FISHERY RESEARCH GALVESTON BIOLOGICAL LABORATORY FISCAL YEAR 1961 UNITED STATES DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE SERVICE BUREAU OF COMMERCIAL FISHERIES CIRCULAR 129 United States Department of the Interior, Stewart L. Udall, Secretary- Fish and Wildlife Service, Clarence F. Pautzke, Commissioner Bureau of Commercial Fisheries, Donald L. McKernan, Director GALVESTON BIOLOGICAL LABORATORY FISHERY RESEARCH for the year ending June 30, 1961 George A. Rovmsefell, Director Joseph H. Kutkuhn, Assistant Director Circular 129 Washington, D. C. July 1961 The Galveston Biological Laboratory and its field stations conduct fishery research in the Gulf of Mexico, as part of the work of the Bureau of Commercial Fisheries in the Gulf and South Atlantic Region (Region 2), which comprises the eight coastal states from North Carolina to Texas. Office of the Regional Director, Seton H. Thompson, is in the Don Ce»«Sar Federal Center, P. O. Box 6Z45, St. Petersburg Beach, Florida. Other offices are: Biological Research Biological Laboratory, Brunswick, Georgia Biological Laboratory, Beaufort, North Carolina Biological Laboratory, Gulf Breeze, Florida Biological Laboratory, Galveston, Texas Biological Field Station, Miami, Florida Biological Field Station, St. Petersburg Beach, Florida Biological Field Station, Pascagoula, Mississippi Industrial Research Exploratory Fishing and Gear Research Base, Pascagoula, Mississippi, auxiliary base at Brunswick, Georgia Marketing •« Market Development Offices in Dallas, Texas; Jacksonville, Florida; and Pascagoula, Mississippi Technology - Technological Laboratory, Pascagoula, Mississippi Resource Development Statistical Center, New Orleans, Louisiana TABLE OF CONTENTS Page Report of the Director 1 Staff "7 Shrimp Fishery Program 9 Early life history of commercial and related shrimps .... 10 Identification and description of shrimp larvae 14 Identification of postlarval and juvenile shrimp 17 Migrations, mortality, and growth of pink shrimp 18 The Campeche pink shrimp population, 1956-1960 22 Industrial Fishery Program 26 Industrial bottom-fish fishery in the north central Gulf of Mexico 27 Preliminary survey of industrial- type bottom fishes in the northwestern Gulf of Mexico 31 Menhaden biology 33 Estuarine Program 34 Evaluation of estuarine data 35 Effects of engineering projects 36 Ecology of nursery areas 38 Trinity Bay project 41 Physiology and Pesticide Program 43 Shrimp physiology 44 Effects of pesticides 49 Red Tide Program 56 Culture and nutrition of Gymnodinium breve 58 Chemical control 59 Ecology of red tide 61 Hydrology of Tampa Bay and adjacent waters 65 Special Reports Sea-water systena 68 Oyster studies 72 Distribution of pink shrimp larvae and postlarvae 75 Seminars and Meetings 77 Publications 78 Manuscripts Submitted 82 COVER: Recirculating sea-water system on the laboratory grounds, completed February 1961. REPORT OF THE DIRECTOR George A. Rounsefell Fisheries of the Gulf of Mexico continue to expand The record 1959 catch of fish and shellfish from Gulf waters, which exceeded a billion pounds (1,155,000,000) for the first time, was surpassed in I960 by some 111 mil- lion pounds or about 10 percent. While the catch in other United States areas decreased by 5. 1 percent, the Gulf catch increased by 9o 7 percent. Although the size of the increase was due in large measure to a record catch of men- haden (841 million pounds), the shrimp catch also rose. Texas, Louisiana, and Florida ranked among the top six states in value of I960 landings. Research highlights of the past year Completed analyses of 4 years (1956- 1959) of detadled observations on catches of shrimp and fishing effort through- out the Gulf show that populations of all three major species, brown, pink, and white, undergo two periods of heightened spawning activity and thus pro- duce two definable broods of young shrimp each year. There is good evidence that hurricanes, sweeping high turbulent waters over the estuaries, can cause decreased survived of a brood of young shrimp. Because fishermen in the high- seas fishery (especially on the Campeche Banks) cull the smaller sizes of shrimp from their catches, it will be difficult to obtain reliable estimates of relative abundance of stocks on these far banks until we can secure unculled samples of the catches. Relatively high recoveries on the Sanibel fishing grounds of juvenile pink shrimp stained and released in Pine Island Sound, coupled with no recov- eries on the Tortugas grounds, indicate that shrimp taken in the Sanibel and Tortugas fisheries may depend on different nursery areas. More exact defin- ition of the boundary must await future releases in the area between Pine Island Sound and Shark River. Larval stages of the seabob, Xiphopeneus kr<^yeri, have been iden- tified and described for a forthcoming publication. The numbers of postlarval shrimp entering Galveston Bay during March and April fell from 582 per sample (17 samples) in I960 to 22 per sam- ple (15 samples)in the same period of I96I. Associated hydrographic data are being analyzed for an answer to this sharp fall in numbers. Preliminary studies of industrial-type fishes off the east coast of Texas over a 9-month period show that the most abundant species by both num- ber and weight was the longspine porgy, Stenotomus caprinus. The second naost abundcuit by weight was the lizardfish, Synodus foetens, followed by the Atlantic croaker, Micropogon undulatus. This contrasts with the findings of a similar study in the Mississippi Sound area in which the leading species was shown to be the Atlantic croEiker. Gulf States Marine Fisheries Commission The meetings of the Commission at St. Petersburg Beach, Florida, and Biloxi, Mississippi, were well attended by laboratory personnel. At the first meeting Mr. Haskell spoke on the Indus- trial fishery of the northern Gulf, and at the second, a tentative program for coordinated estuarine research presented to the Estuarine Technical Coordi«» nating Committee was given to the Commission for study. U. S. Study Commission « Texas Dr. Graham and Mr. Naab attended the September 6 meeting of the Fish and Wildlife Collaboration Group in Fort Worth, Texas, where the effects of water resource plans on estuarine fauna were discussed. The Commission's final report, to be completed in the late summer of 1961, will include a program of research that should be accom- plished along the Texas coast to determine the effects of water resource de- velopments, involving impoundments and diversions in the study area, upon marine fish and shellfish of commercial importance. The program was pre- pared and submitted to the Commission in July. Waste disposal in marine waters As the industrial complex grows the dis»» posal of large volumes of toxic waste materials becomes increasingly difficult. During the year two large companies discussed this problem with us. Both were aware of the possibilities of oceanic disposal damaging marine fauna and were seeking advice. The possibility of disposal by wide dispersion from a moving barge over deep waters to give desired dilution has been under study by an academic research group. Also under study is the feasibility of under- ground disposal into drilled wells. The companies are to be commended on their desire and efforts to avoid any damage to fishery resources. The Mississippi River-Gulf Outlet Project This study, carried on by The Texas A. and M. Research Foundation, is nearing completion after some Z^ years of intensive work. The field station at Hopedale, Louisiana, was closed in April, and the final report will be completed by midsummer. The wealth of data on biota in the low, medium, and high salinity areas, and the exten- sive hydrographic observations will permit, perhaps for the first time, a full evaluation in later years of the long-term effects of a very large-scale channelization project. The Hurricane Protection Project for Lake Pontchartrain is related to the Mississippi River-Gulf Outlet Project because of the wedge of higher salinity water that will enter Lake Pontchartrain along the bottom of the Gulf outlet canal. Laboratory personnel have participated in three meetings in New Orleans with Branch of River Basin Studies and Louisiana Wild Life and Fisheries Commission