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Brackish water pond culture studies have been conducted by the Louisiana Wildlife and Fisheries Commission at the Rockefeller Wildlife Refuge, Grand Chenier, Louisiana, since 1966. Atlantic croaker (Micropogon undulatus) and striped mullet (Mugil cephalus) were among the first species stocked. Various stocking rates and sizes have been tested to determine production without supplemental feed. Polyculture experiments were conducted with striped mulletchannel catfish (Ictalurus punctatus) combinations and striped mullet-Atlantic croaker combinations. Growth data for Atlantic croaker were highly variable; however, striped mullet results were promising, especially for polyculture with catfish. Results from two winter stockings of rainbow trout (Salmo gairdneri) indicate that warmer temperatures and marginal water quality may limit rainbow trout production in southwest Louisiana.

Aquarium studies were employed to elucidate the mode of transmission and progression of lymphocystis disease in croaker (Micropogon undulatus). In host range studies, only members of the family Sciaenidae could be infected with the virus from the croaker.

A primary drawback for cage culture in heated effluent has been extensive mortalities due to gas bubble disease. This malady, endemic to power plant effluent, is caused by supersaturation of atmospheric gases in water. The objective of this research was to determine the effect of hydrostatic pressure as a possible remedy for gas bubble disease in the discharge canal of a Galveston Bay, Texas, steam-electric plant. Seven estuarine fishes, pinfish (Lagodon rhomboides), spot (Leiostomus xanthurus), Atlantic croaker (Micropogon undulatus), black drum (Pogonias cromis), red drum (?Sciaenops ocellata), Atlantic spade-fish (Chaetodipterus faber), and striped mullet (Mugil cephalus), were caged at the surface and bottom of the 3 m-deep discharge canal where total gas saturation frequently exceeded 120% during winter months. Survival in surface cages averaged 1% after 2 weeks, while survival in bottom cages averaged 81% after 12 weeks. No supplemental food was allotted, but an abundance of small organisms was continually sluiced down the discharge canal through the cages. Winter growth rates generally surpassed those of comparable species cultured elsewhere in the cooling water system at ambient temperature and fed a prepared ration. As discharge water temperature approached 35°C, growth rates declined. Other factors affecting growth were cage mesh size, species type, and size of individuals. All fish were maintained in the heated effluent until thermal death to determine the upper lethal temperature limits. These results indicate that submerged cage culture in power plant effluent might offer a significant savings to the culturist by increasing winter growth rates without the expense of feeding.

Atlantic croaker (Micropogon undulatus) and striped mullet (Mugil cephalus) were cultured in cages in the intake area, at the head of the discharge canal, and at three locations in the cooling lake of a power plant near upper Galveston Bay, Texas, from 1 February 1976 to 20 August 1976 to assess the suitability of each location for mariculture. Interpretations were based on daily measurements of six hydrological parameters and survival and growth of fish. Primary sources of mortality included high effluent temperatures, abrupt changes in conductivity, and lymphocystis. Growth rates of fed Atlantic croaker were strongly related to water temperature. Regression procedures were used to develop a polynomial function to describe the parabolic relationship between growth rate of croaker and mean monthly water temperature. The curve described by this model indicated no growth at temperatures below about 13.5°C or above about 33.5°C and maximum growth near 27°C. This information might be valuable in selecting optimum locations for culture of Atlantic croaker or related fishes within thermally heterogeneous environments. Growth rates of unfed striped mullet were not related to water temperature but were linearly related to pH and dissolved oxygen, which were probably indicators of primary production. However, the growth of mullet was poor even at the most productive locations consequently, the use of unfed caged mullet to harvest phytoplankton does not seem feasible unless the primary productivity levels are considerably higher than those in our study area.

Several species of marine fishes were cultured in cages in the intake and discharge canals of the P. H. Robinson Generating Station on Galveston Bay, Texas. Survival in the intake canal cages of Atlantic croaker (Micropogonundulatus), pinfish (Lagodonrhomboides), Florida pompano (Trachinotuscarolinus), white mullet (Mugilcurema), spot (Leiostomusxanthurus), and black drum (Pogoniascromis) was on the average 70% or greater, while that of pigfish (Orthopristischrysoptera), Gulf kingfish (Menticirrhuslittoralis), and silver perch (Bairdiellachrysura) was less than 70%. With the exception of pinfish, survival of caged fish in the discharge canal was extremely poor. Gas-bubble disease was the probable cause of their mortality. Only croaker and pompano adapted to surface feeding in cages. Croaker, pinfish, and pompano cultured in cages were rated acceptable by a 12-member taste panel. Mean taste evaluation scores for croaker, pinfish, and pompano for the appearance, flavor, and overall satisfaction categories were not significantly different (P=0.01). After about 1 year in the water, most cages used in the intake canal were in goad condition, but those located in the discharge canal were in poor condition.

