REPORT OF THE BUREAU OF COMMERCIAL FISHERIES BIOLOGICAL LABORATORY ST. PETERSBURG BEACH, FLORIDA, Fiscal Year 1968 ^''^^- '^ "^^'^'J 'Hnnnn Hni ^ :fii\'-s UNITED STATES DEPARTMENT OF THE INTERIOR U.S. FISH AND WILDLIFE SERVICE BUREAU OF COMMERCIAL FISHERIES Circular 313 UNITED STATES DEPARTMENT OF THE INTERIOR U.S. Fish and Wildlife Service BUREAU OF commercial FISHERIES Report of the Bureau of Commercial Fisheries Biological Laboratory, St. Petersburg Beach, Florida, Fiscal Year 1968 JAMES E. SYKES, Director Contribution No. 49, Bureau of Commercial Fisheries Biological Laboratory, St. Petersburg Beach, Florida 33706 Circular 313 Washington, D.C. May 1969 CONTENTS Page Report of the Laboratory Director 1 Mission of Laboratory 1 Research status and trends 1 Training 2 Presentations 2 Meetings and work conferences 2 Estuarine research program 3 Benthic project 3 Introduction 3 Hydrology 3 Sediments 3 Mollusks 3 Echinoderms and polychaetes 7 Southern quahog 7 Lug worm 7 Squid , 8 Sea grass 8 Dredge -fill 10 Biogeochemical alteration and effect project 10 Faunal production project 1 1 Pompano aquaculture II Pompano ecology 14 Gulf of Mexico estuarine inventory project 15 Area description 15 Biology 16 Biology of industrial schoolfishes program 18 Development of the fishery 18 Program goals 20 Facilities and procedures 21 Progress during the year 21 Red-tide program 22 Toxin research 22 Encystment stage of Gymnodinium breve , ZZ Plankton ecology project 22 Publications 25 Manuscripts in press 25 Report of the Bureau of Commercial Fisheries Biological Laboratory, St. Petersburg Beach, Florida, Fiscal Year 1968 ABSTRACT The major goals of the Laboratory are to explore the relatively unknown scope of biological productivity in the coastal zone of the eastern Gulf of Mexico, to measure the effect of changes in that zone, and to develop methods of increasing estuarine fishery resources. The report describes current research on projects in the Estuarine, Red-Tide, and Industrial Schoolfishes Programs. The projects include studies of sediments and organisms in bay bottoms, plankton crops and fishes residing in and transferring between estuaries and the Gulf of Mexico, toxicity of the red-tide organism, and experimental rearing of pompano in an im- pounded lagoon. A physical, hydrological, biological, and sedimentological inventory of Florida estuaries is also in progress as part of a cooperative effort with the National Oceanographic Data Center and the States of Alabama, Mississippi, and Louisiana. REPORT OF THE LABORATORY DIRECTOR James E. Sykes MISSION OF LABORATORY Research activities of the Laboratory are designed principally to explore the dynamics of plants and animals in the estuarine zone and the relation of these organisms to their coastal environment. The physical and chemi- cal organization of estuarine habitats is con- stantly changing. Some of the changes are subtle and barely detectable; for instance, the natural deposition and resuspension of sediments from inflowing streams. Other alterations produce dramatic and easily measured effects, such as those resulting from the diversion of waterways and dredging and filling by man. The relation of aquatic biota to the natural and altered environment must be understood as we seek to sustain coastal nurseries and insure that they will continue into the future as producers of the fishery resource. RESEARCH STATUS AND TRENDS From 1962 through 1967 most effort in the Estuarine Program of the Laboratory was ap- plied to the collection of data and investigation of matters related to the biological effects of dredging and filling and other disturbances in estuaries. Biologists were called upon fre- quently to appear at public hearings and court- room proceedings to present their findings on those effects. The fact that the researcher's voice was heeded is evidenced by the number of large, prime nurseries which continue to pro- duce fishes but which were originally scheduled to be covered by landfill. Although each de- velopmental proposal was considered sepa- rately, some of the positive results have now been converted into legislative protection for entire estuarine zones by responsible States . The number of requests for us to supply biological data concerning specific proposals for engineering developments that would have damaged estuaries were fewer in fiscal year 1968 than in previous years. We could, there- fore, focus more effort on detailed ecological analysis and upon intensifying progress on a Gulf of Mexico estuarine inventory in coopera- tion with Gulf States. This Federal-State en- deavor is in a healthy condition and is now producing results after the necessary period of negotiation and planning. The Gulf Inventory is approximately 50 per- cent completed. Biological and Hydrological Phases were begun- -both to run simultan- eously among cooperators until March 1969. Area Description and Sedimentological Phases are in progress but are not necessarily simul- taneous with other parts of the study. An oceanographer from the National Oceanogra- phic Data Center was assigned to the Labora- tory to help Inventory participants design data formats and write instructions for ADP (auto- matic data processing). Coding systems were completed, and data coding is now in progress on standard forms accepted by State coopera- tors and BCF (Bureau of Commercial Fisher- ies). The Industrial Schoolfishes Program com- pleted its first year of operation in June 1968. Data obtained on the early life history and com- mercial catch composition of thread herring made it possible for the staff to recommend continuation of the fishery despite pressures from those who would have it abolished. On the basis of our testimony that catches had less than 1 percent food fishes, the court ruled that the fishery could continue if food species did not exceed the 1 -percent level. With the completion of a contract this year on the isolation and identification of red-tide (Gymnodinium breve) toxin, all objectives of the Red- Tide Program written in 1962 were fulfilled. We do not intend to imply, however, that a need for further research on the organ- ism no longer exists or that annethodhas been found to control red tides. Our contract with the University of South Florida succeeded in establishing a qualified research unit on that campus. Now that the contract is terminated, the unit is working in close association with State researchers on other red-tide problems and on an informal basis with the Laboratory. Physical Science Aid Fishery Biologist Fishery Physiol- ogist Nine employees Nine employees Ecologist TRAINING Z-week course, AutoAna- lyzer Techniques, New York, N.Y. 48 class hours, ELemen- tary Statistics, Florida Presbyterian College, St. Petersburg, Fla. (audited course). 