personnel and with the Corps of Engineers concerning tests run in the Lake Pontchartrain model at Vicksburg to determine the ef- fects of the Hurriceine Project on the hydrography of Lake Pontchartrain. Dr. Robert Reid of the Texas A. and M. Research Foundation has acted as hydro- graphic advisor at these meetings. Improvement in research facilities A large recirculating sea-water system on the laboratory grounds was provided during the year, using aji existing ma- sonry building 51 by 37 feet. The system contains two redwood tanks, each holding 28,000 gallons of sea water, which circulates through plastic piping to numerous taiiks in the insulated building cuid then is passed through two large sand and gravel filters. The system, described in detail later in this report, was dedicated on February 17 by Regional Director Seton H. Thompson, in the presence of guests from state cind university laboratories. Corps of En- gineers representatives, and industry members. It is already being used to hold specimens for the physiology and pesticide laboratories, for spawning of shrimp and rearing of shrimp larvae, and other purposes. Construction commenced in January on a constant flow sea- water laboratory on a 140- acre tract owned by the Bureau on East Lagoon about 3 miles east of the laboratory. This building, raised about 15 feet above sea level to avoid hurricajie damage, is on a 40- by 90-foot concrete slab with a large concrete tank on the roof. It will be finished in late summer. Whereas the recirculating system at the main laboratory provides rather well-controlled conditions of salinity and temperature, this system will give an opportunity, especially in the case of estuarine species, to study organisms under semi= natural conditions. The East Beach sea-water laboratory under construction, 3 The pesticide laboratory has been equipped with a special water- spray, airflow hood for safe handling of the more toxic formulations. All of the ground- floor laboratories in Building A now have sea water running through P. V, C. pipe from two 1500-gallon tanks on the upper balcony. The pesticide laboratory has also been provided with an independent air-condition- ing and heating system. Special work conferences Mr. Inglis attended a Corps of Engineers meet- ing in San Antonio concerning the use of gold isotopes to trace sand movements and sedimentation at the jettied entrance to Gcilveston Bay. Mr. Costello conferred with Branch of River Basin Studies from Vero Beach on the possible effects on the valuable Biscayne Bay fishery for bait shrimp of proposed offshore hurricane dikes paralleling the shoreline. Two meetings were held at College Station, Texas, to discuss the preparation of the final report on the Mississippi River-Gulf Outlet Project. Mr. Chin attended the Denver Pesticide Workshop, April 4-6, at the Fish and Wildlife Service's pesticide research center. Annual staff meeting The fourth annual staff meeting held at the Galveston Laboratory, February 14-17, was attended by nine staff members from field stations at Miami and St. Petersburg Beach, Florida, and Pascagoula, Missis- sippi. Mr. Seton Thompson, Regional Director, and Mr. John Glude, Chief of the Branch of Shellfisheries, attended. Because one of the major topics was estuarine research and its uses in connection with engineering projects, the Branch of River Basin Studies sent Mr, Herbert Hunter from the Atlanta Re- gional Office, Mr. John Byrn from the Albuquerque Regional Office, and Mr. John Degani from their Fort Worth field office. Mr. Edgar Arnold, currently working with the Southeast Study Commission, came from our St, Petersburg Beach Regional Office. The contributions of all types of our research to the solution of es- tuarine problems were discussed. A second major topic was the increasing of research production through the use of expanded facilities such as sea- water systems, vessels, field instrumentation, etc. Trainees Mr. Malloothara J. George of the Central Marine Fisheries Department, India, spent 4 weeks at our Miami Field Station and then came to Galveston where he spent 6 weeks reviewing and participating in the shrimp research program. He then went to the Grand Terre Laboratory of the Louisi- ana Wild Life aind Fisheries Commission to aid in studies of larval shrimp. Regional coordination Both at Pascagoula and Galveston, several days were spent in the periodic collection, preparation, and shipment of menhaden speci- mens and of menhaden gillrakers to the Beaufort Laboratory and the Virginia Fisheries Laboratory. Dr. Rounsefell met with the other Laboratory Directors and the Pascagoula Base Director at Pascagoula in July to finish the draft of the supply and production section of the Regional report on the status of Gulf and South Atlantic fisheries. In May Messrs. Haskell and Ragan visited the Brunswick Laboratory to discuss problems in identifying larvjil fishes. Cooperation with Branch of River Basin Studies The laboratory has worked closely with the Branch of River Basin Studies in the Bureau of Sport Fisheries and Wildlife concerning effects of engineering projects on marine fauna. The details are given in the Estuarine section. Public relations The Texas Game and Fish Commission requested and re- ceived assistance in establishing the nature of three discolored-water occur- rences, one in Matagorda Bay and two in the Galveston Bay area. Dinoflagel- lates were indicated in two cases and a blue-green alga in the third. Dr. Kutkuhn gave cin illustrated talk on our research to the Galveston Junior Chamber of Commerce. Dr. Rounsefell spoke on FAO and Turkish fisheries to the Quota Club, Mr. Haskell showed the movie "Trawls in Action" to Pascagoula trawl fishermen. Mr, William Renfro gave a talk on the re- search activities of the laboratory to the Exchange Club of Galveston. Mr. Skud sponsored Eagle Scout Robert Thompson, a Texas City high school sen- ior, at an installation dinner at the Houston International Airport. He is win- ner of a Math, English, and Science award and is interested in oceanography and fisheries as a career. Display of Gulf of Mexico fishes in foyer of the recirculating sea-water labor- atory. 5 The Laboratory put on a 3-day exhibit at the Galveston Farm and Home Show in Moody Center, March 24-26. Featured were collections of fishes, live fish and invertebrates, research photographs and equipm.ent, and projection of colored slides. This exhibit date coincided with National Wndlife Week. The Laboratory's collection of fish and invertebrates has been re- bottled and arranged in dust- free glass cases in the foyer of the new sea- water laboratory building. Several busloads of school children, scout troops from Galveston, Texas City, and La Marque, as well as groups of business people and out-of-town visitors, have examined it. STAFF George A. Rounsefell, Laboratory Director Joseph H. Kutkuhn, Assistant Laboratory Director Bernard E. Skud, Assistajit Laboratory Director (To Feb, 15) Biologiccd Laboratory at GaJLveston, Texas Field Stations at St. Petersburg Beach and Miami, Florida; and Pascagoixla, Mississippi Shrimp Fishery Program Joseph H. Kutkuhn Thomas J. Costello Donald M. Allen Willicum C. Renfro Robert F. Temple Jack G. Robinson Harry L. Cook Carl H. Sciloman Harold A. Brusher Kenneth N. Baxter Carlton H. Furr H. W. Altenhoff Elroy L. Young Carl E. Wood Samuel C. Jernigan Jonathan J. Bernstein John H. Tweedy Benjamin F« McPherson Donald R. Nelson Andrew E. Jones Joseph J. Ewald David T. McBain Howard R. Foulk Estuarine Program Joseph J. GraJiam Ronald C. Naab Anthony Inglis Richard A. Diener Charles H. Koski Cornelius R. Mock Genevieve B. Adams Industrial Fishery Program Winthrop A. Haskell James A. Ragan John M. Hitton, Jr. James G. Smith Charles M. Roithmayr Program Leader (to May 1) Head, Field Station Biologist Biologist Biologist Biologist(on military furlough) Biologist Biologist Biologist Fishery Technician Fish. Mkt. Speciadist Summer Aid Summer Aid Summer Aid Summer Aid Summer Aid Temporary (shrimp marking) Temporary (shrimp marking) Temporary (shrimp marking) Temporary (shrimp marking) Temporary (shrimp marking) Temporary (shrimp marking) Temporary (shrimp marking) Biologist Biologist (trajisferred 12/60) Biologist Biologist Biologist Biologist