele vations range from 45 feet along the northerly divide to 20 to 25 feet along the canal. The soil is mostly fine sands and the native vegetation principally wild grasses, sawgrass. and scattered pine and palmetto growth. St. Lucie Canal is a part of the cross-Stare Okeechobee Water way that extends from the Atlantic Ocean near Stuart to the Gulf of Mexico southwest of Fort Myers. It is one of two primary outlets used in regulating Lake Okeechobee levels under the Central and Southern Florida Flood Control Project. b. St. Lucie Estuary. — ( 1 ) General location. — Si. Lucie Estuary is located in the tidewater area at the junction of the North and South Forks of St. Lucie River near Stuart, in Marlin County. Fla I plate 1), The main river empties into the Atlantic Ocean through St. Lucie Inlet, about 8 miles from where the two forks join. The ourer portion of the estuary is separated from the Atlantic Ocean by two long strips of land between which flows the Indian River. The latter, except for the 8-foot dredged Intracoastal Waterway, is a shallow lagoon that also discharges into St Lucie Inlet. (2) St. Lucie Inlet was opened by citizens in the vicinity in 1892. It was originally 30 feet wide and 5 feet deep, but by 1898 it had widen- ed to 1,700 feet with available depths at low water of 6 to 7 feet. Prior to opening of the inlet. St. Lucie River flowed into Indian River, Tidal currents in the estuary were low. and the water in lower St. Lucie River probably was much fresher than it is now. (3) Description and physical characteristics. — St, Lucie Estuary consists of three mam sections. Pertinent reference points and depth in formation are shown on plate 2. The outer and largest portion of the estuary extends from Sewall Point near the mouth of Indian River to Roosevelt Bridge (US 1) at Stuart. Two points of land there constrict the river opening to separate the outer from the inner estuary. The North Fork and South Fork arms comprise the inner estuary. The North Fork Estuary extends from the junction at Stuart to the mouth of the North Fork River near Kuching Cove. It receives runoff from a drainage area of 450 square miles in St. Lucie and Marlin Counties via the North Fork of St. Lucie River, numerous agricultural drainage canals, and Bessey Creek. The South Fork of the estuary extends from United States High- way 1 bridge to the mouth of St. Lucie River above the Palm Citv bridge. The total surface area, volume of water, and miles of shoreline at mean low water in each of three sections of the estuary are given in table 1, During non-discharge years and low flow periods, tidal waters ex- tend up the South Fork to St. Lucie Lock and several miles up North Fork River. The mean range of tide is 2.6 feet at St. Lucie Inlet and 1.3 feet at Stuart, Normal salinities range from 5.0 to 20.0 parts per thous- — 193 — Plate 2 — A map of the St. Lucie Estuary showing trawl and seine stations and depths in feet. — 194 — and throughout the inner estuary and from 20.0 to 35.0 parts per thousand in the outer estuary. However, normal rain and runoff into either of the forks, or rain on the estuary itself, are likely to make the surface waters of the estuary temporarily fresh to below Stuart, 3. Discharges in St, Lucie Estuary. — a. Through St. Lucie Canal . — Reliable estimates of St. Lucie Canal discharge are available since April 1931 when the United States Geological Survey began operations in the canal. For the purposes of this report, estimated volumes of monthly flows from Lake Okeechobee since 1945 are given in table 2. Lake Okee- chobee stages for the last day of the month dunng the same period are given in table 3, The total annual discharges of St. Lucie Canal at St. Lucie Lock and Dam, which include runoff in some years from the local drainage area, are depicted on plate 3 for the period 1945-58. Although the capacity of St, Lucie Canal was almost doubled by the enlargement in 1949, caving banks and bottom filling since then have reduced the channel efficiency. The latest available rating curve gives maximum regulatory discharges from the lake through St. Lucie Canal fcr various lake stages as follows: Lake Stage Regulatory discharge (ft,) (c.f.s.) 13.5 15.0 15.5 16.5 17.5 18.0 5,500 6,600 6,950 7.800 8.800 9,300 Between 1945 and 1957, the years of prolonged heavy discharge from the lake were 1947-48 and 1953-54, b. From other areas. — - Discharge measurements over a period of record for the North Fork of $t. Lucie River and other areas draining into St, Lucie Estuary are not available. However, the total annual run- off from the North and South Forks, exclusive of Lake Okeechobee re- leases, was estimated from rainfall. The estimated total annual dis- TABLE 1 Total surface area, volume of water, and shoreline miles at mean low water in the three main sections of St. Lucie Estuary Area Surface area (acres) Volume oi water (acre-f' Shoreline (miles) South Fork Head of estuary to U. S. Hwy. 1 bridge - 960 4,720 9.20 North Fork Kitching Cove bridge to U. S. Hwy. 1 1,840 16,740 12.05 Main estuary U. S. Hwy. 1 Point bridge to Sewall 2,730 19.690 14.25 Total 5,530 41,150 35.50 — 197 — TABLE 2 St. Lucie Canal Estimated volumes of monthly discharges Monthly discharge (1,000 acre-fi.) J jn I cb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Total 1 1 10 1 6 1 7 I 8 24 15 16 91 343 258 15 836 1 1 15 1 10 87 1 1 18 8 8 10 109 16 21 464 1 1 1 1 16 224 90 106 290 120 310 402 410 394 2,687 150 11b 290 212 18 24 10 14 90 356 352 336 2*408 140 4 2 1 1 I 1 12 384 3 24 — — 890 — — — — — — 397 130 527 — — — — — — — — — 184 267 — 451 — — — — — — — 151 463 578 499 5 14 2.405 206 — — — 61 110 187 157 107 39 — — 1,469 — — — — — — — — — — — 3 3 46 90 85 385 253 r _ 859 204 115 214 167 310 1 29 148 99 26 — — — 1,872 TABLE 3 Lake Okeechobee stages for last day of month 1945-58 Stage (ft.) Year Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec, Yr. avg. 1945 13.2 13.0 12.9 12.1 1 1.6 1 1.7 12.6 13.2 15.5 15.8 15.4 15.5 13.5 1946 15.4 15.3 15.0 14.1 14.1 14.2 14.4 14.6 15.0 14.7 15.0 15.0 14.7 1947 14.8 14.8 15.3 14.8 14.5 15.2 15.7 15.9 17,9 18.7 18,4 17,4 16.1 1 948 16.9 15.9 14.6 [3.6 13.4 13.0 13.2 13.8 16.2 17.6 16.8 15.6 15.0 1949 14.7 14.1 13.5 13.1 12.6 13.1 13.6 14.6 14.8 14.7 14.8 15.2 14.1 1950 15.0 14.7 14.4 1 3.9 13.5 13.1 13.0 13.0 12.9 13.8 13.8 13.8 13.7 195 l 13.6 13-5 13.1 13.1 12.9 12.8 13.2 13.7 13.9 15.6 15.1 15.0 13.8 1952 14.8 15.0 14.5 13.6 13.1 12.9 13.1 13.6 14.1 15.8 [5.3 15.2 14.3 1953 15.2 14.9 14.2 13.7 12.9 13.3 13,9 14.2 16.0 17.6 17.0 16.1 14.9 1954 15.3 14.9 14.5 14.1 13.5 14.0 14.1 13.5 14.2 14.4 14.4 14.4 14.3 1955 14.4 14.3 13.8 13.5 12.9 13,5 13.5 13.5 13.6 13.3 13.0 12.8 13.5 1956 12.6 1 2.4 1 1,8 1 1.3 10.9 10.5 10.4 10.3 10.8 12.7 12.6 12.6 1 1.6 1957 12.9 12.9 13.2 13.4 13.6 13.3 13,5 13.9 14.9 14.7 14.8 15.5 13.9 1958 16.1 15,2 15.2 14.6 13.5 13.1 1 3.2 13.3 13.6 13.7 13.5 13.8 14.1 Period - of- record average since 1912 14.8 14.6 14.4 14.0 13.7 13.9 14.1 14.4 15.0 15.3 15.1 14.9 14.5 — 198 — charges into St. Lucie Estuary from all sources, except rainfall on the estuary, during the period 1945-58 are shown on plate 4. During years when no lake waters are being released through St. Lucie Canal — such as 1950. 1955, and 1956 — the North Fork contributes most of the total discharge, and its effects are evident. In other years, the effects of discharge from the North Fork area are often masked by the greater discharge from St. Lucie Canal Instantaneous peak flood flows into the estuary from the North Fork River alone have been estimated to be as high as 5.000 cubic feet a second and the total peak flows from all run off into the North Fork may reach 9,000 cubic feet a second under ex isting conditions. C. DISCUSSION OF THE PROBLEM 1. Effects of fresh-ivater discharge. — a. Local contentions. — Lo- cal interests in the Stuart area, primarily through the Stuart News and spokesmen for the St. Lucie-Indian Rivers Restoration League, have contended for many years that the release of turbid, fresh waters through St. Lucie Canal has caused serious damages to fishing, boating, and esthetic attractions in St. Lucie Estuary. In turn, the tourist industry, on which the economy of that community is said to depend, is alleged to suffer in years when winter discharges are made. Specific complaints of damage are many and varied. 2. The sediment problem. — a. Available sediment data. — In 1955 and 1954, the Jacksonville District conducted a study to determine the extent of the sedimentation problem in St. Lucie Estuary resulting from discharges through St. L.ucie Canal. Analysts of the problem was based on data from previously available hydrographic surveys of St. Lucie Canal, River, and Estuary dating back to 1885 and other data as fol- lows: ( 1 ) A series of suspended-sediment samples taken between Port Mayaca and St. Lucie Inlet when full-capacity releases of the canal were being made. (2) Secchi disk observations of turbidity at a number of locations between the lake and St. Lucie Inlet. (3) Chemical and mineral analysis of samples of water flowing through St. Lucie Canal, as well as the amount of material in the water that would be flocculated upon mixing with sea water. (4) Examination of the soils above the waterline along the banks of St. Lucie Canal and in the spillway outlet channels between Lake Okeechobee and St. Lucie Dam during full discharge cond ions. Results of that study were presented in Part IV, Supplement 4, Design Memo randum, Effects of fresh water discharges through St. Lucie Canal, dated 2 7 October 1954 (Jacksonville District). The sedimentation problem in the estuary resulting from St. Lucie Canal discharges, as indicated in Part IV, Supplement 4, and other sources, is summarized below. b. St. Lucie Canal . — Lake Okeechobee water released through St. Lucie Canal carries fine sand, shell fragments, and organic material into St. Lucie Estuary The very fine organic material and clay or muck usual- ly suspended in the lake water gives it a dark, turbid appearance. When releases are being made, the turbid fresh water replaces portions of the salt water in the estuary. Although most of the fine material is carried into the ocean, some is deposited in places in the bay area where — 199 — velocities arc very low or in the mixing zone of fresh and salt water, which causes the material to flocculate, Even though the major portion of the organic material carried from Lake Okeechobee by the releases is not deposited in the estuary, it is objectionable to the people in the area because the water appears dirty and turbid. In addition, some desirable sport fishes may leave the estuary when turbid water is released. Under high flow conditions, there is rather uniform turbidity between Lake Okeechobee and Stuart. When canal discharge is discontinued, turbid conditions in the estuary clear rapidly unless there is heavy runoff from other sources. The principal source of sand material carried by St. Lucie Canal is from bank caving in stretches of the canal between the dam and the lake, Only a minor amount of sediment enters the canal now at the fixed spillways because of the retarding action of the structures and thick cover of vegetation upstream. Increased agricultural development and erosion of farm drainage ditches arc contributing to the sedimentation problem. The heavier sands picked up along the canal are deposited in the estuary as soon as the velocity slows The principal shoaling area is in the South Fork in the vicinity of Palm City (plate 2) where the stream velocities are suddenly reduced by the wider bay area. Hydrographic sur veys indicated the Palm City shoal contained 1.183,000 cubic yards more material in 1954 than in 1932. Channel dredging is required at intervals to restore navigable depths in that vicinity following prolonged periods of discharge. Between 1937 and 1954. hydrographic surveys indicated material was eroded from St. Lucie Estuary downstream from United States Highway 1 bridge at Stuart, showing that the majority of the sediment from St. Lucie Canal is not carried farther than the Palm City area. c. Other sources. — Other streams and agricultural canals in St. Lucie and Martin Counties contribute to the sediment problem in St. Lucie Fistuary. The North Fork Estuary receives sand from agricultural areas and some organic materials from swamps in St. Lucie County. Tur- bid waters from the North Fork area are in evidence far down the main estuary during runoff periods when St. Lucie Canal is not discharging. Secondary drainage canals in St. Lucie County are largely uncontrolled, as is the primary canal (Rim Ditch) leading into the North Fork of St. Lucie River. Under such conditions, sediment materials have been car- ried unimpeded to the mouth of the river where large sandbars and shoals have formed. Boat navigation from the estuary to the North Fork River has been affected by those shoals. The shoals are being removed in the construction of Canals 23A and 24 now in progress. Shoal areas are also found in the mouth of Bessey Creek emptying into the North Fork, and numerous shifting sandbars and shoals are located in. the mouth of the main estuary near the inlet. The latter are believed by some local fishermen to be the result of St. Lucie Canal discharge. However, there is indication that little of the heavier sand material from St. Lucie Canal is carried that far down the estuary. Since those lower shoals are con stantly shifting, it is more reasonable to consider that they are the re suit of storm -tide action on adjacent beaches and relocation of existing shoals through normal tidal action. Finally, sewage from a large por- tion of the local population is discharged into the estuary without treat- ment and no doubt adds to the sediment problem. 200 D. PRMSKNT INVESTIGATIONS 1. Other agencies — a. United Stutes Fish and Wildlife Service. — Under the provisions of the Coordination Act (P.L. 732. 79th Cong.. 1946), the Jacksonville District made funds available to the Fish and Wildlife Service for studies in the St. Lucie Estuary areas as follows: ( 1 ) Central and Southern Flortda Project — St. Lucie County Canals ( Canals 23, 23A. 24, and 25). — The Service was requested to study the effects on fish and wildlife of the proposed improvement of those drainage canals to accelerate surface runoff of floodwaters into the North Fork Estuary and Fort Pierce Harbor. The field investigation was conducted during Fiscal Year 1957 (July 1956 to July I957j, the last year of a very dry period. An interim letter report was submitted in Jan- uary 1957, and a second interim report was submitted April 22, 1959. The latter was a final report on all phases except the effects of discharge into the North Fork on the fishes and conditions of the main estuary. Annual damages resulting from the increased frequency of higher dis- charges into the North Fork, and based on future fisherman-use of that area with and without the project, were estimated to be $46,000. (2) Central and Southern Florida Project — Lake Okeechobee reg- ulation. — A 1-year comprehensive biological study of St. Lucie Es- tuary — with specific reference to the effects on estuarine fishes and ani- mals and fishing, both sport and commercial — of Lake Okeechobee re- leases through St. Lucie Canal was conducted during Fiscal Year 1958. The reporting date was originally scheduled for December 3 1, 1958, but at the request of the Service was delayed until March L 1959. A report on that investigation has not been received. b- Florida State Board of Conservation, which is concerned with the administration and conservation of marine fishes and animals, was requested by the Central and Southern Florida Flood Control District to investigate the effects of all project discharges into St, Lucie Estuary. A preliminary report containing numerous conclusions as to expected damages, but no basic biological data, was submitted to the Flood Con- trol District in October 1957. 2. Corps of Engineers . — a. General plan of investigation , — The concept of the investigation was focused on the specific operational re- quirements of the project with sampling directed to identification of the important indicator species and what happened to them under various conditions related to the project. The foundation of the study was to be a comparison of the fishes, shellfishes, other aquatic organisms, and the physical conditions found at selected stations throughout the estuary in all seasons and under varying conditions of freshwater discharge from St, Lucie Canal. Since sport and commercial fish catches were to be in- cluded in studies of the Fish and Wildlife Service, emphasis in the dis- trict investigation was to be placed on the small food and bait fishes and animals and the young of sport and commercial fishes. 7'hose groups are normal seasonal inhabitants of estuaries. Being more easily sampled than adult forms, they would furnish generally reliable indications of the temporary and permanent effects of physical changes in the estuarine en- vironment. its inhabitants, and overall production. In addition, data on daily fishing pressure and fish catches below St. Lucie Lock and Dam were recorded to determine the effects of varying releases on that fishery. — 201 — Biological sampling, St. I _ vie ic Fsluary. 24 Feb. 1958 Fresh water discharge at St Lucie Lock 4,800 c.t.s.: salinity in estuary less than 1 p.p.t.: turbidity (light penetration • less than 1 foot. Upper: Hmptying trawl after 1 5 minute drag at station TS6. Lower. Por- tion of above trawl sample of fish and crabs at station 1 S 6 . '.02 b. Collection of basic data, — ( 1 ) Sampling gear and methods . — Trawl samples were collected with a 20-foot otter trawl of 1-inch stretch mesh in the main trawl section and -inch stretch mesh in the bag. All trawl hauls were of 15-minute duration in water at least 7 feet deep, (See Figure 1). Seine samples were collected primarily with a 50-foot. Yi -inch-mesh beach seine, the middle 25 feet of which was backed with bobbinet material. Occasional supplemental seine drags were taken with a 20-foot, >4 -inch mesh minnow seine. Top and bottom water tempera- tures and water samples for salinity determination were taken along with each trawl and seine sample. Salinities in parts per thousand were de- termined from direct-reading salinity hydrometers with correction for temperature differences. In certain instances where the salinities in the water samples were too low for accurate determination with the hydro- meters (Jan. 1957, Sept. 1957, and May 1958). total chlorinries were determined by titration by Dr. Robert Miller, Chemist, of Fort Pierce. Fla. Those values were later converted to total salinities. Light penetra- tion or gross turbidity was measured in inches with a standard 12-inch weighted Secchi disk. All fishes and organisms collected in each trawl or seine haul were counted and measured according to species, Specimens whose identity could not be readily determined were preserved for later study at the Gulf Coast Research Laboratory. (2) Location and description of sampling stations. — The ap- proximate locations of the various trawl (TS) and seine (SS) stations are shown on plate 2: detailed station descriptions are given below. (a) Traivl stations , — Seven trawl stations were selected — four in the inner estuary, near the head and mouth of both the South and North Fork sections, and three in the outer estuary. The outermost trawl station was located in the area farthest upstream from the inlet where some bottom salinity could be expected to be maintained by daily tidal action, even during the period of greatest fresh water discharge from St. Lucie Canal, Furthermore, that station was above the mouth of Indian River, a separate water system that also discharges into St. Lucie Inlet. The seven trawl stations are described as follows: TS1 — In Channel above (south) Palm City bridge in the South Fork of St. Lucie River: depth, 9-11.5 feet: bottom — sand and muck: sand shoals on each side of channel. TS2 — At the Y at mouth of South and North Forks between channel marker 24 and Highway 1 bridge; depth, 8.5-12 feet: bottom — muck and sand. TS3 — Near head of North Fork of St. Lucie Estuary: depth, 7-10 feet; bottom — muck. sand, and detritus. TS4 — Off the mouth of Bessey Creek in the North Fork of Sr. Lucie Estuary: depth, 9 feet; bottom — sand and muck. TS5 — - In channel north of Stuart and east of Highway 1 bridge, between beacons 22 and 23: depth, 8 feet: mud bottom with many dead Mufinia shells. TS6 — In main estuary east of Stuart, at bend where river turns south near marker 21: depth, 9 feet: bottom — sand, mud, and detritus. TS7 — Off Port Sewall in outer estuary between markers 14 and 15; depth, 10.5 feet: bottom — muck, trash, and vege- tation. — 203 — Biological sampling with 50-foot beach seine, St. Lucie Estuary, February 1958. Upper: Seine station 5 in North Fork, Lower: Seine station 2 in outer estuary. — 204 — (b) Seine stations. — It was desired to have a complementary seine station on the shore adjacent to each trawl station. However, because of the rim of mangrove trees, especially in the North Fork, and other vege- tation growing down into the water, suitable sites for beaching seines were scarce in the inner estuary (See fig. 2), In the outer estuary, resi- dences were prevalent along the shorelines, and beaches were plentifu 1 (Fig. 2), A total of six seine stations — three each in the inner and out- er estuaries — was selected. Only trawl station No. 4 in the North Fork did not have a complementary adjacent seine station. From I to 3 seine drags, enough to get a representative sample of fish, were made if pos- sible at each station during each sampling period. On two occasions. November 1957 and October 1958, exceptionally high waves and wind tides eliminated beaching sites and prevented sampling of some seine stations. The six seine stations are described as follows: 551 — Beach along Sewall Point on east shore of estuary: sand bottom with mangroves at edge of water: new station (SSI A: see below) used after first sample. SSI A — Beach on west side of estuary near marker 14; sand, shells, and debris: residential area with palm trees and flowering shrubs, several boat docks. 552 — Beach on north shore of estuary opposite Stuart and east of Highway 1 ; sand bottom with some rocks, 553 — Small beach near head of North Fork Estuary on west shore; soft bottom with plants and debris: mangrove trees. 554 — Around shoals in South Fork above (south) Palm City bridge: hard-packed bottom, somewhat slick with algae and mud film: many dead Rangta shells. 555 — Beach in South Fork near Y on west shore opposite Stuart around point SW of marker 25: sand bottom. 556 — Beach at point in outer estuary NE of Stuart where river turns south: SW of marker 21 and TS6. sand bottom. (3) Extent of sampling during period of investigation. — Sam- pling in the estuary was begun January 28-29. 1057, and con mued per- iodically during various discharge conditions for the next 2 years. A total of 10 samples was taken during the 2-year period — 5 in 1057 (Jar . May. June, Sept., and Nov.), 4 in 1958 (Jan., Feb., May, and Oct ), and the final one in January 1959. During five of the sampling periods (Jan., May, and Nov. 1957: Oct. 1958: and Jan. 1959) there was no discharge from St. Lucie Canal. The discharge of lake water on the other occasions was as follows: Discharge (c.f.s. ) Date 2,200 June 1957 6,600 Sept. 1957 7,380 Jan. 1958 4,000 Feb. 1958 5,200 May 1958 Fish samples in January of three different years on about the same dates (27-28), permitted comparative observations during a non- discharge period after 3 years of no discharge (1957): during a period of heavy discharge (1958), and during a nondischarge period, after a year of almost continuous fresh-water releases during most of the - 205 — Plate 5 — The Lake Okeechobee regulation schedule in operation during the study period. — 206 Plates 6 to 1 5 — Bottom and surface salinity characteristics of the St. Lucie Estuary at times of biological sampling. — 207 — LAKE OKEECHOBEE- r H LAKE OKECCHOdtf PI5CHARC-E- o ll 01SCH4*G* q c.pJ L4K£ G«£t HOSES: IS Jun« '957 / LAk £ OKEECHOBEE PtSCHAr*- 2,/bO Cf-2*// (I I DlSCHAASE 6, i80 C- 211 — 212 — spawning and growing period. The total number of trawl and seine hauls taken in the three main sections of the estuary during each sam- pling period is given in table 4. E. PHYSICAL CONDITIONS DURING STUDY PERIOD 1. Fresh water discharge into St. Lucie Estuary. — a. From Lake Okeechobee — Lake Okeechobee stages on the last day of the month for 1957 and 1958 are given in table 3. The lake-regulation schedule in use at that time (plate 5) operated the lake levels seasonally between 12.5 nd 15.5 feet. Under that schedule, discharges were required through St. 