Three species of fish were cultured in 0.1 ha ponds from August 1976 to May 1977. Each pond received a constant flow of thermal effluent from the discharge canal of the Cedar Bayou Generating Station, Houston Lighting & Power Company. Striped mullet (Mugil cephalus) were maintained in polyculture with black drum (Pogonias cromis) and Atlantic croaker (Micropogon undulatus). These fish were also raised in mnoculture. Survival of mullet in polyculture with drum averaged 91.8%; in polyculture with croaker, 96.4%; in monoculture, 96.8%. Black drum survival averaged 95.5% in polyculture and 96.3% in monoculture. Croaker survived slightly better in monoculture at 39.3% compared to 33.5% in plyculture with mullet. Poor croaker survival was attributed to low cool season temperatures and handling mortalities. Growth of all species was improved in polyculture. Mean daily length and weight gains for mullet in monoculture were 0.22 mm/day and 0.35 g/day. These increased to 0.25 mm/day and 0.46 g/day in polyculture with drum, and 0.26 mm/day and 0.60 g/day in polyculture with croaker. Similarly, rates for black drum increased from 0.39 to 0.41 mm/day and from 0.76 to 0.90 g/day when raised with mullet. Monocultured croaker grew 0.21 mm/ day and 0.60 g/day, while in polyculture with mullet these increased to 0.28 mm/day and 0.69 g/day. Competition values indicated that daily yield of mullet and black drum was increased 30% and 20% respectively through polyculture. Growth of croaker was largely unaffected by addition of mullet into the system, but mullet growth was raised 78% through this association. Thermal additions to these ponds proved critical when seasonal grmth trends were examined.

Behavior of Atlantic croaker (Micropogon undulatus), black drum (Pogonias cromis), and striped mullet (Mugil cephalus) was observed in monoculture and polyculture situations. Dominance hierarchies, feeding and aggressive behavior were established for the three species in each culture situation. All fish were acclimated to tanks and artificial food, and were fed a limited amount of food. Four individuals of each species were observed over 4 consecutive days in monoculture. Four striped mullet each were then placed with the Atlantic croaker and black drum. Competition for food and space resulted in higher feeding rates in all three species. Aggression also increased in Atlantic croaker and black drum. Atlantic croaker became territorial in polyculture. In general, growth and condition of a fish was directly correlated with its position in the dominance hierarchy.

Atlantic croaker ( Micropogon undulatus ), Mexican flounder ( Cyclopsetta chittendeni ) and Northern kingfish ( Menticirrhus saxatilis ) are warm water species abundant in the Gulf of Mexico, usually obtained as shrimp by-catch. Gels from these species were obtained by several treatments: (1) setting at 25°C/3 h followed by cooking at 90°C/15 min; (2) setting at 40°C/30 min and 90°C/15 min; (3) 90°C/15 min (control). Three different additives were studied: 0.66% ammonium chloride, 0.2% EDTA and 0.2% calcium chloride. The setting phenomenon was induced at 40°C in the three species. 0.2% calcium chloride improved shear stress and shear strain in surimi gels from Atlantic croaker and Northern kingfish. 87.98 and 98.49 kPa for shear stress, and 2.23 and 2.15 for shear strain were achieved, respectively.

Resumen Resumo The Modori phenomenon occurs in fish species from the Gulf of Mexico. The origin seems to be associated with serine and cisteine-proteases. The objective of this work was to determine the presence of protease inhibitors in crude extracts obtained from commercial leguminoses and to establish its capability to inhibit the proteolytic activity in surimi. The fish species employed were sole (Cyclopsetta chitendenni) and croaker (Micropogon undulatus). The leguminose extracts were obtained from kidney bean, pea, chickpea and soy. The presence of inhibitors in the extracts was confirmed employed trypsin, chymotrypsin and papain (1 g/L), having azocasein as substrate. The textural degradation in surimi gels was determined as changes in shear strength and shear strain (test of torsion). The presence of proteolytic activity at 60°C in surimi as well as the inhibitory effect of leguminose extracts were determined measuring the presence of soluble peptides in 5% trichloroacetic acid. The legu...