Statistical Clerk Head, Field Station Biologist Biologist (resigned 9/60) Biologist (resigned 5/61) Biologist Galveston Miami Miami Galveston Galveston Galveston Galveston Miami Galveston Galveston Galveston Galveston Galveston Galveston Galveston Galveston Miami Miami Miami Miami Miami Miami Miami Galveston Galveston Galveston Galveston Galveston Galveston Galveston Pascagoula Galveston Pascagoula Pascagoula Pascagoula Physiology and Pesticide Program Edward Chin Zoula P. Zein-Eldin John Go VanDerwalker Grant L. MacNichols Gilbert Zamora, Jr. Imogene A. Sanderson Red Tide Program William B. Wilson David V. Aldrich Billie Z. May Alexander Dragovich John Ho Finuccine John A. Kelly, Jr. Gordon R. Rinckey John D. McCormick McKinley W. Jambor Lucius Johnson, Jr. Alice Murphy Domingo R, Martinez Chemistry and Sea- Water Program Leader Biochemist Biologist Biologist (transferred 1/61) Fishery Aid Physical Science Aid Program Leader (on special training program) Acting Prograxn Leader Head, Field Station Biologist Biologist Biologist Biologist Master, M/V KINGFISH Biological Aid (resigned 5/61) Physical Science Aid Biological Aid Biological Aid Laboratories Kenneth T. Marvin Ray S. Wheeler Raphael R. Proctor, Jr. Larence M. Lansford Library Stella Breedlove Technical Services Ruth Wo Yanch Esther Eo Sell Daniel Patlan Petronila C. Prado Mary E. Hippie Nellie P. Benson Chief Chemist Biologist Chemist Chemistry Aid Librarian Secretary Secretary Draftsman Scientific Stenographer Clerk- typist Clerk- typist (WAE) Administration and Maintenance Lawrence E. Wise Laura M. Hermcinn Corinna L. Denbo Glo S. Bcixter Peter M. Villarreal Robert L. McMahon Tidas C. Alcorn Administrative Officer As St. Admin. Officer Purchasing Clerk Clerk- Stenographer Maintenanceman Maintenance man Maintenanceman Galveston Galveston Galveston Galveston Galveston Galveston Galveston Galveston St. Petersburg Sto Petersburg St. Petersburg St, Peter sburg St, Petersburg St, Petersburg St, Petersburg St. Petersburg Galveston Galveston Galveston Galveston Galveston Galveston Gailveston Galveston Galveston Galveston Galveston St. Petersburg Miami Galveston Galveston Galveston Galveston Galveston Galveston Galveston SHRIMP FISHERY PROGRAM Joseph H. Kutkuhn, Acting Program Leader Understanding the dynamics of pre-exploited and exploited phases of any commercial fish or shellfish population is prerequisite to implement- ing a management program for the fishery it supports. Studies on each of three well«defined phases which characterize development in important Gulf of Mexico shrimp populations, viz. , larval and postlarval (pre«exploit ed), juvenile (semiexploited), and adult (fully exploited), continued during the year. In the east Texas coast area, a l»year survey designed to delimit spawning areas and ascertain the seasons and extent of spawning activity in brown and white shrimp populations was undertaken. Superimposed on this survey is a continuation of a project carried out during the period March 1959»« March I960 which sought to explore the feasibility of measuring the density of larval shrimp during their passage from offshore spawning to inshore nurs« cry grounds. Analysis of the earlier project's data is now underway. The re*» suits thereof together with those of the current study will provide (1) a basis for documenting mortality suffered by shrimp populations at successive devel» opmental stages; (2) evidence for linking spawning populations with inshore nursery areas utilized by their progeny; and (3) answers to the question of what mechanisms govern the movement of larvae from spawning to so-called nursery areas. Closely meshed with these early life history studies is a project concerned with outlining procedures for distinguishing larvae and early post- larvae of coexistent Penaeidae. In the 2 years since its inception, consider- able progress in identifying, describing, and comparing the early life history stages of these shrimp can be shown. The most successful technique for ob- taining material which is validly describable has involved capturing shrimp ready to spawn, allowing them to spawn in aquaria free of foreign matter, nurturing the eggs and any resulting larvae, and rearing the latter through as many growth stages as possible. Unfortunately, the inability to rear larvae be- yond a certain critical point (Protozoea I) still limits this technique's usefulness. Information providing a means for evaluating juvenile (or inshore) population phases continues to be secured systematically from the commercial bait shrimp fishery (Galveston Bay). Bait fishery production around the Gulf is still rising annually, but methods which would permit assessment of the re- lationship between increasing exploitation during immature stages and each species potential maximum yield have yet to be devised. Movement patterns, mortality, and growth in exploited (offshore) population phases underwent increasingly intensive study in the south Florida area. Additional mark-recapture experiments in a series started 4 years ago materially supplemented our knowledge of the Tortugas pink shrimp popula- tion's geographical range. A better-than-anticipated rate of mark-recovery in one experiment has encouraged extension of the staining technique for marking shrimp to studies of population mortality. A statistical analysis of Gulf shrimp stocks for the period 1956-1959 indicated that the more important species are generally faring well. Early. Life History of Commercial and Related Shrimps William C. Renfro STATION PATTERN -SPAWNING GROUND STUDY Spawning populations Major objectives of a new sea- sampling project which began in January of this year and is scheduled for completion next December are: (1) to delineate penaeid shrimp spawning grounds in the Gulf of Mexico off east Texas; (2) to determine reproductive status in populations of various species with respect to season and area; (3) to study the effects of environ- mental factors (such as temperature, salinity, and bottom composition) on penaeid distribution, abundance, and spawning activities; and (4) to ascertain seasonal and areal distribution of shrimp larvae and the importance of ocean currents in their movement to inshore nursery areas. To implement this project, the double- rigged shrimp trawler MISS ANGELA of Freeport, Texas, was chartered through June 1961. A cruise pattern to be run at 3- week inter- vals was designed so that as large an area as possible could be cov- ered in a reasonably short inter- val of time (3-4 days). Eleven sta- tions were positioned over an "ef- fective" sampling area of about 6, 200 square miles such that two or nnore sets of hydrographic ob- servations and biological collec- tions could be obtained in subareas characterized by depths of 72, 15, 25, and 45 fathom.s. At each station a "stand- ard" 45-foot flat trawl is towed for 1 hour. Since vessel speed is meas- ured during each haul, the resulting biological samples (assuming ratio between ground and surface speed is reasonably constant) may be treated quantitatively. Captured shrimp are identified as to species and sex, measured, and an ovary sample taken and fixed for cytolog- ical examination in the laboratory. During each trawl haul a 20-minute oblique plankton tow is made with a Gulf V sampler. Profiles of tem- perature and salinity are obtained NAUTICAL MILES Station pattern for shrimp spawning ground survey off east Texas coast. 10 at each station using a temperature and conductivity recorder ("Dynalog, " Foxboro). Current direction and velocity at several standard depths are de« termined by means of a telerecording current meter (Savonius type, Hytech Corp. ) . Trawler MISS ANGELA with Gulf V plankton sampler being lifted aboard. Through June 1961, nine 3- to 4-day cruises were made. The fol- lowing are some observations drawn from, data collected during the first four cruises (January 17-19. February 8-10, February 28-March 3, and March 21-23): 1. Cytological examination revealed that none of the penaeid spe- cies encountered possessed ovaries in the more advanced developmental stages. Ovaries of adult brown shrimp, Penaeus aztecus, and rock shrimp, Sicyonia These species ap- White shrimp, brevirostris, exhibited the greatest degree of maturation. peared most abundant in the depth range 15 to 45 fathoms. Penaeus setiferus; pink shrimp, Penaeus duorarum; Sicyonia dorsalis; 11 Trachypeneus similis; and Solenocera atlantidis had not progressed as far toward the completion of their reproductive cycles and were more prevalent in 7-2 and 15 fathoms. 