1-week course in Marine Pollution Ecology, Fed- eral Water Pollution Control Administration Training Program, Uni- versity of South Florida, Bayboro Harbor Cam- pus, St. Petersburg, Fla. Standard Red Cross First- Aid Course. Advanced Red Cross First- Aid Course. Continued research toward the Ph. D. degree at the University of Florida, Gainesville, Fla. PRESENTATIONS Papers were presented at the following meetings: Florida Academy of Sciences, De- land, Fla.; Marsh and Estuary Management Symposium, Louisiana State University, Baton Rouge, La.; National Association of Soil and Water Conservation Districts, Dallas, Tex.; and Oceanographic Institute, University of South Florida Bayboro Cannpus, St. Petersburg, Fla. A staff member gave a talk to the Marine Biology Group, Gibbs High School, St. Peters- burg, Fla. Five staff members served on the Federal Water Pollution Control Administra- tion faculty in presenting a training course-- "Marine Biology and Pollution Ecology (144)." MEETINGS AND WORK CONFERENCES Figures in parentheses show the number of persons attending. Annual Meeting of the Florida Academy of Sciences, Deland, Fla. (2). Editing assistance, Rome Italy, in prepara- tion for FAO "Conference on Fish Be- havior in Relation to Fishing Techniques and Tactics," Bergen, Norway (1). Five-day trip with representatives of the Vietnamese Directorate of Fisheries to Bureau facilities and points of interest in the fishing industry at Beaufort, N.C., Brunswick, Ga., and Miami, Fla. (1). Gulf States Marine Fisheries Commission-- Estuarine Technical Coordinating Com- nnittee, Montgomery, Ala. (1). Gulf States Marine Fisheries Commission- - Estuarine Technical Coordinating Com- mittee, Panama City Beach, Fla. (2). Internal Improvement Fund Staff Meeting, Tallahassee, Fla. (1). Laboratory Directors' Meeting, Woods Hole, Mass. (1). Marsh and Estuary Management Symposiunn, Louisiana State University, Baton Rouge, La. (1). National Association of Soil and Water Con- servation Districts, Dallas, Tex. (1). Oyster Culture Workshop, University of Georgia, Sapelo Island, Ga. (1). Program Review, Miami, Fla. (1) Steering Comnaittee, Estuarine Workshop Meeting, Charleston, S.C. (1). ESTUARINE RESEARCH PROGRAM The estuarine research program has five projects : bay bottom ecology, plankton ecology, production of marine animals, effects of estu- arine alteration, and an inventory of Gulf of Mexico estuaries. BENTHIC PROJECT John L. Taylor and Carl H. Saloman Introduction Study of benthic ecology in estuaries of the eastern Gulf began at this Laboratory in 1963. The work is designed to give detailed informa- tion on the distribution and abundance of ben- thic species and provide guidelines to assess the biological importance of estuaries and the impact of coastal development. In fiscal year 1968, the fourth in a series of hydrological reports and a sediment report were con-ipleted for Tampa Bay and adjacent waters. Work continued on the identification of bottom animals from the Bay with emphasis on mollusks, echinoderms, and polychaete worms. Biological research was also directed toward four organisms that have actual or potential value as commercial species--the southern quahog, Mercenaria campechiensis : the lug- worm, Arenicola cristata; the squid, Lolligun- cula brevis; and the sea grass, Thalassia testudinum. Finally, several "fact-finding" surveys were made in Tampa and Sarasota Bays to determine the biological resources that exist in areas proposed for dredge-fill development. Hydrology Hydrological data are essential for ecologi- cal studies in the estuary and provide a his- torical record of changes in the aquatic en- vironment. Waters of Tampa Bay are sampled each month at 30 permanent stations. Measure- ments include water temperature, salinity, pH, total phosphorus, total nitrogen, dissolved oxy- gen, and turbidity. The same measurements (plus Secchi disc readings) are made on water sannples collected daily at the Laboratory dock on Boca Ciega Bay. In addition, chlorophyll determinations are made once each week for samples taken at the dock. Hydrological conditions in the Bay in 1965- 67 (fig. 1) differed little from those in 1961-64 (given in the Laboratory's report for fiscal year 1967). One exceptional feature is the rise in concentration of total nitrogen throughout the Bay since 1965. A cause for this increase (8- 16 Mg.at./l. (microgram atom per liter)) is the progressive enrichment of the estuary from domestic and industrial sewage. Sediments Sediment composition has a great influence on the occurrence and distribution of benthic organisms, and established bottom communi- ties have an effect on the physical and chemi- cal nature of bottom deposits. Sediment samples are therefore collected and analyzed in benthic studies and other Laboratory pro- grams. Textural, chemical, and statistical data for more than 500 samples from Tampa Bay have been recorded since 1963. Throughout most of the Bay, the bottom consists of sedi- ments that are more than 20 percent sand, and patches of shelly sand exist in a few locations. Soft sediments of silt and clay are found in natural and manmade depressions and other areas where tidal currents are weak (fig. 2). Soft sediment is mostly confined to Hills- borough Bay where sewage sludge is a major source of fine-grained material and Boca Ciega Bay where dredging has caused siltation in bayfill canals and elsewhere. Soft sediment in these two areas of the Bay has greatly reduced or eliminated benthic invertebrates normally found in other parts of Tampa Bay. Mollusks The study of the relation between mollusks and environmental conditions is complete for three areas of Tampa Bay--Boca Ciega Bay near the mouth of the estuary and Old Tampa Bay and Hillsborough Bay at the head of the estuary. This information shows how the natural environment influences the distribu- tion, abundance, and diversity of shellfish and how development and pollution of parts of the bay can reduce or eliminate mollusks there. In bottom samples fronn undisturbed areas of Boca Ciega Bay, we recorded 155 species of live mollusks in 67 families (table 1). The average sample had 60.5 mollusks. Environ- mental factors that favor such great divers- ity and abundance include high salinity ( > 30 p.p.t.), sandy sediment (91 percent sand and shell), and bottom vegetation (sea grasses and algae). In contrast, dredge hauls from the bayfill canals of Boca Ciega Bay had only five species of mollusks, and the average number of individuals per collection was less than one. Table 1. — Nujnber of species of iToliusKs collected, salinity, and tottom type in tnree areas of Tampa Bay, Fla. 1963-64 Species collecEed Total X Sand and Silt and Area Stations alive species Famlltes Salinitv shell clay Number Number Number Number P.p.t. Wel(,ht percent Boca Ciega Bay fUndredged areas) 2h 155 167 67 32.6 91 9 Boca Ciega Bay ^Dredged areas) 7 5 5 5 32.6 15 85 old Tampa Bay 98 97 120 52 23.8 92 8 Hillsborough Bay 1.5 35 W 1.0 23.1. 