'Lucie Canal whenever the lake elevation was in Zone A. It was also TABLE 4 The number of hauls with different gear in South Fork, North Fork, and outer St. Lupie Estuary for each collection period Collection period and number of hauls Item 1957 1958 1959 Jan. May June Sept. Nov. Jan. Feb. May Oct. Jan. Total Trawl Inner estuary South Fork North Fork Subtotal Outer estuary Total Beach seine (50 ft.) Inner estuary South Fork North Fork Subtotal Outer estuary Total Minnow seine (20 ft.) Inner estuary South Fork North Fork Subtotal Outer estuary Total Grand total 2 2 2 2 4 4 5 3 7 7 2 2 1 2 3 4 2 3 5 7 2 2 2 2 4 4 3 3 7 7 2 2 2 2 4 4 3 3 7 7 2 2 4 3 7 2 20 2 19 4 39 3 29 7 68 5 4 5 4 1 3 2 0 3 2 8 6 5 7 3 6 6 3 6 5 14 12 8 13 8 2 3 2 0 3 111 5 4 3 1 3 4 7 4 8 8 10 5 2 28 0 16 2 44 3 47 5 91 21 — 2 — 0 — 2 — 6 8 19 21 20 15 15 15 — 0 — 2 — 2 — 0 2 17 14 0 2 2 4 2 6 0 6 2 12 14 171 — 213 — necessary that the lake level be lowered to 13.0 feet by June 30, prior to the hurricane season. The average daily rates of discharge through St. Lucie Lock and Dam during 1957 and 1958 are given in tables 5 and 6. TABLE 5 St. Lucie Canal at St. Lucie Lock and Dam Discharges, 1957 (Regulatory releases from Lake Okeechobee) Dale Average daily discharge (c.f.s.) May June Aug. Sept. Oct. I 2,200 5,100 6,830 2 2.210 5,1 10 6,920 3 2,210 5,090 7.400 4 2,210 5,100 7,260 5 2,210 5,480 7,080 6 1 % ,1 1 0 6.020 6,920 7 2,210 5.010 6,840 8 2.200 7.000 6.830 9 2,220 6,750 7,050 10 2.220 7.030 7,070 1 I 2.210 6.780 6,980 12 2,190 6,690 6,900 13 2,190 6,630 6.820 14 2.190 6,640 6,950 15 2,180 6.870 6,990 16 * 2.170 570 6,990 6,4 10 17 330 2.170 1,690 6,920 5.800 18 660 2,160* 2.240 6.890 3.610 19 660 2,170 2,150 6,840 2.350 20 910 2,170 2,240 6,870 2,330 21 1.140 1.090 2,250 6.790 1,3 10 22 1.140 2,260 6.720 23 1. 130 2,270 6.680* 24 1.470 2.270 6,670 25 2.220 2,280 6,630 26 2.230 2.270 6,580 27 2.230 2,620 6,590 28 2.220 4.000 6.570 29 2.210 4,320 6.600 30 2,210 4.290 6.820 31 2.210 4,820 Total : 22.970 44.990 42,540 1 192.460 126.650Total — 1957 Day -second- 429.610 feet 45,940 89,980 85.080 389.920 253,300 Acre-feet 859,220 Days Accumulative 15 21 16 30 21 total 15 36 52 82 103 NOTH: *Biological sampling day. — 214 — TABLE 6 St. Lucie Canal at St. Lucie Lock and Dam Discharges, 1958 (Regulatory releases from Lake Okeechobee) Dare Average daily discharge (c.f.s.) Jan. Feb Mar. April May June July Aug. Sept. 1 — 7,190 3.450 5.830 5,750 4,820 — 2,510 1,580 2 7. 200 3.460 6,360 5,700 4.820 850 2.500 1,580 3 — 7.100 3.470 6,370 5.680 4,780 2,530 2,500 1.580 4 — 6.970 3.440 6.380 5,700 4,700 2,540 2.190 1,580 5 — 6.850 3.410 6,360 5,700 4,700 2,530 1,570 1,590 6 — 6.810 3,420 6.360 5.820 4,720 2,520 1,570 1,590 7 — 6,850 3,440 6,350 5,940 4,710 2.510 1,560 1,600 8 — 6.940 3.440 6,240 5,750 4,650 2,500 1,560 1,600 9 630 6.770 3,440 6,100 5.570 4,600 2,500 1,560 1,060 10 1.870 6,720 3.450 6,050 5,490 4,560 2,490 1,570 1 1 2.790 6,710 3,420 6,400 5,590 4,420 2,500 1,570 1 2 3.070 6.700 3.420 6,470 5,710 3,370 2,510 1.580 1 3 3,090 6,790 3,470 6,300 5.600 2,820 2.510 1.580 14 3,090 6.620 3,490 6,080 5.420 2,470 2,520 1.560 15 3,090 6.690 3,470 5,810 5,330 2,500 2,520 1,580 16 3,130 6.780 3.450 6,070 5.350 1,670 2.530 1,580 17 3,1 10 6,620 3,440 5,840 5.290 2,530 1,590 18 3,090 6.540 3,450 5,920 5,230 2.530 1,590 19 3,060 6,280 3,470 6,150 5,230* 2,530 1,210 20 3,540 5,960 3,480 6,100 5,090* 2,540 840 21 4,200 5,420 3,520 6.080 4,940 2,530 840 22 4,230 4,815 3,470 6,100 4,900 2,530 840 23 4,200 4,440 3,420 6,160 4,860 2.530 1,350 74 5.060 3.930* 3.430 6.100 4.910 2.530 1,600 23 7,220 3,460* 3.815 6,060 5.000 2,520 1.600 26 7,450 3,470 4,890 6,010 4,990 2,510 1,610 27 7.380* 3,500 5,110 5,930 4,910 2,500 1,610 28 7.250* 3.480 5.150 5,880 4,900 2,490 1,600 29 7,200 5.070 5,860 4,960 2,500 1,590 30 7.200 5,030 5,830 4,900 2,500 1,590 31 7,100 5,210 4,830 2,500 1,580 Total: Total - 1958 Day- second- fr. 102.050 167,605 1 17.095 183,550 165,040 64.310 73,830 49,580 13,760 936,820 Acre- ft. 204,100 335,210 234,190 367,100 330.080 128.620 147,660 99.160 27,520 1,873,640 Days 23 28 31 30 31 16 30 31 9 Accumu- lative total 23 5 1 82 1 12 143 159 189 220 229 NOTE: * Biological sampling day. — 215 — TABLE 7 E o' -C ui <%-o *i n - 9 1 o\ c-g o CQ a( M 't- in nj Oi a) q. Vm o JW a v Ol c £ i E 2 r-J in flj E o © a* DO 00 O ^-v. W (B » m 13.8 in ^ w °Sg 0 )0^ 2 s " - qj >. >- Cl ra «5 3 (/i s ; a «r m c 0 * 3 '“ s ° to ^ •» Ql_/ E o <0 LL. w o t >--2 J 5 Z E-*T 3 * ° "S. 6 £ Z 2 © & 3>S c > E £ " 0 1 'of © Si v 2 DO iV c > nj erf u-, vi o -£ a 6 E vo -r ivl J K O 00 ■t- N oo ^ — cs — . , O O vv © OO ^ oo «\ vY © ^ z d 00 o oo d Z- oo 217 Jjn. 27 0 4 < 1.0 2 14. 7-1 7.1 3 2.4- 2.6 2 13.8- 1 5.7 6 6.3-25.9 3 22.2-33.8 (<1.0) (15.9) (2.5) (14.8) (12.3) (26.7) local runoff from the North Fork. On all occasions of lake discharge, there was still bottom salinity at the outermost station of the estuary (TS7). which is considerable distance upstream from the inlet. The lowest bottom reading at that station was 4.5 parts per thousand when 7,380 cubic feet a second was being released through St. Lucie Canal. On other occasions of high discharges (above 4,000 c.f.s. ), the bottom salinity at station 7 was much higher — for example: Discharge Bottom Salinity (c.f.s.) (p.p.t.) 6,680 23.0 5,200 25.5 4,000 29.4 Under normal conditions, the range of salinity from surface to bottom at the same point would often vary 5.0 to 10.0 parts per thousand in thf* inner estuary, probably as a result of local rainfall and light surface runoff. In the outer estuary, the difference in top and bottom salinities was on occasion more than 10.0 parts per thousand because of the in- teraction of fresh water runoff with certain tidal stages. Salinities in the inner estuary ranged from near 0 top and bottom with either lake discharge or local runoff to 5.0-20.0 parts per thousand under normal conditions. A greater range of salinities was found in the outer estuary, from near fresh to full sea strength, with various discharge conditions, but the bottom salinities were less affected by lrcsh water runoff than the inner stations because the salt front remained in that area. The range of normal salinities in the outer estuary was generally from 1 5.0 to 30.0 parts per thousand at the upper stations and from 25.0 to 35.0 parts per thousand at the lower ones. 3. Turbidities. — The Secchi disk readings taken at various sta- tions during each sampling period are summarized here in table 8. The turbidity readings measured during the investigation substantiated the conclusion of previous studies that the turbidity in the estuary varied with the lake discharge and local runoff. On most occasions, the turbidity increased directly with higher rates of lake discharge. However, it was less in September 1957 with 6,680 cubic feet a second discharge than in May of that year when no releases were being made and in June 1957 when only 2,160 cubic feet a second was being released. High winds and wave action in both Lake Okeechobee and the estuary, which keep sedi- ment materials stirred up. are considered responsible for high turbidities at certain times. Turbid waters fom Lake Okeechobee did not appear to penetrate too far into the North Fork, since on several discharge oc- casions when the waters in the South Fork and main estuary were clear to depth of less than 1 foot, turbidity readings were 1 5 to 3 feet higher in the North Fork of the estuary, The highest turbidities were observed in January 1958. With maximum discharge of 7,380 cubic feet a second at that time, turbidities in the outer South Fork and estuary were 6 to 10 inches, Normal turbidities in the inner estuary appear to be 30 to 40 inches and in the outer estuary 36 to 60 inches. A fathometer survey conducted in October 1957 for the purpose of determining changes in depths of bottom sediments in the estuary since 1954 gave inconclusive results in that respect, although there was no evidence of appreciable deposition in the area. Slight deposition of materials in some sections apparently resulted from erosion of oiher reaches nearby. The mineral content of a composite water sample from St. Lucie Canal — 218 — (Sept. 1 1, Oct. 3, and Oct. 15, 1957) at St. Lucie Lock and Dam is list ed in table 9. It shows that the total nitrogen content of the water com- ing into St. Lucie Estuary through St. Lucie Canal was 0.8 parts per million. In other analyses of St. Lucie waters by the United States Geo- logical Survey, the nitrate content (N0 3 ) through the years has varied from a trace to 2.0 parts per million. On the basis of 0.8 parts per mil- lion. th^ie were 987 tons of nitrogen nutrients discharged into the es- tuary in 1957 and 2,040 tons in 1958 by way of St.Lucie Canal TABLE 8 Range and average turbidity readings in the South Fork, North Fork, and outer estuary for each sampling period Month Lake discharge Turbidity South Fork reading (inches) North Fork Outer estuary (c.f.s.) 1957 Jan. 0 36 54 60 May 0 24 24 24 June 2.160 12-15(13.5) 24 22-30(27 Sept. 6,680 28 29 26-27 (26.5) Nov. 0 No readings because of loss of disk 1958 Jan. 7,380 6-12(8) 22-31 (25) 9-12(10) Feb. 4,000 11-12(11) 50 12 May 5.200 16-21(18) 14-24(21) 12-14(14) Oct. 0 34-38(36) 42-48(45) 36-48 (41) 1959 Jan. 0 28-31 (30) 36 36-40(38) TABLE 9 Mineral content of composite water sample from St, Lucie Canal at St. Lucie Lock and Dam (Sept. 1 1, Oct. 3, and Oct. 15, 1957) pH 8. i Item Parts per million Dissolved solids 1 94 Calcium as Ca 32 Magnesium as Mg r 8 Sodium and potassium as Na 16 Iron as Fe (soluble) ._ 0 Silica as SIO 5 Sulfates as SO 4 20 Chlorides as Cl 30 Nitrogen as N $ 0.8 Phosphorus „ 0 Alkalinity (methyl orange) as CaCO* 85 (phenolphthalein) as CaCO* 0 Total hardness as CaCO* 113 Carbonate hardness as CaC0 3 85 Noncarbonate hardness as CaC0 3 — * 28 Free carbon dioxide as CO* 0 — 219 Plate 16 — The numbers of fishes caught during the investigations and the discharge through the St. Lucie Canal at the same periods. — 220 — 4, Temperatures. — a. Water. — The range and average of the sur- face and bottom water temperatures measured at each .sampling station are summarized for all stations for each period in table 10. In 1957, the average water temperatures in the estuary samples varied from a low of 70. 5‘ in November to a high of 87.6° in September. In comparison. 1958 was much colder, with lows of 59 u and 58° in Jan- uary ard February respectively. The surface and bottom water tempera- tures averaged 13 colder m January and 5° colder in May 1958 than in 1957. Surface waters generally averaged a few tenths to 3 degrees warmer than the bottom waters, except in October and November when the reverse condition occurred. The year 1959 was milder than 1958 but not as mild as 1957. b. Air — 1’he average daily maximum and minimum air tem- peratures at Stuart, for the three winter periods of this investigation (Nov. through Feb. 1956-57, 1957 58, and 1958-59), were extracted from Climatological Data for Florida and are summarized in table 11. The winter of 1956-57 was a mild season, with no freezing days dur ing the 4 month period. Only five times — 3 in November and 2 in December — did the temperature reach 40 c or below. The lowest Jan- uary temperature was 42 on one day, and once in February it went down to 44 n . The average maximum and minimum daily temperatures between October and March were about 78° and 58° respectively, In contrast, the winter of 1957-58 after November was an exceptionally cold year for all of Florida. Freezing temperatures were recorded at Stuart on 6 days — once in December, twice in January, and three times in Feb- ruary. Temperatures below 40° were recorded 16 times during the De- cember-February period, 9 of which were in February. Maximum tern peraturcs averaged 10° md 1 2° colder in January and February 1958 than in 1957 ; minimum temperatures averaged 6° and 16° colder, re- spectively. That exceptionally cold winter resulted in heavy losses of tourist business throughout central and southern Florida. The winter of 1958-59 was again a comparatively mild period, and. in November and February, was warmer on the average than the 1956-57 season. In contrast to the previous year, the minimum daily February temperature averaged 20 warmer in 1959 than in 1958. 5. Summary of physical conditions in the estuary during (he study period. — The period of the investigation was one of contrasting phy- sical conditions. The winter and spring collections in 1957 were made when there had been no freshwater discharge from Lake Okeechobee for 3 years. Salinities were high and temperatures mild. There was a heavy discharge period that fall, but none from mid October to January. In 1958, except for brief periods, discharges were moderate to heavy throughout the winter and spring and low to moderate throughout the summer until early September. The inner waters were fresh and tur- bid and the outer waters of low salinity in accordance with the discharge. The winter of 1957-58 was abnormally cold, with several freezes. There was no discharge, and salinities and temperatures were high from Sep tember 1958 until the end of the study in January 1959. Salinities during the period ranged from zero to 20.5 in the inner estuary and from zero to 36.0 parts per thousand in the outer estuary Water temperatures ranged from 59.0' to 87.6' and turbidities from 6 inches to 5 feet, l.ow salinities in the estuary, as result of local runoff from the North Fork watershed, were experienced on several occasions when no lake water was being released, f ish samples were collected on five occasions — 221 — when there were no lake discharges and five when the rate of release ranged from 2,160 to 7,380 cubic feet a second. TABLE 10 Number of readings, range, and surface and bottom water temperatures for all stations during each collection period (Readings in degrees Fahrenheit) Surface Bottom Date No. of Readings Range Average No. of Range Readings Avg. Grand Avg. 1957 Jan. 27 12 73.6 76.8 74.8 7 72.0-76.1 74.4 74.6 May 16 12 79.9-87.3 83.1 7 78.3-80.1 79.5 81.7 June 18 7 82.6-86.5 85.0 5 82.6-84.7 83.5 84.3 Sept. 23 12 82.6-87.6 85.0 6 73.2-82.6 76.8 82.2 Nov. 13 10 70.9-71.8 71.2 7 70.5-71.8 71.5 71.3 1958 Jan. 28 9 59.0-63.9 61.7 5 59.9-62.2 61.2 61.5 Feb. 24 13 58.0-70.0 62.5 7 58.0-66.0 60.4 61.7 May 19 13 76.0-80.0 78.2 7 76,0-81.0 77.8 78.0 Oct. 27 1 1 72.0-78.0 75.3 7 74.0-78.0 75.7 75.5 195 9 Jan. 27 13 68.0-74.0 70.9 7 66.0-72.0 68.0 69,9 TABLE 11 Range and average of maximum and minimum daily air temperatures at Stuart, November through February 1956-57, 1957-58, and 1958-59 Mon th Daily air Maximum temperature (degrees Fahrenheit) Minimum Range Average Range Average Nov, , 1956 69.0-84.0 77.5 34.0-73.0 58.0 Dec. 1956 62,0 87.0 77.1 36.0-70.0 56.6 Jan. 1957 69.0-83.0 77.6 42.0-68,0 56.2 Feb. 1957 73.0-85.0 79.0 44.0-71.0 61.2 Nov 1957 72.0-87.0 80.6 51.0-72.0 65,1 Dec. 1957 56,0-82.0 74.1 29.0-71.0 55.9 Jan. 1958 50.0 78.0 67.6 30.0 64.0 50.0 [ : cb. 1958 53.0-85 0 66.9 30.0-68.0 45.1 Nov . 1958 74.0-90.0 83.6 56.0-74.0 67.7 Dec. 1958 65.0-83.0 74.7 41.0-71.0 57,2 Jan. 1959 59.0 85.0 72.5 33,0-69.0 54.1 Feb. 1059 72.0 88.0 81,1 58.0-72.0 64.9 — 222 — F. RESULTS OF BIOLOGICAL SAMPLING I The fish catch. — Tabic 12 shows that 83 species of fishes were taken during this investigation. Seventeen w r ere fresh- water species; the remainder were marine. The separation is made on the basis of spawn- ing locality — that is. in fresh or salt water. Tablc 13 lists the most abundant fishes taken in this study. Six species made up almost 90 percent of Che total catch, and addition of 7 more species brings *.hat total to over 95 percent. The remaining 70 species made up less than 5 percent of the total catch. Of the 13 most abundant species, only 2 — the black crappie and the white catfish — - were fresh-water species and they made up about 1.5 percent of the num- bers taken. The remaining fishes were all marine, although all but one are capable of undergoing wide salinity changes — that is, arc euryhaline. Therefore, they are largely characteristic of shallow shores and inshore waters. Furthermore, such fishes have a characteristically similar life history. They spawn in high or higher salinity waters and move back into lower salinity waters to grow up. Thus, most estuaries, such as the St. Lucie, are characterized biologically as nursery grounds. Total length data are not presented here, but it may be categorically stated that the majority of fishes caught were the young. Table 14 shows that almost precisely two-thirds of the hauls were made with the minnow seines next to shore. Furthermore, this table shows that the fishes taken in the seine hauls were about four times as numerous per haul as those taken in the trawl catches. Table 15 indicates that the seine catch preponderance — which totaled almost seven times more than trawl catches — was caused by the catch of four species — mullet, menhaden, silversides. and anchovy. These were predominantly larval and juvenile fishes which reside in shallow waters and only the bay anchovy was taken in any numbers in the trawls. Further examination of the data (table 16) indicates that the vast preponderance of young shore fishes, chiefly mullet and men- haden. were caught in January, February and May 1958, when the spillwav gates were open. In the midwinters of 1957 and 1959, the preponderance of seine-caught fishes over trawl catches was considerably less when the gates were closed. If the catch data from the 50- foot seine hauls were expanded to cover the entire 35 -mile shoreline of the estuary, a rough approximation of the number of fish per mile of shoreline would have been 822,000 in January 1958, during the heavy discharges, as compared to 5,400 per mile in January 1957 after a long period of no lake discharge. Similar gross comparisons could be made for other per- iods during the 2 years of sampling. Tabic 17 lists the less numerous fishes in arbitrary divisions of a bundance. Table 18 gives the frequency at which various fishes were taken with different gear. This does not correspond except in a general way with total abundance. For instance, the sea catfish, sand perch, and whiff were taken in a considerable number of hauls but in relatively small numbers. Table 12 lists the numbers of fishes taken in the three divisions of the estuary. In general, the South Fork was no saltier than the North Fork, However, the South Fork salinity varied with the opening of the gates and the North Fork salinity was often low from natural drainage. — 223 — This probably accounts for the larger number of marine fishes taken in the South Fork, although the numbers of species of both fresh and salt water fishes were much the same in both areas. The higher salinity of the outer estuary is reflected in the small number of fresh water fishes and the abundance of marine species. This information is summarized in table 19, An inspection of table 16 reveals that the variations in numbers of the marine fishes is largely a reflection of the numbers of menhaden, mul- let, anchovy, and tidewater silversides. The latter two were most abund- ant in the outer estuary. The menhaden was most abundant in the two inside forks and the little mullet was least abundant in the North Fork, being about equally present in the South Fork and outside estuary. The other most abundant fish, the croaker, did not vary much with opening or closing of the gates — that is. fresh water drainage. The common mojarra became less abundant. Table 16 also indicates that 19 salt water species, including the most abundant ones, and 10 fresh water fishes were most abundant when the water was fresher. That increase included overwhelming numbers of mullet, menhaden and silversides. A few fishes — the pompano. puffers, mojarras. and few other saliniphilous species — - became less abundant when the water was fresher. The commercial fishery catch (see Gunter, 1959) shows similarly that there was increase or decrease of certain species when the locks were open, but there was no decline of salt water commercial species as a whole. In essence, the St, Lucie area is a habitat for estuarine or euryhaline fishes. When the salinity is lowered, many of them flourish in greater numbers than ever and a few high salinity forms leave the area. The region certainly does not become barren, it becomes more productive as indicated by the large crop of young fishes. The menhaden, mullet, and silversides are forage fishes and a greater production of these will lead to an increase of game fishes elsewhere, possibly in the outer estuary, at a later date. Mackerel and pompano and some other high salinity fishes leave when the salinity drops, but the statement that the gate openings result in barren waters and a dearth of small fishes is completely spur ious. Summaries of these data are given in tables, 5. 6, 19, 20, 21, and 22. There is nothing in these observations contradictory to the idea that an opening or flow up to 3,500 cubic feet a second from St. Lucie Lock and Dam is beneficial to the general life of the estuary, and it is believed that a continuous flow of about 2,500 cubic feet a second would be an optimum. Much higher flows ( up to 7,400 cubic feet a second) were not found to be damaging to cstaurine life, and. in fact, the great- est production and survival of young fishes was found to occur in the spring of 1958 during the period of continued high fresh- water dis- charges from Lake Okeechobee (plate 16). The tons of nutrient ma- terial brought in with the fresh water are undoubtedly partly respon- sible for the higher production, since this same phenomenon has been observed and measured in other areas (Viosca, 1938; Gunter. 1953). — 224 — TABLE 12 Total number of each species of fish caught in the South Fork, North Fork, and outer estuary Species Number of fishes caught South Fork North Fork. Outer estuary Stingaree (Dasyatis sabina) 4 Spotted gar (Lepisosteus plaiyrbincus) _ Tenpounder (Elops saurus) 1 Menhaden (Brevoortia smiihi) 1.388 Tbreadfin shad (Dorosoma petenense) — 4 1 Gizzard shad (Dorosoma cepedianum) Sardine (Harengula pensacolae) Striped anchovy (Anchoa hepsetus) _ Bay anchovy (Anchoa mitchilli) 465 Lizardfish (Synodus foetens) I Sea catfish (Galeichthys felis) 111 Gafftopsail catfish (Bagre marina) 6 Channel catfish (Tcralurus punccaius) _ 29 White catfish (Ictalurus catus) 124 Brown bullhead (Ictalurus nebulosus) Golden shiner (Notemigonus crysoleucas) Red minnow (Norropis macttlaius) II Needlefishes (Strongylura spp.) Redfin killifish (Lucania goodei) 4 Marsh killifish (Fuodulus confluentus) __ Seminole killifish (Fundulus seminolis) _ Sheepshead killifish (Cyprinodon variegarus) Flagfish (Jordanella floridae) 7 Mosquitofish (Gambusia affinis) __ 3 Least killifish (Heterandria formosa) _ . 6 Seahorse (Hippocampus hudsonius) Scovell's pipefish (Syngnathus scovelli) Pipefishes (Syngnathus floridae) I ( louisianae) Redear sunfish (Lepomis microlophus) __ I Bluegill (Lepomis macrochirus) 14 Dollar sunfish (Lepomis marginatus) I Bluespotted sunfish (Enneacamhus gloriosus) I Black crappie (Pomoxis nigromaculatus) Round pompano (Tracbinotus falealus) 27 Common pompano (Tracbinotus carolinus) Jacks (Caranx hippos) _ 14 ( “ latus) Bumper (Chloroscombrus chrysurus) Moonfish (Vomer setapinnis) Lookdown (Selene vomer) Leathcrjacket (Oligoplites saurus) 2 Snook (Cemropomus undecimalis) 1 3 Mangrove snapper (Ltitjanus griseus) 3 Spot snapper (Lutjanus synagris) 2 Pigfish (Orthopristis chrysopterus) Sand perch (Diapterus olisthostomus) . .. 