2. There seemed to be little correlation between size of shrimp and degree of maturation. 3. Determination of the degree of ovarian development employing visual criteria proved to have dubious utility. Compared with determinations based on cytological examination of the same ovaries, 40 to 70 percent of vis- ual determinations constituted misclassification. 4. The average catch of larval penaeids was approximately five per tow from, midwjanuary to early March. During the fourth cruise (March 21-23) it rose to 31 as a result of the increasing abundance of S. brevirostris larvae. 5. Penaeus larvae were not taken at those stations located in depths less than 15 fathoms during the first two cruises, but were found at the 72- fathom stations in late February and March. Of special interest was the oc- currence of five Penaeus postlarvae at stations more than 70 miles offshore. 6. Larvae of S. brevirostris were found at the 15-, 25-, and 45- fathom stations. Trachypeneus, Solenocera, and Parapenaeus larvae oc- curred sporadically in samples taken throughout the study area. Distribution and abundance of larvae The last half of I960 was devoted to processing and examining 3, 111 plankton samples taken systematically from passes connecting Galveston Bay with the Gulf of Mexico, and from the Gulf itself. These samples, obtained with a Gulf V sampler from March 1959 through March I960, form the basis for a study designed to determine the fea- sibility of assessing relative seasonal and areal abundance of penaeid larvae. Larvae were sorted from each sample, catalogued and enumerated according to their stage of development and probable identity, and stored in small vials. A system of coding facilitated tabulation. For exanaple, the code 2NI refer- red to a Nauplius I which was most likely the brown shrimp, Penaeus aztecus; 3MII referred to a Mysis II of the white shrimp, Penaeus setiferus; etc. Fifty- seven such code designations have been employed, but as morphological re- lationships between and within species become better understood, this number will gradually be reduced through consolidation of material on a genus or spe- cies basis. An important aspect of this project is the accuracy and compara- bility of the abundance indices determined for each species. Volumes of water 12 strained by the Gulf V plankton net when taking each sample had to be esti- mated by appropriate conversion of flowmeter readings. To this end, cal- ibration factors for plankton net-flowmeter assemblies were computed fronn data obtained expressly for this purpose. Sample counts of individuals com- prising each (coded) larval type have been adjusted accordingly and tabulated. Quantitative analysis is now underway. Sampling of postlarval penaeids twice weekly at a station inside Galveston Entrance near the South Jetty terminated in May. These collec- tions began in November 1959 and resvilted in 141 "standardized" samples yielding more than 14, 000 postlarvae. During I960 postlarvae were found from early January to mid-December with peaks in abundance occurring in the periods mid- March to mid- April and mid-June to late August. None were taken at this station between mid-December and mid-February. In contrast to the large numbers of postlarvae taken during March and April I960 (9, 900 from 17 samples), relatively few (330 in 15 collections) were taken during the same period in 1961. Analysis of these data and associated hydrographic observations will begin shortly and should provide valuable knowledge regard- ing movement of young commercial shrinnps into estuarine areas. One year of systematic plankton sampling in the Galveston Island surf ended in April. Samples and hydrographic observations were secured semiweekly at four equally spaced stations along the beach front. Penaeid postlarvae occurred at these stations throughout the year and with about the same frequency as those at the Galveston Entrance station. The question arises as to whether the small (8-11 mm. total length) postlarvae found in mid-January hatched during December or even earlier and, avoiding the un- suited inshore waters, were spending the ensuing winter months in nearshore waters in a state of reduced activity. 13 Identification and Description of Shrimp Larvae Harry L. Cook Studies of the distribution, abundance, and biology of the larvae of commercially important shrimps depend upon the facility with which the var- ious species and their developmental stages can be differentiated. Initiated in 1959, efforts to rear and describe the larval stages of common penaeids con- tinued during the past year. Rearing trials Gravid females of five species were captured periodically and held in the laboratory for the purpose of securing viable spawn. Larvae hatched from eggs and reared to the stages indicated were obtained for the following species: 1. Xiphopeneus krfl^yeri (seabob) - Larvae reared through Nauplius IV; resulting specimens of Nauplius III and IV supplemented descriptive mate- rial obtained from a spawn in 1959. 2. Sicyonia brevirostris - Larvae reared to Protozoea I; most of the specimens preserved were in poor condition (broken setae or badly entan- gled in detritus) and could not be used for descriptive purposes. ii I J Nauplius I of Sicyonia brevirostris Stimpson, ventral view. 14 Protozoea I of Sicyonia brevirostris Stimpson, ventral view. 3. Sicyonia dorsalis - Larvae reared to Protozoea I; preserved specimens are now being examined. Captive shrimp frequently aborted non- viable eggs which were usu- ally misshapen, discolored, and deposited in clumps. Sometimes a few devel- oped into nauplii or to a point where the nauplius could be seen within the egg. Exanaination of thelycai-/ indicated that the above conditions resulted more from a lack of (or incomplete) fertilization than from incomplete development of the eggs themselves. Of 11 X. kr^yeri which spawned in the laboratory, those re- leasing eggs that failed to develop had retained the implanted spermatophores, whereas those spawning viable eggs had lost all or at least a portion of theirs. As soon as captive shrimp spawn, an examination of each thelcyum might indi- cate which of several individuals spawning simultaneously most likely yielded viable eggs. From the standpoint of minimizing the time spent searching for viable material, such lots of eggs would subsequently receive nnost attention. Modifications of methods used in earlier rearing trials have given encouraging results. Attempts to reduce the adverse effects of excessive de- tritus and various micro-organisms had involved the use of sand- filtered and 1/ Female structure which receives spermatophore (sperm sac) from male. 15 artificial sea-water media, treating these with antibiotics, various chemicals, and ultra-violet radiation, and by gentle preheating. Transfer of eggs and larvae through serial baths of clean water was also tried. None of these meth- ods, however, proved entirely satisfactory. Better results are now being ob- tained using a circulating rearing medium which is first passed through glass wool and cellulose ("Aqua-pure", Cuno) filters and then irradiated ("Steritron", Englehard Hanovia, Inc. ). Identification of larvae On several occasions larvae and postlarvae were brought to the laboratory for rearing to identifiable sizes. Some were reared in isolation, attempts being made to recover casts for descriptive purposes from each instar. Although this technique has proved feasible in the case of postlarvae, casts from nauplii and protozoea are usually too badly damaged during the molting process to be so utilized. Casts of mysis stages nave not been evaluated. Larvae belonging to the genera Penaeus, Sicyonia, Solenocera, and Parapenaeus can now be identified as such using existing reference material. Nauplii and Protozoea I of the species X. krjJyeri and S. brevirostris may be identified through comparison with specimens of known identity reared in the laboratory. The concurrent spawning population survey, which employs cytolog- ical techniques to determine extent of gonad maturation, shows promise of also aiding in the identification of larvae. On several occasions, for example, large numbers of larvae identified as Sicyonia sp. occurred together with ripe and spent adults of S. brevirostris, the only Sicyonia species (adults) collected. The conclusion logically following is that the larvae were also largely S. brevi- rostris. aOULT FEMALES RVAE AND POSTLARVAE NUMBER IN STATION SPECIES SAMPLE NUMBER IN GENUS SAMPLE Sicyonia P«noaus 10 25 S.c^oma Penaeus 1'" 0 ^ ■ S brevirostris 15 ■ Sicyonia Penaeus Unidentified 52 H ^ S bretrirosfris Solenocera atlantidis 10 ■^ Sicyonio Penaeus Salenacera Unidentified >76 J ■ 1 ' 1 Coincidence of ripe female and larval shrimp at selected stations, Cruise No. 4 (March 21-23, 1961), spawning population survey. 