78 22 AREA 1 W. lomp. 24.80 Sol. 23.81 pH 7.87 Tot. N 51.18 Tot. P 22.16 DO 4.56 Turb. 6.44 AREA II W. temp. 24.88 Sal. 23.41 pH 793 Tol.N 72.32 Tot.P 23.16 DO 4.58 Turb. 12.35 AREA III W.lemp. 24.78 Sal. 26.57 pH 792 Tot.N 51.42 Tot.P 22.76 DO 4.25 Turb. 4.73 AREA IV W.lem p. 23.75 Sol. 32.04 pH 797 Tot.N 44.00 Tot.P 16.88 DO 4.08 Turb. 8.89 AREA V W.tem p. 23.48 Sol. 32.61 pH 8.01 Tot.N 46.36 Tot.P 12.45 DO 4.03 Turb. 6.67 AREA VI w.tem p. 24.11 Sol. 2902 pH 785 Tot.N 46.34 Tot.P 18.69 DO 3.93 Turb. 6.20 AREA VII w.tem p- 24.36 Sol. 34.58 I 83°00'W. 82 30 W. Figure 1.— Hydrological measurements for different areas of Tampa Bay, Fla., and adjacent waters of the Gulf of Mexico, January 1965 through August 1967— water temperature (w. temp.), Oc; salinity (sal.), p.p.t.; pH; total nitrogen (tot. N.), u%. at./l.; total phosphorus (tot. P.), ^/g. at./l.; dissolved oxygen (DO), ml,/l.; turbidity (turb.), J.T.U. 83 00 W. Figure 2. —Schematic illustration of sediment types in Tampa Bay, Fla. — sediments of more than 80 percent silt and clay by weight (crosshatchlng); sediments of more than 80 percent sand and shell by weight (hatching); sediments of more than 20 percent sand by weight (unshaded). TAMPA BAY 82 30 W. Figure 3. — Benthic life zones in Hillsborough Bay, Fla., based on the comparative diversity of mollusks — healthy zone (unshaded); marginal zone (hatching); unhealthy zone (crosshatching). Soft sediments ( > 80 percent silt and clay) and lack of vegetation account for the few shellfish in deep dredged canals. Old Tannpa Bay is more brackish ( < 25 p.p.t.) than Boca Ciega Bay, but sediments are mostly sandy and submerged vegetation is ex- tensive. Bottom samples there contained 97 species of live mollusks in 52 fan^ilies. Al- though the number of species in Old Tampa Bay was 62 percent less than in Boca Ciega Bay, the cause is lower salinity rather than dredging or pollution. Only 35 species of live mollusks were col- lected in Hillsborough Bay, where salinity is about the same as in Old Tampa Baybut where dredging and pollution are responsible for widespread accumulation of soft sediments and elimination of bottom vegetation in water more than a few feet deep. Furthernnore, no live mollusks were collected at 19 of the 45 stations sampled. On the basis of these 19 stations and the incidence of four species in other samples (Mulinia lateralis, Annygdalum papyria, Tagelus plebeius, and Nassarius vi- bex), we divided Hillsborough Bay into three life zones --healthy, marginal, and unhealthy (fig. 3). These four species apparently are tolerant to a high degree of pollution. They made up less than 50 percent of the species present at healthy stations and 50 percent or more of the species present at marginal stations; no living mollusks were found at stations designated unhealthy. Most of the healthy areas are between Hillsborough and Tampa Bays where pollutants are somewhat diluted and much of the bottom remains sandy and vegetated. The term "healthy" is partially nnisleading, however, because many species found in Old Tampa Bay have not been found in any part of Hillsborough Bay. Echinoderms and Polychaetes Work this year on taxonomy of echinoderms raised the number of species recorded from Tampa Bay to 36. Lowell Thomas, University of Miami, identified the brittle stars. Elisa- beth Deichmann, Harvard University Museum of Comparative Zoology, identified the sea cucumbers. Polychaete worms from stations within Tampa Bay have been sorted to family or lower taxonomic level. Thirty-nine families and more than 140 species were recorded. Southern Quahog Growth of a clam population in lower Boca Ciega Bay was recorded for the fifth year. Average length of individuals in the sample was 5 mm. greater than in 1967 and nearly twice the mean length of clanns measured in 1964. A poor set on the bed is illustrated again this year by the scarcity of small clams (fig. 4). SHEll IINGTH IN MIOPOINt CLASSES 23' SHELL lENCTH Cl'^t^HES]) (^SMM^ Figure 4, — Size frequency distribution (May 1968 — sample size 520) and average shell length (arrow) of the southern quahog (M. campechiensis) from a population in Boca Ciega Bay, Fla,, 1964-68 (1 mm. =0.04 inch). Table 2. — Biometric data for six large southern quahogs from Boca Ciega Bay, Fla. Clam condition Estimated age Length Height Width Fresh whole weight Shell weight Weight of nMiat and luice Years Mm. Mm. Mm. £i G. G^ Alive SO 172 I6l 102 2,100 I,lilt2 658 Alive 19 169 170 99 2,W5 1,865 620 Alive 20 167 159 109 2,3511 1,681 673 Alive 17 166 161. 105 2,21l7 1,51*9 698 Dead ll4 179 168 102 - - - Dead 19 173 172 102 - - - We also collected more than 100 large clams in northern Boca Ciega Bay where a record- size clam was reported in 1964. The specimen was 168 mm. long and weighed 3 kg. (kilo- grams). Our collection had two living and two recently dead clams whose length exceeded that of the record specimen (table 2). We deter- mined the age of the clams by counting annual growth lines on the shell; the distance between successive annuli showed yearly increments of growth. To help identify the annuli, we used a diamond-toothed saw to cut shells trans- versely from the umbo to the ventral edge (fig. 5). The estimated age of the six largest clams in the collection was 14 years or more (table 2), The largest living clam had a shell length of 172 mm. (fig. 6) and an estimated age of 20 years. Lugworm A large marine baitworm commonly called the lugworm (Arenicola cristata) was intro- duced this year as a prospect for aquaculture. The worm is good bait for spotted sea trout, sheepshead, and red and black drums. The Figure 5. — Cross section of a southern quahog shell (M. campechiensis) showing laminated structure. Dark bands (closely spaced laminae) represent annuli that appear as deep depressions on the outer surface of the shell (marked by lines). Figure 6. — Largest known southern quahog (M. campechi- ensis)— 172 mm. — collected alive from Boca Ciega Bay, Fla. The shell has been cut transversely to show lami- nated structure from which the age of the clam can be determined. characteristic that makes it well suited for aquaculture is its mode of reproduction. Eggs are laid in a jelly mass attached to the bay bottonn where they can be picked up at low tide and transferred to prepared trays of sediment in tanks of running sea water. Preliminary experiments show that at least 72 worms with an average length of 15.2 cm. can be harvested in 6 months from a 15 -cm. layer of sand, 1 m.