3 3 1,386 15 1 77 22 I 22 3 6 1 1 2 14 57 I 84 1 1 4 17 1 2 974 25 4 55 22 8 24 15 260 4 I 7 2 1 4 15 1 2 1 1 16 7 22 1 2 1 116 1 5 1 6 3 1 5 21 2 7 9 2 48 — 225 — TABLE 12 Total number of each species of fish caught in Fork, and outer estuary the South Fork, North Number of fishes Soccics South Fork North Fork caught Outer estuary Mojarra (Eucinostomus gula) 125 361 490 Yellow tail (Bairdiella chrysura) 76 9 12 Spotted weakfish (Cynoscion nebulosus) - 1 - White trout (Cynoscion regalis) 48 16 66 Spot (Leiostomus xanthurus) 22 23 138 King whiting (Menticirrhus americanus) - 1 12 Croaker (Micropogon undulatus) 824 355 794 Black drum (Pogonias cromis) 6 1 17 Red drum (Schenops ocellata) 35 51 41 Star drum (Stellifer lanceolatus) - - 4 Sheepshead (Archosargus probatocephalus) - 5 - Pin fish (Lagodon rhomboides) 3 32 12 Spadefish (Chaetcdipterus faber) 1 - 20 Sergeant major (Abudefduf saxatilis) - - 1 Cutlass fish (Trichiurus lepturus) - - 1 Mapo (Bathygobius soporator) - - 1 Darter goby (Gobionellus boleosoma) __ 8 3 40 Ocean goby (Gobionellus gracillimus) - - 1 1 8 Sharprail goby (Gobionellus hastatus) - 1 6 Naked goby (Gobiosoma bosci) 1 - - Violet goby (Gobioides broussonneti) __ 1 1 4 Barracuda (Sphvraena barracuda) - - 1 Silver mullet (Mugil curema) 12 2 - Striped mullet (Mugil cephalus) _ 1 5.570 1,774 5,047 Rough silverside (Membras martinica) __ 9 1 - i idewater silverside (Menidia beryllina)__ 486 179 1.041 Scorpionfish (Scorpaena grandicorais) __ - - 1 Sea robin (Prionot us tribulus) 1 - 3 Gulf whiff (Citharichthys macrops) - - 1 Spotfin whiff (Citharichthys spilopterus) 18 30 44 Fringed flounder (Etropus crossotus) - - 8 Sole (Achirus lineatus) - 9 - Hogchoker (Trinectes maculatus) 20 10 39 Tonguefish (Symphurus plagiusa) 6 4 1 1 Northern puffer (Sphoeroides maculatus) - - 2 Florida puffer (Sphoeroides nephelus) _ - - 1 Marbled puffer (Sphoeroides testudineus) - 1 19 Spiny box fish (Chilomycterus schoepfi) - - 3 Total; Fishes - 9.586 4,790 10,407 Species 48 45 70 Number of samples 50 39 89 Average number oi rishes per sample 191.7 122.8 126.8 NOTE: 1 dead eel (Anguilla rostrata) was caught in the November 1957 trawl catch in the South Fork and several dead tarpon (Megalops atlantica) were observed floating and caught in trawl hauls in all three reaches in February 1958. — 226 — TABLE 13 Total numbers of fishes caught and percentage of total catch for al! species with more than 100 specimens — St. Lucie Estuary Scientific name Common name Total no. catch Percentage o total catch Mugil cephalus Striped mullet 12,391 50.0 Brevoortia smithi Menhaden 3.748 15.1 Micropogon undulatus Croaker 1.973 8.0 Menidia beryllina Silversides 1.706 6.9 Anchoa mitchilli Bay anchovy 1.466 5.9 Eucinostomus gula Mojarra 976 3.9 Subtotal 22,260 89.8 Galeichthys felis Sea catfish 393 1.6 Pomoxis nigromaculatus Black crappie 185 0.2 Leiostomus xanthurus Spot 183 0.7 Ictalurus catus White catfish 163 0.7 Trachinotus falcatus Round pompano 143 0.6 Cynoscion regalts White trout (weakfish) 130 0.5 Sciaenops ocellata Red drum (red fish) 127 0.5 Subtotal 23,584 95.2 70 others 1,199 4.8 Total 24,783 100.0 TABLE 14 Average catch per haul of fishes ta+ten in trawls and seines in each collection in St. Lucie Estuary Date Number of hauls average catch Seines Trawls and Total Jan. 1957 14. 7. 21 65.3 58.6 63.0 May 195 7 12 7 19 77.2 46.0 65.7 June 195 7 _ . . . . _ 16 5 21 15.4 94,0 34.1 Sept. 1957 13 7 20 47.6 47.6 47.6 Nov. 1957 . 8 7 15 8.5 28.7 17.9 Tptai number of hauls, 1957 63 33 96 Average catch 44.0 52.6 47.0 Jan. 1958 . 8 7 15 774.0 32.8 428.1 Feb. 1958 8 7 15 893.1 64.1 506.3 May 1958 10 7 17 372.1 80.8 252.2 — 227 TABLE 14 Average catch per haul of fishes taken in trawls and seines in each collection in St. Lucie Estuary Date Number of hauls average catch Seines Trawls and Total Oct. 195 8 7 7 14 46.7 33.6 40.1 Total number of hauls. 1958 . _ _ _ 33 28 6] Average catch - 526.8 52.8 309.2 Jan. 1959 7 7 14 184.8 16.3 100.6 Grand total number of hauls -103 68 171 Grand average catch . _ 208.3 49.0 144.9 TABLE 15 Order of abundance of most numerous fishes taker* in seines and trawls in St, Lucie Estuary Seine catches Trawl catches Species Number of fishes caught Species Number of fishes caught Striped mullet 12,387 Croaker 1,471 Menhaden 3,745 Sea catfish 381 Tidewater silversides 1,706 Bay anchovy 262 Bay anchovy 1,204 Black crappie 183 Mojarra 832 White catfish 161 Croaker 502 Mojarra 144 Spot 158 White trout 128 Round pompano 143 Yellowtail 97 Red drum 1 27 Spotfin whiff 81 Least killifish 64 Sand perch 78 Sardine 55 Hogchoker 69 Threadfin shad 47 Threadfin shad 34 Darter goby 46 Channel catfish 33 Pinfish 46 Spot 25 Total 21 .062 Total 3,147 NOTH: The above catches of 2 3 species represent 97.5 percent of the total of all fishes collected. 228 TABLE 16 u S 2 -iN„ _0) i7» O - ° CN o * u _^ q -2'2 5 - ~ (O'".: u os m — — • o 9-0 - ~- --£ £ £ s2 O 03 a . ^ GO i/s, _C Lfl io ^ O o C L N ^ ft * O _ - ^ V, ^ >. U __ " n r] « K S) OTJ n o "i; — * ia CL 4 - £ o ‘ N lN u tf) w I IA •S O ^ OO CJs J 1 ^ ~ rg — C "O ns i s. S 5 ^ 2 a S. - ^ «T*c ° n,C E 'i n 4 : £ '5 2 a o 2 ^ £ Z £ 229 yprinodon vanegatus TABLE 16 Total number of each species of fish in each collection from St. Lucie Estuary, January 1957 to January 1959 (lak,e-discharge condition in- dicated for each sampling period u u / r! i 0 - 20 - o ' « 1 o o o ir> - cs oo . a s o w Q -2 ^ »n W w ON w Cu m ^ V4-, -W f'- . - 00 u-\ o ' J "i 3 °® u t-j 1 in 2 B fl O N n J 2 5 ^ {J ^ On 8 -g c :3 - j- « C , in « o ^ OO ON U u ^ t-CS | t ft M i On I ft-l — i^-rvi cs - o N ri « I I I " | N , | CN | NO N UN N . .in 00 r<1 m I I— i CTN on k m in I o .2 S C ‘ 3 ‘5 re _ o gr :s £ .E O = 5 2 3 .S 3 3 a re re ‘E •s va S I g 3 a • Is .a £ E E rs rs *TT x: ^ o » , C rt e ■= X2 X! tl 7 ! m w re re *“* 3 C OO 00 c a E E X 1/3 C/3 _J re 3 6 j* .2 S S * . §. £ c7 3 ►J W in O O x .S .5 O 43 X n: ra r\ w in <£(-(- 2 .5 „ ■ 4 i a S H 2 E & 8 « ° X o ** C b. • O -C 3 MX "b in w p 2 o — & CL O O £3 » C o u la re 5 > sr-s ° w w .2 § 3 3 2 2 c e “* &* re re ° £ 3 O t ^ J j O Q 230 TABLE 16 Total number of each species of fish in each collection from St. Lucie Estuary, January 1957 to January 1959 {lake-discharge condition in- dicated for each sampling period Gates Gates 2,100 6.680 Gates 7.3B0 4,000 5,200 Gates Gates Total O ccs SO tr Os IT, t}- <— pc' m in ■<}- I'-. Tf N tn do - s© cm cm rj- cm — _ OS -H ^ O K - « - LI-', —l Os ITS OS O ITS O SO CM -if CM CM , •SO O OO cn <*S CM Os ■ — • CM — — * — * 'CCS PCS CM O >- CM < oo ”5 OS LTS — OS rs so cm o M- VO pcs fCS CM pc> ITS CM i/j SJ X oo Lf\ Os irs CM O SO CM m SO I OS . 00 00 C n in *o > o (Cl Z. ~ r " C— • O, PC “ in N LTS os 1 ^ § “ t- - 1 LfS Os TO so N — i in -2 2 _0 OO OS so 00 -f .CM , — pcs SO , t-v . rn m m- Ostt-tS3t-M — 1 CM CM . — i — . , — < in m oo e s v rJ _ ? 3 g »1 « t 3 D J3 £ E ^ 2 s J2 LTO tS! o o .S 5 tj vc ‘j ,h a s ns uj w cQ 3 a o <2 •£ 5 S, « S> Sr * c c a o o g 'S a 2 O O so c c o Ic. 3, Ck, u U X - 3 a -o c O U S' 3 o o. . o S c 'n c o so d — O «o — w TO T3 12 o, E o i n -C 3 H 00 5 g "5 .2 O 'O J3 o u oC 2 a o .5 v) X 3 PJ 2 « s S. o •6 3 tj kj w ^ 2 d (✓) t/) < J _c ^ U < 2 o 2 o a "> eu (/i « ,5 2 *° 7: o ^ 00 -c ^ o* x; "C ^5 CQ *5 2 X) 00 H c c ,0 o X io o o u a 231 Gobionellus hastatus Gobiosorna bosci Gobioides broussonneti Sphyracna barracuda TABLE 16 ^ VIA ^ BJ C N u-. ^ *n co i , sis'!" S-S°S£ O m >■ rJ O ir> ° *? ja ^ 00 tS-g-q S' * .a .9 rc o'? fe Q. S ■5-2 g>(? 03 w = ®°v a c Cio P 00 CN Jo « _c i— *s> se v **’ ^“5 o h- nj ^ o 0 3®- , A C U N &J!* o U oi Q) O TJ re a 4 - « o s rm U s j= m .y UCM3 0J a) H- >> ° Q i- 3 w c -Q 03 3 .. c ^ — TO J2 ^ o tj I- LU W* a. ro 14J .CJ rv| r^- 7- in S ® N "2 >s v) re vo fv -2 S ^ £ ^ "t- v> w? o4 >s >- o -C -C h V *0 _c X 2 u a - “> — — -o "Q M « £ C 3 3 qj Cu» 2 222 1 'C '2 ^ 3 re m O. v- £ ■£ 2 .5 uuw< o o J2 -C Xi ■ = - Q, a. r® 1/1 « u 232 January 1958 trawl collection and several dead tarpon (Megalops atlantica) were observed floating and caught in the trawl in February 1958. TABLE 17 List of fishes caught in St. Lucie Estuary by ail methods for all species with less than 100 specimens in the total catch 1 specimen Florida spotted gar (Lepisosteus platyrhincus) Golden shiner (Noiemigonus crysoleucas) Marsh killifish (Fundulus confluentus) Sheepshead Gllifish (Cyprinodon variegatus) Seahorse (Hippocampus hudsonius) Redear sunfish (Lcpomis microlophus) Moonfish (Vomer setapinnis) Spotted trout (Cynoscion nebulosus) Sergeant major (Abudefduf saxatilis) Cutlass fish (Trichiurus lepturus) Mapo (Bathygobius soporator) Naked goby (Gobiosoma bosci) Barracuda (Sphyraena barracuda) Scorpionfish fScorpaena grandicornis) Gulf whiff (Cttharichthys macrops) Florida puffer (Sphoeroides nephelus) 2 to 4 specimens Tenpoundcr (Elops saurus) Gizzard shad (Dorosoma cepedianuin) Seminole killifish (Fundulus seminolis) Dollar sunfish (Lepomis marginatus) Bluespottcd .unfish (Enneacanthus gloriosus) Bumper (Chloroscombrus chrysurus) Pigfish (Orthopristis chrysopterus) Star drum (stellifer lanceolatus) Sea robin (Prionotus tribulus) Northern puffer (Sphoeroides inaculatus) Spiny boxfish (Chilomycrerus schoepfi) 5 to 10 specimens Sliugaree (Dasyatis sabina) Brown bullhead (Ictalurus nebulosus) Gafftopsail catfish (Bagre marina) Redfin killifish (Lueapia goodei) Flagfish (Jordanella floridae) Pipefishes (S’yngnathus spp.-louisianae) floridae) Lookdown (Selene vomer) Mangrove snapper (Lutjanus griseus) Sheepshead (Archosargus probatocephalus) Ocean goby (Gobionellus gracillimus) Sharptail goby (Gobionellus hastatus) Violet goby (Gobioides broussonneti) Rough silversides (Membras martinica) Sole (Achirus Jineatus) Fringed flounder (Etropus crossotus) 11 to 25 specimens Striped anchovy (Anchoa hepsetus) Lizardfish (Synodus foetens) Red minnow (Notropis maculatus) — 233 — TABLE 17 List of fishes caught in St. Lucie Estuary by all methods for all species with less than 100 specimens in the total catch Needlefishes (Strongylura spp. -marina) notata) Mosquitofish (Gambusia aff inis) Sco veil's pipefish (Syngnachus scovelli) Common pompano (Trachinotus carolmus) Learherjack.'t (Oligoplites saurus) Snook (Centropomus undecimalis) Spot snapper (Lutjanus synagris) King whiting ( Menticirrhus americanus) Black drum (Pogonias cromis) Spadefish (Chaetodipterus faber) Silver mullet (Mugil curcma) Tonguefish (Symphurus plagiusa) Marbled puffer (Spboeroides testudineus) 26 to 50 specimens Channel catfish (Ictalurus punctatus) BluegiU (Lcpomis macrochirus) Jacks (Caranx spp.-latus) -hippos) Pinfish (Lagodon rhomboides) 50 to 100 specimens Threadfin shad (Dorosoma petenense) Sardine (Harengula pensacolae) Least killifish (Heterandria formosa) Sand perch (Diapterus olisthostomus) Silver perch — yellowtail (Bairdiella chrysura) Darter goby (Gobionellus boleosoma) Spotfin whiff (Cithariehthys spilopterus) Hogchoker (Trinectes maculatus) TABLE 18 Frequency of occurencp of fishes in the trawl and seine collections for those species appearing in above 5 percent of the total station collections Item Trawls Seines All stations dumber of station collections 68 53 121 Species Frequency (percent) Croaker (Micropogon. undulatus) 81 17 53 Striped mullet (Mugil cephalus) 13 66 39 Bay anchovy (Anchoa mitchilli) 24 55 37 Mojarra (Eucinostomus gula) 18 55 34 Sea catfish (Galeichthys felis) 50 8 31 Tidewater silversides (Menidia beryllina) 0 66 29 Sand perch (Diapterus olisthostomus) 28 23 26 Spotfin whiff (Cithariehthys spilopterus) 34 13 25 — 234 — TABLE 18 Frequency of occurence of fishes in the trawl and seine collections for those species appearing in above 5 percent of the total station collections Item Hogchokef (Trinectes maculatus) Spot (Leiostomus xanthurus) White trout (Cynoscion regalis) Threadfin shad (Dorosoma perenense) Snook (Centropomus undecimalis) Menhaden (Brevoortia smithi) Marbled puffer (Sphoeroides testudineus) Darter goby (Gobionellus boleosoma) White catfish (Ictalurus catus) Yellowtail (Bairdielta chrysura) Pipefishes (Syngnathus spp.) Tonguefish (Symphurus plagiusa) Bluegill (Lepomis macrochirus) Red drum (Sciaenops ocellara) Black drum ( Pogonias cromis) Pinfish (Lagodon rhomboides) Jacks (Caranx spp.) Channel catfish (Ictalurus puncratus) Whiting (M.enticirrhuS americanus) Round pompano (TYacbinotus fakatus) Needlefishes fStrongylura spp,) Ocean goby (Gobiosoma gracillimus) Leatherjacket (Oligoplites saurus) Lizardfish (Synod us foetens) Tenpounder (Elops sautus) Mosquitofish (Gambusia affinis) Red minnow (Notropis maculatus) Striped anchovy (Anchoa hepsetus) Stingaree (Dasyatis sabina) Trawls Seines All stations 41 0 23 12 30 23 35 2 21 1 9 13 17 16 9 13 4 30 13 12 15 1 3 7 17 1 2 19 2 1 2 19 0 1 1 0 25 I 1 15 6 1 1 4 17 10 0 23 10 1 6 0 9 2 19 9 3 15 8 1 3 2 8 10 4 7 0 17 7 0 17 7 1 3 0 7 0 15 7 2 1 I 6 6 6 6 0 1 3 6 0 I I 5 0 1 1 5 7 2 5 TABLE 19 Salinity average of seinp stations and bottom samples at trawl stations, together with numbers, of species and numbers of individuals of marine and fresh-water fishes in each portion of the estuary South Fork North Fork Outer Estuary Average salinity (p.p.t.) 6,0 6.3 14. 1 Salinity range (p.p.t.) 0,14-20.5 0.14-20.2 0.1 5*36.0 Number of fiesh- water species 1 2 1 3 1 3 Number of fresh* water fishes 24 2 304 86 Number of marine species 35 32 57 Number of marine fishes 9.344 4,486 10.321 235 — co O' O ™ o oo N ^ „ (A C~4 rA O ° O' o — • IN OO N N CS O OO rs O IT » t ^ 40 O Nf^ ^ CO O 1-3 £j T -3 O U *-* i- *-« -c JJL, M> u, S. 236 (2) Based on spawning habitat. Q C TJ m C 3 ■3 +- |lS5 TO e -3 CD d _ -C LO CS^ I 1U u 1 -I -~ c ^ >-* I- +r -*- CTJ T3 C ro > +- 'c ro C/1 o o- in ON CS 't UN OV d — — oo ro vo ■O'Or^ior^' rorooN.oorv.c-i,-cCT\ ff'tNOinKO'WCO' 0, f^ ,s| 0‘'^0'MvO fN) rrv — — 1 n vo oo ■ — • oo vo ~ to ■ £ s 2 £ ~ rsi CO oo k ^m--n VO LTV O -tf* — ' <3 rt CJ IVI . ; — T3 u -o r m 3 ra S; *» O fc rt ■S#a£A°J< t * t se5 -a b _ _ . ,. 2Uw’^hXh § I «i/ T3 d S3 -* LT -* 2 G4 > j-i o .££ ►*, &> O oc ° • — rt .s S o a 2 . S O e. z 00 w f- o z 237 (2) 97 percent of all fish taken. TABLE 22 Less abundant fishes taken in St. Lucie Estuary in certain salinity ranges (Salinity readings in parts per thousand) Above 30.0 only Hippocampus hudsonius (sea horse) Scorpaena grandicornis (scorpionf ish) Citbarichthys macrops (gulf whiff) Above 25.0 only Chilomycterus schocpfi (boxfish) Vomer setapinnis (moonfish) Sphoeroides nephelus (Florida puffer) Abudefduf saxatilis (sergeant major) Above 20.0 only Chloroscombrus chrysurus (bumper) Sphoeroides maculatus (N. puffer) Orthopristis chrysopterus (pigfish) Harengula pensacolae (sardine) Etropus crossotus (fringed flounder) Above 15.0 only Selene vomer (lookdown) Above 10.0 only Synodus foetens (lizardfish) Menticirrhus americanus (whiting) Membras martinica (rough silversides) Gobiosoma bosci (naked goby) Chaetodipterus faber (spadefish) Above 5.0 only Prionotus tribulus (sea robin) Syngnathus spp (pipefishes) Trachinotus carolinus (pompano) Below 0.5 only Dorosoma cepedianum (G. shad) Notropis maculatus (red minnow) Lepomis microlophus (redear sunfish) Lepomis marginatus (dollar sunfish) Cyprinodon variegatus (shcepshead killifish) Jordanella floridae (flagfish) Lepisosteus platyrhincus (spotted gar) Below 2,0 only Lepomis macrochirus (bluegill) Notemigonus crysoleucas (golden shiner) Ictalurus punctatus (channel cat) Below 5.0 only Lucania goodei (redfin killifish) Fundulus confluentus (marsh killifish) Gambusia af finis (mosquitofisb) Cynoscion nebulosus (spotted trout) Sphyracna barracuda (barracuda) Heterandria formosa (least killifish) Bathygobius soporator (mapo) Fundulus seminolis (Seminole killifish) Trichiurus lepturus (cutlass fish) Below 1 0,0 only Ictalurus nebulosus (speckled bullhead) — 238 — TABLE 22 Less abundant fishes taken in St. Lucie Estuary in certain salinity ranges (Salinity readings in parts per thousand) Elops saurus ( lenpounder) Enneacanthus gloriosus (bluespoLted sunfisb) Mugit curema (silver mullet) Scattered throughout range from 0.5 to 30.0 Syngnatbus scovelli (Scovell s pipefish) Sphocroidcs tcstudineus (marbled puffer) Pogonias cromis (black drum) Gobionellus gracillimus (ocean goby) Symphurus plagiusa (tonguefish) Lagodon rhomboides (pinfisb) Strongylura spp, (needlefishes) Bagre marina (gafftopsail catfish) Caranx spp. (jacks) Oligoplites saurus (leatherjacket ) Centropomus undecimalis (snook) Lut janus griseus (gray snapper) Anchoa bepsetus (striped anchovy) Lutjanus synagris (spot snapper) Achirus lineatus (sole) Archosargus probatocephalus (sheepshead) Gobionellus boleosoma (darter goby) Gobionellus hastatus (sbarptail goby) Gobioidcs broussonneti (violet goby) Stellifer lanceolatus (star drum) Dasyatis sabina (stingaree) 2 .Species account. Fishes , DASYATIDAE Dasyatis sabina (LeSueur) , Stingaree, Eight specimens were caught in the trawls and the catch data are given in Table 23. It is well known that this ray enters fresh water and goes far upriver (Gunter, 1938) and it should be noted that five of the seven stingarees caught were taken in salinities of 0.2- 0,3 parts per thousand, which is fresh water, A dead specimen was taken at SS #2 on 24 February 1958. It was not measured. Presumably this specimen had been killed by previous hard '.old waves. Gunter (1945) thought the birth of stingarees takes place during an extended period over the warm part of the year in Texas waters. His smallest specimens, 13 0 cm in disk length, were taken in November. We also took a 13.0 cm specimen in November. We took two at still smaller sizes in September, which were probably born early that month or pos- sibly in August. Numerous ichthyologists have seen stingarees give birth to young after being caught, but disk length data on newborn young seem to be lacking. Such data would be of some value even though the birth of captured stingarees might be premature. — 239 — TABLE 23 Catch records of Dasyatts sabina Total No. of length in Salinity Dare Station Specimens millimeters Temp. °C o/oo Jan. 28, 1957 TS#4 1 455 23.8 20.0 May 16, 1957 TS#1 1 305 26.0 10.0 Sept. 23, 1957 TS#2 2 118-120 28.1 0.17 Nov. 13, 1957 TS#2 1 130 22.1 14 8 May 19, 1958 TS#2 2 230 25.6 0.15 May 20, 1958 TS#6 1 170-350 25.6 0.34 LEPISOSTEIDAE Lepisosteus platyrhincus DeKay. Florida spotted gar. One gar, 51.8 cm in total length, was taken at SS #3 on 19 May in water with a temperature of 25.6°C and a salinity of 0.28 o/oo. ETOPIDAE Elops *aurus Linnaeus. Tenpounder. Two live fish were taken at SS #2 and TS #6 on 24 February 1960, and a third was caught at SS #5 on 19 May 1958. The lengths were 58.2, 28.5 and 35.5 cm and the temperatures and salinities, re spectively, were 17,2, 16.1 and 24.4°C and 1.0, 7.0 and 0.15 parts per thousand. Two unmeasured dead fish were taken at TS #4 on 24 Feb- ruary 1958. Two dead fish, 46.9 and 30.6 cm long, were taken at TS #3 and TS #2 on 24 and 25 February 1958. Numerous tenpounders were also seen along the shoreline at this time. They were evidently kill ed by the cold and will be discussed further under cold kills. MEGALOPIDAE Megalops atlantica (Cuvier and Valenciennes). Tarpon. No live specimens were taken. One dead tarpon, estimated to weigh about 60 pounds, was found floating at TS #3 on 24 February 1960. Another dead tarpon 75.0 cm long was taken at TS #5 and several unmeasured dead ones were seen along the shore at SS #3 on the same date. These fish were evidently killed by the previous cold. CLUPEIPAE Breuoortia tyrannus (Latrobe) . Atlantic menhaden. Data on the menhaden catches are given in Tabic 24. When the writers began this work, it was assumed that only B. tyrannus was pre- sent, and in fact neither B. tyrannus nor B. smuhi had been reported in the literature so far south on the Atlantic. Since then Springer and Woodbum (1960) reported B. tyrannus young in the St. Lucie. The — 240 — table shows that only three menhaden were taken in trawls among the 3,748 fishes of both species caught. It seems clear that both species use the St. Lucie as a nursery ground and leave it quickly as they grow up. Otherwise greater numbers of menhaden would have been taken in the trawls. In the southern part of it* range B. tyrannus spawns in midwinter in contrast to a spring and summer spawning in the North Atlantic and New England stares (see Gunter and Christmas, I960, for literature) . It should be noted in the table that no fish taken in January and Febru- ary was longer rhan 33 mm total length. The size grouping is narrow, 20-33 mm, and frequency curves are not presented. These little menhaden all come from a winter spawning, and correspond in that respect to B. patronus on the Gulf Coast (Cf. Springer and Woodburn, op. at,) . It should be noted that very few menhaden, 83, were taken in Jan- uary 1957 when salinities were high and the St. Lucie Locks were clos- ed, and similarly none were caught in January 1959. If small menhaden were present in these two years, they were farther back in the estuary than our stations extended. TABLE 24 Catch records of Brevoortia tyrannus and B. smithi Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Brevoortia tyrannus Jan. 29, 1957 SS#2 45 larvae no lengths 24-1 20.1 Jan. 29, 1957 SS#3 31 22-28 24.9 14.0 Jan. 29, 1957 SS#4 4 '* 27-33 24.3 17.0 Jan. 29. 1957 SS‘#5 3 26-28 24.0 19.3 June 18. 195 7 TS#4 1 56 29.3 < June 1 8. 1957 TS#5 1 60 28.8 1.2 Jan. 28, 1958 SS#5 5 larvae 23-27 17.4 0.35 Jan. 28, 1958 SS#1 A 1 31 16.8 1.26 Jan. 28. 1958 SS#1 A 47 20-25 16.8 1.26 Jan. 28. 1958 SS#6 750 25-30 — 0.32 Jan. 28. 1958 SS#2 5 24-27 — 0.34 Feb. 24. 1958 TS#1 1 62 14.4 < LO Feb. 24, 1958 SS#1A 25 24-33 16.7 4.9 Feb. 24. 1958 SS#5 500 22-33 17.2 < 1.0 Feb. 24. 1958 SS#6 33 21-30 17.8 < 1.0 Total 145 2 Brevoortii a smithi May 19, 1958 SS#2 20 16-3# 26.1 0.19 May 19. 1958 SS#1 A 13 41-62 25.6 1.04 May 19. 1958 SS#3 1354 28-61 25.6 0.28 May 19. 1958 SS#5 880 19-39 24.4 0.15 May 20. 1958 SS#6 29 24-41 25.6 0.30 2296 Grand total 3 748 — 241 — Brevoortia smithi Hildebrand. Atlantic fine-scale menhaden. A few fish of this species may have been mixed with B. tyrannus, but by and large they were only taken in May 1958 when the lock gates were open and the salinities were low. This species spawns later than J3. tyrannus and the occurrence of larvae in May corresponds with the find- ings of Springer and Woodburn concerning B. smithi on the Florida Gulf Coast. In May 1957 when the locks were closed and salinities were comparatively high, the young fish were rare or absent from the areas we fished and the large population of young fish was not encountered. The flow of fresh water into the St, Lucie obviously enhances its po- tentialities as a nursery ground for both B. tyrannus and B . smithi . The table shows that the young of both species were taken in abundance at salinities within the fresh water range. Dorosoma petenense (Gunther ) . Threadfin shad. This is a fresh water species which is commonly found in salt water along the Gulf Coast at larger sizes. Table 25 shows that only a few young and juveniles were taken in the St, Lucie at low salinities. Ap- parently, this fish leaves the estuary before it attains adult size. The smallest fish were taken in September and spawning probably takes place in late summer and early fall. This fish is also known to spawn in the spring and our data show two size groups in the early fall. Probably the fish spawns twice during the warm season, at least in south Florida. TABLE 25 Catch records of Dorosoma petenense Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo June 18, 1957 TS#5 1 69 28.8 1.2 Sept. 23, 1957 TS#3 1 55 23.1 0.17 Sept. 23, 1957 TS#4 12 41-62 22.9 0.18 Sept. 23, 1957 TS#5 3 79-90 23.8 0.20 Sept. 23. 1957 TS#6 1 84 23.4 0.34 Sept. 23, 1957 SS’#4 25 23-28 28.1 surf 0.16 Sept. 23, 1957 SS#5 1 27 29,5 ” 0.18 Sept. 23, 195 7 SS#6 15 48-70 30.9 ” 0.25 Jan 27, 1958 TS#l 4 46-48 15,5 0.18 Jan 27. 1958 TS#2 3 62-78 15.8 0.23 Feb. 24, 1958 TS#1 2 63-65 14.4 < L0 Feb. 24. 1958 TS#2 2 53-68 16.7 < i.o Feb. 24, 1958 TS#4 1 79 14.4 < i-o Feb, 24, 1958 TS#6 1 50 16.1 7.0 Feb, 24. 1958 SS#IA 1 47 16.7 surf 4.9 Feb. 24. 1958 SS#5 2 52-53 17.2 < May 19. 1958 TS#3 1 73 27.2 0.27 May 19, 1958 TS#5 1 78 25.6 0.15 May 20. 1958 SS# 1 A 2 40-72 25,6 1.04 May 19. 1958 SS#5 2 71-73 24.4 0.15 Grand total 81 — 242 Dorosoma cepedianum (LeSueur). Gizzard shad. This is also a fresh water fish which occasionally enters waters of moderate to high salinity on the Gulf coast (Gunter, 1945). Four speci- mens were caught in the St. Lucie. Three fish, 64-80 mm long, were taken at TS #5 on 23 September 1957. The water temperature was 23 -8°C and the salinity was 0.2. One fish, 27.0 cm long was caught at SS #2 on 19 May 1958. The temperature was 26.1°C and the salinity was 0.19 o/oo. Harengula pensacolae (Goode and Bean). Sardine, This fish is somewhat sahniphilous and apparently is only a stray in the outer estuary when salinities are high. Fifty-four Harengula . 27-34 mm long, were taken at SS #1A in the lower estuary on 16 May 1957 at a temperature of 28.0°C and a salinity of 21.5. One fish, 10.7 cm long, was taken at the same station on 27 October 1958 when the temperature was 25-6°C and the salinity was 27,4. Gunter (1945) found 33 mm fish in June in Texas. Springer and Woodburn report young in May in 1959, but the year before they appeared in June. The St. Lucie young seem to be earlier than those previously reported. UNGRAULIDAE Anchoa hepsetus (Linnaeus) * Striped anchovy. This anchovy is very abundant in nearshore and offshore shallow waters, but it is generally found in much higher salinities than A . mit- chilli , the bay anchovy. It has a very large larva, up to about 35 mm total length. Table 26 shows that a high percentage of the 24 specimens caught in the St. Lucie were larvae. The remainder were juveniles. Gunter (1945) gave the top size in Texas waters as 141 mm. The largest fish taken in the St. Lucie was 67 mm long. All anchovies of this species were taken in the lower estuary. The catch records are given in Table 26. One group of six fish was taken at a salinity of 1.0, which is the lowest salinity at which the species has been reported. The smallest fish were found in October and January. This puts a different light on the life history from the record presented by Gunter (1945) for Texas fishes, but it corresponds in part to what Springer and Woodburn found on the Florida Gulf coast, where the smallest specimens were taken in January. Springer (i960) did not report this species from the St, Lucie. TABLE 26 Catch records of Anchoa hepsetus Date Station No. of Specimens Total length in millimeters Temp. °C Salinity o/oo Sept. 23. 