16 Identification of Postlarval and Juvenile Shrimp Williana C. Renfro Postlarvae of the three species of Penaeus common in the Louisiana- Texas area are difficult to separate when less than 20 mm. long. White shrimp, P. setiferus, 20 mm. or more in total length, are easily identified and hence distinguished from the others by the absence of grooves flanking the postrostral ridge. On the other hand, separation of the "grooved" shrimps, P. aztecus and P. duorarum, is not easily accomplished until they reach a size at which their external genitalia are well developed. In an attempt to identify post- larvae systematically collected inside Galveston Entrance and along the Gal- veston Island beach front, specimens were brought to the laboratory for rear- ing individually or en masse to sizes at which non-grooved (white) and grooved species could be distinguished. Specimens reared individually were isolated in small covered dishes and fed newly hatched brine shrimp nauplii. Although mortality was low, they grew slowly, their monthly length increments averaging less than 9 mm. over 1^- to 2-|-month periods. The rearing containers were inspected daily and any casts removed and preserved for study. In this manner a series of exoskele- tons was obtained from shrimp during metamorphosis through postlarval to separable juvenile sizes. Examinations of casts obtained from non-grooved (white) and grooved shrimp as length increased from 12 to 17 mm. have not yet revealed morphological characters sufficiently diagnostic to separate the two groups within this size range. It was noted, however, that "grooved" shrimp (postlarvae) as short as 15 mm. could be identified as such through faint grooves alongside the postrostral ridge, which become readily discern- ible when the partially dried cast of the cephalothorax is viewed under strong incident light. Groups of postlarvae reared en masse in aquaria of up to 300 gallons capacity were fed fine pieces of shrimp or fish in addition to brine shrimp nau- plii. Mortality due to cannibalism was high, and the highest rate of growth within any group was a rather low 13. 5 mm. per month. Weekly samples of shrimp were measured and preserved for morphological studies. The results of six rearing trials showed that postlarvae of grooved shrimp, most likely the brown shrimp, P. aztecus, were present in Galveston Entrance from April through mid-December. Only one group of postlarvae sub- sequently proved to be white shrimp, these having been collected in late Novem- ber I960. 17 Migrations, Mortality, and Growth of Pink Shrimp Thomas J. Costello and Donald M. Allen Migrations Two mark- recapture experiments executed during the period November-May (1960-61) extended a series of similar experiments initiated in 1958 to circumscribe the geographical range of stocks supporting the Tor- tugas pink shrimp fishery. Responding to intensified publicity (and a sizeable monetary induce- ment), commercial fishermen turned in 56 and 149 recaptures, respectively, of shrimp stained and released as juveniles at Bottle Key (13, 309) in Novem- ber, and Lower Pine Island Sound (32, 913) in December. Of the Bottle Key recaptures, 10 came from Florida Bay within 6 miles of the release site, and 46 from the Tortugas grounds about 120 miles to the west. The last of these was made early in May, 6 naonths following release, confirming the stated durability of certain biological dyes as shrimp-marking agents. All Pine Island Sound recaptures were made on the Sanibel fishing grounds within a 30-mile radius of the release site. The accompanying table and figure summarize the results of com- pleted experiments. These results tentatively indicate that all of Florida Bay constitutes nursery area for pre-recruit segments of the Tortugas pink shrimp stock, whereas Barnes Sound and Biscayne Bay on the Florida east coast, and estuaries north of Cape Romano on the west coast do not. More- over, migration patterns ex- hibited by these experinnental populations suggest the gen- eral movement of immature shrimp to be , somewhat ra- dially, in an east-west (on- shore-offshore) rather than in a north- south (coastwise) direction. This relationship between inshore nursery areas and directly opposing offshore spawning areas seeras to hold regardless of Release sites for mark- recapture experiments, . . j-^^.^ „„„ ■ ^ ^ the migration distances in- and probable routes of juvenile pink shrimp to , , ^, . . ^ ^<.-ii ^ J i- X- volved. The questions still recapture area, Florida Bay and Gulf of Mexico, . , 4. /i\ •^ ■' rennain, however, as to (1) 1958-1961. 18 :3 o :i ac o o •n c nS 13 o o M Ti M 0) V 00 ^ (\1 s ;3 0) 0) 2 ^1 >+H 0) nJ -H Q (I) m o ^ M (h 0 rt "o £ O (U ■u tn s ^ n! o CQ H (U >s d u p o UH Ifl 0 m z O- 2h ^ "^ (U 9 1 t rt C ^ I o < O CQ o ^ o p ' s T3 !-i C O 2 H C d >- oJ n! •^ 1-1 1-3 s ' C^ o 1 ' in in Vh w a nj ^ 0) :i <^ P on GD T3 2 P) C ■M i^ nj u ^ ^ •— ( O ° 1— 1 >>« >.2 0) P t3 u ^ ■ H 0 0 ^ ^H 2 W o O *"* .-H t-H o -^ vO sO o o '^ c r— 1 •— t >> >> ^ o r^ o ^ o^ ^ ^ ^ T}< c» ^ O fvj ^ 00 m ^£) m in vO M r- 00 fo -1 o 1— 1 ro N r~- o o vD 00 ro o ^ ^ r~ sO ^ > o ^' > o ^ o ^ 2 vO a> 0 dJ o h Z p (U T3 -I (1) O cd « O PQ O !>^ T3 rt >N (U 13 O >x 0) ^ a XI >< ^ DO 3 g erson nes S Pi 0 X ■r-t a; tn l-H to nj Testing toxicity of pesticides on postlarval shrimp contained individually in 250-cc. reagent bottles. 49 ti o o u tti o o to >> (0 ^ u T5 0) M (ti •H >^ )-< 43 o ^ B^ S 2: is a o .? « >^ •I-l ^ u Ul •I-l X C 0 O 0) ^H > Xi d CUD » Hut. ^2^ V V , • * vO in r^ IT) O^ o o O V V (M i M '^ CO PO r^ ■* ■* •— t CO *< (M 00 r~- m -H ^ (NJ 00 (M OJ OJ fVl CO CO I— c v£) sO — I O O (M ro ro 00 tvJ tM ro ■— I r^ — I o vO vO 00 in vo o^ "-^ o r^ 00 t I I I I I I 00 vO 00 CO in o o osj tj* sD ^ r — \0 ^ O 00 o o in o r-, r-, -^ o in in o o o -^ o o r~- r- o V V o o o o o og r-f o o o r- 00 I I .-c 00 -* ^ ^ o o r-H r-^ O O ro CO on ro ■^ ro CO ro 00 00 00 00 00 00 oj 00 00 00 oo 00 00 00 00 00 00 00 00 00 00 vO vo o in o •-< o 00 CJ^ --I O^ CT^ O^ •— I i t I t i t I r~ -"t r~ 00 r~ o oo vO r~ r~ r~ vX) r^ 00 00 vO r~- o •^ t^ nO vO r^ t ^ •— 1 r-H Tf 00 in r^ 00 00 vo r- r~- 00 00 00 00 00 C7^ 50 n3 o £ Pi (U o a- S.2 , --■^ M t 1 A 00 ^"^ Tt* CO u si 1 i H cL oj -~ H k ^ s 4 J 00 H a, oj ^ H S ^ V ^.r-.. tX) , c ■'— ' CU CI SI •H rt CO 0) 2 «M in --I (M * « in o t-H nO tM I OS ^ •-I '^ IT) O o O -H f— 1 1 t rH in 4 00 CO t>- 00 Tj* vO 00 o^ 0 00 rt lU >^ •H ^ > Oh ^1 0 3 Q Q H H S K o V o I IT) O O^ IT) o o o inroinoor^LninLn V r^-^-^oroomomoo A^ro^fMunfMinfMino A^^^ooLnr-in '^ A A Tf Tf oo rvj tM (M (M (VJ fvj CM I t t 11 oO-^fMotMrOcOi-ti-H^H—i fM(M(MfM(M(M(M'..) 2000 1500 TOTAL PHOSPHATE PHOSPHORUS (ng.ot./i I CALCIUM (ug.ot/i ) ALKALINITY (Hg.Ot 'I. of H*) I 00 (Jig. of./i ) NITRATE-NITRITE NITROGEN 05 (ng Ot./I.) Upper Tompo Bay Lower Tompo Boy ■ 40 miles offshor* Chemical and physical parameters at three depths and three selected stations from July I960 to March 1961. Salinity distribution was similar to that of last year. Occasionally salinity slightly lower than in surrounding areas occurred offshore during the Slimmer and fall months but to a lesser, degree than last year. Lower abun- dance of G. breve this year compared to last suggests that last year's lower salinity rnay be associated with increased growth of G. breve. 