^. Locally, the worms sell for 50 cents per dozen. At this rate, worm production from one sediment tray is worth $3,00 every 6 months. Feed- ing the worms is no problem, because they consume algal detritus that accumulates inthe tanks. The marine baitworm business now depends on blood and clam worms dug along the coasts of New England and Eastern Canada. These worms are hard to rear because they spawn into the sea and produce planktonic larvae that are difficult to obtain and feed. We believe that the culture of lugworms can be a profitable business capable of increasing the income from marine bait worms (now valued at about $1.3 million annually). Squid Biological collections in Tampa Bay in 1961 and 1962 showed that the squid (Lolli- guncula brevis) occurs throughout the Bay, especially in the brackish waters of Old Tampa Bay, Hillsborough Bay, and upper Tampa Bay. In 1968, egg masses of L. brevis were found in Tampa Bay in February and April. These finds are of interest because the embryological development of L. brevis has never been described. Embryos were maintained in the laboratory, and a develop- mental series for further study was photo- graphed and preserved. Gross anatomical features of the embryonic squid are clearly visible through the clear matrix of the egg mass and egg (fig. 7). Sea Grass We started a cooperative project with the BCF Technological Laboratory in College Park, Md., inthe summer of 1967 todetermine the nutritional value of a sea grass known as turtle grass (Thalassia testudinum). Turtle grass is the most common sea grass in Tampa Bay and in shallow water along the west coast of Florida. Grass beds harbor a rich assemblage of marine life and produce enor- mous amounts of organic matter. In the past, biologists have successfully used leaves of turtle grass as a mulch and fertilizer on an experimental basis for crops such as tomatoes and strawberries. 2MM. LATERAL FIN MANTLE PIGMENT SPOT FUNNEL EYE ARM YOLK SAC Table 3." Proximate analysis of turtle grass from Boca Ciega Boy, Fla. Plant part Protein Moisture Ash Fat Percent Percent Percent Percent Leaves 11.76 7.62 ".6.57 0.66 Roots and rhizomes 10.27 7.60 1>2.15 0.27 Debris tv.53 1.65 88.61 0.10 Figure 7. --Late embryo of the squid, L. brevis. from Tampa Bay, Fla. Analysis of whole plants of turtle grass shows that it is notably high in protein (table 3), and this knowledge prompted us to ex- plore the idea of using turtle grass as a feed for livestock. In August about 363 kg. (dry weight) of turtle grass were harvested and shipped to College Park (fig. 8). The grass was processed and fed to sheep. One group of sheep was fed a normal diet, and an experimental group was fed in the same way except that turtle grass was substituted for 20 percent of the regular ration. Sheep that received the feed containing turtle grass grew significantly more than the control group. Figure 8.— Harvesting turtle grass (T. testudinum). A— turtle grass beds along the west coast of Florida; B— mower for cutting sea grass; C~harvesting operation; D— rinsing racks and drying turtle grass leaves. Dredge-fill On many occasions governmental agencies have asked us to miake bottom surveys of areas proposed for dredge -fill development. Our findings are used to estimate the value of endangered biological resources. This value must be weighed against anticipated benefits of bayfill projects. To facilitate the collection of quantitative field data, we designed several pieces of equipment for use in estuaries along the Florida west coast {fig. 9). The plug sampler is a box of stainless steel .125 m. wide, .125 m. long, and 23 cm. deep. Handles (1.2 cm. in diameter) and screening (0.701 mm.^ mesh) are welded to the top. In operation, the sampler is pushed into the bottom, dug out with a shovel, and emptied into a sieve box (0.701 mm.^ mesh) that is supported on a screen-covered frame with styrene plastic flotation. The sample is then washed free of fine sediment and preserved. Jars, preservative, thermometer, water sample bottles, notebook, and other equip- ment can be transported on the water in a tub placed inside an inflated tire tube. The sampler can also be used by divers for surveys in deep water; one man operates the sampler and shovel, and another transfers Table 4. — Number of bentiilc species and irdlviduals in 10 sainplee or 0.125 m.^ from each of three subtidal beds of turtle grass in Sarafiota Bay, Fla. , December 7, 1967J/ Tax on Otter Key South Lido Key Pansy Bayou Specli • s Individuals Spect Indi .viduals Species Individuals Number Platyhelmlnthes - - I 2 Rhynchocoela - 2 3 I 1 Mollusca 12 23 17 h^ 12 17 Annelida Oligochaeces 1 18 53 1 23 Polychaetes 15 73 21 65 13 151* Arthropoda Decapods 11 2k 11 22 9 26 Amphipods 3 39 125 U IU7 Isopods 1 2 5 2 Ul Photonlda - - 3 - Echlnodermata 1 1 2 11 1 lit Totals hh l8o 60 352 Ml U25 Total Individuals 957 Average Individuals per sample 32 Individuals per square meter 2,) Figure 14. — Relations of the human population In seg- ments of the Florida west coast to estuarlne acreage filled for residential and industrial use. (1 acre = 0.405 hectare). Coastal segment Industrial pollutants Domestic-^ pollutants Population 1 H.g.d. 3/ H.g.d. 3/ Thousands 10 2 0.018 0.090 1 3 3/ 7.190 72 k 10.309 82.689 71*6 5 6 3.008 1/ 6.797 3/ 71 It 7 3/ 0.951 6 8 118.231 22.310 186 Total 131.566 120.027 1,096 Grand total of all pollutants 251 593 —'To convert millions of gallons per day to millions of liters per day, multiply by 3.785. i/.Includes plant design capacity where true flow is unknown. -^ Insignificant . have compared the earliest charts of the coast with present charts to map filled areas and have supplemented this work with field observations. The total filled area is 8,851 ha. (hectares). As one would expect, the greater the human population the greater the area that has been filled, with the exception of the northwestern segment of the coast where little filling has been done up to now (figs. 13 and 14). The location, nature, and quantity of pollu- tion were determined from available sources and the rates of flow totalled by segment (table 7). Although the general magnitude of pollution of estuaries has been known for several years, the specific points of discharge and their relation to the living resources-- such as oyster and clam beds and submerged vegetated areas--have not been mapped and described previously. Thus, the Area Description study generates basic knowledge that is statistical in nature and can be mapped readily to show the extent of man's inroads into estuarine resources. It will provide new, basic information for those who are acting to protect the fisheries. Biology The purpose of the Biology phase is nnore dynamic than that of the Area Description phase. It documents the importance of the estuaries as nurseries and contributors to the success of the Gulf of Mexico fisheries. The participants have unanimously agreed to define: 1. The major connmercial species appearing in the estuaries as immature animals and, within sampling limitations, as adults. 