Ten hemoglobins from the teleost Micropogon undulatus were separated in native polyacrylamide gel electrophoresis. In a large sample taken from a tributary of the Chesapeake Bay in Virginia, the distribution of these hemoglobins confirmed a polymorphic condition, which was previously known in North Carolina animals. The intraspecific variation was unrelated to body length, indicating that it is an adult phenomenon. The 10 hemoglobins were expressed in seven different phenotypic banding patterns. Although several morphs were infrequent, no single phenotype comprised a majority of the sample, indicating that the variation is quite great. Several phenotypes differed from those in North Carolina animals and, conversely, several North Carolina phenotypes were not recovered from the Chesapeake Bay sample. This finding suggests that the polymorphism is more complex than observed in either investigation alone. The O 2 binding of hemolysates stripped of co-factors by dialysis revealed functional differences between some, but not all, Chesapeake Bay morphs. The most variable property was O 2 affinity, although a few differences in pH dependence and cooperativity were also observed. The O 2 binding of red blood cell preparations also differed. These differences were not identical to those between dialyzed hemolysates, suggesting that organic PO 4 co-factors may be involved as well.

Various biomarkers were used to determine the exposure of fish (Arius felis and Micropogon undulatus) from Galveston Bay (GB), Texas, USA to organic contaminants. Sediment levels of polynuclear aromatic hydrocarbons (PAHs) in GB ranged from 81 to >1000 ng/g and polychlorinated biphenyls (PCBs) were

Two experiments were conducted to determine the nutritional value of various dietary proteins for juvenile red drum. In the first 8-week feeding trial, diets containing similar quantities of lipid, carbohydrate, available energy and ash with 35% crude protein from either lyophilized whole-body croaker ( Micropogon undulatus ), striated beef muscle, red drum processing waste or commercially processed menhaden ( Brevoortia tyrannus ) fish meal were fed to juvenile red drum in brackish (6 ppt) water along with a control diet containing lyophilized muscle of red drum. The control diet produced significantly ( P

The Galveston Bay estuary exhibited a contamination gradient for polynuclear aromatic hydrocarbons (PAHs) and halogenated aromatic hydrocarbons, and the comparative sensitivity of various biomarkers in fish from different bay locations were determined. Two fish species, hardhead catfish (Arius felis) and Atlantic croaker (Micropogon undulatus), were collected from four stations where sediment total PAHs ranged from 68 to >1,000 ng/g. The induction of cytochrome P4501A-(CYP1A-) dependent hepatic ethoxyresorufin-O-deethylase (EROD) activity, CYP1A mRNA levels, or CYP1A immunoreactive protein in hardhead catfish was highly variable in the field-collected fish and in fish dosed with up to 15 mg/kg benzo[a]pyrene (BaP). In contrast, significant differences were seen in biliary concentrations of naphthalene, phenanthrene, and BaP metabolites in hardhead catfish from polluted versus less polluted areas. In croakers taken from the same four Galveston Bay locations, EROD and glutathione S-transferase activities, immunoreactive CYP1A protein, biliary PAH metabolites, and PAH–DNA adducts were higher at the contaminated stations compared with less polluted locations. These studies suggest that the croaker is a good species for monitoring contaminants that induce CYP1A-mediated responses. Biliary PAH metabolites and PAH–DNA adducts were also sensitive indicators of exposure to PAH contamination in both species of fish.

Heading and evisceration of Atlantic croaker and grey trout soon after harvest was shown to promote higher quality maintenance during iced but not frozen storage for both species. Fish eviscerated immediately upon landing maintained class 1 quality (FDA) 7–10 days longer than iced uneviscerated fish or fish eviscerated 3 days after harvest. Total volatile nitrogen levels and miccrobial counts (7° and 25°C incubation) increased more rapidly than trimethylamine levels as storage time progressed. Both Torrymeter readings and hypoxanthine levels served as good indicators of “freshness” (time/temperature age). However, of the two tests only Torrymeter values reflected quality differences between fish stored iced for an equal period of time (equal “freshness”) but varying in quality, due to the evisceration treatment.

Effects of moisture loss in tray-packed fresh fillets of Flounder (Pogonias cromis), Red Snapper (Litjanus blackfordii), Croaker (Micropogon undulatus) and Ocean Perch (Sebastes marinus) were studied. The fish, purchased from seafood suppliers and processed into fillets at their prospective plants, were packaged in plastic foam trays lined with absorbent pads, overwrapped, and subsequently stored at 2°C (35.6°F) for 8 days. Gross and net weights decreased whereas the percent drip increased for all fish during storage. Except for croaker, the total moisture content remained virtually unchanged for all fillets during storage. The acceptability of all fillets decreased as the Trimethylamine-Nitrogen concentrations increased.