66 Total phosphorus Owing to the well-established fact that phosphorus is im- portant to phytoplankton growth, field observations of this nutrient were con- tinued. The major features of phosphorus distribution were (1) the maximum zone in upper Tampa Bay and (2) rapidly diminishing seaward concentrations. The monthly changes in total phosphorus show higher concentrations (21. l->29.0 p.g. at. /L) in upper Tampa Bay during September and October after hurricanes "Brenda" and "Donna" passed through Florida. Extremely high total phosphorus concentrations (33. 3->33. 3 ^ig.at. /i) were recorded in March throughout the waters of upper Tampa Bay. These high values were observed during relatively strong onshore winds (20-25 m.p.h.), suggesting phosphorus enrichment from stirring of bottom sediments. This supposition was verified by phosphorus analysis of bottom sediments and supernatant water containing bottom sediment. Total phosphorus was more than adequate for phytoplankton growth in the waters of Tampa Bay and up to 10 miles offshore. Seaward from 10 miles offshore phosphorus concentrations rarely exceeded 1.0 |jig.at. /Land in three instances were recorded as low as 0. 1 jig. at. /I. Nitrogen There w^as no apparent relationship between the incidence of G. breve and nitrate-nitrites. Comparatively low concentrations (0. 0-2. 0 |ig.at./l) of nitrate-nitrite nitrogen continued to persist in Tampa Bay and adjacent waters. The concentrations of nitrate-nitrites during 1959, a year with heavy rainfalls, were higher than during the period of this report. During this latter period nitrogen varied from 0. 1 to 0. 5 fig. at. /l.in 87. 2% of the samples; in 6. 1% of the samples the concentrations varied from 0. 6 to 2. 0 |j.g. at. /I,, while in 6. 8% of the samples there were no measurable quantities. Atypical of the nitrate- nitrites distribution usually observed in an estuary, there were no maxima near the fresh-water end of Tampa Bay. Although some higher concentrations of nitrate-nitrites were noted during the fall, winter, and early spring months, the seasonal distribution pattern continued to be very irregular. The greatest depletion occurred during July, when in 20. 8% of the samples the nitrate- nitrites were completely exhausted. Concentrations of ammonia ranged from 0.0 to 30.0 jxg.at. /I. Dur- ing the first 11 months (April I960 - March 1961) the spatial distribution of ammonia shows concentrations in upper and central Tampa Bay two to three tinnes higher than in the offshore waters. From April I960 to the present, 241 inorganic nitrogen and organic nitrogen determinations have been performed on filtered sea water. In Decem- ber I960, experiments showed that the HA millipore filters used in micro- filtration were adding erratic amounts of a substance which reacted with the sodium phenate reagent to give an erroneous color development. Since January 1961, all determinations have been made on unfiltered sea water. Total inor- ganic nitrogen in unfiltered samples varied from 0. 0 to 6. 7 |j.g.at. /I. while total organic nitrogen ranged from 3.7 to 30.9 H-g*^t. /I. Total organic nitrogen ex- ceeded total inorganic as a rule and represented 87.4% of the total. The lon- gitudinal distribution of total nitrogen indicates existence of maximum values in Tampa Bay with a decreasing trend seaward. In contrast to the low levels of nitrate-nitrite nitrogen, the observed concentrations of ammonia and total nitrogen are comparable to those of other marine areas of the world. 67 SPECIAL REPORTS Sea-Water System Kenneth T. Marvin and Ray S. W-heeler The recirculating sea-water laboratory completed in January 1961 provides excellent space and facilities for holding large quantities of shrimp and fish, enabling us to undertake studies which should add measurably to our knowledge of these organisms. Studies now under way include the determina- tion through bioassays of the effects of toxicant materials on marine organ- isms, the spawning and rearing of larval shrimp to aid in the identification of different species, and the testing of stains for marking shrimp to determine their growth, mortality, and migration routes. As space permits, the sys- tem's facilities will be available for research on marine problems by other than Bureau investigators, e.g.. The Marine Laboratory of the A. and M. College of Texas is using it in experiments on oyster nutrition. Sea water is brought to the system in a 4, 000 gallon stainless steel water truck, run through the filter beds, and pumped into two 28, 000- gallon redw^ood tanks. Water flows by gravity from either or both 28, 000- gallon tanks to the laboratory through a 4- inch polyvinylchloride pipe. After entering the laboratory, the pipe branches into 3- inch ceiling pipes that supply water to the three laboratory tank rooms. Petcocks in the ceiling pipes conduct the water into the holding and experimental tanks. From the tanks water flows into concrete return troughs connected to the filter. Water from the tanks can also be directed into other troughs connected to a drain to facilitate cleaning. The two filter beds are similar in design to those of mixnicipal water treat- ment plants and consist of washed (river) sand on a bed of graded gravel. The gravel overlays a network of small perforated polyvinylchloride pipes leading into a 4- inch pipe that discharges into a 9, 000- gallon concrete sump located The two filter beds which lie on top of a 9, 000- gallon sump. 68 directly under the filter beds. T'wo Tg^hp. centrifugal pumps (one a standby), located 15 feet below ground level, pump the water from the sump back to the redwood storage tanks, thus completing the cycle. The system is designed to circulate a maximum of 8, 000 gallons of sea water an hour. The plastic valves and piping and the concrete return troughs and sump minimize the dan- ger of metal contamination. Both laboratory and filter house are insulated, and the laboratory is air-conditioned to maintain the water at a relatively con- stant temperature. T ^ East tank room showing the two tiers of fiber-glass tanks and a third tier of glass aquaria. The three tank rooms cover more than 1, 000 square feet of space and contain a sufficient variety of sizes of redwood, fiberglass, and plate- glass tanks to give the individual investigator a wide selection for his partic- ular needs. In the east tank room (Laboratory A), which has an area of 428 square feet, advantage is taken of the high outlets by arranging the tanks in three tiers along one wall. Eventually all tanks in this room will be simi- larly arranged. 69 Laboratory B, the center tank room (170 square feet), is some- what limited as to the number and sizes of tanks by the relatively short (15 feet) trough space. It is used primarily for experiments requiring small aquaria and also to house monitoring and other equipment. West tank room showing large redwood holding tanks. The west room (Laboratory C), containing the same space as Lab- oratory A, is filled to capacity with redwood tanks ranging in size from 100 to 500 gallons. We plan to place 30-gallon glass aquaria on shelving over the red- wood tanks. A 5-hp. compressor, located in the equipment room between Lab- oratories B and C, supplies air to the three tank rooms. The food preparation room, which is situated in the southwest corner of the building, contains the necessary mixing, cold storage, disposal, etc., facilities for preparing the variety of diets to condition fish and shrimp for experiments. 70 The leaching of wooden tanks and the concrete troughs and sump was accomplished by recirculating tap water through the system for a month. During this period minor changes were made to increase the velocity and de- crease the water depth in the return troughs, and to increase the efficiency of oxygen exchange and thus the holding capacity of the entire system. The sand filters perform satisfactorily. Their effectiveness was particularly apparent after the first addition of muddy (15-inch Secchi disc reading) sea water. After several days of recirculation, the clarity equaled that of tap water. Periodically the beds have to be backf lushed with large volumes of tap water to float off the accumulation of particulate matter. This is always followed with a salt-water backflush to avoid dilution problems. Sanaples of the water are analyzed three times weekly for salinity, oxygen, ammonia, nitrate, nitrite, phosphate, pH, alkalinity, carbon dioxide, protein, and carbohydrate. 