16 2. The quantitative distribution of each of the species by season and area for 1 to 2 years; all participants are to sample simultaneously for the minimunn period April 1, 1967, through March 31, 1969. 3. The value of harvested species that live in estuaries during part or all of their lives. 4. The correlation between hydrological characteristics and relative abundance of se- lected organisms, mainly with respect to salinity and temperature. All participants are using 30.4-m. seines, 4.9-m. flat otter trawls, and 1/2-m. plankton nets that are fitted with No. 2 plankton netting and flow meters. The west coast of the Florida peninsula is sampled once each nnonth at five locations from Chokoloskee, in the Ten Thousand Islands, to the St. Marks River estuary (fig. 13). We chose the stations because they are physically and hydrologically similar. The five sampling stations are on 644 km. of coast, which is sannpled in 5 days whereas previous studies of this kind have been confined to single or adjacent estuaries. The seasonal and geographic variations in the species and numbers of fish are marked. From January through May, total number of fish were in the ratio 1:3:3:5:5 for January, February, March, April, and May, respectively (table 8). More fish were caught at the three more southerly stations than at the two northerly stations. Grand totals of abundance were in the ratio 4:4:7:1:1 from southernmost to northernmost locations. Seventy-eight species were identified. Twelve occurred universally along the 644 km. of coast; 8 at either the three northernmost or the three southernnnost locations only; and the rest at only one or two adjacent locations. As the waters warmed in the spring, many species increased their distribution, especially northward. Although it is too soon to attempt to evaluate biological results, it appears that a new con- ception will emerge of the seasonal and geographical population dynamics of fishes-- especially of commercial species which inhabit the estuaries as young. Table 8. — Numbers of fish caught by seine and trawl nets at five locations on the Gulf of Mexico coast of Florida, January through May 1968 Month Locations and principal species January Grand February March April May total Number Chokoloskee Anchoa mitchilli (bay anchovy) Lagodon rhomboides (pinfish) Others Total Bokeella Anchoa mitchilli (bay anchovy) Lagodon rhomboides (pinfish) Menidla beryllina (tidewater silverside) Others Total Maximo Point Anchoa mitchilli (bay anchovy) Lagodon rhomboides (pinfish) Menidia beryllina (tidewater silverside) Others Total 116 1,700 700 - 3 - 9 k - 610 223 65 U5 33 31^3 339 1,77'^ 7kg 33 956 - 7 6 . - 3 1^38 165 567 1,159 25 7 kl 960 113 7 kh 11 155 192 35 hgd 223 1,682 1,464 3,851 3,900 267 533 1,520 - 261 18 3 25 1,254 612 36 9 2 258 12 426 146 113 609 703 747 691 1,660 2,121 1,588 6,807 17 Table 8. --Numbers of fish caught by seine and trawl nets at five locations on the Gulf of Mexico coast of Florida, January, through May 1968--Continued Locations and principal species Month January February March Grand April Ifey total Cedar Key Anchoa mitchilli (bay anchovy) Lagodon rhomboides (pinfish) Menidia beryllina (tidewater silverslde) Others Total St. Marks Lighthouse Lagodon rhomboides (pinfish) Menidia beryllina (tidewater silverside) Others Total Number U5 - 19 20 - - 3 5 2 9 Ill 1*3 85 401 21 25 18 20 125 172 281 Gk 129 51+8 202 - 8 21+ 12 93 - 185 5 28 190 - 90 17 69 11+6 - 283 U6 109 1+29 1,221+ 867 Grand total 1,1+02 3,308 2,807 It, 1*93 i*,639 16,61+9 BIOLOGY OF INDUSTRIAL SCHOOLFISHES PROGRAM Charles M, Fuss, Jr. , and John A, Kelly, Jr. This program was initiated at the beginning of the fiscal year to study the biology of thread herring (Opisthonema oglinum) and other potential industrial schoolfishes (excluding menhaden) in coastal waters of the eastern Gulf of Mexico. A preliminary study entitled "Biology of Thread Herring" under the East Gulf Estuarine Program was activated 3 months earlier (April 1, 1967). Recent industrial interest in the use of thread herring as an alternate to diminishing menhaden stocks stim- ulated us to expand our efforts in this area. Aerial and surface surveys by the Explora- tory Fishing and Gear Research Base at Pascagoula, Miss., and IRT (aerial infrared temperature) surveys by this Laboratory have shown that thread herring occur in extensive concentrations along the west coast of Florida. Biological information on the species is ex- tremely sketchy, but the present study is expected to provide many of the data needed to ensure the orderly development and ex- pansion of the fishery on the basis of sound biological principles. DEVELOPMENT OF THE FISHERY An industrial thread herring fishery in the eastern Gulf began in August 1967 when the Protein Products Corporation opened its pro- cessing plant on Charlotte Harbor near Fort Myers. A locally based, Bureau- financed vessel (fig. 15) began fishing in late August, and a typical menhaden vessel joined the operation fronn October to December 1967 and again in February 1968. In November and December 1967, a number of Louisiana -based menhaden vessels entered the fishery, landing catches at the Ocean Protein, Inc., plant at 18 Figure 15. — Single-boat-rig purse seiner used in thread herring fishery. DuLac, La. In May 1968, the original single- boat-rig purse seiner was replaced by a men- haden vessel. Fishing has been restricted to a relatively (ft small area between Gasparilla Island and Sanibel Island in nearshore waters 6 to 20 m. deep (fig. 16). Poor bottom conditions to the north and south and a scarcity of fish in off- shore waters have restricted the fishing area. Almost 5,100 metric tons of fish were landed at the Fort Myers plant from August 1967 to June 1968 despite a series of legal conflicts concerning the taking of food fish that were incidental to the thread herring in the catches. The food fish problem was eventually settled with Bureau assistance by a court decision in February 1968 that allows a small percentage of food fish in catches of industrial fish. About 1,150 metric tons of thread herring were landed in Louisiana during the winter. The new thread herring fishery is of great importance because of the continuing decline of menhaden stocks and an increasing demand for animal protein. The commercial catch of about 6,250 metric tons in 10 months despite adversities shows that the fishery has capacity for further development. 