Alkaline protease in croaker exists not only in the sarcoplasmic fraction of skeletal muscle but also in the skin and internal organs. As characterized by optimal pH, thermal stability, and column chromatography, the alkaline proteases obtained from different fish tissues such as muscle, skin, kidney, and alimentary canal exhibit similar enzymatic properties. An experiment using chloramphenicol to inhibit bacterial growth suggests that the heat-stable alkaline protease present in the minced (mechanically separated) croaker is likely not of bacterial origin. The high specific activity of alkaline protease from kidney, liver, and visceral tissue in comparison to that of skin and muscle suggests that inclusion of residual tissue in even small amounts from the former sources could contribute greatly to the total activity measured in fish mince.

Sheepshead ( Archosargus probatocephalus ), Atlantic croaker ( Micropogon undulatus ) and pinfish ( Lagodon rhomboides ) were each exposed to aqueous solutions of reagent grade cupric chloride in artificial seawater in four static bioassays. The 24, 48, 72 and 96-h TL m were determined to be, respectively, 4.17, 3.02, 2.19 and 1.14 mg Cu 2+ ·I −1 for sheepshead, 9.15, 7.55, 7.20 and 5.66 mg Cu 2+ ·I −1 for croaker, and 7.33, 4.43, 4.14 and 2.75 mg Cu 2+ ·I −1 for pinfish. These results are compared with literature values of experimental concentrations of copper producing subtle behavioural changes in these species.

To estimate the growth rate of the Atlantic croaker 113,670 juveniles were marked and released between 23 January and 23 March 1975. The experiment was divided into five tests; in each, the fish were marked with a different fluorescent pigment. Recapture efforts produced 110 usable returns. Individual croakers appear to have had an average maximum stay of 1.8 months in the nursery. Growth rate was estimated by the regression of length of recaptured juveniles on time; estimates ranged from 0.51 to 0.99 mm/day, all of which were considerably higher than most estimates in the literature. There was a trend of increasing growth rate through the five tests. Length frequencies of 159,381 croakers taken in a trap at the study area outlet could not be interpreted in a reliable manner for growth rate estimates. Future attempts to estimate young-of-the-year croaker growth rates should use methods other than length frequency.

Descriptions of the emigration patterns of juvenile Atlantic croakers, Micropogon undulatus, from their nurseries have varied from (1) gradual seaward movements, to (2) mass outward movements, to (3) a “bleeding off” of the larger individuals. The present study was conducted at a semi-impounded marsh within a few kilometers of the Gulf of Mexico. Emigration patterns were monitored by trawling within the nursery and continuous trapping in the nursery outlet. Early in the year (February and March) croakers were small and tended to move in and out of the nursery with the tide. Thereafter there was an increasing divergence in the size of trawl- and trap-caught croakers; the fish taken in the trap were consistently the larger, indicating that the larger juveniles were continually “bleeding off” and emigrating back to the Gulf.

Micropogon undulatus L. were sampled from Galveston Bay, Texas, and transported to the research laboratory. Groups of five fish were exposed to 5 and 10% dilutions of the water soluble fraction (WSF) of southern Louisiana crude oil for 1, 3, 7, 14 and 21 days. Selected histochemical parameters of liver sections from control and WSF-exposed fish were evaluated. Glycogen was reduced in amount while glucose-6-phosphate dehydrogenase, lipid and cholesterol were increased in liver sections of WSF-exposed fish. These observations support a hypothesis that exposure to petroleum hydrocarbons increases mixed-function oxidase activity. The alterations were more obvious in sections from fish exposed to the higher level of the WSF. The histochemical parameters appeared most altered in hepatocytes near afferent hepatic blood vessels. These hepatocytes were the first cells of the liver to contact the pollutants.

Vertical responses of juvenile Atlantic croakers (Micropogon undulatus) to acute supersaturation of nitrogen and oxygen and to changing temperature were observed in a 2.5-m-tall test cylinder supplied with flowing estuarine water. Supersaturation of nitrogen caused an initial upward movement of fish, although a compensatory downward response seemed to occur after 2–4 hours of exposure. Supersaturation of oxygen resulted in an almost immediate downward movement of fish. Abrupt upward displacement of fish followed water-temperature changes, especially increases. Similarities between the behavior of croakers in these experiments and the behavior of other physoclists after swim-bladder volume manipulation suggested that gas supersaturation caused the swim bladders of our fish to inflate, resulting first in upward drift and then in downward swimming to restore neutral buoyancy. A nonlinear response model incorporating this hypothesis accounted for 62% of the variation (over all experiments) in mean ve...