1957 SS#1 A 9 44-67 31.1 7.5 Nov. 13, 1957 SS#6 1 38 — 23.1 May 20, 1958 SS#1 A 6 41-55 25.6 1.04 Oct. 27, 1958 SS#6 1 23 24.4 19.0 Jan. 27, 1959 SS'#1A 7 larvae 25-30 21.1 25.9 — 243 — TABLE 27 Catch records of Artchoa mitchilli Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 28. 1957 TS#1 4 38 61 24.1 17.0 Jan. 28, 1957 TS#2 5 44-66 23 3 20.5 Jan. 28. 1957 TS#3 1 57 23.3 14.8 Jan. 28, 1957 TS#4 2 46-48 23.8 20.0 Jan. 28, 195 7 TS#5 131 34-66 24.5 21.0 Jan. 29, 1957 TS#6 2 47-55 23.7 29.2 Jan. 29, 1957 SS#3 7 36-48 24.9 14.0 Jan. 29, 1957 SS#3 70 larvae 26-37 24.9 14.0 Jan. 29, 1957 SS#4 48 25-48 24.3 17.0 Jan. 29, 1957 SS#5 48 39-58 24.0 19 3 May 16, 1957 TS#5 1 60 26.7 19.9 May 16, 1957 TS#6 1 40 26.7 22.9 May 16, 1957 SS#1 A 120 27-64 28.0 21.5 May 16. 1957 SS#2 10 43-58 30.7 9.3 May 16, 1957 SS#3 1 47 28.3 3.7 May 16. 1957 SS#5 13 39-50 28.0 5.7 May 16, 1957 SS#4 223 31-54 28,0 9.5 June 18, 1957 SS#6 1 25 — 2.7 June 18, 1957 SS#2 17 42-49 30.0 0.8 June 18, 1957 TS’#5 75 36-69 28.8 1.2 June 18, 1957 SS#5 12 35-39 — < 1.0 Sept. 23, 1957 TS#3 1 40 23.1 0.17 Sept. 23, 1957 TS #4 18 39-55 22.9 0.18 Sept. 23, 1957 TS#5 4 47-60 23.8 0.20 Sept. 23, 1957 TS#6 9 46-56 23.4 0.34 Sept. 23, 1957 TS#7 1 36 — 23.5 Sept. 23, 1957 S’S#1 A 55 28-58 31.1 7.5 Sept. 23, 1957 SS#5 82 larvae 17-25 29.5 0.18 Sept. 23, 1957 SS#4 7 34-50 28.1 0.16 Nov. 13, 1957 SS#5 1 1 26-29 21.6 14.5 Nov. 13, 1957 SS’#6 21 27-41 — 23.1 Jan. 27. 1958 SS#1 A 38 22-47 16.8 1.26 Jan. 27, 1958 SS#6 302 28-30 — 0.32 Feb. 24, 1958 SS#1A 2 40-46 16.7 4.9 Feb. 24, 1958 SS#2 1 31 17.2 < Feb. 24, 1958 SS#6 9 20-33 17.8 < io May 19, 1958 SS#2 4 25-44 26.1 0.19 May 19, 1958 SS#1A 4 20-65 25.6 1.04 May 19. 1958 SS#3 75 24-47 25.6 0.28 May 19, 1958 SS#5 6 30-50 24.4 0.15 May 19, 1958 SS#6 5 55-77 26.1 0.30 Oct. 27, 1958 TS#2 6 46-58 23.9 20.3 Oct. 27, 1958 TS#5 1 49 23.3 26.3 Oct. 27, 1958 TS’#6 7 41-52 23.3 26.3 Oct. 27, 1958 SS#3 2 39-46 25.0 7.8 Jan. 27, 1959 SS#1A 2 48-55 21.1 25.9 Jan. 27, 1959 SS#1A 3 22-28 21.1 25.9 Jan. 27, 1959 SS#6 3 22-24 22.2 10.4 Grand total 1471 — 244 — Anchoa mitchilli Cuvier. Bay anchovy. Table 27 gives the catch records for this species. The larvae are easily overlooked. This little fish is ubiquitous in bays and estuaries and probably has the greatest species mass of any fish in estuarine waters of the south Atlantic and Gulf. Ripe fish and the smallest fish were taken in January and small fish were also, taken in May and November. A long spawning season is indicated, as Gunter (1945) found in Texas waters. Small fish were found in both low and intermediate salinities. Gunter (op. cit.) noted that small fish were also found at high salinities and concluded that salinity was a minor factor in determining distribution of this anchovy. Present data reinforce this conclusion. Springer and Woodburn say that their data are in contrast to Gunt- er (1945) and others “who noted that this species occurred primarily in open bays” (p. 21). Gunter (op, cit.) has shown that these little fish sometimes leave the shore. Springer and Woodburn’s results may not be in contrast to previous findings at all and can be more logically explained on the grounds that these little fish sometimes leave shallow waters near shore, especially in winter, and in fact, the large populations may have been in the open bay at the time the inshore catches of Springer and Woodburn were low. SYNODIDAE Synodus foetens (Linnaeus) . Lizard fish. Table 28 shows that the lizard fish was only taken in the St. Lucie when salinities were comparatively high. The smallest fish were taken in January. Springer and Woodburn (1960) found their smallest specimens in November and December, Gunter (1945) found no lizard fish in bay and inshore Gulf waters during the winter in Texas. These data and those of Reid (1954) and Springer and Woodburn show that on the warmer Florida coasts lizard fish arc to be found inshore in winter. TABLE 28 Catch records of Synodus foetens Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 29. 1959 TS#6 1 365 23.7 29.2 Jan. 29. 1959 SS#1 1 52 24.6 29.0 Jan. 29, 1959 SS#4 1 48 24.3 17.0 Oct. 27. 1958 S’S#6 4 48-81 24.4 19.0 Oct. 27. 1958 SS#1 A 5 54-81 25.6 27.4 Jan. 27, 1959 SS#1 A 3 49-50 21.1 25.9 Jan. 27, 1959 SS#6 1 69 22.2 10.4 Grand total 16 ARIIDAE Galeichthys felts (Linnaeus). Sea catfish. The seacat was a common component of the trawl catches and at some stations it was the major part of the catch. It is well known that this species is euryhaline and it was found at all salinities. At salinities between 20 and 29.2 fifty-six fish were caught, with an average of 6.2 fish per haul where they were caught (not including stations where they were absent). At salinities of 10.0-19.9 seventy-two fish were caught with an average of 7.2 fish per haul where they were caught. At salinities of 0.15 to 9.9 two hundred and sixty-five catfish were caught with an average of 13.3 per haul where they were caught. It appears that the majority of the sea catfish in the St, Lucie preferred low salinity waters. Gunter (1945) found that in Texas waters not many fish were found at salinities below 5.0 per mille. Springer and Woodburn (1960) found, in contrast, that all but two of 736 specimens were taken at sa- linities close to 4.0 in the Tampa region. The present data confirm their findings relative to the distribution of Galeichthys fetis in low salinity waters in Florida. A brief analysis of the size of G. felis taken at different salinities shows that the fish taken in low salinities were somewhat smaller than fish at higher salinities. The data are as follows: Salinity Length range Average No. Specimens 0.2-0. 7 43-340 152 166 1 .0-9.9 77-308 137 99 10,0-19.9 125-440 208 72 20.0-29.2 43-345 170 56 The very smallest fish were taken in May and evidently they were hatched during that month. Ripe and spent females were also taken dur- ing that month. The breeding seasou in these waters seems to be at least a month earlier than reported for Texas waters (Gunter, 1945). One fish measured 440 mm long, being the largest ever reported for this species. Total length frequency curves were drawn for G. felis but they are not presented. The size ranges of the fish are shown in Table 29. The most abundant group in June 1957 was 141-150 mm in length. In September of that year the only mode was at 88 mm, undoubtedly made up of fish spawned early in the summer or late spring. There were slight signs of a second peak at 103 mm. In November 1957 the double peaks were more pronounced at 103 and l 18 mm. In January 1958 the double peak showed at 1 1 8 and 133 mm. There was also a sharp mode of larg- er fish at 193 mm. A month later the two smaller peaks had more or less run together with a peak at 118-123 mm. The larger peak showed at 188 mm. It would seem that in midwinter most young of the year are a- round 118 mm long and a second group approaching two years of age is around 185-190 mm long. Other size groups and year classes doubtless exist in the population at that time, but they were taken too few times to show distinctly in the length frequency curves. The large size of some of these fishes is shown by the length ranges in Table 29. — 246 — TABLE 29 Catch records of Galeichthys felts Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 28. 1957 TS#1 5 128-151 24.1 17.0 Jan. 28. 1957 TS#5 1 345 24.5 21.0 Jan. 28. 1957 TS#6 1 74 23.7 29.2 May 16. 1957 TS#1 7 205-305 26.0 10.0 May 16, 1957 TS#1 6 140-168 26.0 10.0 May 16, 1957 TS#2 3 144-211 26.7 15.2 May 16. 1957 TS#3 1 258 26.5 5.4 May 16. 1957 TS#4 4 145-325 26.5 12.7 May 16, 1957 TS#5 7 125-150 26.7 19.9 May 16, 1957 TS#6 7 140-145 26.7 22.9 June 1 8, 195 7 TS#2 1 285 28.7 0.7 June 18, 1957 TS#2 2 42-165 28.7 0.7 June 18, 1957 TS#6 10 145-267 28.3 22.8 June 18, 1957 TS#5 I 247 28.8 1.2 Sept. 23, 1957 TS#1 2 295-299 28.0 0.27 Sept. 23. 1957 TS#5 36 79-107 23.8 0.20 Sept- 23. 1957 TS#6 2 178-270 23.4 0.34 Sept. 23. 1957 TS#7 1 265 — 23.5 Nov. ; 13, 1957 TS#1 34 82-120 21.9 11.5 Nov. 13, 1957 TS#Z 2 176-325 22.1 14.8 Jan. 27, 1958 TS#2 26 109-206 15.8 0.23 Jan. 28, 1958 TS#5 3 104-268 — 0.22 Jan. 28, 1958 TS#6 72 100-340 15.0 0.36 Jan. 27. 1958 TS#7 15 98-263 16.5 4.5 Feb. 25. 1958 TS#2 2 236-275 16.7 < 1.0 Feb. 24. 1958 TS#5 2 120-314 14.4 < i-o Feb. 24, 1958 TS#6 77 100-308 16.1 7.0 Feb. 24, 1958 TS#7 1 1 189-300 18.9 29.4 May 19, 1958 TS#3 7 123-245 27.2 0.27 May 19, 1958 TS#4 4 113-203 25.6 0.22 May 20, 1958 TS#7 6 43-195 24.4 25.5 May 19. 1958 SS#5 3 195-260 24.4 0.15 May 20, 1958 SS#6 7 135-292 26.1 0.30 May 20, 1958 SS#1 A 1 230 25.6 1.04 May 19, 1958 SS#3 1 240 25.6 0,28 Oct. 27. 1958 TS#2 14 70-179 23.9 20.3 Oct. 27, 1958 TS#4 5 154-230 25.6 20.2 Jan. 27, 1959 TS#1 2 149-208 18.9 14.7 Jan. 27. 1959 TS#2 2 193-440 20.0 17.1 Grand total 393 Bagre marina (Mitchill). Gafftopsail catfish. Catch records for the six specimens of gafftops are shown in Table 30. The smallest fish was taken in June. This catfish is evidently un- common in the estuary. — 247 — TABLE 30 Catch records of Bagre marina Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo May 16, 1957 TS#2 1 172 26.7 15.2 June 18, 1957 TS#2 4 91-110 28.7 0.7 Oct. 27, 1958 TS#2 1 190 23,9 20.3 ICTAXURIDAJE Ictalurus punctatus (Rafinesque) . Channel catfish. Table 31 catch records show that this fresh water catfish came into the estuary sporadically when the salinities were low. Thirty-four specimens were caught. The highest salinity where the catfish was caught was 0,3, which is within the fresh water range. Ictalurus catus (Linnaeus) , White catfish. The white catfish was more abundant in the estuary than the chan- nel cat, but similarly it was restricted to fresh water. Seventy-seven fish were taken when there were high influxes of fresh water. Small newly hatched fish were taken in May. Catch records are given in Table 32. Ictalurus nebulosus (LeSueur) . Brown bullhead. Only five specimens of this catfish were taken in the St. Lucie. Table 33 shows that it differed from the other two species of fresh water catfish in that it entered low salinity water, 6.3 parts per thousand. TABLE 31 Catch records of Ictalurus punctatus Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo June 18, 1957 TS#1 4 18-25 28.5 © V Sept. 23, 1957 TS#I 6 54-284 28.0 0.27 Sept. 23. 1957 TS#2 7 74-121 28.1 0.17 Sept. 23, 1957 TS#5 3 84-106 23.8 0.20 Jan. 27, 1958 TS#1 6 62-196 15.5 0.18 Jan. 27, 1958 TS#2 1 158 15.8 0.23 Feb. 24, 1958 TS#2 1 141 16.7 < 1.0 May 19, 1958 TS#1 2 165-170 24.4 0.14 May 19, 1958 TS#2 2 96-157 25.6 0.15 May 19, 1958 T$#4 1 124 25.6 0.22 May 19, 1958 SS#6 1 154 26.1 0.30 - 248 TABLE 32 Catch records of Ictalurus cams T otal No. of length in Salinit v Date Station Specimens millimeters Temp. °C o/oo Sept. 23, 1957 TS#5 5 76-118 23.8 0.20 Jan. 27, 1958 TS#1 I 184 15.5 0.18 Jan- 27, 1958 TS#2 7 165-137 15.8 0.23 Jan. 27, 1958 TS#5 1 93 — 0.22 Feb. 24. 1958 TS#1 2 92 93 14.4 < io Feb. 24, 1958 TS#2 55 62-185 16.7 < io Feb. 24, 1958 TS'#4 8 105-242 14.4 < i-o Feb. 24, 1958 TS#5 7 69-160 14.4 < io May 19. 1958 TS#1 12 16-31 25.6 0.14 May 19. 1958 TS#1 6 90-140 25.6 0.14 May 19, 1958 TS#2 I 16 25.6 0.15 May 19, 1958 TS#2 40 91-172 25.6 0.15 May 19, 1958 TS#3 5 124-263 25.6 0.27 May 19. 1958 TS#4 9 117-165 25.6 0.22 May 19, 1958 TS#5 2 97-188 25.6 0.15 May 19. 1958 SS#2 2 150 160 26.1 0.19 TABLE 33 Catch records of Ictalurus nebulosus Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Feb. 24, 1958 TS#5 I 156 14.4 < 1.0 May 19. 1958 TS#3 2 174-205 25.6 0.27 May 19. 1958 TS#4 1 205 25.6 0.22 Jan. 27. 1959 SS#2 1 105 22.8 6.3 CYPRINIDAK Notemigonus crysoleucas (Mitchill) . Golden shiner. One fish 28 mm long was taken at SS #1A on 27 January 1958. The water temperature was 1 6.8°C and the salinity was 1.26 per mille. Notropis maculatus (Hay). Red minnow. Table 34 shows that fifteen specimens were taken at various seine stations in the estuary when the salinity was equivalent to fresh water. We are indebted to Dr. R. D. Suttkus for checking the identifications. — 249 — TABLE 34 Catch records of Notropts maculatus No. of Total length in Salinity Din.' Stat ion Specimens millimeters Temp. °C o/oo Sept. 23. 1957 SS#4 3 30-34 28.1 0.16 Jan. 27. J 95 8 SS#4 4 33-42 — 0.25 I : eb. 24. 1958 SS#2 2 39-44 17.2 < 1.0 f : eb. 24. 1958 SS#4 5 30 56 14.4 < L* I'eb. 24. 195 8 SS#6 Grand 1 total 1 5 42 17.8 < i-o ANUUILTJDAE Anguilla rostrata (LeSueur). American eel. No live specimens were taken. A dead one was taken at TS #2 on 27 January 1958. This followed a cold spell and other dead fishes were taken at the same time. It was not measured. BELONIDAE Strongylura notata (Poey). Needlegar, and Strongylura sp. The first four specimens listed in Table *15 were identified as S. no- tata at the Gulf Coast Research Laboratory. The others were listed as Strongylura sp. in the field. It is our impression that they were largely notata with some 5. marina. The smallest needlegars were taken in May. Two 5 notata were taken at 0.25 salinity, which is fresh water. This adds another belonid to the list of euryhaline fishes of North America (Gunter 1956) . TABLE 35 Catch records of Strongylura notata and Strongylura sp. Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo S. notata May 16. 1957 SS#1 A 1 50 28.0 21.5 May 16. 1957 SS#3 l 93 28.3 3.7 Sept. 23, 1957 SS#6 2 106-247 30.9 0.25 Strongylura sp. May 19. 1958 SS#2 1 36 26.1 0.19 May 20. 1958 SS#I A 1 76 25.6 1.04 May 19. 1958 SS#3 5 40-81 25.6 0.28 May 20. 1958 SS#6 3 62-74 26.1 Oct. 27, 1958 SS #2 5 137 160 25.6 14.0 Oct. 27. 1958 SS#1 A l 470 25.6 27.4 Jan. 27, 1959 SS#IA I 360 21.1 25.9 Grand loi.il 21 250 — CYPEINODONTIDAE Lucania goodei Jordan. Red killifish. One fish 23 mm long was taken at SS #3 on 16 may 1957 where the water temperature was 28.3°C and the salinity was 3.7. Four speci mens were taken at SS #5 on 27 January 1959. Their length range was 17-29 mm. The water temperature was 20.0°C and the salinity was <1.0 Evidently this fresh water killifish ventures into low salinity waters a: times. Funduhis confluent us Goode and Bean. Marsh killifish. One specimen was taken at SS #3 on 16 May 1957. It was 13 mm long. The water temperature was 28.3°C and the salinity was 3.7 o/oo. Fund ulus seminolis Girard. Seminole killifish. One unmeasured specimen was taken at SS #3 on 27 January 1958 and another 21 mm long was taken at the same station precisely one year later. The respective temperatures were 17.7 and 20.6°C and the salinities were 0.26 and 2.4 o/oo. Evidently this fresh water killifish ventures at times into low salinity waters. We are indebted to Dr. R. R. Miller for checking the identification. Cyprinodon variegatus Lacepede. Sheepshead minnow. A single specimen, 25 mm long, was taken at SS #2 on 28 January 1958. The salinity was 0.34. The water temperature was not taken. Jordanella floridae Goode and Bean. Flagfish. One specimen was taken at SS #4 on 27 January 1958 and four were taken at the same station 19 May 1958. The first was unmeasured and no temperature was taken. The salinity was 0.25. The second group of four fish ranged from 19-23 mm in length. The temperature was 26.1°C and the salinity was 0.14. Two specimens were taken on 27 January 1959. They were 18 and 30 mm long: the water temperature was 25.6 and the salinity was <1.0. Apparently this little cyprinodon- tid only ventures into low salinity waters. POECLLIIDAE Gambusia af finis (Baird and Girard) . Mosquitofish. Nineteen specimens were taken in seine hauls. The catch data are shown in table 36, The fish were all taken in fresh water except one group of nine taken at a salinity of 3.7. Gunter (1950) has noted that only one fish among 416 caught on the Aransas Refuge in Texas was taken in waters with a salinity as high as 3.1. This species was included on the list of euryhaline fishes of North America (fQunter, 1942) on evidence of Dr. S. F. Hildebrand, but it seems not to enter high salinity water very often, and possibly never when a choice is possible. Hetecandria formosa (Agassiz) . Least killifish. Sixty-four specimens were taken from low salinity water. In fact, all of them were in fresh water except at one station where 57 individ- uals were taken at a salinity of 3.7. Catch records are shown in table 37. Briggs (1958) lists this fish as euryhaline, but we believe that is an error for we know of no records of the fish in sea water. Our experience here and on the Florida Gulf coast indicates that the species is very simi- lar to Gambusia af finis in its affinity for salt water, i.e., it is a fresh water species that ventures rarely into low salinity brackish waters. — 251 — TABLE 36 Catch records of Gambusia affinis Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo May 16. 1957 SS#3 9 23-35 28,3 3.7 Jan. 27. 1958 SS#4 1 23 — 0.25 Jan. 27. 1958 SS#3 2 22-27 17.7 0.26 Jan. 27, 1958 SS#5 1 19 17.4 0.34 Feb. 24, 1958 SS#2 2 23-24 17.2 < 1-0 Feb. 24, 1958 SS#3 3 17-21 16.7 < i.o Feb 24, 1958 SS#5 1 29 17.2 < 1.0 TABLE 37 Catch records of Heterandria formosa Total No. of length in Salinitv Date Station Specimens millimeters Temp. °C o/oo May 16, 1957 SS#3 57 15-30 28.3 3.7 June 18, 1957 SS#4 3 19-25 29.0 < 1.0 Sept. 23, 1957 SS#4 2 22-23 28.1 0,16 Jan, 27, 1958 SS#4 1 29 — 0.25 Jan. 28, 1958 SS#6 1 20 — 0.32 Grand total 64 SYXGNATHIDAE Hippocampus hudsonius DeKay. Seahorse. One specimen. 182 mm long, was taken in the outer estuary on 29 January 1957 at TS #7. The bottom temperature and salinity were 22.2°C and 36.0 per mille. Syngnathus scovelti (Evermann and Kendall) . Pipefish. This is the commonest pipefish of the shores of the South Atlantic and Gulf. The fish is euryhaline and is found over most of peninsular Florida. However, our records (table 38) show no specimens in lower salinities than 1.04. According to Springer and Woodburn the males mature at about 60 mm. They report that breeding goes on most of the year at Tampa. Our smallest fish were large juveniles (40-4 lmm long) and were taken in January and May. We took 18 S. scooelli in the sam- ples. Syngnathus louisianae (Gunther) . Longnose pipefish. Table 39 shows that this pipefish was only taken in the cooler months of the year and generally at high salinities. Only six specimens were caught, ranging from 80 to 111 mm in length. 252 — TABLE 38 Catch records of Syngnathus scovelli Date Station No, of Specimens Total length in millimeters Temp. °C Salinity o/oo Jan. 29, 1957 SS#1 1 62 24.6 29.0 Jan. 29, 1957 SS#2 1 94 24,1 20.0 May 16, 1957 SS#1 I 40 28.0 15.5 May 16, 1957 SS#2 1 58 30.7 9.3 Jan. 27, 1958 S'S#1A 2 67-82 16.8 1.26 Feb, 24, 1958 SS#1A 7 46-87 16.7 4.9 May 20. 1958 SS#1A 1 62 25.6 1 .04 Jan. 29, 1959 SS#IA 4 Grand total 18 41-78 21.1 25.9 TABLE 39 Catch records of Syngnathus louisianae Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 29, 1957 SS#5 l 82 24.0 19.3 Nov. 13, 1957 SS#1A 1 80 21.6 29.8 Oct. 27, 1958 SS#1 A 1 100 25.6 27.4 Jan. 27, 1959 SS#1A 1 107 21.1 25.9 Jan. 27, 1959 SS#2 2 110-111 22.8 6.3 CENTRARCHIDAE Lepomis microlophus (GUnther), Shellcracker. On 27 January 1958 one specimen was taken at TS #1. It was 138 mm long. The bottom water temperature was 15.5°C and the sa- linity, 0.18, was in the fresh water range. Lepomis macrochirus (Rafinesquc). Bluegill. Table 40 shows that the bluegill was caught in more hauls than any centrarchid taken in this study, but it was not the most abundant. Twenty-six specimens were taken in January, February and May 1 958. The smallest fish, 34-35 mm long, were taken in January and February. The fish were all taken at salinities within the fresh water range. 0.15- 0.38 o/oo, except for one specimen taken at a salinity of 1.04. Lepomis marginatus (Holbrook). Dollar sunfish. On 27 January 1958 one fish 37 mm long was taken at SS #5 where the temperature was 17.4°C and the salinity was 0.35 per mille The next day another specimen 26 mm long was taken at SS #2 where the salinity was 0.34. The temperature was not taken. Enneacanthus gloriosus (Holbrook). Bluespotted sunfish. Table 41 shows that three small fish were taken in January 1958 in very low salinity water, and that a still smaller fish, only 20 mm long, was taken in October at a salinity of 7.8, the maximum known for this species. 253 — TABLE 40 Catch records of Lepomis macrochirus Date Station No. of Specimens Total length in millimeters Temp. °C Salinity o/oo Jan. 27, 1958 SS#5 4 1 8 43 17.4 0.35 Jan. 28. 1958 SS#2 2 34-40 — 0.34 Jan. 27. 1958 TS#1 2 130-175 15.5 0.18 Jan. 27. 1958 TS#3 1 57 16.6 0.24 Jan. 27, 1958 TS#4 1 134 16.8 0.26 Feb. 24. 1958 SS#2 6 35 60 17.2 < 1.0 Feb. 24. 1958 SS#4 6 42-75 14.4 < 1.0 Feb. 25. 1958 SS#5 1 75 17.2 < i-o Feb, 24. 1958 SS#6 13 35-90 17.8 < 1.0 May 20. 1958 SS#1 A 1 70 25.6 1.04 May 19. 1958 SS#5 1 Grand total 38 51 24.4 0.15 Pomoxis nigramaculatus (LeSueur) . Speckled perch. Table 42 shows that this species was taken on five occasions but one trawl haul contained 182 specimens. Probably the trawl was drag- ged through a school of fish. One fish was taken at a salinity of 4.1, which is the maximum reported for this species. The others were prob- ably all in fresh water. The largest fish, 270 mm long, was taken dead on 24 February 1958 following a cold spell. TABLE 41 Catch records for Enneacanthus glot'iosus Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 27. 1958 SS#5 1 30 17.5 0.35 Jan. 28. 1958 SS#2 1 50 — 0.34 Jan. 28, 1958 TS#6 1 30 15.0 0.36 Oct. 27, 1958 SS#3 1 20 25.6 7.8 TABLE 42 Catch records for Pomoxis nigromaculatus Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 28, 1958 TS#6 1 118 15.0 0.36 Feb. 24. 1958 TS#4 182 100-232 14.4 < 1.0 Feb. 24. 1958 TS#5 1 270 14.4 < 1.0 Feb. 24. 1958 SS#1 A 1 135 16.7 4.9 Feb. 24. 1958 SS#2 1 102 17.2 < 1.0 Grand total 1 186 — 254 CARANGIDAE Trachinotus falcatus (Linnaeus). Round pompano. This pompano at small sizes was the most abundant carangid in the St. Lucie. One hundred and forty-three fish were taken. Table 43 shows that they were generally taken at moderate salinities. However, seven small fish were taken at a salinity of 1.04 and one was taken at 0.8, the lowest known salinity at which this pompano has been taken. Springer and Woodburn only found small T. falcatus at salinities above 33.3. Fish 16 to 17 mm long were taken in May and November and a long spawning season is indicated. The total lengths shown in table 43 might also be interpreted in terms of a spring and late summer spawning similar to what Springer and Woodburn believe takes place in the Tampa Bay area. Small T. falcatus have a great deal of black on the body and some of them are almost totally black except for the orange fins. It is our im- pression that this black color is less' noticeable on young from the out- side beaches, which we have observed in other areas. TABLE 43 Catch records of Trachinotus falcatus Total No.' of length in Salinity Date Station Specimens millimeters Temp. °C o/oo May 16, 1957 SS#1 A 42 19-40 28.0 21.5 May 16, 1957 SS#2 9 17-45 30.7 9.3 May 16, 1957 SS#5 27 25-46 28.0 5.7 June 18. 1957 SS#2 I 18 30.0 0.8 Nov. 13, 195 7 SS#1A I 16 21.6 29.8 May 20, 1958 SS#1A 7 18-32 25.6 1.04 Oct. 27. 1958 SS#2 13 32-89 25.6 14.0 Oct. 27. 1958 SS#6 21 20-34 24.4 19.0 Oct. 27, 1958 SS#1A 16 18-36 25.6 27.4 Jan. 27, 1958 SS#6 2 34-62 22.2 10.4 Jan. 27, 1958 SS#6 4 163-192 22.2 1 0.4 Grand total 143 TABLE 44 Catch records of Trachinotus carolinus Total Date Station No. of Specimens length in millimeters Temp. °C Salinity o/oo May 16, 1957 SS#1 A 13 22-36 28.0 21.5 May 16, 195 7 SS#2 1 41 30.7 9.3 Feb. 24, 1958 TS #7 1 Grand total 1 5 182 18.9 29.4 Trachinotus carolinus (Linnaeus). Pompano. — 255 — Table 44 shows that mostly small fish were taken in the St. Lucie. The smallest fish were taken in May. In Texas waters Gunter (1945) found the smallest fish in June and Springer and Woodburn reported the same thing for the Tampa region. One fish was taken at a salinity of 9.3 which is the lowest of record for this pompano. Caranx hippos (Linnaeus) . Jack. Fourteen specimens of small jacks were definitely identified as Caranx hippos and they are listed in table 45. This fish is euryhaline and it is not surprising to find the small fish in low salinity water. Caranx latus (Agassiz) . Hardtail jack. Table 46 gives catch records on C. latus . It was taken in more hauls than C. hippos but was not more numerous. Both C. hippos and C. Mr us enter fresh water. We have seen schools of jacks feeding at the surface in the North Fork and in the St. Lucie Locks when the waters were fresh, but the species could not be de- termined. TABLE 45 Catch records of Caranx hippos Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo May 16, 1957 SS#5 3 25-37 38.0 5,7 June 18. 1957 SS#4 2 56-72 29.0 < 1 .0 June 18. 1957 SS#5 9 39-90 — < 1.0 Grand total 14 TABLE 46 Catch records of Caranx latus Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Nov. 13, 1957 TS'#5 2 132-170 21.8 16.2 Feb. 24, 1958 TS#7 1 210 18.9 29.4 May 19. 