19 28' 27' 26" 25' 1 84° I I— I— I I I — I — I I I—'—' I ./ O 82' • TAMPA ST. PETERSBURG ■, - ,/ TAMPA BAY FISHING AREA -»- CAPE SttLC DDT TORTUGkS 1 I— I — I I x: 28' 25° N. 84* 83* 82°W. Figure 16. — Thread herring fishing grounds on the Florida west coast. PROGRAM GOALS Board program goals were developed to formulate future management principles for taking thread herring and other potential industrial fish along the Florida west coast. Because of limited funding and personnel, however, we have had to restrict the initial objectives to the studies considered most important to the immediate needs of the de- veloping thread herring fishery. We have emphasized goals that may be achieved in 5 20 years. Life history, distribution, commercial catch analysis, and some aspects of natural behavior are priority items. Some of the immediate questions to be an- swered are as follows: 1. How long do thread herring live, and how fast do they grow? 2. What year classes make up the commer- cial catch, particularly during the early stages of the developing fishery? 3. When and where does spawning occur, and what areas serve as nurseries? 4. Do thread herring migrate, and if so, what are seasonal patterns? 5. How does water temperature affect the distribution of stocks? 6. What factors affect vertical distribution of fish and schools of fish? 7. Do game fish feed on thread herring, and if so, to what extent? FACILITIES AND PROCEDURES The R/ V Kingfish is equipped with a hydraulic power block for fishing monofilament gill nets of various mesh sizes. Adult fish are sampled in Tampa Bay, Charlotte Harbor- Pine Island Sound, and nearshore Gulf waters between the two estuaries. At each gill net station, plankton tows are made for eggs and larval fish, and oceanographic data are recorded. Beach seines and lift nets were used to collect junvenile thread herring in shallow areas and near docks and bridges. We have collected samples of the catch of commercial vessels since the beginning of the fishery. Commercial fishermen have co- operated in providing samples from purse seine catches along with information on fishing effort and areas of operation. Fishing logbooks have been placed aboard all vessels engaged in the fishery. Conversion of part of a dockside warehouse gave us a new laboratory for processing fish samples. Laboratory processing of fish sann- ples includes measurements of body length and depth, body weight, and where applicable, gonad weight. Fish are sexed, and scales, stomach, and gonad samples preserved for future analysis. Samples from our fishing operations and from commercial catches re- ceived the same treatment. A through-flow sea-water system is avail- able for holding live fish. Attempts are being made to hold fish for long periods to provide data for age and growth studies and for ex- periments in artificial fertilization. PROGRESS DURING THE YEAR The highlights of research results during the first year are as follows: 1. Analyses of connmercial catches landed at the Protein Products plant showed that food fish taken incidentally in thread herring purse seine sets did not exceed about 0.35 percent (by weight) of the total catch. At court hearings on the food fishproblem, we presented these data along with opinions stating that the thread herring fishery would have no significant adverse effects on stocks of food and sport fish. As a result, the court delivered a declaratory judgment permitting the taking of a small amount (unofficial agreement is 1 percent) of food fish in purse seining for nonfood fish. Testimony given has thus been instrunnental in assuring the continued growth and development of the thread herring fishery on the Florida west coast. 2. Thread herring catches per unit of effort (30-minute set with a 5.1-cm. mesh, 30.5 m. by 3.1 m. monofilament gill net) in Gulf waters off St. Petersburg Beach reached a peak in late spring and early summer and declined with falling water temperatures in the fall. Very few thread herring were taken during the winter (fig. 17). When coastal waters cool, the thread herring concentrate in the south, and when the waters warm, the fish disperse to the north, and possibly offshore. 3. Catch per set by commercial vessels off Fort Myers reached a peak in winter and declined with the warming of coastal waters in the spring. Warming water and possibly factors associated with warming water, such as feeding and spawning habits, seem to affect the schooling behavior of thread herring. In the warmer months many surface schools occur off Fort Myers, but individual schools contain fewer fish than in the cooler months. Purse seine sets therefore produce fewer fish in the summer. 4. Juvenile thread herring appeared in beach seine samples along Gulf beaches in the Tampa Bay area in July and disappeared by October. Figure 17. — Mean number of thread herring caught per set of a 30.5-m„ 5.1-cm. mesh monofilament gill net In Gulf waters off St. Petersburg Beach. 21 5. Fully developed gonads were found in thread herring 140 to 165 mna. fork length taken off St. Petersburg Beach in early April. Spent gonads, indicative of spawning, were found by late May when water temperature was about 27° C. Gonad developnaent indicates a spawning peak in June. 6. The ratio of males to females in the summer thread herring population off St. Petersburg Beach was about 1 to 5 whereas that in the winter population off Fort Myers was about 1 to 1 . 7. Ripe thread herring were induced to spawn in laboratory tanks, but the eggs did not survive. 