Atlantic croaker, Micropogon undulatus L., were sampled from an estuary and selected offshore sites in the Gulf of Mexico. Liver samples were collected for light and transmission electron microscopy. Histologically, the Atlantic croaker liver parenchyma was arranged in tubular units. The tubules were similar to those of the primitive marine hagfish but contained unique features such as a central sinusoid and intercellular bile canaliculi. This liver structure may represent an evolutionary step from the primitive tubular hagfish liver to the muralium pattern of higher vertebrates. Pigments which may have occurred from disturbances in the normal oxidative pathways of hepatic lipids were also present in the liver.

When examined in relatlon to their availability in the plankton, the organisms eaten by larval spot Leiostomus xanthurus and Atlantic croaker Micropogonias undulatus collected in the northern Gulf of Mexico indicated that these larvae feed selectively. Two electivity indices indicated that both small (1.00 to 5.00 mm) and large (5.01 to 10.00 mm) spot larvae selected copepodid and adult copepods (Stages C1 to CVI), pteropods, and pelecypods. Small croaker larvae also selected copepodid and adult copepods, as did large croaker larvae. Small and large larvae of both species selected Oncaea sp. from among the copepods, while one or more length categories of either species selected Oithona spp., Paracalanus spp., Corycaeus spp., and Acartia tonsa. Select~on appeared to be related not only to the width, but also to the sw~mming behavior and color of food organisms.

Many of the most productive fishing grounds in the United States are estuaries and bays which are located near population and industrial centers, and therefore subjected to pollution. Observations made on 17 fish species from commercial catches harvested in north Biscayne Bay, Florida, an urban area, showed high numbers of individuals suffering from abnormalities and diseases. Seven groups of disorders most frequently affected bottom feeders. Fin and integumental hemorrhages occurred in all individuals in 26 of 43 catches of Mugil cephalus (striped mullet), and in all individuals in 24 of 30 catches of Micropogon undulatus (Atlantic croaker). Disorders occurring consistently in a location exposed to pollutants, but uncommon in other areas of the species' range, point to environmental stress as a probable cause.

The responses of liver microsomal monooxygenases in three teleost species, croaker (Micropogon undulatus), rainbow trout (Salmo gairdneri) and scup (Stenotomus chrysops) to polynuclear aromatic hydrocarbon (PAH) induccrs were compared. In all three species PAH induced higher raies of ethoxyresorufin and/or benzo[a]pyrene (B[a]P) metabolism and levels of cytochrome P-450, but the species differed in some other responses. The induction of P-450 appears to be associated with the synthesis of new (or additional) microsomal protein at 57000 daltons in trout and 54000 daltons in scup, identifiable by SDS-polyacrylamide gel electrophoresis. Further da.a suggest that ethoxyresorufin metabolism in scup may be catalyzed by a minor form of P-450 distinct from the major induced protein. All scur examined thus far from natural populations exhibit properties of hepatic microsomes characteristically associated with the induced state. B[a]P is metabolized by control and untreated scup with a high regiospecificity normally associated with the production of reactive and mutagenic metabolites. which may have implications for animals in the field.

The greater texture breakdown observed in gel-type products prepared from mechanically separated tissue as opposed to manually separated tissue can to some extent be attributed to the significantly higher protease activity measured in mechanically separated tissue. Failure to thoroughly wash eviscerated fish prior to mincing appears to result in the retention of tissue from internal organs as evidenced by a concommitant increase in protease activity in the minced tissue. Alkaline protease activity in croaker kidney and liver is several thousand fold higher than in skeletal muscle. Addition of kidney and liver tissue to deboned tissue from thoroughly washed fish results in increased protease activity and degradation of the fish tissue upon comminuting and cooking at 60°C. Isoelectric focusing provided evidence that the increased alkaline protease activity observed in mechanically separated fish tissue resulted to some degree from retention of kidney tissue in the fish mince. Isolation of Ca++-dependent protease fractions from liver also implicated contamination from this source as an additional contribution to the total protease activity of minced fish.

Digenetic trematodes from the white perch, Morone americana, were identified by Linton (1900) as Distomum areolatum Rudolphi, 1809. He (1901) referred specimens from the cunner, Tautogolabrus adspersus, and the winter flounder, Pseudopleuronectes americanus, to the same species. These worms were collected at Woods Hole, Massachusetts. Other specimens were taken from Bairdiella chrysura, Micropogon undulatus, Orthopristis chrysopterus, and Sciaaenops ocellatus at Beaufort, North Carolina. Linton (1940) included all these worms in a new species, Lepocreadium trullaforme. But they are not specifically identical with L. trullaforme and their taxonomic status has been uncertain. The metacercariae of these worms have been known for many years an unencysted distomes in the ctenophores and medusae taken in plankton collections. The discovery of an ophthalmotrichocercous cercaria from Nassarius trivittatus with the same morphology, has led to the completion of the life-cycle and the resolution of the taxonomic sta...