71 Oyster Studies Sammy M. Ray Galveston Marine Laboratory, A. and M. College of Texas and David V. Aldrich The following report summarizes the data obtained in preliminary studies to determine the response of oysters to conditions in the new sea- water laboratory. The shell movement and water pumping rate of two oysters were continuously Experimental set-up used for recording shell movement and pumping rate of oysters in the sea-water laboratory. 72 recorded on a kymograph to check their feeding activity. In a parallel study the immersed weight of 50 other oysters under various conditions was followed as an index of growth. The data obtained by the kymograph recordings for one of these oys- ters (about 4 inches long) are presented in the figure. The three highest peaks of water pumping and shell opening were associated with the addition of some fresh sea water to the system, A fourth peak of activity, especially shell open- ing, occurred from May 15 through May 17, Since the daily log book of the sea-water laboratory gives no indication of either fresh sea-water additions or other changes, we are unable to suggest any possible causes for this peak. ' r r - r - □ - T„ne op.n - \ \ □ - Wo.ar cu„.p. - If r ; / n i L L, 1 V I\ 1 m - - Ln u \ "^'^ ^"U r le ' ' ' *25 '2 9 16 '23 30 APRIL MAY Daily record of number of hours open and volume of water pumped by aJi oyster maintained in sea- water laboratory. Because of failure in the experimental set-up no record of volume of water pumped was ob- tained on May 17, 18, and 19. Arrows indicate the dates that some fresh sea water was added to the system. The volume of feces deposited by the two oysters used in our experi- ments was roughly proportional to the amount of water pumped. There are, however, indications that feces deposition per volume of water filtered de- creases as the sea water ages. Such a decrease is to be expected since the water passes through a sand and gravel filter bed each time it is recycled. A maximum pumping rate of about 20 liters per hour was obtained during these studies. The volume of water pumped during the first 2 or 3 days following the addition of fresh sea water was comparable to that observed for oysters of similar size in running sea water at Pensacola, Florida. Our pre- liminary studies indicate that frequent additions of fresh sea water will prob- ably be necessary for the long-time maintenance of oysters in this system. If the reduction of the oyster feeding activity associated with the aging of the water is due solely to a diminution of the food supply, the problem may be solved by artificial feeding. 73 While shell movement and pumping rate serve as good indices of immediate responses of oysters, they cannot at present be directly related to growth. Four groups of West Bay oysters were used to study such relation*- ships and to determine the effects on growth of various water treatments. Three of these groups, containing 10 individuals each, were maintained in the sea-water laboratory. These groups received untreated water, filtered water, and filtered ultraviolet-irradiated water, respectively, at the rate of about 60 liters per hour. Filters (Aqua-Pure, Cuno) containing elements with a por- osity of 5 microns were used. The fourth group was maintained in Offats Bayou in a tray suspended from a pier. Growth rate of oysters main- tained in sea-water laboratory and Offats Bayou. The death of the largest oyster in the group receiving untreated system water accounts for the sharp decrease in the mean immersed weight of this group between May 16 and May Z3. Oyster growth was measured in terms of immersed weight, a method that circumvents the inaccuracies of either weight-in-air or length measure- ments. The range of the initial immersed weights for each group was about 5 to 20 gra} IS. The results are presented in the figure. The most striking result is the difference between growth rates of the Offats Bayou and sea- water laboratory groups. The more rapid growth of the former group probably stems from a greater abundance of food. Since oyster food is generally considered to be particulate, unfiltered water contain- ing such material should support better growth than filtered water. This was not the case in this experiment. The growth rates of laboratory oysters in fil- tered water were highly similar to those of the oysters in unfiltered water. This similarity suggests that a shortage of particulate food is inherent to the laboratory water. It is interesting that both immediate and long-term oyster responses to an artificial environment provide similar indications. 74 Distribution of Pink Shrimp Larvae and Postlarvae C. P. Idyll, F. F. Koczy, Albert C. Jones, M. O. Rinkel, and D. Dimitriou University of Miami, Institute of Marine Science (Contract No. 14-17-002-29) Investigation of the relative abundance and distribution of larvae and postlarvae of the pink shrimp (Penaeus duorarum) in Florida Bay and the adjacent Gulf of Mexico has been carried on by the Institute of Marine Science of the University of Miami. Research has been divided into three phases: (1) identification of the larval stages; (2) hydrography of Florida Bay and the adjacent Gulf of Mexico; and (3) geographical and seasonal distribution of the larvae. The first phase of the program, involving the collection, identifica- tion, rearing, and description of pink shrimp larvae and postlarvae, has been completed. Investigation of the current system in Florida Bay and on the Dry Tortugas fishing grounds (second phase) has not shown the presence of an on- shore current which could of itself transport shrimp larvae from offshore spawning grounds to inshore nursery areas. The main water movements in this region are due to tidal currents with a superimposed wind-driven com- ponent. The influence of the tidal currents decreases with increased depth and distance from shore until the wind-driven component becomes the major factor in the water movement near the western limits of the spawning grounds. High salinity values on the bottom at the time of tidal change together with theoretical considerations required a study of the bottom currents. Using a nnodification of the Carruther's bottom current meter and a newly developed Niskin "gimball" bottom current meter, measurements of bottom currents were determined within 1 foot to 6 inches of the bottom. Velocity data from these bottom current readings indicate that a continuous easterly current is not present in the area, and that the current is, as expected, of low^ velocity (well under 5 cm. /sec. ). The third phase of the program, seasonal and geographical distri- bution of pink shrimp larvae and postlarvae, has continued. From July I960 to April 1961, 11 sampling cruises were made. A total of 758 plankton sam- ples was collected. Of these, 550 have been examined. Examination of the 740 samples collected over the period July 1959 to June I960 was also com- pleted. In addition, 95 plankton samples were taken this year from Florida Keys highway bridges, from Everglades National Park, and from the Tor- tugas fishing grounds with the Beyer plankton sled. 75 The Beyer sled, used to sample plankton occurring near the sea bottom. Sampling was done in nearly every month of the year and over as wide a geographical area as possible in order to obtain a complete picture of the distribution of pink shrimp larvae in this area. Plankton was collected from Sanibel Island to south of the Florida Keys and from the 100-fathom line inshore to 2 fathoms. The majority of samples were taken in the middle of this area and few were taken in fringe areas. Few pink shrimp in early life history stages were found to the east of Key West during any season of the year. In almost all cases those taken have been in the postlarval stage of development. Samples during the current year revealed a center of abundance of larvae, which is believed to represent a center of spawning. This center of abundance is located on the Tortugas fishing grounds and shifted position dur- ing the season. 