8. The stomachs of ZOO mackerel taken by conamercial fishermen in the Naples area were examined, and no thread herring were found. RED-TIDE PROGRAAA TOXIN RESEARCH Dean F. Martin The University of South Florida completed a contract with this Laboratory to isolate and characterize the fish-killing toxin of red tide. Contract research demonstrated that there are two chemically distinct toxins. Aprocedure was developed to isolate and purify both sub- stances from cultures and natural blooms. One toxin is minor and can be isolated only in trace quantities. The major substance is a neurotoxin, and properties from samples isolated from unialgal cultures and blooms of Gymnodinium breve appear to be identical on the basis of infrared data. The major toxin isolated is a light yellow, low-melting solid. Qualitative elemental analysis identified the presence of carbon, hydrogen, and phosphorus. Sulphur, chlorine, bromine, and nitrogen were absent. The sub- stance was characterized by the absorption spectra (ultraviolet and infrared), the nuclear magnetic resonance spectrum, and optical activity nneasurements. A molecular weight of 650 and the formula C90 H^gj "^17 ^ were determined for the major toxic substance. ENCYSTMENT STAGE OF GYMNODINIUM BREVE William N. Lindall, Jr. Studies on the encysted forms of G. breve were completed through use of an electron nriicroscope. By using standard fixation solu- tions (gluteraldehyde and osmic acid) with variations in fixing times and dehydration, repeatable results were obtained. These re- sults are not ideal because of difficulties in preserving, dehydrating, and embedding such a fragile organism, but the basic organelles within the cell were photographed and identi- fied. Trichocysts were found within the cells, which to our knowledge have never been re- ported in G. breve. The reason for labeling the results "not ideal" is that the cytoplasnn is vacuolated and appears to have been leached out during the harsh preparation that is required for electron microscopy. This vacuolation may, however, be characteristic of the cyst form, which is rounded and smaller than the motile fornn. The same techniques are being applied to the motile cell in an attempt to compare the two forms. PLANKTON ECOLOGY PROJECT J. Kneeland McNulty A study of primary productivity in Tampa Bay continued in the past year. Its purpose was to learn more about fundamental ecological processes at work in the Bay, especially those which relate directly to the production of phytoplankton including Gymnodinium breve, the causative agent of red tide. All fisheries depend directly or indirectly on plant production. Even so, estimates of phyto- plankton productivity are available for less than 10 inshore areas worldwide. The Tampa Bay study may be the most extensive of its kind in any estuary. It dates from September 1962, and covers representative areas seasonally. The sequence of pertinent ecological events in Tampa Bay in fiscal year 1968 is described in this report to illustrate the seasonal inter- relationships of environmental and biological processes. The data are graphed as if they were in chronological sequence despite the dis- continuity between June 1968 and July 1967 (fig. 18). Moving averages of the order three \vere used to smooth the data. Average annual solar radiation at Tampa is one of the highest at a seacoast location in the Nation. Seasonal variations during the past year were typical. Solar radiation rose sharply in March, peaked in late May, dropped to a summer low in August because of summer rains, reached a second peak from mid- August to late September, then dropped steadily to the winter minimum in mid- December. Primary productivity attained two peaks-- one in April- May and the other in August- September. Separate stimuli apparently trig- gered the two peaks. The spring increase began when water temperature reached about 22° C., 40 days after solar radiation began to 22 E Oo.2e 3 ll iJzi -— A..--^ — y^ — \-/- -ta|w 1 \ r— ULTRAVIOLET Figure 18. — Comparison of selected properties of the environment in fiscal year 1968. Moving averages of the order three were used to smooth the data except for ultraviolet absorption — for it, raw data were used. Transparency is the depth (m.) to which 35 percent of surface light penetrated. Dashed lines indicate discontinuity between June 1968 and July 1967. JAN. FEE MAR. APR. MAY JUN. I JUL. AUG. SEP OCT. NOV. DEC. 1968 1967 23 increase rapidly. The summer increase began when salinity began to decrease, i.e., from runoff of sun-inner rains entering the Bay. Thus, the spring bloom appeared to be temperature- related, probably through the release of nu- trients by bacteria at a critical temperature, whereas the summer increase was probably salinity- related. As would be expected, water transparency decreased at the same time that phytoplankton production increased. Ultraviolet absorption was measured during the past year as it has been since February 1963. Two peaks occurred, one in early April and the other in September. The early April peak preceded the spring bloom of phytoplank- ton by a few days; the September peak was coincident with a minimum of salinity and a nnaximum of phytoplankton productivity. The fact that the spring increase occurred at a time of increasing salinity shows that river runoff and laltraviolet absorption are not nec- essarily related. The ultraviolet absorption test was initiated in 1963 because of its possible utility in pre- dicting red-tide outbreaks. The test is simple and rapid. The reasoning was that ultraviolet absorption might be an indicator of the presence of nutrients which are essential to a bloom of G. breve. Ultraviolet absorption is related to the organic content of water; therefore, un- usually high or low absorption might indicate unusually high or low concentrations of the nutrients associated with organic substances. Field data substantiated this reasoning. In the spring of 1963, ultraviolet absorption increased markedly just before a red-tide outbreak and decreased markedly just after the bloom. There were no red-tide outbreaks from then until September 1967, when a relatively mild one occurred. Again, ultraviolet absorption in- creased markedly just before and during the outbreak. However, unusually high values of ultraviolet absorption are not necessarily ac- companied by a red-tide bloom. An increase in absorption in September 1965 was not ac- companied by unusually high counts of G. breve. Increases of ultraviolet absorption are usually accompanied by decreases of salinity, but the relation is only approximate as shown by the graph of maximum, minimum, and average values of both properties from February 1963 to June 1968 (fig. 19). How does the phytoplankton primary pro- ductivity of Tampa Bay compare with that of other inshore areas? The average gross annual rate in fiscal year 1968 was 401 g.C/m.