Atlantic menhaden, Brevoortia tyrannus, and Atlantic croaker, Micropogon undulatus, captured in the lower Cape Fear River, North Carolina in 1977 were examined for body site preference, seasonality, abundance, and incidence of the parasite Lernaeenicus radiatus in relation to water temperature and salinity variations. On three size groups of Atlantic menhaden and of Atlantic croakers studied, body regions extending from nape to anal fin and including the dorsal and pectoral fins were preferred attachment sites. Fins were preferred attachment sites in Atlantic croakers regardless of fish size. Mean number of parasites/fish increased with size of host. Atlantic menhaden condition factors were slightly lower with high parasite incidence. Highest incidences of L. radiatus on each species occurred in April. Parasite abundance increased inversely to water temperature and salinity with highest incidences occurring in fish from lower saline and colder waters.

Otoliths from 1,291 Atlantic croakers Micropogonias undulatus, with total lengths from 113 mm to 417 mm, from the northern Gulf of Mexico were examined to determine age and growth. Marginal increment analysis was used to determine that otolith marks formed annually. Ages ranged from 0 to 8 years. No significant difference was found for length at age between males and females. The von Bertalanffy equation was Lt = 419.2[1 - e−0.273(t+1.405)], where Lt = total length (mm) and t = age (years). The length-weight relationship (r = 0.99) was W = 5.302 × 10−6TL3.134 where W = weight (g) and TL = total length (mm).

Two significant fish kills occurred in the Pamlico River estuary (North Carolina, USA), one in December 1981 and January 1982, and the other in June 1982. The first involved only the southern flounder(Paralichthys lethostigma). Histopathologic examination of morbid and moribund flounder revealed extensive sloughing and necrosis of the mucosa of the pyloric caeca and intestine, and inflammation of the submucosa of the pyloric caeca. Brain and internal organ homogenates from morbid and moribund flounder were assayed on CHSE-214 cells, and a virus was isolated. Virus titers ranged from≤8.4 · 102 to 6.3 · 107 TCID50 per gram of tissue. Cross-plaque neutralization assays indicated that the southern flounder virus was infectious pancreatic necrosis virus serotype Ab. Immersion challenge showed the isolate is only slightly virulent for fry of brook trout(Salvelinus fontinalis). The second fish kill involved the southern flounder and six other species: hogchoker(Trinectes maculatus), Atlantic silverside(Menidia menidia), spot(Leiostomus xanthurus), Atlantic croaker(Micropogon undulatus), silver perch(Bairdiella chrysura), and striped mullet(Mugil cephalus). Virus was isolated from southern founder, hogchoker, Atlantic silverside, and spot. Neutralization assays indicated that the four isolates were nearly identical; however, the diversity of species affected suggests that the virus might not have been the specific cause of mortality.

Larvae of seven species of estuarine fishes (Atlantic menhaden, Brevoortia tyrranus; pinfish, Lagodon rhomboides; flounder, Paralichthys dentatus, P. albigutta, P. lethostigma; spot, Leiostomus xanthurus and Atlantic croaker, Micropogon undulatus) were exposed to sea water extracts of sediments from Charleston Harbor, S.C., for periods of time up to 14 days. Survival of the larvae in various concentrations of the extracts was measured. Survival of the larvae was affected at the highest concentrations of extract tested and indications are that different species of fish have different survival rates. In the selection of disposal areas for dredged material, consideration should be given to its relative toxicity to organisms.

INTRODUCTIONThe caesium radionuclides, caesium-137 and caesium-134, are important constituents of aqueous radioactive effluents discharged to the environment of the United Kingdom from fuel re-processing plants and nuclear power stations (Howells, 1966; Mitchell, Harvey & Smith, 1968; Harvey, Baker & Mitchell, 1969). Their accumulation by marine fishes has been the subject of several previous studies, beginning with that of Chipman (1959) who noted that caesium-137 was accumulated in the flesh of the killifish(Fundulus heteroclitus)and that accumulation continued even after a period of 72 days. Similarly, Hiyama & Shimizu (1964) showed that the muscle of the common goby(Acanthobus flaviamus)continued to accumulate caesium-134 from sea water after periods of 30 days. Baptist & Price (1962) have examined the whole body uptake of caesium, by absorption from sea water, in two marine species, the flounder(Paralichthys dentatus)and the Atlantic croaker(Micropogon undulatus), and they also investigated the accumulation, tissue distribution and excretion of caesium-137 in the croaker, the little tuna(Euthynnus alleteratus)and the bluefish(Pomatomus saltatoux), following oral administration of single doses. These authors concluded that the heart, liver and spleen of the croaker absorbed caesium-137 from sea water at a faster rate than the muscle, and that orally administered caesium-137 was rapidly absorbed from the digestive tract. Tissue distributions were similar in the croaker, bluefish and tuna. The retention of caesium-137 in croaker tissue was described as a multiple rate process. In later experiments Hiyama & Shimizu (1969) compared turnover rates in various organs and tissues following uptake from sea water and from single injection experiments, and obtained good agreement between the values from the two methods.