1958 SS#2 1 24 26.1 0.19 May 20, 1958 SS#1 A 5 22-29 25.6 1.04 May 20, 1958 SS#6 3 25-32 26.1 0.30 Oct. 27, 1958 SS#2 3 59-80 25.6 14.0 Oct. 27, 1958 SS#6 1 50 24.4 19.0 Grand i total 1 6 Chloroscombrus chrysurus (Linnaeus) . Bumper. Three fish were taken at TS #6 on 28 October 1958 and 27 Jan- uary 1959. The salinities were 26.3 and 24.0, respectively. The bottom temperature was 23.3 °C at the first station and was unmeasured at the second. The two fish taken in 1958 were 62 and 64 mm long; the 1959 specimen was 91 mm long. Vomer setapinnis (Mitchill). Moonfish. — 256 One fish 131 mm long was taken on 29 January 1957 at TS #6 The temperature of the bottom water was 23.7°C and the salinity was 29.2. Selene vomer (Linnaeus). Lookdown. Table 47 shows that six fish, ranging from 44 to 117 mm in length were taken in the fall of 1957 and 1958. The salinity of 16.2 in November 1957 is considerably lower than any previously reported for this species. TABLE 47 Catch records of Selene vomer Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Nov. 13. 1957 TS#5 1 150 21.8 16.2 Nov. 13, 1957 S'S#IA 1 92 21.6 29.8 Oct. 27, 1958 TS #4 1 44 25.6 20.2 Oct. 27, 1958 TS#5 3 67-117 23.3 26.3 Grand total 6 TABLE 48 Catch records of Oligoplites saurus Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o /oo May 16, 1957 SS‘#2 2 32-33 30.7 9.3 May 16, 1957 SS#5 1 50 28.0 5.7 June 18, 1957 SS#4 1 43 29.0 < i-o June 18, 1957 SS#6 7 40-92 — 2.7 Sept. 23, 1957 SS#6 2 92-120 30.9 0.25 Oct. 27, 1958 SS#2 8 67-98 25.6 14.0 Oct. 27, 1958 SS#6 1 42 24.4 19.0 Jan. 27, 1959 SS#2 1 82 22.8 6.3 Grand total 23 Oligoplites saurus (Bloch and Schneider) . Leatherjacket. Table 48 shows that twenty-three fish were caught in the seines. Schools of leatherjackets were often seen near shore but the fish general- ly eluded the seine. The smallest fish were taken in mid May and they were probably spawned in late April. We took two fish at a salinity of 0.25, in the fresh water range, and this record adds another species to the euryhaline fishes of North America. CEWTROPOMIDAK Centropomus undecimalis (Bloch). Snook. Table 49 gives the catch record on the snook. It was the commonest — 257 — large fish taken in the trawls, with the exception of Diapterus. The snook is euryhaline and the table show's that it pays little attention to salinity of the water In fact, most fish were taken in fresh water. This fish is one of those caught in greatest abundance by pole and line fish- ermen at the St. Lucie Locks when the gates are open and large quantities cf Lake Okeechobee water are flowing through. No small snook were taken and we have little to add to the life history except to say that this species seemed to be least abundant in the St. Lucie Estuary during the colder months. The species belongs to a tropical family and is evi- dently sensitive to cold. Many dead snook were seen on 24 February 1958 following the coldest weather of record for Stuart, Florida. TABLE 49 Catch records of Centropomus undecimalts Total No. of length in Salinitv Date Station Specimens millimeters Temp. °C o/oo May 16, 1957 SS#3 1 48 28.3 3.7 June 18. 1957 TS#1 1 304 28.5 < i.o June 18, 1957 SS#4 1 103 29.0 < 1.0 June 18. 1957 SS#2 1 115 30.0 0.8 Sept. 23. 1957 TS# 1 1 550 28.0 0.27 Sept. 23, 1957 TS#2 1 398 28.1 0-17 Sept. 23. 1957 TS#3 2 45-344 23.1 0.17 Sept. 23, 1957 SS#4 1 128 28.1 0.16 Nov. 1 3, 1957 TS#1 6 270-405 21.9 11.5 Feb. 24, 1958 TS#2 1 420 (dead) 16.7 < i.o Feb. 24. 1958 SS#3 numerous dead snook observed along 17.2 < i.o shoreline floating in water Feb. 24. 1958 SS#3 (cold kill) Feb. 24, 1958 TS#5 1 321 (dead) 14.4 < 1.0 May 19, 1958 SS#2 1 235 26.1 0.19 Oct. 27, 1958 TS#1 1 375 23.9 7.8 Oct. 27, 1958 TS#4 1 468 25.6 20.2 Jan. 27. 1959 TS#1 1 380 18.9 14.7 Grand total 21 LUTJAN1DAE Lutjanus griseus (Linnaeus). Mangrove snapper. Table 50 shows that this snapper was taken six times in fresh, or nearly fresh water and only once at a high salinity. Lutjami'i synagris (Linnaeus) . Lane snapper. Eight specimens, 29-57 mm long, were taken on 27 October 1958 at SS #1A. The water temperature was 25.6°C and the salinity was 27.4. A 73 mm fish was taken on the same date at TS #6. where the temperature was 23.3°C and the salinity was 26.3. Springer and Wood- burn took this species in the Tampa area only from October to Decem- ber and found the smallest specimens in November. — 258 — TABLE 50 Catch records of Lutjanus gciseus Date No. of Station Specimens Total length in millimeters Temp. °C Salinity o/oo June 18, 1957 SS#5 3 122-144 — < 1.0 Sepl. 23, 1957 S'S#5 2 75-117 29.5 0.1 7 Jan. 28, 1958 TS#6 1 1 18 15.0 0.36 Feb. 24. 1958 TS#7 1 Grand total 7 238 18.9 29.4 POMADASYIDAE Orthopristes chrysopterus (Linnaeus). Pigfish. This is a rather handsome fish which takes its name from the noise it makes when caught. On 18 June 1957 one fish 202 mm in length was taken at TS #6 at a water temperature of 28.3 and a salinity of 22.8. A fish 217 mm long was taken at TS 47 on 20 May 1958. The bot- tom temperature was 24.4 and the salinity was 25.5 o/oo. GERRIDAE Diapterus olUthostomus (Goode and Bean). Sand perch. Several large specimens were taken in the trawls and sometimes in seines, and table 51 shows that it was taken in greater numbers than any other large fish. The salinities were generally quite low and this mojarra was taken several times in fresh water. Briggs (1958) has pre- viously listed the fish as euryhaline. The smallest fish were taken in May. Several Diapterus were killed by cold waves in February 1958. Eucmostomas argenteus (Baird and Girard) . Mojarra. Most mojarras were identified in the field and undoubtedly there was some confusion between this species and the succeeding species, E. guta. It is our impression that E. argenteus was most abundant in the St. Lucie Estuary and that £, gula was less numerous during the time of our work. Table 52 shows that 565 fish were listed as E. argenteus. Many of them were taken at very low salinities. The species should be included among the euryhaline fishes. Fish over 100 mm long were taken in the months of May 1957, and January 1958 and 1959. Fish 20 mm long or a little less were taken in May, September, and November 1957 and January 1959, This presents a seeming anomalous situation for marine organisms do not ordinarily breed in both the warm and cold periods of the year according to Orton’s rule (see Gunter, 1958 for discussion). However, Springer and Woodburn (1960) found a somewhat similar situation with regard to E. argenteus in the Tampa region. Their small- est fish were taken in October, November and June, and fish of a size equivalent to our smaller ones were taken in November and December. At least it can be concluded that E . argenteus has a long spawning sea- son. 259 — Dead tarpon found Hunting in North Fork St. Lucie Fstuary after cold kill, February 1958. — 260 Sample of live fish (croaker, spot, sand perch, pig fish, puffers, gobies) and crabs collected with trawl at TS7, St. Lucie Estuary, during February 1958 when large numbers of tropical forms were killed throughout the estuary by low temperatures. — 261 — TABLE 51 Catch records of Diapterus oli&thostomus Total No. of length in Salinity Date Station Sped mens millimeters Temp. °C o/oo May 16. 1957 TS#4 2 30-71 26.5 12.7 May 16. 1957 SS#5 4 34-44 28.0 5.7 June 18, 1957 SS#4 1 48 29.0 A b June 18, 1957 TS#4 2 44-51 29.8 29.3 June 18, 1957 SS#5 2 107-115 — o V Sept. 23, 1957 TS’#2 1 340 28.1 0.17 Sept. 23. 1957 TS#3 2 118-200 23.1 0.17 Sept, 23, 1957 TS#4 2 98-116 22,9 0.18 Sept. 23. 1957 TS#5 4 65-95 23.8 0.20 Sept. 23, 1957 TS#6 5 92-103 23.4 2.34 Sept. 23, 1957 TS#7 1 93 28.1 0.16 Nov. 13. 1957 TS#l 3 69-103 21.9 1 1.5 Nov. 13, 1957 TS’#2 1 98 22.1 14.8 Jan. 27, 1958 SS#1A 1 99 16.8 1.26 Jan. 27, 1958 TS#2 7 109-201 15.8 0.23 Feb. 24. 1958 TS#3 9 205-309 (dead) 18.9 < i-o Feb. 24, 1958 TS#6 14 120-258 16.1 7.0 Feb. 24, 1958 TS#6 1 360 (dead) 16.1 7.0 Feb. 24. 1958 TS'#7 1 266 18.9 29,4 Feb. 24, 1958 SS #6 2 211-338 17.8 o V May 19. 1958 TS#3 1 280 25.6 0.27 May 19, 1958 SS#1 A 1 198 25.6 1.04 Oct. 27, 1958 TS#1 2 126-140 23.9 7.8 Oct. 27, 1958 TS#2 10 66-85 23.9 20.3 Oct. 27, 1958 TS#4 4 43-84 25.6 20.2 Oct. 27, 1958 TS#5 3 65-77 23.3 26.3 Oct. 27, 1958 TS#6 2 79-83 23.3 26.3 Oct. 27, 1958 SS#2 1 78 25.6 14.0 Grand total 87 TABLE 52 Catch records of fish identified as Eucinostomus argenteus Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 29, 1957 SS#3 8 39-79 24.9 14.0 Jan. 29, 1957 SS#4 9 31-68 24.3 17.0 Jan. 29, 1957 SS#5 4 32-45 24.0 19.3 May 16, 1957 TS#3 1 25 26.5 5.4 May 16, 1957 SS#3 H3 18-74 28.3 3.7 May 16. 1957 SS#5 37 26-1 10 28.0 5,7 May 16, 1957 SS#4 8 19-55 28.0 9.5 June 18, 1957 SS#4 12 52-70 29.0 < 1.0 June 18, 1957 SS#6 15 45-74 — 2.7 June 18. 1957 SS#2 1 70 30.0 0.8 - 262 TABLE 52 Catch records of fish identified as Eucinostomus argenteus Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo June 18, 1957 SS#5 8 49-68 — o V Sept. 23. 1957 TS#3 3 38-53 23.1 0.17 Sept. 23, 1957 TS#4 4 33-68 22.9 0.18 Sept. 23, 1957 TS'#6 1 40 23.4 0.34 Sept, 23, 1957 SS#1A 5 22-40 31.1 7.5 Sept. 23, 1957 SS#3 4 39-70 28.6 0.17 Sept. 23, 195 7 SS#4 43 20-56 28.1 0,16 Sept. 23, 1957 SS#5 6 46-84 29.5 0.17 Nov. 13. 1957 TS#3 4 32-55 22.1 10.1 Nov. 13, 1957 TS#4 18 27-75 22.1 12.7 Nov. 13, 1957 TS#5 3 20-67 21.8 16.2 Jan. 27, 1958 SS#1 A 12 40-97 16.8 1.3 Jan. 27, 1958 TS#6 6 84-132 15.0 0.36 Feb. 24, 1958 SS#1A 5 44-85 16.7 4.9 Oct. 27, 1958 TS#1 2 67-79 23.9 7.8 Oct. 27, 1958 TS#2 1 29 23.9 20.3 Oct. 27. 1958 TS#4 3 29-39 25.6 20.2 Oct. 27, 1958 SS#3 24 29-53 25.0 7.8 Jan. 27, 1959 SS#2 13 26-113 22.8 6.3 Jan. 27, 1959 SS#3 183 17-33 20.6 2.4 Jan, 27, 1959 SS#4 2 20-23 20.0 < i.o Jan. 27, 1959 SS#5 2 26-28 20.0 < 1.0 Grand total 560 TABLE 53 Catch records of fishes listed as Eucinostomus gula Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 29, 1957 TS#6 I 38 23 .7 29.2 Jan. 29, 195 7 SS#1 18 30-47 24.6 29.0 May 16. 1957 SS#1 3 61-78 28.0 15.5 May 16. 1957 SS#1 A 1 85 28.0 21.5 Sept. 23. 1957 TS#7 8 53-87 — 23.5 Nov. 13. 1957 SS#I A 9 13-81 21.6 29.8 Oct. 27, 1958 TS#5 2 72-76 23.3 26.3 Oct. 27. 1958 TS#6 58 45-97 23.3 26.3 Oct. 27, 1958 TS#7 4 58-98 25.6 31.5 Oct. 27. 1958 SS#2 23 64-101 25.6 14.0 Oct. 27. 1958 SS#6 22 13-68 24.4 19.0 Oct. 27. 1958 SS#1 129 36-91 27.4 27.4 Jan. 27. 1959 SS#l 144 27-94 21.1 25.9 Jan. 27. 1959 SS#6 21 43-91 22.2 10.4 Grand total 44 3 — 263 Eucinostomus gula (Cuvier and Valenciennes). Mojarra. Four hundred and forty- three fish of this species were listed and the catch records are given in table 53. They apparently became more common in late 1958 and 1959 when the St. Lucie Lock gates were closed and the salinities rose. The very smallest fish were taken in October and November which corresponds to what Springer and Woodburn found for E, argenteus at Tampa. Possibly, the species were confused. In any case, it is clear that E. gula is generally found at higher salinities than E. argenteus , as Springer and Woodburn also found. SOI AENIDAE Bairdiella chrysura (Lacep'ede). Yellowtail. Ninety-seven fish were taken, as shown in table 54, generally in waters of moderate and high salinities, However, four fish were taken in fresh water in November 1957 and the species belongs on the list of euryhaline fishes. The smallest fish were taken in May, as Springer and Woodburn found in the Tampa region and, presumably, spawning took place in April. The collections were not extensive enough to yield furth- er information. We took one fish 212 mm in total length which seems to be the largest reported for the South Atlantic and Gulf. TABLE 54 Catch records of Bairdiella chrysura Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 28, 1957 TS#5 9 126-174 24.5 21.0 Jan. 28, 1957 TS#6 1 184 23.7 29.2 May 16, 1957 TS‘#1 1 155 26.0 10.0 May 16, 1957 TS#2 4 62-68 26.7 15.2 May 16. 1957 TS#3 2 30-34 26.5 5.4 May 16, 1957 TS#4 7 32-51 26.5 12.7 June 18, 1957 TS#2 47 61-84 28.7 0.7 Sept. 21 , 1957 TS#2 3 98-104 28.1 0.17 Sept. 23, 1957 TS#5 l 108 23.8 0.20 Nov. 1 3. 1957 TS#1 3 99-109 21.9 1 1.5 Nov. 13, 1957 TS#2 2 88-97 22.1 14.8 Feb. 24, 1958 TS#6 1 140 16.1 7.0 Oct. 27. 1958 TS#2 16 55-212 23.9 20.3 Grand total 97 Leiostomus xanthurus (Lacepede) . Spot. One hundred and eighty-three spots were taken. Ninety-seven of them were small fish 16-34 mm in total length taken in very low salinity waters within the fresh water range in January 1958. Thirty-two more fish 25-46 mm long were taken a month later in waters with salinities less than 1.0. The larger fish were generally taken in saltier waters. — 264 — Larger spots in the St. Lucie were taken somewhat sporadically. As the smaller fish grow, they move out to saltier water which causes them, as with many other estuarine species, to have a generally direct relation be- tween salinity and size. Springer and Woodburn also showed that small spots appeared in Tampa Bay in January ; this is earlier than Gunter (1945) found them in Texas waters but corresponds to Pearson’s (1929) findings for the same region. The young Tampa Bay spots were in salinity of 5.0 per mille , somewhat higher than found in the St. Lucie. This is not surpris ing for, as was stated above, the relation of size to salinity is not absolute. Young spots will probably grow in waters with a considerably higher salinity than 5.0, especially if no lower salinity area is available. Catch records are given in table 55. TABLE 55 Catch records of Leiostomus xanthurus Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo May 16, 1957 TS#2 4 90-112 26.7 15.2 May 16. 1957 TS#4 3 89-113 26.5 12.7 May 16, 1957 TS#5 1 114 26.7 1 9. 9 May 16, 1957 SS#3 4 63-73 28.3 3.7 May 16, 1957 SS#4 4 96-1 17 28.0 9.5 Jan. 27, 1958 SS#4 2 — — 0.25 Jan. 27, 1958 S‘S#3 7 21-31 17.7 0.26 Jan. 27. 1958 SS#5 4 26-34 17.4 0.35 Jan. 27, 1958 SS#I A 74 20-34 16.8 1.26 Jan. 27. 1958 SS#2 4 27-33 — 0.34 Jan. 27. 1958 SS#6 5 16-34 — 0.32 Jan. 27. 1958 TS#2 1 28 15.8 0.23 Feb. 24. 1958 TS#5 4 25-33 14.4 o V Feb. 24, 1958 TS#6 3 199-209 16.1 7.0 Feb. 24, 1958 SS#1 A 27 27-44 16.7 4.9 Feb. 24, 1958 SS#2 15 30-46 17.2 < i-o Feb. 24. 1958 SS#3 1 31 16,7 < i-o Feb. 24. 1958 SS#5 2 25 33 17.2 < i-o Feb. 24, 1958 SS#6 3 33-37 17.8 < 1.0 Feb. 24. 1958 TS#2 3 34-38 16.7 < 1-0 Feb. 24. 1958 ST #4 4 30-35 14.4 < i.o May 19. 1958 SS#2 1 89 26.1 0.19 May 20. 1958 SS#1 A 1 41 25.6 1.04 May 19, 1958 S'S#3 4 85-96 25.6 0.28 Oct. 27, 1958 TS#2 1 143 23.9 20.3 Jan. 27. 1959 TS#2 1 245 20.0 17.1 Grand total 183 Merit icirrhus americanus (Linnaeus) . Whiting. The literature indicates that this fish has a long spawning season — 265 — over the warmer months. Table 56 shows that the smallest fish we caught were taken in November. This fish was not abundant and only a dozen were caught. It does not venture into low salinity waters. The lower salinity limits given by Gunter (1945), Reid (1954). and by Springer and Woodburn (1960) are 14.4, 17.5, and 13.7. We found 12.7 as the lower limit in the St. Lucie. TABLE 56 Catch records of Menticirrhus americanus Date Station No. of Specimens Total length in millimeters Temp. °C Salinity o/oo Jan. 28, 1957 TS#5 1 149 24.5 21.0 May 16. 1957 TS#4 1 216 26.5 12.7 May 16, 1957 TS#5 1 203 26.7 19.9 May 16, 1957 TS#6 2 42-245 26.7 22.9 Sept. 23. 1957 TS#7 1 97 — 23.0 Nov. 1 3. 1957 TS#7 3 23-34 — 23.1 May 20. 1958 TS#7 2 69-99 24.4 25.5 Oct. 28, 1958 TS#6 1 68 23.3 26.3 Oct. 28, 1958 SS#1 A 1 Grand total 13 43 25.6 27.4 Micropogon undulatus (Linnaeus) . Croaker. The catch records are given in table 57. It is clear that a number of specimens were taken in quite low salinity water. However, there was no large effect to be noted when the lock gates were opened or closed and the salinity varied. It is well known that this species is euryhaline. Contributions to the life history of the croaker on the Gulf coast have been presented by Pearson (1929), Gunter (1945), Suttkus (1955) and Springer and Woodburn (1960). In the northern Gulf croakers spawn in outside waters from October to January and the larvae come into the bays from January to March. Springer and Wood- burn found croakers 16 to 25 mm in standard length in Tampa Bay only in April, which indicates a slightly different spawning season in south Florida. However our data from the St. Lucie are somewhat different. In the first place, small croakers were taken in the months of November, January and February and this appears to be quite similar to the fall and winter spawning and influx of the young known for the northern and western Gulf. The most interesting fact was the taking of small croakers in June 1957. We took 19 fish measuring 22 to 28 mm in total length. Insofar as we measured to the tip of the attenuate tail these fish were quite small, 16-17 mm in standard length. They were taken after the winter and spring influx of young had ceased. There is certainly a second spawning coming at the beginning of summer. This means that the croaker spawns on rising as well as falling temperatures and thus violates Orton's rule (see above) . — 266 — Gunter and Shell (1958) also found a small influx of very small croakers into White Lake, Louisiana, in mid-summer. However, as was explained in that paper, the raw data were lost during a cross- country move of the senior author and since total lengths were not a- vailable, the fact was not mentioned. In any case, there seems to be no doubt that in widely scattered areas and years there is sometimes a late spring and summer spawning of the croaker, quite distinct from the fall and winter spawning. This complicates life history interpretations of size and growth data. This seems to be a more plausible explanation of some of the anomalies noted by Springer and Woodburn (p. 61) than different growth rates and "stunting" which they seem to favor. Small fish that fail to get enough food fail to grow, but they also die and stunting is an improbable explanation of different size groups of fishes in the rich waters of the shallow Gulf. Length frequency curves were drawn for seven months of the work, but they are not presented and instead the general features are given in table 58. Gunter (1945) reported the largest croaker taken among 15,857 specimens on the Texas coast as 370 mm long. One fish taken 24 Feb- ruary 1958 at TS #6 was 445 mm in total length. It is significant that none of these temperate zone fish were killed by the cold. All specimens were taken alive and vigorous among other dead fishes following cold spells. TABLE 57 Catch records on Micropogon unchilatus Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 28, 1957 TS#1 1 315 24.1 17.0 Jan. 28, 1957 TS#I 105 27-111 24.1 17.0 Jan. 28, 1957 TS#2 2 174 23.3 20.5 Jan. 28, 1957 TS#2 38 40-103 23.3 20.5 Jan. 28. 1957 TS#3 5 42-54 23.3 14.8 Jan. 28, 1957 TS#4 1 1 26-113 23.8 20.0 Jan. 28, 1957 Ts:#5 21 56-206 24.5 21.0 Jan. 28, 1957 TS#6 12 87-207 23.7 29.2 May 16, 1957 TS#I 7 73-275 26.0 10.0 May 16. 1957 TS#2 20 61-252 26.7 15.2 May 16> 1957 TS#3 8 36-70 26.5 5.4 May 16. 1957 TS#4 141 28-133 26.5 12.7 May 16, 195 7 TS#4 1 214 26.5 12.7 May 16, 1957 TS#5 23 37-128 26.7 19,9 May 16. 1957 TS#6 11 39-137 26.7 22.9 June 18. 1957 T$#2 7. 262-282 28.7 0.7 June 18, 1957 TS#2 195 25-145 28.7 0.7 June 18, 1957 TS#] 2 34-36 28.5 < i-o June 18. 1957 TS#4 88 22-98 29.3 < 1.0 June 18. 1957 TS#5 1 34 28.8 1.2 June 18, 1957 TS'#6 4 30-46 28.3 22.8 - 267 TABLE 57 Catch records on Micropogon undulatus Total No. of length in Salinity Dare Station Specimens millimeters Temp. °C o/oo June 18. 1957 TS#5 1 1 95-180 28.3 22.8 Sept. 23. 1957 TS#2 19 94-127 28.1 0.17 Sept. 23. 1957 TS#2 1 242 28.1 0.17 Sept. 23. 195 7 TS#3 1 100 23.1 0.17 Sept. 23, 1957 TS#4 7 1 14-170 22.9 0.13 Sept. 23. 1957 TS#4 1 266 22.9 0.18 Sept. 23, 1957 TS#5 2 268-329 23.8 0.20 Sept. 23, 1957 TS#5 93 1 14-170 23,8 0.20 Sept. 23, 1957 TS#6 25 83-140 23.4 0.34 Sept. 23, 1957 TS#6 2. 174-200 23.4 0.34 Sept. 23. 1957 TS#7 2 136-165 — 23.0 Nov. 13, 1957 TS#1 17 30-81 21.9 11.5 Nov. 13. 1957 TS#1 1 108 21.9 1 1.5 Nov. 13. 1957 TS#2 14 34-77 22.1 14.8 Nov. 13, 1957 TS#2 5 116-153 22.1 14.8 Nov. 13. 1957 TS#3 2 38-50 22.1 10.0 Nov. 13. 1957 TS#4 3 23-42 22.1 12.7 Nov. 13. 1957 TS#4 1 119 22.1 12.7 Nov. 13. 1957 TS#5 1 65 21.8 16.2 Nov. 13, 1957 TS#5 37 111-171 21.8 16.2 Nov. 13, 1957 TS'#6 1 45 22.0 27.2 Nov. 13, 1957 TS#7 1 29 21.4 31.3 Jan. 27. 1958 TS#2 2 74-77 15.8 0.23 Jan. 27, 1958 TS#2 2 136-148 15.8 0.23 Jan. 27, 1958 TS#3 1 74 16.6 0.24 Jan. 27. 1958 TS#4 1 74 16.8 0.26 Jan. 28, 1958 TS#5 1 155 — 0.22 Jan. 28, 1958 TS#6 1 68 15.0 0.36 Jan. 28, 1958 TS#6 9 128-175 15.0 0.36 Jan. 28. 1958 TS#7 1 92 16.5 4.5 Jan. 28, 1958 TS#7 7 116-180 16.5 4.5 Feb. 24, 1958 TS#2 3 107-158 16.7 < i-o Feb. 24, 1958 TS#4 1 104 14.4 < 1.0 Feb. 24, 1958 TS#5 1 92 14.4 < 1.0 Feb. 24. 1958 TS#6 7 139-205 16.1 7.0 Feb. 24, 1958 TS#6 1 445 16.1 7.0 Feb. 24, 1958 TS#7 8 95-180 18.9 29.4 Feb. 24. 1958 TS#7 8 210-285 18.9 29.4 Feb. 24, 1958 TS#7 2 304-375 18.9 29.4 Feb. 24, 1958 SS#1 A 72 30-39 16.7 4 9 Feb, 24, 1958 SS#2 29 22-39 17.2 < i-o Feb. 24, 1958 SS#5 22 24-40 14.4 < 1.0 Feb. 24, 1958 SS#6 36 16-35 17.8 < 1.0 May 19, 1958 TS#2 21 46-75 25.6 0.15 May 19, 1958 33 80-130 25.6 0.15 May 19. 1958 TS#3 10 86-103 25.6 0.27 May 19, 1958 TS#4 3 105-127 25.6 0.24 May 19, 1958 TS#4 17 49-93 25.6 0.24 — 268 TABLE 57 Catch records on Micropogon undulatus Due Station No. of Specimens Total length in millimeters Temp. °C Salinity o/oo May 19, 1958 TS#5 103 44-127 25.6 0.15 May 19, 1958 TS#6 4 37-58 25.6 0.34 May 19, 1958 TS#6 108 72-139 25.6 0.34 May 19. 1958 TS#6 I 214 25.6 0.34 May 19, 1958 TS#7 35 107-176 26.7 25.5 May 19, 1958 19 190-268 26.7 25.5 May 19, 1958 SS#5 6 53-102 24.6 0.15 Oct. 27, 1958 TS#2 8 17-53 23.9 20.3 Oct, 27, 1958 TS#2 1 96 23.9 20.3 Oct. 28, 1958 TS#5 5 32-58 23.3 26.3 Oct 28. 1958 TS#6 6 133-230 23.3 26.3 Oct, 27. 1958 TS#7 1 265 25.6 31.5 Jan, 27, 1959 TS#1 19 31-99 18.9 14.7 Jan. 27, 1959 TS#2 65 30-64 20.0 17,1 Jan. 27, 1959 TS#4 4 24-57 18.9 15.7 Jan. 27, 1959 SS#2 84 16-22 22.8 6.3 Jan. 27, 1959 SS#3 39 15-32 20.6 2.4 Jan. 27. 1959 SS'#4 36 17-20 20.0 < Jan. 27, 1959 SS#5 Grand 177 total 1965 14-24 20.0 < 1.0 TABLE 58 Length frequency data on Micropogon undulatus Month No. fish Mode Size limits (mm.) 1957 Jan. 195 48 28 315 1957 May 210 43-68 28 268 1957 Sept. 153 108 88 328 1957 Nov. 83 43. 128 23 178 1958 Ian. 25 — 68 178 1958 May 308 58. 103 43 268 1959 Jan. 336 23 15 177 Pogonias cromis (Linnaeus) , Black drum. Table 59 shows that 24 black drum were taken in the trawls and mostly in moderate to high salinities. The size range was 205-467 mm in total length. None were seen killed by cold, and this is expected, for the black drum is a temperate rather than a tropical fish. Sciaenops ocellata (Linnaeus) . Red drum. One hundred and twenty-seven fish were taken ranging from 12 to 104 mm in length. Small fish were taken in October, January and Feb- ruary, which corresponds to the well known fall and winter spawning for this fish on the northern Gulf. Catch records are given in table 60. The young came into the estuary whether the salinity was high or low — 269 — and the greatest numbers were taken when the salinity was high. This active fish is seldom taken in trawls or in small seines, except for the smaller specimens. TABLE 59 Catch records of Pogonias cromis Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 28, 1957 TS#2 2 223-335 23.3 20.5 Jan. 28. 1957 TS#4 1 218 23.8 20.0 May 16. 1957 TS#1 1 405 26.0 10.0 May 16, 1957 TS#2 1 308 26.7 15.2 June 18. 1957 TS#6 3 360-467 28.3 22.8 Nov. 13, 1957 TS#2 2 315-380 22.1 14.8 Nov. 13, 1957 TS#5 2 205-228 21.8 16.2 Jan. 28. 1958 TS#6 1 208 15.0 0.36 Jan. 28, 1958 TS#7 4 220-315 16.5 4.5 Feb. 24, 1958 TS#7 6 210-380 18.9 29.4 Oct. 28. 1958 TS#6 1 250 23.3 26.3 Grand total 24 TABLE 60 Catch records of Sciaenops ocellata Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 29, 1957 SS#1 20 19-44 24.6 29.0 Jan. 29, 1957 SS#2 16 12-22 24.1 20.0 Jan. 29, 1957 SS#3 48 17-38 24.9 14.0 Jan. 29, 1957 SS#4 31 16-30 24.3 17.0 Jan. 29. 1957 SS#4 3 92-104 24.3 17.0 Jan. 27. 1958 SS#5 1 47 17.4 0.35 Jan. 27, 1958 S'S#I A 1 64 16.8 1.26 Feb. 24. 1958 SS#1A 1 30 16.7 4.9 Feb. 24, 1958 SS#6 1 35 17.8 < 1.0 Oct. 27, 195 8 SS#3 1 26 25.0 7.8 Oct. 27, 1958 SS #6 2 60-65 24.4 19.0 Jan. 27. 