^ (grams of carbon per square meter), whereas the annual rates published for other waters are 99.6 in shallow North Carolina estuaries, 39 to 1 75 in certain Danish bays, and 380 g.C/m.2 in Long Island Sound. Thus, Tampa Bay's phy- toplankton primary production is one of the highest that has been measured. The productivity of Tampa Bay can be viewed also in relation to terrestrial plant production. SALINITY [Rangt J UtanJ W- i i^^*liiltmt^ii'itiimt^iii|i»lifttllitfH*ifi F A J A 1963 ULTRAVIOLET (Rongt a Mtonl ODPAJAODFAJAODPAJAOOPAJAODFAJ 1964 1969 1966 1967 1968 Figure 19. — The range and mean of monthly salinity and ultraviolet absorption from February 1963 through June 1968. Red tide was coincident with two of three periods of high ultraviolet absorption. The orange crop is by far the most valuable of Florida' s agricultural products. Orange groves abound in the Tampa Bay area. The Statewide average production of oranges over a recent representative 5-year period was 3,937 kg./ ha. /year (kilograms per hectare per year) (dry weight) whereas the average production of phytoplankton in Tampa Bay was 10,017 kg./ ha. /year in fiscal year 1968. Benthic algae and grasses boost the total annual production of plant material in Tampa Bay to two or three times the annual phytoplankton production, so that the total is in the range of 20,000 to 30,000 kg. /ha. per year. For comparison, the world average annual production of wheat is about 3,400 kg. /ha., and the highest production of wheat and corn in northern Europe is about 16,000 kg. /ha. per year, including straw and roots. Thus, the annual production of plant material in Tampa Bay is high con-ipared with the annual production of terrestrial crops, just as it is high in relation to production of phyto- plankton in other inshore marine areas. The waste of organic material in Tampa Bay and other fertile estuaries is prodigious in terms of potential direct benefits to man. It is tempt- ing to speculate that herbivore yield ashighas 10 to 20 percent of primary production of plants is theoretically possible, as has been attained in the conversion of corn to hogs, although a yield of 3 percent is apparently the highest yet achieved in marine farm ponds. The usual harvest of seafood is a small fraction of 1 percent of primary production. The losses occur at various stages in the complicated food chains between primary production and edible fishery products. Man's grasp of the facts is fragmentary and hence his control of the processes involved is insignificant. One of the major scientific and engineering challenges of our time is to attain better control of the proc- esses involved in estuarine seafood production. 24 PUBLICATIONS DRAGOVICH, ALEXANDER, JOHN A.KELLY, JR., and H. GRANT GOODELL. Hydrological and biological characteristics of Florida's west coast tributaries. U.S. Fish Wildl. Serv., Fish. Bull. 66: 463-477. FINUCANE, JOHN H., and GORDON R. RINCKEY. A study of the African cichlid, Tilapia heudeloti Dumeril, in Tampa Bay, Florida. Proc. Southeast Game Fish Comm. 18th Annu. Sess: Z59-269. FUSS, CHARLES M., JR. The new thread herring fishery in eastern Gulf of Mexico. Commer. Fish. Rev. 30(6): 36-41. SALOMAN, CARL H. Diel and seasonal occurrence of pink shrimp, Penaeus duorarum Burkenroad, in two divergent habitats of Tampa Bay, Flor- ida. U.S. Fish Wildl. Serv., Spec. Sci. Rep. --Fish. 561, iii + 6 pp. SALOMAN, CARL H., DONALD M. ALLEN, and THOMAS J. COSTELLO. Distribution of three species of shrimp (genus Penaeus) in waters contiguous to southern Florida. Bull. Mar. Sci. 18: 343-350. SALOMAN, CARL H., and JOHN L. TAYLOR. Hydrographic observations in Tampa Bay, Florida, and the adjacent Gulf of Mexico -- 1965-66. U.S. Fish Wildl. Serv,, Data Rep. 24, 393 pp. on 6 micro- fiches. SYKES, JAMES E. Report of the Bureau of Commercial Fish- eries Biological Laboratory, St. Peters- burg Beach, Florida, fiscal year 1966. U.S. Fish Wildl. Serv,, Circ. 257, iii + 18 pp. Report of the Bureau of Commercial Fish- eries Biological Laboratory, St. Peters- burg Beach, Florida, fiscal year 1967. U.S. Fish Wildl. Serv., Circ. 290, iii + 17 pp. The role of research in the preservation of estuaries. Trans. 32d N. An-ier. Wildl. Natur. Resourc. Conf.: 150-160. Commercial values of estuarine-generated fisheries in the south Atlantic and Gulf of Mexico coasts. Proc. Symposiunn on Marsh and Estuary Management, La. State Univ., Baton Rouge, La., July 19-20, 1967 (ed., John D. Newsom): 73-78. TAYLOR, JOHN L., and CARL H. SALOMAN. The oarfish, Regalecus glesne; a new oc- currence and previous records from the Gulf of Mexico. Copeia 1968: 404- 405. Rearing lugworms for fish bait. Commer. Fish, Rev. 30(8-9): 61-63. MANUSCRIPTS IN PRESS DRAGOVICH, ALEXANDER. Preliminary observations of morphological variations of Gymnodinium breve Davis under natural conditions. J. Fla. Acad. Sci. FINUCANE, JOHN H. Ecology of the pompano (Trachinotus caro- linus ) and the permit (T. falcatus) in Florida. Trans. Amer. Fish. Soc. Antimycin as a toxicant in a marine habitat. Trans. Amer. Fish. Soc. FINUCANE, JOHN H., and RALPH W. CAMP- BELL II. Ecology of American oysters in Old Tampa Bay, Florida. J. Fla. Acad. Sci. FUSS, CHARLES M., JR., and JOHN A. KELLY, JR. Transplanting, survival, and growth of sea grasses under artificial conditions. Bull. Mar. Sci. MARTIN, ROBERT A., and JOHN H. FINUCANE. Reproduction and ecology of the longnose killifish, Fundulus similis. J. Fla. Acad. Sci. TAYLOR, JOHN L., and CARL H. SALOMAN. Some effects of hydraulic dredging and coastal development in Boca Ciega Bay, Florida. U.S. Fish Wildl. Serv., Fish. Bull. MS #1863 25 GPO 870.866 MBL WHOI Llbinr" 5cnals 5 WHSE 00479 As the Nation's principal conservation agency, the Depart- ment of the Interior has basic responsibilities for water, fish, wildlife, mineral, land, park, and recreational re- sources. Indian and Territorial affairs are other major concerns of America's "Department of Natural Resources." The Department works to assure the wisest choice in managing all our resources so each will make its full contribution to a better United States — now and in the future. UNITED STATES DEPARTMENT OF THE INTERIOR U.S. FISH AND WILDLIFE SERVICE BUREAU OF COMMERCIAL FISHERIES WASHINGTON, D.C. 20240 POSTAGE AND FEES PAID U.S. DEPARTMENT OF THE INTERIOR THIRD CLASS OFFICIAL BUSINESS Return this sheet to above address, if you do NOT wish to receive this material [ | , or if change of address is needed | | (indicate change including ZIP Code).