The average swimming speed of two estuarine fishes, spot (Leiostomus xanthurus) and croaker (Micropogon undulatus), was determined in the laboratory under a constant and a changing salinity regime. It was found that croaker moved faster under 5 and 10% salinity change hr—1 as compared to the fixed salinity regime. Spot increased its speed of movement only under the 10% change hr—1 condition. These results suggest that (1) those portions of the estuary possessing similar salinity changes may be avoided by spot and croaker and that (2) possibly the rate of change in salinity rather than the actual salt concentration limits the distribution of these species.

Croakers of varying ages and with approximately an equal distribution of the sexes were studied to determine gonad development. Data gathered indicate that males mature earlier than females. The smallest male to reach sexual maturity was 24 centimeters long, whereas smallest ripe female was 27.5 centimeters long, total length. The ages of these fish, as indicated by scale examinations, were 2 and 3 years, respectively. All fish 3 years or older had ripening gonads. The fish studied were collected by random sampling, in which the ratio of males to females in the areas changed from 50:50 in June to a ratio of approximately 35:65 during early August. This evidence, further supported by records of ocean catches, indicates that males begin their spawning migrations out of the bay earlier than females. At the time of departure whether males or females, the gonads have reached comparatively complete maturity. Evidence based upon tagging, gonad development, and samples from commercial catches, shows that...

A survey of sportfishing activity at the P. H. Robinson Generating Station discharge into Galveston Bay, Texas was taken from 21 October 1968 through 8 November 1969. During 108 daily checks, 1,063 fishermen were interviewed and 2,635 fish counted. Fishing activity was related to season and temperature of the heated effluent. Maximum fishing pressure and largest catches occurred during the period December 1968 through April 1969 and November 1969 when discharge water temperatures and flow rates were minimum. Lowest angling activity and catch rates were recorded from June through September 1969 when water temperatures approached 40 C in the upper part of the fishing area. Atlantic croaker, Micropogon undulatus; sea catfish (hardhead), Arius felis; sand seatrout, Cynoscion arenarius; black drum, Pogonias cromis; red drum, Sciaenops ocellata; and spot, Leiostomus xanthurus, in order of decreasing abundance, accounted for 96.7% of the fish counted during the study. Seine, trawl, and trammel net data ...

Laboratory experiments were conducted to measure uptake of fission products by fish from water and from oral doses. Availability of fission products to the fish was curtailed considerably by the formation and settling of radioactive particles in the water and by sorption to abiotic surfaces. Spot, Leiostomus xanthurus, and Atlantic croaker, Micropogon undulatus, accumulated relatively low levels of radioactive material from seawater. Following a single oral dose, croaker assimilated a maximum of 14% in 4 hours, but 94% of the original dose was eliminated after 4 days. Bluefish, Pomatomus saltatrix, assimilated only 3% of the cumulative dose of mixed fission products administered in shrimp meat on alternate days for 55 days. Of the amount assimilated from oral doses by croaker and bluefish, the largest concentrations were found in the internal organs.

Iridoviruses have been identified in a variety of vertebrate and invertebrate hosts. Amphibian iridoviruses, discussed by Granoff elsewhere in these proceedings, have been isolated from normal or diseased adult leopard frogs (Rana pipiens), normal larval or adult newts (Triturus viridescens), and diseased bullfrogs (Rana catesbeiana). Isolation of piscine iridoviruses from normal adult goldfish (Carassium auratus), some freshwater fish (e.g., Micropogon undulatus and Cynosciau arenius) with papilloma-like lesions, and redfin perch (Perca fluviatilis) with hepatocellular and hematopoietic necrosis has been reported by Berry et al. (1983), Christmas and Howse (1970) and Langdon et al. (1986), respectively. These viruses have been placed in the family Iridoviridae based on icosahedral morphology, cytoplasmic site of replication and a large DNA genome. Among iridoviruses, frog virus 3 (FV3), isolated from the renal adenocarcinoma of the leopard frog Rana pipiens (Granoff et al.,1966) is the only member of the family Iridoviridae that has been the subject of detailed molecular analyses (reviewed in Willis et al.,1985).