76 SEMINARS Training program in Washington, Bernard E. Skud Activities of the Honolulu Biological Laboratory. Joseph J. Graham Methods and significance of salinity measurements, Kenneth T, Marvin Navigation and navigational astronomy. William Renfro Poison bait for nutria control. James Ragan Estimating mortality in a tagged shrimp population. Joseph H. Kutkuhn Shrimp fishery in India. Malloothara J. George, Mandapam Gamp, South India Respiration and metabolism in crustaceans. Zoula Zein-Eldin Circulating water systems: pros and cons, Ray Wheeler Marine pond cxxlture in British Guiana. W, H. L. Allsopp, British Guiana Biological responses to polarized light. David V. Aldrich Oyster culture. John VanDerwalker Biologiccd factors affecting population fluctuations. Harry Cook International Indian Ocean Expedition. Kenneth N. Baxter. MEETINGS ATTENDED* Tortugas Shrimp Commission, U. S. Section, Miami, July (2) Tortugas Shrimp Commission, Havana, July (1) American Institute of Biological Sciences, Stillwater, Oklahoma, August (4) American Fisheries Society, Denver, September (2) Southwest Field Committee, Denver, September (1) U. S. Study Commission- Texas, Fort Worth, September (2) Water for Texas, College Station, Texas, September (2) Texas Bait Shrimpers Association, Highland Bayou, September (1) Gulf States Marine Fisheries Commission, St. Petersburg Beach, October (5) Gulf and Caribbean Fisheries Institute, Miami, November (3) Southeastern Fisheries Association, St. Simons Island, Georgia, November (1) Biological Research Laboratory Directors' Meeting, Washington, D. C. , Dec, (1) Arkansas- White-Red River Interagency Committee, New Orleans, Jan. (1) Southwest Field Committee, New Orleans, Jan. (1) Nutria Control Conference, Beaumont, January (1) Texas Shrimp Association, Houston, January (3) North American Wildlife Conference, Washington, D. C. , March (1) Gulf States Marine Fisheries Commission, Biloxi, March (2) American Society of Ichthyology and Herpetology, Austin, March (1) Welder Wildlife Foundation, Sinton, Texas, April (2) North Atlantic Fish Marking Symposiunn, Woods Hole, Mass., May (1). ♦Attendance shown in parentheses. 77 PUBLICATIONS Aldrich, David V. i960. The physiology of fishes, edited by Margaret E. Brown. /a review7. Transactions of the American Fisheries Society, vol. 89, no. 3, p. 316. Aldrich, David V. , and William B. Wilson. i960. The effect of salinity on growth of Gymnodinium breve Davis. The Biological Bulletin, vol. 119, no. 1, p. 57*-GT. Arnold, Edgar L. , Ray S. Wheeler, and Kenneth N. Baxter. i960. Observations on fishes and other biota of East Lagoon, Galveston Island. U. S. Fish and Wildlife Service, Special Scientific Report--Fisheries 344, 30 p. Breedlove, Stella. 1961. Current bibliography for aquatic sciences and fisheries, com- piled by Food and Agriculture Organization, Fisheries Biology Branch. [A review/. Transactions of the American Fisheries Society, vol. 90, no. 1, p. 86. Christmas, James Y. , and Gordon Gunter. i960. Distribution of menhaden, genus Brevoortia, in the Gulf of Mexico. Transactions of the American Fisheries Society, vol. 89, no. 4, p. 338-343. Christmas, James Y. , Gordon Gunter, and Edward C. Whatley. 1960. Fishes taken in the menhaden fishery of Alabama, Mississippi, and eastern Louisiana. U. S. Fish and Wildlife Service, Special Scientific Report— "Fisheries 339, 10 p. Craig, William L. , and Joseph J. Graham. 1961. Report on a co-operative preseason survey of the fishing grounds for albacore (Thunnus germo) in the eastern North Pacific, 1959. California Fish and Game, vol. 47, no. 1, p. 73-85. Dragovich, Alexander. 1961. Relative abundance of plankton off Naples, Florida, and as- sociated hydrographic data, 1956-57. U. S. Fish and Wildlife Service, Special Scientific Report--Fisheries 372, 41 p. Dragovich, Alexander, John H. Finucane, and Billie Z. May. 1961. Counts of red tide organisms, Gymnodinium breve, and associ- ated oceanographic data from Florida west coast, 1957-59. U. S. Fish and Wildlife Service, Special Scientific Report-- Fisheries 369, 175 p. Finucane, John H. , and Billie Z. May. 1961. Modified Van Dorn sampler. Limnology and Oceanography, vol. 6, no. 1, p. 85-87. Gunter, Gordon, and James Y. Christmas. 1960. A review of literature on menhaden with special reference to the Gulf of Mexico menhaden, Brevoortia patronus Goode. U. S. Fish and Wildlife Service, Special Scientific Report-- Fisheries 363, 31 p. * Gunter, Gordon, and William J. Demoran. 1961. Lateral lines and an undescribed sensory area on the head of the Gulf menhaden, Brevoortia patronus. Copeia, 1961, no. 1 (March), p. 39-42. Haskell, Winthrop A. 1961. Gulf of Mexico trawl fisheries for industrial species. U. S. Fish and Wildlife Service, Commercial Fisheries Review, vol. 23, no. 2 (February), p. 1-6. Inglis, Anthony. 1961. Ecology of inland waters and estuaries, by George K. Reid. /a review/. Transactions of the American Fisheries Society, vol. 90, no. 2, p. 232-233. Iversen, Edwin S. , Andrew E. Jones, and Clarence P. Idyll. i960. Size distribution of pink shrimp, Penaeus duorarum, and fleet concentrations on the Tortugas fishing grounds. U. S. Fish and Wildlife Service, Special Scientific Report-«»Fisheries 356, 62 p. *Koczy, F. F., M. O. Rinkel, and S. J. Niskin. I960. The current patterns on the Tortugas shrimp grounds. Pro- ceedings of the Gulf and Caribbean Fisheries Institute, 12th Annual Session, 1959, p. 112-125. 79 Marvin, Kenneth T., Zoula P. Zein-Eldin, Billie Z. May, and Larence M. Lansford. 1960. Chemical analyses of marine and estuarine waters used by the Galveston Biological Laboratory. U. S. Fish and Wildlife Service, Special Scientific Report--Fisheries 349, 14 p. May, Billie Z. i960. Stabilization of the carbohydrate content of sea water samples. Limnology and Oceanography, vol. 5, no. 3, p. 342-343. McGary, James W. , and Joseph J. Graham. i960. Biological and oceanographic observations in the central North Pacific July-September 1958. U. S. Fish and Wildlife Service, Special Scientific Report--Fisheries 358, 107 p. Naab, Ronald C. i960. Principles of fisheries development, by C. J. Bottemanne. /_A review/. Transactions of the American Fisheries Society, vol. 89, no. 3, p. 317. Renfro, William C. 1960. Salinity relations of some fishes in the Aransas River, Texas. Tulane Studies in Zoology, vol. 8, no. 3, p. 83-91. Rounsefell, George A. 196la. How can research production be measured? Proceedings of the Gulf and Caribbean Fisheries Institute, 13th Annual Session, I960, p. 139-150. 196lb. Living fishes of the world, by Earl S. Herald. [A. review/. Transactions of the American Fisheries Society, vol. 90, no. 3, p. 341. 196lc. Fishery management, by R. S. Fort and J. D. Brayshaw. [a. review?. Transactions of the American Fisheries Society, vol. 90, no. 3, p. 341-342. Skud, Bernard Einar. 1961. Education and recruitment of oceanographer s in the United States. A report by the Committee on Education and Recruit- ment, American Society of Limnology and Oceanography, Inc. , August 30, I960, /a review?. Transactions of the American Fisheries Society, vol. 90, no. 2, p. 232 . 80 Skud, Bernard E. , and William B. Wilson. 1960. Role of estuarine waters in Gulf fisheries. Transactions of the 25th North American Wildlife and Natural Resources Conference, p. 320-326. Thompson, John R. , and Winthrop A. Haskell. I960. From trash to treasure. Petfood Industry, vol. 2, no. 12, p. 10-13. U. S. Fish and Wildlife Service. I960. Galveston Biological Laboratory Fishery Research, for the year ending June 30, I960. U. S. Fish and Wildlife Service, Circular 92, 77 p. Zein-Eldin, Zoula P. 1960. Endocrine control in crustaceans, by David B. Carlisle and Sir Francis G. W. Knowles. /A review/. Transactions of the American Fisheries Society, vol. 89, no. 4, p. 385. 1961. Plankton pigments in East Lagoon, Galveston, Texas. Trans- actions of the American Fisheries Society, vol. 90, no. 1, p. 32-41. * Contract research 81 MANUSCRIPTS SUBMITTED FOR PUBLICATION Allen, Donald M, , and T. J. Costello. Grading large numbers of live shrimp for marking experiments. Kutkuhn, Joseph H. Gulf of Mexico commercial shrimp populations— trends and charac- teristics 1956-1959. Marvin, Kenneth T. , and Larence M. Lansford, Phosphorus content of some fishes and shrimp in the Gulf of Mexico, Rounsefell, George A. Classification of North American Salmonidae. 82 INT.DUP. ,D.C.61-i ril 38 MBL WHOI Library - Sen, 5 WHSE 00225