1959 SS#3 2 33-39 20.6 2.4 Grand total 127 Stellifer lanceolatus (Holbrook) . Stardrum. Catch records are given in table 61. Only four fish were taken. It is not often taken in low salinity waters. Gunter (1945) reported 8.9 as the lowest salinity where the fish was caught in Texas, but we took a 20 mm specimen in May at a salinity of 1.04 o/oo. This small fish -r- 270 — was taken at the time expected from known spawning dates (Gunter, op.cit.) . TABLE 61 Catch records of Stellifec lanceolatus T ota! Date Station No. of Specimens length in millimeters Salinity Temp. °C o/oo Feb. 24, 1958 TS#6 1 122 16.1 7.0 Feb. 24, 1958 TS#7 2 93-118 18.9 29.4 May 20, 1958 SS #1 A 1 20 25.6 1.04 Cynoscion nebulosus (Cuvier and Valenciennes) . Spotted squeteague. This fish seems not to be abundant in the St. Lucie. One specimen was taken at SS #3 on 16 May 1957. It was 52 mm long. The water temperature was 28.3°C and the salinity was 3.7. Cynoscion regalis (Bloch and Schneider). Weakfish, Weakfish have not been reported previously as far south as the St. Lucie Estuary. For that reason the senior author checked specimens with Mr. Isaac Ginsburg. the taxonomic authority on the group. Catch rec- ords are shown in table 62. One hundred and thirty-one fish were caught, all in the trawls except two. The size range was 34 to 280 rmm. The fish were generally taken in moderate to high salinities bur 35 specimens, especially smaller fish, were taken in fresh water and the species is eury haline. Fish 34 and 35 mm long were taken in June and September. There is probably a long spawning season. SPARIDAE Archosargus probatocephalus (Walbaum). Sheepshead. On 13 November 1957 three sheepshead, ranging from 187 to 232 mm in length, were taken at TS #4 at a temperature of 22.1°C and a salinity of 12.7. On 27 January 1958 at the same station two more fish were caught. They were 26.8 and 27.9 mm long. The bottom water temperature was 16.8. The salinity was 0.26 o/oo. Lagodon rhomboides (Linnaeus) . Pinfish. Catch records are given in table 63. Nearly all specimens were larvae or juveniles. The very smallest specimens were taken in May. but small fish were also taken in January. 'Gunter (1945) and previous workers found this fish to be a winter spawner. However, Springer and Woodburn seem to think the pinfish spawns a couple of months later in south Florida. Our data indicate that both ideas are correct. EPHIPPIDAK Chaeiodipterus faber (Broussonet) . Spadefish. Twenty-one fish were caught at moderate to higher salinities. The — 271 — data are given in table 64. The smallest fish was taken in September. Springer and Woodburn took smaller fish from June to September. TABLE 62 Catch records of Cy noscion regalis Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 28. 1957 TS#2 1 167 23.3 20.5 Jan. 28, 1957 TS#5 6 127-180 24.5 21.0 Jan. 28, 1957 TS#6 5 72-280 23.7 29.2 May 16. 1957 TS#1 2 73-74 26.0 10.0 May 16, 1957 TS#5 2 108-113 26.7 19.9 June 18. 1957 TS#2 2 102-113 28.7 0.7 June 18, 1957 TS#4 1 35 29.3 A © Sept. 23. 1957 TS#5 6 50-197 23.8 0.20 Sept. 23. 1957 TS#6 6 34-237 23.4 0.34 Nov. 13, 1957 TS#1 1 93 21.9 11.5 Nov. 13, 1957 TS#2 7 45-206 22.1 14.8 Nov. 13. 1957 TS#4 2 62-100 22.1 12.7 Nov. 13, 1957 TS#5 8 109-187 21.8 16.2 May 19, 1958 TS#2 5 67-83 25.6 0.15 May 19. 1958 TS#3 4 42-79 25.6 0.27 May 19, 1958 TS#4 6 48-75 25.6 0.22 May 19, 1958 TS#5 13 63-93 25.6 0.15 May 19. 1958 TS#6 12 31-78 25.6 0.34 May 19, 1958 TS#7 1 230 24.4 25.5 May 19. 1958 SS#6 2 48-71 26.1 0.30 Oct. 27, 1958 TS#1 I 109 23.9 7.8 Oct. 27, 1958 TS#2 2 201-233 23.9 20.3 Oct. 27, 1958 TS#2 28 44-139 23.9 20.3 Oct. 27. 1958 TS#4 3 47-91 25.6 20.2 Oct. 27. 1958 TS#5 2 57-90 23.3 26.3 Oct. 27. 1958 TS#6 3 62-272 23.3 26.3 Grand total 131 TABLE 63 Catch records of Lagodon rhomboides Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 29. 1957 SS#3 2 20-22 24.9 14.0 May 16, 1957 SS#3 6 38-82 28.3 3.7 June 18, 1957 SS#6 1 52 — 2.7 June 18. 195 7 TS#5 1 75 28.8 1.2 J une 18. 1957 SS#5 1 87 — < 10 Jan. 27. 1958 SS#1 A 1 22 16.8 1.26 May 19. 1958 SS#2 8 31-65 20.6 0.19 May 19. 1958 SS#3 23 29-47 25.6 0.28 — 272 TABLE 63 Catch records of Lagodon rhomboides Date Station No. of Specimens Total length in millimeters Temp. °C Salinity o/oo May 19. 1958 SS#5 2 19-34 24.4 0.15 May 20. 1958 SS#1 A 1 10 25.6 1.04 Jan. 27, 1959 SS#3 1 Grand total 47 30 20.6 2.4 TABLE 64 Catch records of Chaetodipterus faber Total Date Station No. of Specimens length in millimeters Temp. °C Salinity o/oo Sept. 23, 1957 TS#7 1 18 — 23.0 Feb. 24, 1958 TS#7 1 108 18.9 29.4 Oct. 28, 1958 TS#6 18 36-81 23.3 26.3 Jan. 27. 1959 TS#1 Grand 1 total 2 1 70 18.9 14.7 POMACENTRIDAE Abudefduf saxatilis (Linnaeus) . Sergeant major. One specimen was taken in the outer estuary on 28 January 1957, but the station is unknown. TRICHIURIDAE Trichiurus tepturus Linnaeus. Cutlass fish. One fish 111 mm long was taken on 27 January 1958 at TS #7, where the bottom temperature was 16.5°C and the salinity was 4.5. GORIIDAE Bathygohius soporator (Cuvier and Valenciennes). Goby. One fish 23 mm long was taken at SS #1A on 27 January 1958. The temperature was 16.8 and the salinity \yas 1.26. Gobionellus boleosoma (Jordan and Gilbert). Darter goby. Catch records are shown in table 65. This species was caught more often than any other goby. Most specimens were taken in low salinities or fresh water, but one fish was taken at a fairly high salinity. The smallest fish was taken in January. Gunter (1945) found the smallest fish in Texas waters in January. The species appears to be euryhaline. — 273 — TABLE 65 Catch records of Gobionellus boleosoma Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 27. 1958 SS#5 2 19-30 17.4 0.35 Jan. 27. 1958 SS#1A 8 23-32 16.8 1.26 Jan. 27, 1958 TS#2 1 88 15.8 0.23 Feb. 24, 1958 TS#2 1 60 16.7 o V Feb. 24. 1958 SS# 1 A 14 28-35 16.7 4.9 Feb. 24, 1958 SS#5 2 26 28 14.4 < 1.0 May 19. 1958 TS#4 1 34 25.6 0.24 May 19, 1958 SS#3 2 30 33 25.6 0.28 May 19, 1958 SS#4 2 41-52 26.1 0.14 May 20, 1958 TS#6 2 35-41 25.6 0.34 May 20, 1958 SS#1 A 14 26-36 25.6 1.04 Jan. 27, 1959 SS#1A 2 27-38 21.1 25.9 Grand total 51 Gobionellus gracillimus (Ginsburg) . Sharptail goby. The writers feel that the taxonomy of the gracillimus-hastatus- oceanicus is in an unsettled state and at present we put little faith in published identifications. Nevertheless, we checked some of our speci- mens of this species with Mr. Isaac Ginsburg and table 66 gives the de- terminations as we made them in the field. TABLE 66 Catch records of fish identified as Gobionellus gracillimus Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 27, 1957 TS#2 1 47 23.3 20.5 Jan. 27, 1957 TS#5 1 73 24.5 21.0 May 16, 1957 TS#5 1 67 26.7 19.9 May 16, 1957 TS#6 1 68 26.7 22.9 Sept. 23. 1957 TS#6 1 103 23.4 0.34 Nov, 13, 1957 TS#6 1 80 22.1 27.2 Jan. 27. 1958 TS#3 1 112 16.6 0.24 Jan. 27, 1959 TS#5 1 120 20.0 22.2 Jan. 27, 1959 TS#6 2 55-75 — 24.0 Grand total 1 0 Gobionellus hastatus (Girard), Sharptailed goby. There was overlap with G. gracillimus and G. hastatus in size of the tail. Some were quite short and some were very long. Table 67 gives the catch records Some specimens were taken in very low salinity water. — 274 — TABLE 67 Catch records of fish identified as Gobionellus hasiatus Date Station No. of Specimens Total length in millimeters Temp. °C Saliniiv o/oo Jan. 28. 1958 TS#6 1 128 15.0 0.36 Jaa. 28, 1958 TS#7 1 156 16.5 4.5 May 19, 1958 TS #4 1 124 25.6 0.24 May 19, 1958 TS#5 3 35-84 25.6 0.15 May 19, 1958 TS#7 1 Grand total 7 67 24.4 25.5 Gobiosoma bosci. (Lacepede) . Naked goby. One specimen was taken on 16 May 1957 at TS #1. It was 33 mm long. The salinity was 10.0 and the temperature was 26.0°C. Gobioides broussonneti (Lacepede) . Violet goby. Catch records are given in table 68. The fish was taken in fresh water and once at a high salinity. One was the largest specimen ever re ported. The species appears to be euryhaline. Specimens killed by the cold were seen on 24 February 1958. TABLE 68 Catch records of Gobioides broussonneti Date Station No. of Specimens Total length in millimeters Temp. °C Salinity o/oo June 18, 1957 TS#2 l 331 28.7 0.7 Jan, 28, 1958 TS#5 2 350-590 — 0.22 Feb. 24, 1958 TS#2 3 250 455 (dead) 16.7 <1.0 Feb. 24, 1958 TS#5 4 398-4 84 (dead) 14,4 <1.0 Feb. 24, 1958 TS#6 I 555 16.1 7.0 May 19. 1958 TS#4 1 290 25.6 0.24 May 19, 1958 TS#7 Grand 1 total 13 320 26.7 25.5 SPHYRAENIDAK Sphyraena barracuda (Walbaum). Great barracuda. One little fish 31 mm long was taken at SS #6 on 18 June 1957. The salinity was 2.7. MUGIEIDAE Mugil curema (Cuvier and Valenciennes). Silver mullet. Catch records are given in table 69. Juvenile fish were taken in June and in fact the species was only seen in May and June. — 275 — TABLE 69 Catch records of Mugil curema Total Date Station No. of Specimens length in millimeters Temp. °C Salinity o/oo May 16, 1957 SS#3 1 169 28.3 3.7 May 16. 1957 SS#4 l 156 28.0 9.5 June 18. 1957 SS#4 1 1 40-62 29.0 < 1.0 May 19, 1958 SS#3 Grand 1 total 14 200 25.6 0.28 TABLE 70 Catch records of Mugil cephalus Total No. of length in Salinity Date Sralion Specimens millimeters Temp. °C o/oo Jan. 29. 1957 SS#1 378 18-33 24.6 29.0 Jan. 29. 1957 SS#3 44 24 33 24.9 14.0 Jan. 29. 1957 SS#4 10 26-29 24.3 17.0 Jan. 29, 1957 SS#5 49 23-28 24.0 19.3 May 16. 1957 SS#2 6 23-28 30.7 9.3 May 16. 1957 SS#3 22 28-74 28.3 3.7 May 16. 1957 SS#4 104 (4 124-249 28.0 9.5 (100 23-95 May 16. 1957 SS#5 24 querimana stage 28.0 5.7 June 18, 1957 SS#4 65 (4 152-170 29.0 < (61 20-82 June 18. 1957 TS#4 1 35 29.8 < io June 18, 1957 SS#6 6 28-35 — 2.7 June 18, 1957 TS#5 1 (dead) 405 28.3 1.2 June 18. 1957 SS#5 2 61-241 — < 1.0 Nov. 13. 1957 SS#1 A 1 21 29.8 21.6 Nov. 13, 1957 SS’#6 1 141 — 23.1 Jan. 28, 1958 SS#1 A 676 querimana stage 16.8 1.3 Jan. 28, 1958 SS#1 A 2 121-132 16.8 1.3 Jan. 28, 1958 SS#2 175 25-30 — 0.34 Jan. 28, 1958 SS#2 2 122-225 — 0.34 Jan. 27, 1958 SS#3 428 24-32 17.7 0.26 Jan. 27, 1958 SS'#4 2 93-127 — 0.25 Jan. 27. 1958 SS#4 1,178 21-33 — 0.25 Jan. 27. 1958 SS#5 104 21-31 17.4 0.35 Jan. 28, 1958 SS’#6 2,050 21-31 — 0.32 Jan. 27, 1958 TS#6 1 283 15.0 0.36 Feb. 24. 1958 TS#6 2 242-258 16.1 7.0 Feb. 24, 1958 SS#1 A 230 20-34 16.7 4.9 Feb. 24, 1958 SS#2 650 25-36 17.2 < io Feb. 24. 1958 SS#3 1.220 28-34 16.7 < 10 — 276 — TABLE 70 Catch records of Mugil cephalus Total No. of length in Salinity Due Station Specimens millimeters Temp. °C o/oo Feb. 24, 1958 SS#4 288 25-35 14.4 < 1.0 Feb. 25. 1958 SS#5 2.900 21-35 17.2 < 1.0 Feb. 24. 1 958 SS#6 766 26-31 17.8 < 1.0 May 19, 1958 SS#3 55 32-59 25.6 0.28 May 19. 1958 SS'#4 408 34-78 26,1 0.14 May 20. 1 958 SS#6 1 54 26.1 0.30 Oct. 27, 1958 SS#6 9 22-24 24.4 19.0 Jan. 27, 1 959 SS# 1 A 1 26 21.1 25.9 Jan. 27, 1959 SS#2 88 21-33 22.8 6.3 Jan. 27, 1959 SS#3 4 22-24 20.6 2.4 Jan. 27. 1959 SS'#4 105 21-27 20.0 < 1.0 Jan. 27, 1959 SS#5 331 22-29 20.0 < io Jan. 27. 1959 SS#6 1 150 22.2 10.4 Grand total 1 2,39 1 Mugil cephalus (Linnaeus) riped mullet. The striped mullet was very abundant in the minnow seine hauls. Table 70 shows that 12,391 specimens were taken. Only five speci- mens were taken in the trawls and one of these was dead, Gunter (1945 and previously) has remarked upon the general absence of this species in trawl catches. The fish generally stays close to shore in shallow waters where larger individuals may be caught in great numbers in large nets, which were not used in this investigation. Table 70 shows that the young, many of them in the querimana stage, were taken from November to May, with the greatest numbers in January and February. There is evidently a long breeding season from fall to spring with a peak in early winter. By far the greatest number of mullet were taken in waters of very low salinity, within or close to the freshwater range, during the time when the spillway was open. In fact, only 493 fish were taken at salinities above 15 parts per thousand and almost 12,000 were caught at lower salinities. The writers fished by stations and did not attempt to accumulate large numbers of specimens merely for the sake of num- bers alone. In one haul on February 25, 1958 we caught 2,900 mullet. Attempts to catch small mullet in the numerous shoals which were seen along shore from time to time could have easily resulted in several hundred thousand fish caught in one day, ATHEKIIMDAE Membras martinica (Valenciennes) . Rough silverside. Only 10 specimens were caught, all in seine hauls on 29 January 1957 at intermediate salinities. The data arc given in table 71. This little fish is apparently as uncommon on the east coast of southern Florida as it is on the west coast, where Springer and Woodburn took only 2 fish of this genus among several thousand specimens. Gunter (1945) and Reid (1954) found this species more abundant in the shallow waters of the northern Gulf. Menidia beryllina (Cope). Silverside. We took 1,708 specimens, all at seine stations at salinities ranging from fresh water to 29.8 per mi tie. An examination of table 72 shows that the greatest numbers were taken in low salinity waters. In fact only 294 fish were taken at salinities above 1.0 and only 69 were taken at salinities above 3.0 Fifty-six fish per haul were taken in twenty-nine hauls in low salinity (<3.0) and only fourteen per haul at five higher salinity stations. Gunter (1945) and Springer and Woodburn (1960) found that the fish is almost oblivious to salinity, although the larger specimens tend to be taken in the saltier water. Hildebrand and Schroeder (1928) found that this fish had two spawning peaks a year in Chesapeake Bay. Gunter (op. at.) found a spawning peak in the spring and another in the fall in Texas waters, and Springer and Woodburn (op. at.) found the same thing on the west coast of south Florida. Our data show the same thing. The very smallest fish were taken in September in 1957 and in May 1958. Four investi- gations, thirty-two years apart in time and over a thousand miles in space show the same thing. It is certain that Menidia beryllina spawns twice during the warm season and the young enter the population in the late spring and early fall. Total length measurements were made of all specimens, but the length frequency curves are scattered by three month gaps and show nothing not previously presented by Gunter (1945) and Springer and Woodburn. Therefore, they are not presented. TABLE 71 Catch records of Membras martinica Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 29. 1957 SS'#3 1 51 24.9 14.0 Jan. 29, 1957 SS#4 5 47-65 24.3 17.0 Jan. 29, 1957 SS#5 4 52-62 24.0 19.3 TABLE 72 Catch records of Menidia beryllina Date Station No. of Specimens Total length in millimeters Temp. °C Salinity o/oo June 18, 1957 SS#4 9 23-47 29.0 < 1.0 June 18, 1957 SS#6 36 25-44 — 2.7 June 18, 1957 SS#2 1 30 30.0 0.8 June 18. 1957 SS#5 17 63 25-44 < i.o — 278 TABLE 72 Catch records of Menidia beryllina Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Sept. 23, 1957 SS#1A 10 17-29 31.1 7.5 Sept. 23, 1957 SS#2 145 17-34 30.0 0.19 Sept. 23, 1957 SS#3 1 30 28.6 0.17 Sept. 23, 1957 SS#4 15 23-44 28.1 0.16 Sept. 23. 1957 SS#5 162 13-48 29.5 0.18 Sept. 23, 1957 SS#6 23 20-34 30.9 0.25 356 Nov. 13, 1957 SS#1A 5 26-33 21.6 29.8 Nov. 13, 1957 SS#5 1 29 21.6 14.5 Nov. 13, 1957 SS#6 10 1 f 21-38 — 23.1 Jan. 27, 1958 SS#4 1 0 9 24-40 0 0.25 Jan. 27, 1958 SS#3 8 25-42 17.7 0.26 Jan. 27, 1958 SS#5 133 22-52 17.4 0.35 Jan. 27. 1958 SS#1A 32 20-34 16.8 1.26 Jan. 27, 1958 SS#2 89 20-69 — 0.34 Jan. 27. 1958 SS#6 4 22-32 — 0.32 275 Feb. 24, 1958 SS#1 A 4 32-40 16.7 4.9 Feb. 24. 1958 SS#2 7 50-81 17.2 < io Feb. 24, 1958 SS#2 22 21-42 17.2 < 1.0 Feb. 24, 1958 SS#3 127 20-51 16.7 < io Feb. 2.4, 1958 SS#4 3 27-37 14.4 < i-o Feb. 24, 1958 SS#4 4 51-77 14.4 < 1.0 Feb. 25, 1958 SS#5 44 20-44 17.2 < io Feb. 24. 1958 SS#6 23 20-33 17.8 < 1.0 234 May 20, 1958 SS#1 A 175 19-32 25.6 1.04 May 19. 1958 SS#2 28 17-40 26.1 0.19 May 19, 1958 SS#3 24 23-34 25.6 0.28 May 19. 1958 SS#4 33 19-24 26.1 0,14 May 19, 1958 SS#5 45 18-45 24.4 0.15 May 20. 1958 SS#6 425 15-38 26.1 0.30 730 Oct. 27, 1958 SS#3 19 28-44 25.0 7,8 Oct. 27, 1958 SS#6 2 7 1 38-44 24,4 19.0 Jan. 27. 1959 SS#5 L 1 1 1 44-61 20.0 A o Grand total 1.708 SCORPAENIDAE Scorpaena grandicornis Valenciennes. Scorpion fish. One specimen was caught on 16 May 1957 at TS #7. It was 104 mm long. The water temperature was 28 0°C and the salinity was 25.7 o/oo. — 279 THKJIJDAE Prionotus tribulus (Valenciennes). Sea robin. Four specimens were taken in January 1957 and January 1958. The catch records are given in table 75. Gunter (1945) found the least numbers of this fish in summer in Texas waters Springer and Wood- burn H960) took the species only from October to February. Kilby (1956) only took this species from October to February in the marsh areas of Cedar Keys, Florida. Reid (1954) found the species most abund- ant in the waters off Cedar Keys from November through March. It is clear that this triglid moves inshore during the cooler months of the year. At this time it ventures into low salinity water and we took one specimen at a salinity of 6.5. the lowest yet recorded for this species. Gunter (1945) took his smallest specimens (55 mm) in March. We took two 28 mm long in January. Apparently the fish spawns in the late fail or early winter. TABLE 73 Catch records of Prionotus tribulus Djre Station No. of Specimens To*al length in millimerers Temp. °C Salinity o/oo Jan. 29. 1957 TS’#6 l 28 23.7 29.2 Jan. 29. 1957 SS#2 1 7 28 24.1 20.0 Jan. 27. 1959 SS#2 l 96 22.8 6.3 Jan. 27. 1959 TS# 1 ! 2 108 18.9 14.7 ROTH I DAE Citharichthys macrops Dresel One specimen 61 mm long was taken at TS #7 on 16 May 1957. The temperature was 28.0°C and the salinity was 25.7. This offshore species is not commonly taken inshore. Citharichthys spilopterus (Gunther). Ninety two specimens were caught at salinities ranging from 0.15 (which is fresh water) to 29 2 Most fish were taken above 20.0 per mille salinity and below 5.0. The smallest specimens were taken in May 1957 and 1958 This species was not recorded by Springer and Wood- burn in the T ampa region. Gunter (1945) found the smallest fish in April in south Texas. Apparently the species spawns in early spring. In the Texas region Gunter found that this fish moves out of the bays and offshore in the winter, but there were no signs of such a movement in the St. Lucie, where several specimens were taken in midwinter. All but ten specimens were taken in trawls. Similarly Gunter caught only 5 out of 75 specimens in seines and apparently the fish does not com- — 280 — monly inhabit the shallows near shore. This is probably the explana- tion of rhe hiatus of Springer and Woodburn with regard to this species for those authors collected only with seines. Our catches are recorded in table 74. TABLE 74 Catch records of Cithurichthys spilopterus Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 28, 1957 TS#2 1 28 23.3 20.5 Jan. 28, 195 7 TS#4 2 40-69 23.8 20.0 Jan. 28. 1957 TS#5 4 40-48 24.5 21.0 Jan. 28, 1957 TS#6 9 44-74 23.7 29.2 May 16. 1957 TS#2 2 66-82 26.7 15.2 May 16, 1957 TS#4 4 25-84 26.5 12.7 May 16, 1957 TS#5 5 36-103 26.7 19.9 May 16. 1957 TS#6 3 5 7-112 26.7 22.9 June 18, 195 7 TS#2 1 52 28.7 0.7 June 18, 1957 TS#6 2 34-90 28.3 22.8 Sept. 23, 1957 SS#4 2 79-87 28.1 0.16 Nov, 13, 1957 TS#6 2 46-59 21.6 22.0 Jam. 27. 1958 SS#4 1 29 — 0.25 Jan. 27, 1958 SS#1 A 2 38-39 16.8 1.26 Jan. 28, 1958 TS#6 1 60 15.0 0.36 Jan. 27. 1958 TS#7 2 42-50 16.5 4.5 May 19, 1958 TS#2 8 30-53 25.6 0.15 May 19, 1958 TS#3 4 36-52 25.6 0.27 May 19, 1958 TS#4 18 19-62 25.6 0.24 May 19, 1958 TS#5 5 26-71 25.6 0.15 May 20. 1958 TS#7 2 42-47 24.4 25.5 May 19, 1958 SS#3 1 47 25.6 0.28 May 19. 1958 SS#5 2 78-78 24.4 0.15 May 20, 1957 SS#6 I 28 26.1 0.30 Oct. 27. 1958 TS#6 1 94 23.3 26.3 Jan. 27, 1959 TS#2 1 54 20.0 17.1 Jan. 27, 1959 TS#4 1 64 18.9 15.7 Jan. 27, 1959 TS#5 1 61 20.0 22.2 Jan. 27. 1959 TS#6 3 78-110 — 24.0 Jan. 27. 1959 SS#1 I 47 21.1 25.9 Grand total 92 Date Jan. 29, 1957 June 18. 195 7 TABLE 75 Catch records of Etropus crossotus No. of Station Specimens Total length in millimeters TS#6 4 94-136 TS#6 1 80 Salinity Temp. °C o/oo 23.7 28.3 — 281 29.2 22.8 TABLE 75 Catch records of Etropus crossotus Date Station No. of Specimens Total length in millimeters Temp °C Salinity o/oo May 20. 1958 TS#7 1 47 24.4 25.5 Jan. 27. 1959 TS#6 I 120 21.1 24.0 Jan. 27, 1959 TS#7 Grand 1 total 8 125 22.2 ■n.8 Etropus crossotus (Jordan and Gilbert) . Only 8 specimens were caught, as shown in table 75, and all of them were taken in trawls. The salinity ranges were all high, 22.8-33.8 In Texas waters, Gunter (op. cif.) took only one of 210 specimens in seines, and the remainder were taken in trawls. Springer and Woodburn took only one specimen in the Tampa region and concluded that the specios is rarer there than in northwest Florida. That my be true but we believe that trawling in deeper water there would yield more speci- mens. Our collections in the St. Lucie are in agreement with Gunter’s (1945, p. 86) previous conclusion that “the fish does not like brackish waters.” SOUBIDAE Achirus tineatus (Linnaeus) . Lined sole. Nine specimens were caught, (table 76), one in fresh water. This salinitv, 0.18, is the lowest at which the species has been reported and the species must be added to the list of euryhaline fishes. Trinectes maculatus (Bloch and Schneider). Broad sole. Sixty-nine fish were caught ranging in total length from 25 148 mm (table 77). Three specimens carrying eggs were noted on 19 May 1958. They were 115-138 mm long. The smallest fish, 25-34 mm long, were taken in the months of September and October. The smallest fish Gunter (op. cit.) took in Texas were 51 mm long and they were taken in November and December. The available evidence points to a summer spawning, It is well known that this species is euryhaline. Twenty-three of the St. Lucie specimens were taken at salinities within the fresh water range, There was some relation between salinity and size as Springer and Woodburn previously noted. Fish taken in the fresh water range aver- aged 83 mm in length, while those taken at salinities above 20.0 were 104 rrm in average length, Sumphurus plagiusa (Linnaeus). Tonguefish. Twenty -one specimens were caught. The data are given in table 78. The size range was 29-134 mm. The smallest fish was taken in October which is the same month that Springer and Woodburn found the smallest tonguefish in Tampa Bay, Gunter (1945) found the salinity range of this fish in south Tex- — 282 — as waters to be 17.1-36.7, but Springer and Woodburn found the fish at salinities of 5,0-33.0 in Tampa Bay. In the St. Lucie Estuary, the fish were taken where the salinities ranged from <1.0 to 24.0. Four fish were taken at salinities below 7.0 and the remainder were in water with salinities above 19.0. TABLE 76 Catch records of Achirus lineatus Total Date Station No. of Specimens length in millimeters Temp. °C Salinitv o/oo Sept. 23. 1957 TS#4 1 31 22. 9 0.18 Nov. 13, 1957 TS#4 5 27-45 22.1 12.7 Nov. 13, 1957 TS#3 Grand 3 total 9 35-40 22.1 10.1 TABLE 77 Catch records of Trinectes maculatus Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/ oo Jan. 28, 1957 TS#5 1 105 24.5 21.0 May 16, 1957 TS#1 2 118-130 26.0 10.0 May 16, 1957 TS#5 1 125 26,7 19.9 June 18, 1957 TS#2 1 134 28.7 0.7 June 18. 1957 TS#4 1 60 29.3 < i-o Sept. 18. 1957 TS#3 2 25-30 23.1 0.17 Sept. 18, 1957 TS#5 1 25 23.8 0.20 Sept. 18, 1957 TS#6 1 39 23.4 0.34 Nov. 13. 1957 TS#5 I 80 21.8 16.2 Nov. 13, 1957 TS#6 1 80 22.0 27.2 Jan. 27, 1958 TS#2 4 81-145 15.8 0.23 Jan. 27, 1958 TS#3 2 73-100 16.6 0.24 Jan. 28, 1958 TS#5 3 100-130 — 0,22 Jan. 28. 1958 TS#6 4 74-147 15.0 0.36 Jan. 27. 1958 TS #7 I 1 94-135 16.5 4.5 Feb. 24, 1958 TS#1 I 72 14.5 < i-o Feb. 24. 1958 TS#2 6 96-128 16.7 < i-o Feb, 24. 1958 TS’#3 I 85 18.9 < 1.0 Feb. 24. 1958 TS#6 1 128 16.1 7.0 Feb. 24, 1958 TS#7 3 95-148 18.9 29.4 May 19, 1958 TS#3 3 82-132 25.6 0.27 May 19. 1958 TS#4 l 46 25.6 0.24 May 19, 1958 TS#6 I 1 15 25.6 0.34 May 19, 1958 TS#7 9 101-140 24.4 25.5 Oct. 27, 1958 TS'#! l 145 23.9 7.8 Oct. 27, 1958 TS#2 3 34 34-102 23.9 20.3 Jan. 27, 1959 TS#2 1 140 20.0 17. 1 283 — TABLE 77 Catch records of Tcinectes maculatus No. of Total length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 27, 1959 TS#3 1 135 18.9 13,8 Jan. 27. 1959 TS#5 1 Grand loial 69 128 20.0 22.2 TABLE 78 Catch records of Symphurus plagiusa Total No. ot length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 28, 1957 TS#2 1 47 23.3 20.5 Jan. 28, 1957 TS#4 2 59-86 23.8 20.0 Jan. 28. 1957 TS#5 1 80 24.5 21.0 May 16. 1957 TS#6 4 109-134 26.7 22.9 Jan. 27. 1958 TS#7 1 147 16.5 4.5 Feb. 24, 1958 SS#3 1 37 16.7 < i-o Feb. 24. 1958 TS#6 1 35 16.1 7.0 Feb. 24. 1958 SS#1A 1 42 16.7 4.9 Oct. 27. 1958 TS#2 5 40-56 23.9 20.3 Oct. 27. 1958 TS#4 1 55 25.6 20.2 Oct. 27. 1958 SS#6 1 29 24.4 19.0 Jan. 27, 1959 TS#5 1 76 20.0 22.2 Jan. 27, 1959 TS#6 1 75 21.1 24.0 Grand total 21 TETRAODONTIDAE Sphoeroides maculatus (Bloch and Schneider), Marbled puffer. Catch records are given in table 79. The three fish were all taken at fairly high salinities, 22.8-27,4. A 21 mm fish was taken in Novem- ber 1957. Sphoeroides testudineus (Linnaeus) Northern puffer. Table 80 shows that twenty fish of wide size range were taken in various months and at surprisingly varied salinities, 0.36 (not quite fresh water) to 29.4. A ten mm fish was taken in January, an 18 mm fish in May and a 17 mm fish in November. Evidently the breeding season is a long one. DIODONTIDAE C hilomycterus schoepfi (Walbaum) . Three fish were caught in high salinity water, 29.2 to 36.0 (table 81). A 15 mm fish was taken in January. — 284 — TABLE 79 Catch records of Sphoeroides maculatus Date Station No. of Specimens Total length in millimeters Temp. °C Salinity o/oo June 18. 