Mark-recapture experiments conducted in a small 17.5 ha lake in Barataria Bay, Louisiana, were used to estimate the efficiency of a 4.9-m (16-foot) otter trawl in capturing brown shrimp, Atlantic croaker, and spot in water 1.5 m deep. The trawl was observed to sweep an area 2.5 m in width. Trawl efficiency was determined to be approximately one-third to one-half for brown shrimp, one-fourth for Atlantic croaker, and only 6 percent for spot.

Eleuterius, Charles K. 1978. Classification of Mississippi Sound as to estuary type by vertical salinity structure. Journal o j the Mississippi Academy of Sciences Eleuterius, Lionel N. 1978. Population variation in the salt 23(Sup.):9 1. marsh rush, Juncus roemerianus. Journal of the Mississippi Academy ojSciences 23(Sup.):6. . 1978. Observations on the red alga, Caloglossa Ieprieurii, in salt marshes. Journal of the Mississippi Academy of Sciences 23(Sup.):7. Foster, Carolyn A. and T. G. Sarphie. 1978. Ectocommensal relationship of the peritrichous ciliate Zoothamnium sp. to Penaeid shrimp: electron microscopic observations. Journal of the Mississippi Academy of Sciences Fusco, Alan C. 1977. Hemoglobins of the nematode Spirocamallanus sp. and its piscine host ,Micropogon undulatus. Program and Abstracts of the American Society of Parasitologists 52ndAnnualMeeting, 14-1 9August 19 77, p. 63. Higgins, George G. and Charles K. Eleuterius. 1978. Mississippi Sound: volume, surface area and bathymetric statistics. Journal of the Mississippi Academy of Sciences Hossler, F. E., J . R. Ruby and T. D. McIlwain. 1978. Surface morphology of the gill filaments of the mullet, Mugil cephalus. Proceedings of the 7th Annual Texas Society of Electron Microscopy-Louisiana Society of Electron Microscopy Symposium 7( 1):40. Lofton, S. R. and D. W. Cook. 1978. Evaluation of the 48hour IMViC plate procedure for identification of Escherichia coli from seafoods. Journal of the Mississippi Academy of Sciences 23(Sup.):77. Lukens, Ron. 1978. Notes on Stenopus scutellatus and S. hispidus (Decapoda, Stenopodidae) from Mississippi. Journal of the Mississippi Academy of Sciences 23(Sup.):113. McGraw, Katherine A. 1977. Oyster growth and survival study in Mississippi Sound. University of Washington (Seattle), College of Fisheries, 1977 Research in Fisheries. Contribution No. 470:75. Ogle, John T. 1978. Predator prey relationship betwecn blue crabs and cultchless oyster seed. Journal of the Mississippi Academy of Sciences 23(Sup.): 112. Otvos, E. G. and Wade Howat. 1978. Surface and nearsurface Pleistocene littoral-marine deposits, Mississippi coast. Journal of the Mississippi Academy of Sciences Overstreet, Robin M. 1977. Infections of the trypanorhynch cestode Poecilancistrium caryophyllum in flesh of a marine fish. Program and Abstracts of the American Society of Parasitologists 52nd Annual Meeting, 14-1 9 August 1977, p. 52. Snazelle, Theodore E. and David W. Cook. 1978. Carbohydrate inhibition of pigment formation in a pigmented, asporogenous mutant of Bacillus cereus. Journal of the Tennessee Academy of Sciences 53(2):61. Stapp, Dennis S. 1978. A method of thermal structure prediction for estuaries. Journal of the Mississippi Academy of Sciences 23(Sup.):90. 23(Sup.): 1 11.

A fibroblast-like cell line, CrF, has been developed from muscle tissue of the marine teleost fish Micropogon undulatus (the Atlantic croaker). The line was initiated by subculture of cells from explanted tissue of a single male fish. The growth medium employed contained L-15 basal medium supplemented with 15% fetal calf serum, 1 to 5% human serum, and antibiotic-antimycotic mixture. The line was characterized fully and carried through 85 subcultures. Karyological analysis showed the line to be heteroploid, with a modal chromosome number of 48 at low passage levels and 49 at high levels. All chromosomes are small and telocentric. Growth characteristics were carried out under varying conditions of incubation. Optimal growth occurred at 26 to 32° in growth medium adjusted to a NaCl molarity of 0.147 to 0.177 M (although a wider range was tolerated). A plating efficiency of up to 30% and freeze viability rates of 65 to 70% were observed. The line was shown to be susceptible to lymphocystis virus, but...