1957 TS'#6 1 180 28.3 22.8 Nov. 13, 1957 SS#6 1 21 — 23.1 Oct. 27. 1958 SS#1 A 1 47 25.6 27.4 Grand total 3 TABLE 80 Catch records of Sphoeroides testudineus Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 28. 1957 TS#5 1 127 24.5 21.0 Jan. 29, 1957 TS‘#6 1 91 23.7 29.2 Jan. 28, 195 7 SS#2 1 10 24,1 20.0 May 16. 1957 TS#6 1 155 26.7 22.9 May 16. 1957 SS#JA 1 158 28.0 21.5 May 16. 1957 SS#2 2 18-257 30.7 9.3 Sept. 23, 1957 TS#7 1 132 — 23.0 Nov. 13, 1957 SS#1 A 1 17 21.6 29.8 Jan. 28, 1958 TS#6 1 215 15.0 0.36 Feb. 24, J 958 TS#7 4 154-190 18.9 29.4 May 20, 1958 SS#1A 2 135-145 25.6 1.04 Jan, 27. 1959 TS#4 1 41 18.9 15.7 Jan. 27, 1959 SS#JA 2 106-141 21.1 25.9 Jan. 27, 1959 SS#2 1 30 22.8 6.3 TABLE 81 Catch records of Chilomycterus schoepfi Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 29, 1957 TS#6 1 15 23.7 29.2 Jan. 29, 1957 TS'#7 1 140 22.2 36.0 May 16, 1957 TS#7 1 182 25.7 32.4 LEPTOCEPHALI Seventy-nine leptocephali were taken in seines in the months of January and February (table 82), The size range was 33-43 mm and the salinity range where they Were taken was 0.32 to 25.9 per mille. These larvae could have belonged to Albula, Elops, Megalops or some species of eel and we venture no guess as to the identification. — 285 — TABLE 82 Catch records of Leptocephali Total Date Station No. of Specimens length in millimeters Temp. °C Salinity o/oo Jan. 29, 1957 SS#1 4 35 39 24.6 29.0 Jan. 29, 1957 SS#4 16 33-43 24.3 17.0 Jan. 28, 1958 SS'#1 4 35-42 16.8 1.26 Jan. 28, 1958 SS#5 1 42 17.4 0.35 Jan. 28. 1958 SS#6 40 35 — 0.32 Feb. 24. 1958 SS#1 A 1 — 16.7 4.9 Feb. 24, 1958 SS#6 1 — 17.8 < 1.0 Jan. 27, 1959 SS#1 A 12 Grand total 79 21.1 25.9 3. Invertebrate catch. - - Table 83, which lists the most abundant invertebrate animals caught, is in considerable contrast to table 12, which is the comparable one for fishes, in that no great predominance of a few numerous species is demonstrated. However, the jelly-like ctenophores could not be counted, and it was noted that the trawl hauls sometimes consisted virtually of a mass of jelly with the remaining less numerous organisms interspersed: If there was any dominant invertebrate it was the ctenophore, Mnemiopsis . The remaining most abundant inverte- brates were two commercial shrimp. Penaeus aztecus and P . duorarum; two swimming crabs. Callinecte s; a jellyfish; a small dam; and a small marine snail. Only one of the invertebrates, the river shrimp, Macro- brachium, was a fresh-water species. The three Palaemonetes shrimp noted are difficult to define. At least two of them seem to be estuarine or marine. Several of the invertebrates, such as the squid, chiton, stone shrimp, and sea hare, were taken only in fairly high salinities and only a few rimes, as indicated in table 84. TABLE 83 Most abundant invertebrate animals caught in each of th/e three main areas of St. Lucie Estuary Number of each species caught Species South Fork Ndrth Fork Outer Estuary Total Mnemiopsis mccradyi (ctenophore) Numerous Few Numerous Numerous Aurellia aurita (jellyfish) Numerous Few Numerous Numerous Penaeus aztecus (brown shrimp) 248 76 167 491 Penaeus duorarum (pink shrimp) 156 35 32 223 Callinectes sapidus (blue crab) 75 32 87 194 Callinectes ornatus (ornate crab) 29 3 100 132 Mulinia lateralis (clam) — 127 127 Nassarius vibex (common nassa) — 1 126 127 — 286 — TABLE 83 Most abundant invertebrate animals caught in each of the three main areas of St. Lucie Estuary Species Number of each species caught South North Outer Total Fork Fork Estuary Rangia cuneata (rangia clam) 5 76 6 87 Palaemonetes spp. (grass shrimp) 16 16 17 49 Macrobrachium acanthurus (river shrimp) 12 10 13 35 Clibanarius vitattus (hermit crab) 1 1 25 27 Penaeus fluviaulis (white shrimp) 16 — 1 17 Congeria leucophaeta Few Several — Aplysia wilkoxi (sea hare-inkfish) — — 1 1 1 1 TABLE 84 Average salinity and range at which invertebrate animals were collected in St. Lucie Estuary Species Salinity (p.p.t.) Average Range Pagurus pollicaris (hermit crab) 36.0 36.0 Paguristes hummi (hermit crab) 36.0 36.0 Calliactes tricolor (sea anemone) 36.0 36.0 Area sp. (ark shell) 36.0 36.0 Canthurus multangulus 33.8 33.8 Ophiothrix orstedii (serpent star) 33.8 33.8 Chaetopleura apiculata (chiton) 33.8 33.8 Astropecten articulatus (starfish) 33.8 33.8 Clathrodrillia ostrearum 33.8 33.8 Aplysia willcoxi (sea hare-inkfish) 33.0 29.2-36.0 Sicyonia typica (stone shrimp) 29.2 29.2 Lolliguncula brevis (squid) 28.0 27.2-29.2 Mulinia lateralis (clam) 25.2 20.0-29.2 Solen viridis (razor clam) 22.9 22.9 Polinices duplicata (mooneye) 22.8 22.8 Crepidula plana 22.8 22.8 Mnemiopsis mccradyi (comb jelly) 21.2 13.8-33 8 Congeria leucophaeta 20.2 20.2-20.3 Aurellia aurita (moon jelly) 20,2 7.8-32.4 Penaeus duorarum (pink shrimp) 19.9 13.8-27.4 Nassarius vibex (common nassa) 19.0 0.34-29.4 Callinectes ornatus (ornate crab) 18.9 0.34-36.0 Cancroid crab 18.8 7.8 36.0 Clibanarius vitattus (hermit crab) 17.5 2.34-36.0 Palaemonetes vulgaris (grass shrimp) 16.5 3.7-39.2 Molgula manhattensis (onion tunicate) 15.1 10.0-20.2 Penaeus fluviaulis (white shrimp) 14.0 0.7-21.0 Penaeus aztetus (brown shrimp) 13.4 0.22-29.2 Rangia cuneata (rangia clam) 9.7 0.15-26.3 Callinectes sapidtis (blue crab) 9.4 0.15-29.4 Neritina reclivata (olive nerite) 7.8 7.8 — 287 — TABLE 84 Average salinity and range at which invertebrate animals were collected in St. Lucie Estuary Salinity (p.p.t.) Species Average Range Palaemonetes paludosus (grass shrimp) 1.6 0.14-14.8 Macrobrachium acanthurus (river shrimp) 1.3 < 1 .0-4.9 Palaemon floridana <1.0 <1.0 Fresh water snail <1.0 <1.0 Neritina virginea (Virginia nerite) <1.0 <1.0 Sesarma cinereum (land crab) 0.8 0.8 Palaemonetes pugio (grass shrimp) 0.19 0.16-0.22 TABLE 85 Number of inverebrate animals with less than five spejcimjsns in total collections in St. Lucie Estuary Four specimens Cancroid crab Three specimens Astropecten articulatus (starfish) Lolliguncula brevis (squid) Two specimens Mogula manhattensis (onion tunicate) Neritina virginea (Virginia nerite) Area sp. (ark shell) Crcpidula plana Palaemon floridana Chaetopleura apiculata (chiton) Polynices duplicata (mooneye) One specimen Neritina reclivata (olive nerite) Pagurus pollicaris (hermit crab) Paguristes hummi (hermit crab) Solen viridis (razor clam) S’icyonia typica (stone shrimp) Sesarma cinereum (land crab) Canthurus multangulus Clathodrillia ostrearum Ophiothrix urstedii (serpent star) Calliactis tricolor (sea anemone) Fresh-water snail Table 85 lists the numbers of organisms which were caught only a few times. The invertebrate fauna in the estuary can be divided into several categories. The fresh water component (Macrobrachium, possibly Pal- aemonetes , and the fresh water snail) was quite few in numbers. The same thing can be said of the squid, sea hare, and chiton, which came into the outer estuary only when salinities were quite high. A third — 288 — group — such as Rangia, Mulinia, and the ctenophores — in indigenous. The latter seems to be most abundant at moderately high salinities, and Rang«a clams are most abundant at low salinities. A fourth group raises in the estuaries similar to the fishes noted above. This includes three penaeid shrimp and the two swimming crabs. It was noted that the brown shrimp was found in lower salinities than the pink shrimp and in general the blue crab was in lower salinities than the ornate crab. One of those two crabs (blue crab) and the three penaeid shrimp are the only commercial invertebrates. The white shrimp, brown shrimp, and blue crab were common at quite low salinities and are known to raise in such areas (Gunter, 1950). The brown shrimp were most abundant seasonally in May, in both 1957 and 1958. Pink shrimp were found only in October 1958 and January 1959, after the gates were closed. The catch of blue crabs did not vary greatly at any time, and the white shrimp were not abundant at any time. In brief, the opening and clos ing of the St. Lucie spillway gates might cause a lowering in abundance of the pink shrimp, and possibly the brown shrimp, but it has no effect on the blue crab, the only other indigenous species present in any num- bers. Oysters, where they are present, can tolerate a wide range of salini- ties and sediment conditions, and are most abundant where there is a continuous supply of fresh water drainage. The St, Lucie Estuary has never been an important producer of commercial shellfish. 4, Species account. Invertebrates . The shrimp and larger crabs were counted and measured as taken, but for many of the smaller invertebrates the records were not routinely kept, partly due to their small size and partly because of identification difficulties. Where we are sure of the identifications the records are presented. Studies of fouling organisms were not made. COELENTERATA Dactylometra and Stomolophus , so commonly reported on the Texas coast (cf. Gunter 1950), were not seen in the St. Lucie Estuary. Aurellia aunta Lamarck. The catch records are given in table 86. Exact counts of jellyfish are hard to make after they have been rolled around in the trawl, and they were not attempted in most instances. Similarly, size measurements were not made. The salinities where these jellyfish were caught ranged from 7,8 to 32,4, but all specimens except one were taken at salinities ^f 15.0 and above. Gunter (1950) took this jellyfish in waters with a ilinity range of 18.9 to 30.9 on the Texas coast. CTENOPHORA Mnemiopsis >m'ccrad yi A. Agassiz. Ctenophores are, of course, more difficult to handle and count than jellyfish. Comments on abundance of this species are given in table 87. The salinity range where it was caught ranged from 13.8 to 33.8. — 289 — TABLE 86 Catch records of Aurellia aurita Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo May 16. 1957 TS#2 50 bell 80 mm. & less 26.7 15.2 May 16. 1957 TS#5 few — 26.7 19.9 May 16. 1957 TS#6 1 — 26.7 22.9 May 16, 1957 TS #7 few — 25.7 32.4 Oct. 27. 1958 TS#2 few — 23.9 20.3 Oct. 27. 1958 TS#3 many — 24.4 15.0 Oct. 28. 1958 TS‘#5 many — 23.3 26.3 Oct. 28. 1958 TS#6 2 — 23.3 26.3 Oct. 27. 1958 SS#3 1 — 25.0 7.8 Jan. 27. 1959 TS#2 1 — 20.0 17.1 Jan. 27. 1959 TS#4 2 — 20.0 15.7 Jan. 27, 1959 TS#6 1 21.1 24.0 TABLE 87 Catch records of Mnemiopsis mccradyi Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 28, 1957 TS#1 very abundant 24.1 17.0 May 16, 1957 TS#2 a few 26.7 15.2 May 16, 1957 TS#5 many 26.7 19.9 May 16, 1957 TS#6 several 26.7 22.9 Oct. 28. 1958 TS#5 100-200 22.3 26.3 Oct. 28, 1958 TS#6 several hundred 23.3 26.3 Oct. 27, 1958 TS#7 many 25.6 31.5 Jan. 27, 1959 TS#1 many 18.9 14.7 Jan. 27. 1959 TS#2 many 20.0 17.1 Jan. 27, « 1959 TS#3 few 18.9 13.8 Jan. 27, 1959 TS#4 many 18.9 15.7 Jan. 27, 1959 TS#7 many 22.2 33.8 MOLLUSC A AMPHINEURA Chaetopleura apiculata Say. Two of these chitons were taken at TS #7 on 27 January 195i>. The water temperature was 22.8 and the salinity was 33.8. TTie speci- mens were not measured. — 290 — PEL ECYPODA Solen viridis Say. One specimen was taken at TS#6 on 16 May 1957. The water temperature was 26.7 and the salinity was 22.9. Congeria sp. Several small specimens were taken at TS#2 and 4 on 27 October 1958. The water temperatures were 23.9 and 25.6 C and the salinities were 20.3 and 20.2. This species is ordinarily taken in low salinities. Thousands of them are found at times coating the walls of the St. Lucie Locks. Guntei and Shell (1958) found C. teucophaeta in Grand Lake, Louisiana growing ir tufts on live shells of Rangia cuneata where the salinity was never above 2.7 and averaged 0'.65. Kfulinia lateralis Say This species is evidently vastly abundant at times in the St. L.ucie. Thousands of dead shells were taken in the lower estuary in the trawls, which is not a good collecting gear for this little mollusk. Table 88 gives the catch records. Dead shells were found at low and high salinities, but live specimens were taken only at salinities from 20.0 to 29.2. Pos- sibly, this mollusk only lives at moderately high salinities and is killed at times by influxes of fresh water into the St. Lucie Estuary. Simmons (1957) found that in the Laguna Madre of Texas, this little clam sur- vived up to salinities of 45 per mille. TABLE 88 Catch records of Mulinia lateralis Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 28, 1957 TS#5 Great many shells (dead) 24.5 20.0 Jan. 28. 1957 TS#6 Numerous live and dead 23.7 29.2 Jan. 29. 1957 SS#2 3 6-12 mm. 24.1 20.0 June 18, 1957 TS#5 Thousands of empty shells 28.8 1.2 Nov. 13, 1957 TS#6 2 dead 22.0 27.2 Oct. 28. 1958 TS#6 124 live 23.3 26.3 Jan. 27. 1959 TS#5 Many empty shells 20.0 22.2 Rangia cuneata Gray. Many dead shells were found at SS #3 and 4 and TS #3 and 4. No live specimens were taken. Polgmesoda caroliwana Bose Catch records are given in table 89, Sixty specimens were taken, mostly at very low salinities. All specimens caught were small, the size range being from 6-18 mm in total length. Crassostcea virgimea (Gmelin) . Oyster shells were taken at TS #1,4 and 5. Live oysters were not seen. — 291 — GASTROPODA Crepiduta plana Say. One specimen was taken at TS #6 on 18 June 1957 in an empty Polynices shell. The temperature was 28.3°C and the salinity was 22.8. Polynices duplicatus Say. Nine empty shells were taken at trawl stations 2, 5, 5 and 6. Two live specimens. 31 and 36 mm in shell length were taken at TS #6 on 18 June 1957. The water temperature was 28.3°C and the salinity was 22,8. Cantharus multangulus Philippi One specimen was taken at TS #7 on 27 January 1959. It was not measured. The water temperature was 22.2 and the salinity was 33.8. Clathrodrillia os t rear urn One unmeasured specimen was taken at the same station as the above on the same date. Nassarius cm hex Say One hundred and twenty-eight of these little snails were counted and we feel that a great many more were brought up by the trawls. It is certainly the most abundant gastropod in the St. Lucie. Table 90 gives the catch records. It was taken only in trawls; all specimens but one were TABLE 89 Catch records of Polymesoda caroltniana Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo May 19. 1958 TS#2 5 7-11 25.6 0.15 May 19. 1958 TS#3 2 10-14 25.6 0.27 May 19. 1958 TS#4 50 6-10 25.6 0.24 May 19, 1958 TS#5 1 (many dead shells) 13 25.6 0.15 May 19. 1958 TS’#6 1 dead 25.6 0.34 May 19, 1958 TS#7 1 8 24.4- 25.6 Oct. 28, 1958 TS#5 3 13-18 23.3 26.3 TABLE 90 Catch records of Nassarius vibex Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 28, 1957 TS#6 35 — 23.7 29.2 May 16, 1957 TS#6 33 10-14 26.7 22.9 Sept. 23, 1957 TS#7 1 12 • — • 23.0 Nov. 13, 1957 TS #4 1 — 22.1 12.7 Nov. 13, 1957 TS#6 15 — 22.0 27.2 Feb. 24. 1958 TS#5 1 12 14.4 < io Feb. 24. 1958 TS#7 15 — 18.9 29.4 May 20. 1958 TS #6 6 11-13 25.6 0.34 May 20. 1958 TS#7 20 12-16 24.4 25.5 Grand total 127 — 292 — taken in the lower estuary. Apparently, this Nassarius likes moderately high salinities, but it was present when fresh water had moved down in- to its regular habitat. Many small hermit crabs utilize the shell of this little gastropod; they were rarely examined. Neritina recltvata Say. Two unmeasured specimens were taken at SS #5 on 25 February 1958. The temperature was 17.2 and the salinity was <1.0. A speci- men 15 mm long was taken at SS #3 on 27 October 1958. The tem- perature was 25.0 and the salinity was 7.8. TABLE 91 Catch records of Aply&ia willcoxi Date No. of Station Specimens Total length in millimeters Temp. °C Salinity o/oo Jan. 28. 1957 TS#6 4 25 23.7 29.2 Jan. 29. 1957 TS#7 4 — 2 2.2 36.0 Jan. 27. 1959 TS#7 5 Grand total 1 1 30-no 22.2 33. S A PJLYSIDAE Aplysia ujillcoxi Heilprin Eleven specimens were taken, all at high salinities at the outermost trawl stations. The records are given in table 91. They were all taken in midwinter. Most of the specimens were small. CEPHALOPODA Lolliguncula brevis de Blainville. 7'wo specimens. 20 and 35 mm long, were taken on 28 January 1957 at TS #6 The temperature was 23.7°C and the salinity was 29.2. Another specimen 33 mm long was taken at the same station on 13 No- vember I 9 5 7 . The temperature was 22.0 and the salinity was 27.2. This species and the one above illustrate what Gunter ( 1 945, 1 950) has noted before, that it is often the young of high salinity organisms which enter inshore waters of lower salinity. CRUSTACEA Palaemonetes paludosus (Gibbes) Table 92 gives the catch records. The size range was 17-35 mm in length and the salinities were all low. Females with eyed eggs were taken in February. For some reason this shrimp was taken only at relatively low temperatures. 16.7-20.6°C. Palaemonetes pugio Holthuis. Three specimens 25-28 mm long, the smallest with eggs, were taken at SS #4 on 23 September 1957 when the temperature was 28.1 and the salinity was Q. 16. Another was taken at TS #4 on 19 May — 293 — 1958. It was 27 mm long. The temperature was 25.6 and the salinity was 0.22. TABLE 92 Catch records of Paleomonetes paludosus Date No. of Station Specimens Total length in millimeters Temp. °C Salinity o/oo Jan. 27, 1958 SS # 1 A 3 23-34 16.8 1.3 Jan. 27. 1958 SS#3 5 18-31 17.7 0.26 Jan. 27. 1958 SS#4 5 18-28 — 0.25 Jan. 27. 1958 SS#5 3 17-29 17.4 (eyed 0,35 Feb. 24. 1958 SS# 1 A 9 17-32 eggs) 16.7 4.9 Feb. 24. 1958 SS#2 4 15-35 17.2 < 1.0 Feb. 24. 1958 SS#5 5 — 17.2 < 1.0 Jan. 27, 1959 SS#3 7 17-28 20.6 2.4 Jan. 27. 1959 SS #4 1 Grand total 4 2 18 20.0 o V TABLE 93 Catch records of Macrobrachium acantburus Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo June 18, 1957 TS#1 2 56-87 28.5 < i-o Sept. 23, 1957 TS#I 1 92 (eggs) 28.0 0.16 Sept. 23. 1957 TS#2 3 59-64 28.1 0.18 Sept. 23. 1957 TS#5 4 36-55 23.8 0.17 Nov. 13, 1957 TS#2 t 96 (eggs) 22.1 14.80 May 19. 1958 TS#l 1 78 25.6 0.14 (3 60-85 May 19, 1958 TS#2 4 (1 94 (eggs) 25.6 0.15 May 19. 1958 TS#4 10 (9 32-72 (1 green eggs 55 25.6 0.22 May 19. 1958 TS#5 4 34-45 25.6 0.15 May 20. 1958 TS#6 4 (light 48-66 25.6 0.34 green eggs) May 20. 1958 SS#2 1 33 26.1 0.19 Grand total 35 Palaemonetes vulgaris (Say) . One shrimp 22 mm long bearing eggs was taken on 28 January 1957 at TS #6. 'The water temperature was 23,7°C and the salinity was 29.2. Three shrimp 19-37 mm long were taken 16 May 1957. The temperature was 28.3 and the salinity was 3.7. Palaemon floridana Chace. Two specimens 24 and 32 mm were taken at SS #5 on 27 Jan- uary 1959. The water temperature was 20.0°C and the salinity was 1.0. This little shrimp has thin, bright red lines as markings, which fade quickly in preservative. For this reason it is called the peppermint shrimp. — 294 — Macrobrachium acanthurus (Weigmann) . Tabic 93 gives the catch records. The 35 specimens varied from 32-96 mm long. Shrimp bearing eggs were taken in the months of May, September and November. The water temperatures were all relatively high, 22. 1-28.5 C. The salinities were all low except that one sped men *Tc largest with eggs, was taken at a salinity of 14.8. Gunter (1938) has previously noted that another species of this genus, M. ohione . enters waters of intermediate salinities when carrying eggs. This habit certainly permits the species to spread from one coastal watershed to another, Penaeus aztecus Ives Four hundred and ninety-one brown shrimp were taken, Catch records are given in table 94. The smallest shrimp were taken in Jan- uary, February, May and October. The fall and summer months were the rimes of least abundance. Most shrimp were taken at salinities above 20.0, but 146 were taken at salinities below 5.0. Four shrimp were taken at salinities of 0.22 and 0.36. The former is in the fresh water range and is the lowest salinity at which the brown shrimp has been re ported. These four shrimp were 28-38 mm long. Gunter (1950) found the smallest brown shrimp on the Texas coast in October, April and May Penaeus duorarum Burkenroad Catch records are given in table 95. Two hundred and twenty- three pink shrimp were taken. Quite small shrimp were taken in October. The lowest salinity at which this shrimp was caught was 13.8. This shrimp was taken only during two surveys, but was fairly abundant during October 1958. Some early juveniles were taken at that time. The color markings of this shrimp have never been fully described. Actually, the shrimp has a saddle shaped mark extending from the so- called spot on the third abdominal pleon diagonally across the second and over the back end in the spot on the third segment. These markings are relatively clear and are to be found at quite small sizes in freshly caught shrimp. Definitely, marked small pink shrimp are unmistakable when fresh. A pale one may sometimes be mixed with the browns, but the re- verse situation does not occur. Museum workers have trouble with these two shrimp at small sizes because the colors fade. Penaeus fluvia tilts Say. Only 17 specimens of the white shrimp were caught (table 96). This shrimp is approaching the end of its disjunct range on the south- east Florida coast, and apparently it is not abundant in the St. Lucie area or more would have been taken at low salinities, as is the case in other parts of its range. White shrimp probably raise in the St. Lucie in small numbers for one juvenille, 50 mm in length, was taken in June. It has not been reported south of the St. Lucie on the east Florida coast, Sicyonia typica (Boeck ) One specimen, 20 mm long, was taken at TS #6 on 28 January 1957. The temperature was 23.7° and the salinity was 29.2. Callinectes ornatus Ordway. Catch records are given in table 97. The salinity range was 0.34 to 36.0. One hundred and thirty-two specimens were caught. Only five small specimens were taken at salinities below 5.0. The smallest sped mens were taken in January 1957 and January 1959. Females ranging in carapace width from 73-120 mm were taken in October 1958 and — 295 TABLE 94 Catch records of Penaeus aztecus No. of Total length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 28, 1957 TS#1 41 31-91 24.1 . 17.0 Jan. 28, 1957 TS#2 9 7 (20-38) 2(74-78) 23,3 20.5 Jan. 28, 1957 TS #4 2 54-55 23.8 20.0 Jan. 28, 1957 TS#5 12 28-71 (aver. 47.6) 24.5 21.0 Jan. 28, 1957 TS#6 3 37-71 23.7 29.2 Jan. 29, 1957 SS#2 2 47 24.1 20.0 Jan. 29. 1957 S$#4 4 20-46 24.3 17.0 May 16, 1957 TS#1 118 35-77 (aver. 60) 26.0 10.0 May 16, 1957 TS#2 20 36-78 26.7 15.2 May 16, 1957 TS#4 52 19-70 26.5 12.7 May 16. 1957 TS#5 1 1 37-76 (aver. 53) 26.7 19.9 May 16, 1957 TS#6 1 1 47-82 26.7 22.9 May 16, 1957 SS#4 1 40 28.0 9.5 June 18. 1957 TS'#2 49 34-87 28.7 0.7 June 18, 1957 TS#4 17 25-60 29.3 < 1.0 June 18, 1957 TS#6 3 36-85 28.3 22.2 Sept. 23, 1957 TS#6 2 48-51 23.4 2.34 Sept. 23, 1957 TS#7 1 43 — 23.5 Sept. 23. 1957 SS#1A 1 45 31.1 7.5 Nov. 13, 1957 TS#2 2 45-57 22.1 14.8 Nbv. 13, 1957 TS#3 1 30 22.1 10.1 Nov. 13. 1957 TS#6 3 39-53 22.0 27.2 Jan. 28. 1958 TS#6 2 28-37 15,0 0.36 Jan, 27, 1958 TS#7 1 40 16.5 4.5 Jan. 27, 1958 SS#1A 1 34 16.8 1.3 Feb. 24, 1958 SS#1 A 1 20 16.7 4.9 May 19, 1958 TS#4 2 34-38 25.6 0.22 May 20, 1958 TS#6 51 20-53 25.6 0.34 May 20, 1958 TS#7 35 22-88 24.4 25.5 May 20, 1958 SS#1A 20 18-54 25.6 1.04 Oct. 27. 1958 TS#1 1 39 23.9 7.8 Oct. 27. 1958 TS#2 3 56-64 23.9 20.3 Oct. 27, 1958 TS#4 2 49-59 25.6 20,2 Oct. 28, 1958 TS#6 5 50-78 23.3 26.3 Oct. 27, 1958 SS#1 A 2 Grand total 490 20-67 25.6 27.4 January 1959. The time of appearance of smaller specimens and of eggs shows that this crab is a fall and winter spawner in south Florida CaUwectes supidus Rathbun. Catch records are given in table 98. One hundred and ninety- four specimens were caught. Smaller crabs, 15 mm in carapace length and — 296 — less, were taken in the months of September, November, January, Feb ruary and May, Females bearing eggs were taken in January and May 1957 and in May 1958. The salinity and temperature ranges where egg-bearers were caught were 20.0-29.2 per mille and 23.7-26. 7°C. January is not the ordinary spawning month for the blue crab over most of its range and we thought this was a phenomenon peculiar to south Florida, until it was realized that unpublished data show that crabs off the northern Gulf coast (Mississippi) also carried eggs in January 1957, a heretofore unheard of thing. An examination of the table will show that the Jan- ury 1957 temperatures were considerably higher than in January 1958 and 1959 when no crabs in berry were taken. Jt is well known that this crab is euryhaline (Cf. Gunter, 1938). The salinity range at which it was caught was 0 14 to 29.2 per mille. Forty-eight crabs ranging in carapace length from 12 to 128 mm were taken in the fresh water range (see table 98). Sesatma cinereum Say. One female, 25 mm wide, with reddish orange eggs was taken at SS #2 on 16 May 1957. The water temperature was 30.0 and the salinity was 0.8. TABLE 95 Catch records of Penaeus duorarum Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Oct. 27, 1958 TS#2 149 24-77 23.9 20.3 Oct. 27, 1958 TS#3 8 22-49 24.4 15.0 Oct. 27, 1958 TS#4 21 17-63 25.6 20.2 Oct. 28. 1958 TS#5 27 32-69 23.3 26.2 Oct. 28, 1958 TS#6 1 41 23.3 26.3 Oct. 27, 1958 SSf\A 3 13-32 25.6 27.4 Jan. 27, 1959 TS#1 2 38-47 18.9 14.7 Jan. 27, 1959 TS#2 5 42-74 20.0 1 7.1 Jan, 27, 1959 TS#3 2 48-59 18.9 13.8 Jan. 27, 1959 TS #4 4 56-68 18,9 15.7 Jan, 27. 1959 TS#5 1 65 20.0 22.2 Grand total 223 TABLE 96 Catch records of Penaeus fhioiatilis Total No. of length in Salinity Date Station Specimens millimeters Temp. °C o/oo Jan. 28. 195 7 TS#1 1 105 24.1 17.0 Jan. 28, 1957 TS#5 1 104 24.5 21.0 May 16, 1957 TS#2 1 145 26.7 15.2 June 18. 1957 TS#2 12 50- 1 25 28-7 0.7 Oct. 27. 1958 TS#2 2 103-104 23.9 20.3 Grand total 1 7 TABLE 97 Catch records of Callinectes ornatus Date Station No. of Specimens Total length in millimeters Temp, °C Salinity o/oo Jan. 29, 1957 TS#7 3 15-20 22.2 36.0 Jan. 29. 1957 SS#2 33 12-33 24.1 20.0 Jan. 29. 1957 SS#5 2 24-39 24.0 19.3 May 16, 1957 TS#1 25 33-52 26.0 10.0 May 16, 1957 TS#Z 1 48 26.7 15.2 May 16, 1957 TS#3 2 27-31 26.5 5.4 May 16, 1957 TS#5 3 16-37 26.7 19.9 May 16. 1957 TS#6 8 (7 (1 44-77 72 26.7 22.9 May 16, 1957 TS#7 1 82 25.7 32.4 June 18. 1957 TS#4 1 16 29.3 < 1.0 June 18. 1957 TS#5 1 20 28.8 1.2 June 18. 1957 TS#6 2 30-36 28,3 22.2 June 18, 1957 SS#6 1 29 — 2.7 May 20, 1958 TS#6 2 15-19 25.6 0.34 May 20, 1958 TS#7 2 25-51 24.4 25.5 Oct. 28. 1958 TS#5 1 27 23.3 26.3 Oct. 28. 1958 TS#6 I 37 23.3 26.3 Oct. 27, 1958 TS#7 4 (2 85 (2 - 1 20 (brown 19-85 eggs) 25.6 31.5 Oct. 27, 1958 S‘S # 1 A 6 17-43 (eggs above 73 25.6 mm.) 27.4 Jan. 27, 1959 TS#6 15 (11 (4 59-85 55-100 21.1 24.0 Ian. 27. 1959 TS#7 1 35 22,2 33.8 Jan. 27. 1959 SS#1 A 9 12-40 21.1 25.9 Jan. 27. 1959 SS#2 8 Grand total 132 11-15 22.8 6.3 Paguristes hummi Wass. Hermit crabs were not examined closely, because they were often small and hid in their shells too long. We saw several specimens of P hummi, which heretofore has only been reported from the northwest part of the Florida peninsula: however, we have only one definite rec- ord. One specimen was taken at TS #7 on 29 January 1957. It was in a shell 13 mm long. The water temperature was 22.2 and the salinity was 36.0. Pagurus pollicaris (Say) . One specimen in a PoUmces shell 40 mm long was taken at the same station as the above. The shell bore one Adamsia tricolor , a common associate of this crab, and several Crepidula plana. CUbanarius vitattus (Bose; Catch records are given in table 99. Twenty-six live and one dead specimen were taken in shells, mostly Pohnices, ranging from 26 38 mm long. The temperature ranged from 16,5-31.1 °C and the salinity range was from 2.3-36.0. — 298 — TABLE 98 Catch records of Callinectes sapidus No. of Date St at ion Specimens Jan. 28 1957 TS#1 3 Jan. 28. 1 957 TS #2 I Jan . 28. 195 7 TS#4 1 Jan . 28. 1957 TS#5 2 Jan. 28. 1957 TS#6 5 Jan. 28. 1 957 SS#4 1 May 1 6. 1 957 TS# 1 9 May 16. 1957 TS#2 1 May 16. 1957 TS#4 3 May 16. 1957 TS#6 2 May 1 6. 1957 SS#3 1 June 18. 1957 TS #4 1 June 1 8. 195 7 TS#6 17 Sept. 23. 1957 TS#2 1 Sept. 23. 1957 TS'#3 1 Sept . 23. 1957 TS#4 2 Sept. 23, 1957 TS#5 l Sept . 23. 1957 SS#4 2 Nov. 1 3. 1957 TS#1 1 Nov, 1 3. 1957 TS#2 2 Nov. 1 3. 1957 TS#3 3 Nov. 13. 1957 TS#4 ( Nov. 13. 1957 TS#5 1 Jan. 27. 1958 TS# 1 l Jan. 27, 1958 TS#2 1 Jan. 27. 1958 TS#4 1 Jan. 28. 1958 TS #6 3 Jan. 27. 1958 TS#7 6 Jan. 27. 195 8 SS#4 4 Jan. 27, 1 958 SS#5 4 Feb. 24, 1958 TS#4 1 Feb. 24. 1958 TS#5 1 Feb. 24. 1958 TS#6 3 Feb. 24. 1 958 TS #7 9 Feb. 24. 1958 S S # 1 A 10 Feb. 24. 1 958 SS #2 3 Total length in Salinity millimeters Temp. °C o/oo <2 87-180 ( 75 24.1 17.0 18 23.3 20.5 195 23.8 20.0 160-162 24.5 20.0 (brown eggs) {2 22-127 (dk. yellow eggs) (3 83-99 23.7 29.2 37 24.3 17.0 (2 85-145 (7 83-135 26.0 10.0 156 26.7 15.2 14-17 26.5 12.7 165-195 26.7 22.9 Ytllowish-dk. brown . sponge 21 28.3 3.7 152 29.3 < 1.0 120-173 28.3 22.8 (av. 145) 106 28.1 0.17 18 23.1 0.17 12-150 22.9 0.18 1 9 23.4 0.34 15-36 28.1 0.16 38 21,9 1 1.5 26-194 22.1 14.8 15 40 22.1 10.1 19 22.1 1 2.7 not measured 21.8 16.2 98 15.5 0.18 46 15.8 0.23 122 16.8 0.26 (2 98-120 (1 125 15.0 0.3 6 (5 126-195 16.5 4.5 (1 120 (3 57-78 — 0.25 (1 61 (2 18-23 1 7.4 0.35 (2 1 7-30 142 14.4 < 1.0 1 15 14.4 < 1.0 (2 68 85 16.1 7.0 { 1 170 80-175 1 8.9 29.4 8-20 16.7 4.9 (2 22-35 17.2 < i-o ( 1 36 — 299 — TABLE 98 Catch records of Callinectes sapid us Total No. of length in Salinity Dale Station Specimens millimeters Temp. °C o/oo Feb. 24, 1958 •SS#3 1 12 16.7 < 1-0 Feb. 24, 1958 SS#4 1 42 14.4 < i.o Feb, 24. 1958 SS#5 1 58 17.2 < i.o Feb. 24, 1958 SS#6 1 35 17.8 < i.o May 19, 1958 TS#2 8 (5 85-108 25.6 0.15 (3 96-138 May 19. 1958 TS#3 1 40 25.6 0.27 May 19, 1958 TS#4 4 (3 38-145 25.6 0.24 (1 125 25.6 0.24 May 19, 1958 TS#5 1 178 25.6 0.15 May 20, 1958 TS‘#6 4 15-60 25.6 0.34 May 20. 1958 TS#7 2 (yellow 140-164 24.4 25.5 eggs) May 19. 1958 SS#2 3 17-58 26.1 0.19 May 19. 1958 SS#3 3 28-94 (soft) 25.6 0.28 May 19. 1958 SS#4 4 (3 28-75 26,1 0.14 (1 45 Oct. 27, 1958 TS#1 6 (2 22-33 23.9 7.8 (4 40-155 23.9 Oct. 27, 1958 TS#2 10 (8 21-152 23.9 20.3 0 97 (1 16 Oct. 27, 1958 TS#3 1 150 24.4 15.0 Oct. 27, 1958 TS #4 1 170 25.6 20.2 Oct. 27, 1958 TS#5 1 38 23.3 26.3 Oct. 28, 1958 TS#6 1 32 23,3 26.3 Oct. 27, 1958 SS#3 1 24 25.0 7.8 Ocr. 27, 1958 SS#2 1 33 25.6 14.0 Jan. 27. 1959 TS#1 8 (2 85-148 18.9 14.7 (6 45-200 Jan. 27, 1959 TS#2 4 (2 60-85 20.0 17.1 (2 145-175 20.0 Jan. 27, 1959 TS#3 3 (1 160 18.9 13.8 (2 77-177 Jan. 27, 1959 TS#4 2 (1 53 18.9 15.7 (1 47 Jan. 27, 1959 TS#6 6 (4 150-160 21.1 24.0 (2 102-137 Jan. 27, 1959 ss#i 1 145 21.1 25.9 Jan. 27, 1959 SS#2 2 35-35 22,8 6.3 Jan. 27. 1959 SS#4 1 14 20.0 < 1.0 Jan. 27, 1959 SS#5 1 13 20.0 < i-o Jan. 27. 1959 SS#6 1 20 10.4 Grand total 1 94 ECHINODERMATA Astropeclen articulatus (Say). Three specimens. 110 to 160 mm across were taken at TS #7 on — 300 — 27 January 1959. The largest specimen was carrying eggs. The water temperature was 22.2 and the salinity was 33.8. Onhiothrix orstedii Lutkcn. One specimen, 85 mm across, with eggs, was taken at the .same station as the above. TABLE 99 Catch records of CUbanarius vitattus Date Station No. of Specimens Total length in millimeters Temp. °C Salinity o/oo Jan. 28, 1957 TS#2 1 (Poliniccs shell) 23.3 20.5 Jan. 28. 1957 TS#3 l (Po Unices shell) 26 (barnacles) 23.3 14.8 Jan. 29. 1957 TS #7 6 (Pol in ices shell) 10-30 22.2 36.0 June 18, 195 7 TS#6 3 (Polinices shell) 24-30 28.3 22.8 Sept. 23, 1957 TS#6 3 (Polinices shell) 35-38 23.4 2.3 Sept. 23, 1957 SS# 1 A 1 (Polinices shell) 32 31.1 7.5 Nov. 13. 1957 TS#6 1 dead 22.0 27.2 Jan. 27 ( 1958 TS#7 1 (Polinices) 16.5 4.5 Feb. 24. 1958 TS‘#7 1 (Polinices) 35 18.9 29.4 Jan. 27, 1959 SS#6 Grand total 9 all in Polinices, taken from tree roots on 27 shore 22.2 10.4 CHORDATA Molgula manhattensis DeKay. One small unmeasured specimen was taken at TS #1, 16 May 1957, when the temperature was 26.0 and the salinity was 10. Another, 8 mm in diameter when contracted was taken at TS #4 27 October 1958. The temperature was 25.6 and the salinity was 20.2, 5. Cold kill of fishes, January -February 1958 — As was shown with the temperature data given earlier in this report, the winter of 1957-58 was one of the coldest of record for central and southern Florida. In connection with the several periods of freezing temperature that occurred in January and February, fish kills of considerable pro- portions also occurred throughout this State and other coastal sections of the southeast United States, During the February 24-26, 1958, sample, large numbers of dead fish were observed floating in the estu- ary and lying along the shorelines (Figure 3). These were predominant- ly lady fish or ten-pounder ( Elops saurus) and sand perch ( Diaprerus olisthostomus ) , with some snook, tarpon, and mullet. Many specimens which had been dead for some time were dragged up with the trawl. The great majority of the dead fish were adults, with some of the tar- pon measuring up to 5 feet. There was considerable evidence that the cold weather was the cause of the kill as follows: a. The kill occurred in all parts of the estuary, including far up the North Fork, which area was unaffected by discharge from St. Lucie Canal. b. Fish kills were reported abouf the same time for other parts of Florida (Tampa Bay and Biscayne Bay) and for coastal areas in Georgia and South Carolina and to the west in Mississippi and Texas. The — 301 — Jacksonville District made inquiries of State and Federal fish and wild- life agencies and university laboratories to verify such reports. c. Just prior to the observed kills in St. Lucie Estuary, the Stuart News reported the lowest weekly average temperature of record. d. The fact that primarily large fish were killed is a known phe nomenon associated with temperature kills of fishes ( Brongersma-Sand- ers. 1 °57 ; Gunter, 1947). e. The fishes killed in St. Lucie Estuary were principally those with tropical distribution. Such species are more susceptible to decreas- ing temperature changes and generally leave the colder inner waters dur- ing the winter for the deeper, warmer waters of the ocean. However, quick drops in temperature will trap many of them in the inner bays before they are able to leave. f . The largest number of fish taken in any of the 10 samples over the 2-year period were collected in the February 1958 sample. If the fish kill had resulted from anything but the cold temperatures, such as fresh- water discharge or pollution, it would have been more widespread and less selective of adult, tropical species. g. Data from the cold kill also furnished evidence that the fresh- water discharge does not drive our or destroy all the large game fishes. If it had done so during the previous month of continuous high dis- charge, then there would have been no large tarpon, snook, and lady- fish remaining in the estuary to be killed by the cold. In addition to the many small live fish that were taken, edible size croaker and drum, whrh are more tolerant of cold waters, were abundant in the outer estua r y (Figure 4) . G. SUMMARY AND CONCLUSIONS The St, Lucie Canal is one of the two available outlets from Lake Okeechobee, whose level must be controlled for irrigation and hurricane- tide control. The other outlet discharges to the Gulf of Mexico through Caloosahatchee River The St. Lucie Canal was originally constructed by the Everglades Drainage District between 1916 and 1924. It was taken over by the Corps of Engineers in 1930, following serious hur- ricane damage and the loss of many lives on the shores of Lake Okeecho- bee. The canal leaves Lake Okeechobee at Port Mayaca and extends northeast 25.6 miles to the south fork of St. Lucie River. St. Lucie Lock and Dam are located 1.9 miles west of the easterly end of the canal and about 23.7 miles from Lake Okeechobee, St. Lucie Canal is part of the main channel of east and west boat traffic between the Gulf of Mexico and the Atlantic Ocean. Navigable depth is 8 feet. St. Lucie Estuary^ consists of a North Fork and South Fork and a main estuary roughly in the shape of a Y. It empties into a coastal lagoon — Indian River — near the entrance to the Atlantic Ocean. The sur- face area is 5,530 acres; the water volume is 41,150 acre^feet; and length of the shoreline is 35.5 miles. Discharge through St. Lucie Lock and Dam into the South Fork of the estuary has a peak rate of about 9,000 cubic feet a second when the Lake Okeechobee level is near 18.0 feet. Peak flood drainage into the North Fork through creeks, drainage ditches, and small canals is at a- bout the same rate. Discharges through St. Lucie Canal between 1945 and 1958 ranged - 302 — from zero in 1950 and 1956 to 2,687,000 acre-feet in 1947. 1 he years 1947. 1948, mi, 1954, and 1958 were those of high discharges. In other years, the discharge was moderate, low, or zero. I he average an- nual discharge during that period was 1.062,000 acre-feet. 1 he heaviest discharge has been from August to December in most years, with lesser peaks from January to April in a tew years. 1 he present investigation was begun in January 1957 and was ter- minated in January 1959 . the chiet aim was to sample the population of fishes in all three branches of St. Lucie Estuary as well as it could be done by trawls and by small seines on shore. I bis method does nor sample the larger fishes very well, but it is generally good for the small fishes and invertebrates. 1 his matter is ot particular importance because of local contentions that the small fishes were killed by the fresh water and because nays and estuaries are primarily nursery grounds (cf. Gunt- er 1945, page 1 19). Seven trawl stations and six seine stations were set up at localities described in the text, liottom and surface temperatures and salinities were determined at each trawl station, and one salinity and one temperature were taken at the shallow shore stations. Each station was visited roughly every 3 months and a complete round of all stations was made 10 times during the 2-year period. Thus, the data give some information on seasonal changes. Five of these biological surveys of the area were made during times of no discharge; five were made during periods of discharge, and three were made during very heavy discharges. One of the surveys was made following one of the most extreme cold spells the region has experienced since the Weather Bureau records were started in south Florida. In the course of this study, 68 trawl hauls and 103 seine hauls were made. All animals caught were identified and measured, except in certain instances when there were hundreds of small fishes with a size range of only a few millimeters. In such cases, only the maximum and minimum sizes were determined. Organisms which could not be identified in the field were preserved and studied more carefully at the Gulf Coast Research Laboratory. Secchi disk determinations of turbidity were made at each station. Air temperatures were also taken at each station and they were supplemented by the study of maximum and minimum daily air temperatures at Stuart. Eighty-three species of fishes and 24,783 specimens were taken. Sixty -four of those species were marine, and the total number of marine specimens was 24,151. Nineteen species of fresh-water fishes and 632 specimens were taken. Although the salinity of the water at various stations was often very low. and in or near the fresh water range, the predominance of marine fishes was overwhelming. The 13 species which were taken more than 100 times each made up 95.2 percent of the iutal catch and the remaining 70 species made up only 4.8 percent of the catch. The white catfish and the black crappie were the only fresh- water fishes taken more than 100 times. Five species — the striped mullet, menhaden, croaker, s' ’ water silverside, and the bay anchovy — were taken more than IT ,mes each. They made up 89 percent of the catch. Those fish ire ah rorage fishes and they are extremely important to the biologic-' .conomy of the area. Small mullet alone made ud almost 50 percent of the catch. Those fishes regularly grow up in estuarine areas at low salinities, and their condition is evidently enhanced by the release of fresh water into the es- tuary. This is shown by the fact that the greatest number of specimens — 303 — was taken in January and February 1958 when the releases through the lock were at 7,380 and 4,000 cubic feet a second respectively. During these two surveys, 14,016 fishes were taken — considerably more than half of the total. The greatest numbers of species taken during any one survey (40) were taken in January 1958. At that time, there was no particular dim- inution in the number of marine species, but an increased number of fresh-water fishes was taken. During November 1957, only 269 fishes were taken During October 1958, only 562 were taken. The locks were closed at those times. In January 1959, when the locks were closed, 1,- 408 fish were taken — a decrease of more than 78 percent from the previous year when the locks were open. This figure is due largely to the diminution of the numbers of the five forage fishes mentioned a bove. Many large snook were taken in the trawls when the water was extremely turbid. Sand perch, croakers, spot and whFe trout were also taken in the trawls and they did not leave the area when the salinities were low. The pompano and the small snappers were absent from, the low salinity water. Fishes which live in estuaries are capable of standing quite large variations in salinity, especially towards the lower side, and the general population of fishes in St. Lucie Estuary is very similar to that of other areas. Their condition seems to be generally enhanced bv moderately low salinities and they are not produced in great numbers when the salinity is high, as in a salt-water lagoon. Thus, their numbers increased when there was a flow of water through St. Lucie Lock. The greatest numbers of mullet, menhaden and croakers, silver- sides, and anchovies were taken when the salinity of the water was less than 0,5 o/oo. In fact, the numbers of those species taken at that sa- linity — which is drinkable water — was almost three-fourths of the total catch of the investigation. Thirty-six species of invertebrates were caught and there were sev- eral differences betwen the invertebrate and the fish catch. Less than 2,000 specimens were taken, if the comb jelly Mnemiopsis is dis- counted. This little jellyfish was extremely abundant at salinities above 13.8 o/oo and often the trawl catch was a mass of jelly, quite indis- tinguishable so far as numbers are concerned. Aside from that animal, seven species were taken more than 100 times. These, in order of a- bundance, were the brown shrimp, the pink shrimp, the cloverleaf jelly- fish, the blue crab, a small clam. Mulinia, the ornate crab, and Nassarius, a marine snail. One hundred and fourteen specimens of that snail were taken. Four hundred and ninety-one brown shrimp and 224 pink shrimp were taken. There were 186 blue crabs. White shrimp were also found in the estuary, but they are not abundant and only 17 were taken. One species of grass shrimp, a river shrimp — Maccobrachiurn, and one speci- men of fresh -water snail were the only fresh- water species taken. They numbered less than 75 specimens. Thus, the salt-water contingent of the invertebrates greatly outnumbered the fresh-water specimens, similar to the case with the fishes. Most of those animals were s'malf The blue crab, the brown shrimp, and the pink shrimp are the only animals of commercial importance. The first two were taken at times below 0.22 o/oo salt. This is fresh water and below the salinity of hard fresh wat- er. It is a well known fact that these two species raise in estuarine water of low salinity, as off the Louisiana coast, and it is obvious that the in- — 304 — flux of fresh water does them no damage. The salinity ranges at which the most important invertebrates were taken are given in table 84. Salinity maps of the area f plates 8 through 17) show that there is a wedge of salt water in the lower part of the main estuary above a- bout 25.0 o/oo at all times except during the very highest discharges from St. Lucie Lock and Dam — such as occurred in January and Feb- ruary 1958. This means that even the most sahniphilous species of fishes can find a refuge to their liking in the lower estuary during all but the most extreme discharges. It would suggest that they might even be concentrated there. The cold kill of many large fishes — tenpounders, sand perch, tar- pon. and others — noted in the estuary in February 1958 followed the lowest recorded average weekly air temperature at Stuart. These fishes are predominantly of tropical dis' ribution. Numbers of croakers, spot, pigfish. and gobies — - fishes of temperate distribution — were taken alive in the trawls at the same time. Thp outflow of water through St. Lucie Lock and Dam does not damage commercial fishing. It causes turbid conditions which clear up quicklv when the flows are stopped. A few high salinity species are pushed into the lower estuary and — at times of the heaviest discharge — into Indian River or the ocean. No fishes are killed by fresh water and, to the contrary, the reproduction of common estuarine forms is enhanced. These produce forage fishes which serve as food for other larger fishes, and the total production and fertility of the area are increased by out- flows of fresh water. Fishing from the St. Lucie Lock and Dam area and possibly from the bridge in the main estuary is benefited by low to mod- erate fresh-water outflow and this compensates in part, if not altogether, for the migration of certain saliniphilous species. A great many of the common sports fishes do not leave the area even when the salinities are quite low, This study produced no evidence as to whether they bite less during such periods. St. Lucie Estuary is characterized as an area of high production of a wide variety of sport and food fishes, a condition which has developed and been enhanced by periodic discharges of fresh water and nutrient materials. From the overall and long-range viewpoint, moderate flows of fresh water through St. Lucie Lock and Dam (2,500 to 3,500 c.f.s,, or thereabout), especially during certain periods of the year, would con- tinue to benefit the fisheries of St. Lucie Estuary. LITERATURE CITED Briggs, J. C. 1958. A list of Florida fishes and their distribution. Bulletin Flori- da State Museum, 2 (8) :223-3 1 8. Bongersma-Sanders, M. 1957. Mass mortality in the sea. Chapter 29, "Treatise on Marine Ecology and Paleoecology."' Geological Society of America, Memoir 67, Vol. 1, pp. 940-1010. Gunter, G. 1937. Observations on the river shrimp, Macrobrachium ohionis (Smith). The American Midland Naturalist, 18 ( 6) : 1 038 - 1042. — 305 — 19^8. Notes on invasion of fresh water by fishes of the Gulf of Mexico, with special reference to the Mississippi- Atchafalaya river system. Copeia, 1 938 ( 2) : 69-72. 19^8. The common blue crab in fresh waters. Science, 87(2248) : 87-88. 1942. A list of the fishes of the mainland of North and Middle America recorded from both freshwater and sea water. The American Midland Naturalist. 28(2): 205-326. 1945. Studies on marine fishes of Texas. Publications of the In- stitute of Marine Science. 1 ( 1 ).: I- 190 . 1947. Differentia! rate of death for large and small fishes caused by hard cold waves. Science, 106(2759:472. 1950, Seasonal population changes and distributions as related to salinity, of certain invertebrates of the Texas coast, including the commercial shrimp. Publications of the Institute of Ma- arinc Science. 1(2): 7-51, 1950. Distributions and abundance of fishes on the Aransas Na- tional Wildlife Refuge. Publications of the Institute of Ma- rine Science, 1 (2) ;89-101. 1953, The relationship of the Bonnet Carre Spillway to oyster beds in Mississippi Sound and the ' Louisiana marsh", with a report on the 1950 opening. Publications of the Institute of Marine Science, 3(1): 17-71. 1956. A revised list of euryhaline fishes of North and Middle America. The American Midland Naturalist. 56 (2) :345- 354. 1959. Biological investigations of St. Lucie Estuary in connection with Lake Okeechobee discharges through St. Lucie Canal. A report to the District Engineer, Jacksonville District. Corps of Engineers, v-f- 75 pp.. 24 pis. (Processed). Gunter G. and J. Y. Christmas 1960 A review of literature on menhaden with special reference to the Gulf of Mexico menhaden. Brevoortia paironus Goode. O S. Fish and Wildlife Service Special Scientific Re- port — Fisheries No. 363, iv'~p 31 pp. Gunter, G., and W. E. Shell. Jr. 1958. A study of an estuarine area with water-level control in the Louisiana marsh. Proceedings of the Louisiana Academy of Sciences, 21:5-34. Kilby, J. D. 1955. The fishes of two Gulf coastal marsh areas of Florida. Tu- lane Studies in Zoology, 2 (8) : 1 76-247. Pearson, J. C, 1929. Natural history and conservation of the redfish and other commercial sciaenids on the Texas coast. Bulletin U. S. Bureau of Fisheries, 44 ( 1 928 ) : 1 29-2 1 4. Reid. G. K., Jr 1954. An ecological study of the Gulf of Mexico fishes in the vicinity of Cedar Key. Florida, Bulletin of Marine Science of Gulf and Caribbean. 4 ( l ) : 1 -94. Simmons, E. G. 1957. Ecological survey of the upper Laguna Madre of Texas. Pub- lications of the Institute of Marine Science. 4(2): 156 200. — 306 — Springer, V. G. 1960. Ichthyological surveys of the lower St. Lucie and Indian Rivers, Florida east coast. Florida State Board of Conserva- tion Marine Laboratory, pp. 4-20. (Mimeographed report). Springer, V. G. and K. D. Woodburn 1960. An ecological study of the fishes of the Tampa Bay area. Florida State Board of Conservation Professional Papers No. 1, 104 pp. Suttkus, R. D. 1955. Seasonal movements and growth of the Atlantic croaker (M icropogon undulatus) along the east Louisiana coast. Proceedings of the Gulf and Caribbean Fisheries Institute, 1954:151-158. Viosca, P. 1938. Effect of Bonnet Carre Spillway on fisheries. Louisiana Conservation Review, Winter issue. — 307 —