ABSTRACTIn 1983 and 1984, the endangered shortnose sturgeon,Acipenser brevirostrum, was successfully spawned and progeny reared as part of a cooperative culture program between the U.S. Fish and Wildlife Service and the State of South Carolina. Wild‐caught adults were induced to spawn through injection of either carp or sturgeon pituitaries. Ovulated eggs were removed through an abdominal incision or through manual stripping. In one case, an uninjected female spawned in a tank with ripe males. Hatching began at 111–121 hours at 20°C and 136 hours at 18°C. Fish hatched at a mean size of 9.6 mm TL and grew to 28.9 mm by day 35.Tank‐held spawned brood stock and wild‐caught non‐brood stock decreased in size in spite of the availability of natural foods, however, pond‐held adults grew in size.
ABSTRACTPrawn (Macrobrachium rosenbergii) postlarvae (average weight 0.04 g) were stocked at 40/m2 into circular plastic nursery pools with a surface area of 7.3 m2 and water depth of 0.5 m. The use of fertilizers in place of feeds, pre‐treatment of fertilized pools with trichlorfon to reduce predacious insects and/or competitors and the use of additional substrate were evaluated for prawn nursery rearing. After a 35‐day nursery period, average survival and weight in fertilized pools with additional substrate were 65% and 0.301 g, in fertilized pools with additional substrate and pre‐treated with trichlorfon 66% and 0.231 g, in pools receiving feed with additional substrate 74% and 0.352 g, and in pools receiving feed but having no additional substrate 83% and 0.305 g. There were significant differences in survival and growth between the treatments. The results of this study suggest prawn growth and survival were improved with feeds, while improvements from a trichlorfon pretreatment or additional substrate were not substantial.
ABSTRACT Aquaculture facilities are often located in the proximity of agricultural, industrial, or urban sources of pollution. Utilization of water downstream from pollution sources is a general concern to aquaculturists. Rivers and coastal waters receive heavy metals from industrial and urban wastes and effluents. In most aquatic animals, the main route of heavy metal entry is via food and drink. In addition to the accumulation of heavy metals in aquatic species, we and others have shown that HgCl 2 and CH 3 HgCl inhibit intestinal absorption of amino acids and sugars. Here we present data to show the generality of this effect among several species. The data also show that HgCl 2 is a more potent inhibitor than CH 3 HgCl. In order to further elucidate the mechanisms of action of mercury, we have examined the movement of 203 HgCl 2 and CH 3 203 HgCl from the intestinal lumen to the blood using a free swinnning in vivo procedure in the toadfish, Opsanus tau . Intestinal tissue and luminal fluid were analyzed after each incubation period. It was observed that both compounds appear in the tissue fraction within the first hour. CH 3 HgCl rapidly transfers to the blood, while HgCl 2 exhibits a slow but evident transfer. Much of the HgCl 2 in the tissue fraction was carried back to the luminal fluid by the mucus, suggesting binding to the luminal surface with little intracellular entry. CH 3 HgCl mainly moved into the tissue and then the blood with little or none being returned to the luminal fluid bound to mucus. Differences in the site of action of these two compounds was suggested.
ABSTRACTReproductive performance of unilateral eyestalk ablated and unablated wild and pond rearedPenaeus semisulcatuswas compared in a series of experiments in Eilat, Israel. Tagging techniques were used to study the maturation and spawning of individual females. The average numbers of spawns and eggs per ablated females were more than double those produced by unablated females, although fewer eggs per spawn were produced by ablated females. There were no significant differences in spawn quality, as measured by the percent fertility, hatch, and metamorphosis to zoea 1, between ablated and nonablated females. Egg production of ablated females was consistent for 70 to 80 days after which a decline was observed. The average rate of egg production of nonablated shrimp was more erratic with an apparent decline only after 100 to 110 days.No significant differences were found in spawn size or spawn quality between the first three spawns of ablated and nonablated females. A significant reduction in spawn size was apparent over the molt cycle although the percent fertility remained constant. Spermatophore transfer rates of 84 to 92% were achieved with female to male rations of 1.8:1 to 2.5:l. A reduction in fecundity was observed for successive generations of pond‐reared brood stock.Eyestalk ablation was used to stimulate spawning of P.semisulcatusin captivity with no significant reduction in brood stock survival or in spawn quality.
ABSTRACTThe importance of highly unsaturated fatty acids (HUFA) such as 20:5ω3 and 22:6ω3 has been investigated for the larvae of the blue shrimpPenaeus stylirostris. HUFA‐rich or HUFA‐enrichedArtemianauplii yielded higher production results in the hatchery than HUFA‐poorArtemia, especially when yeast was used as a substitute for algae during the early larval stages. Best results were obtained when a HUFA‐rich formulated diet was used as a supplement to the yeast and as an enrichment for theArtemianauplii. Differences in production results could be attributed to the HUFA content in living and non‐living larval diets.
ABSTRACTA staged rotating biological contactor (RBC), packed tower (PT, trickling filter) and fluidized bed reactor (FBR) were tested simultaneously using common water from a fish culture tank. The culture tank was stocked with channel catfish (Ictalurus punctatus) at three different densities (approximately 227, 113 and 57 kg/m3) to provide solute concentrations in the filter influent similar to those expected under intensive culture practices.Mean concentrations of total ammonia nitrogen (NH4+‐N + NH3‐N) in the culture tank were 1.46 (3.50‐0.42), 1.26 (1.78‐0.95) and 0.36 (0.48‐ 0.28) mg N/liter at the respective stocking densities. The RBC provided the best nitrification efficiencies (74%, 82% and 76%, respectively). The efficiency of the PT (23%, 42% and 51%) was somewhat better than the FBR (8%, 28% and 32%). The rate of ammonia removal across the entire RBC was 0.79, 0.63 and 0.19 g N/m2d‐1, with removal across the first two stages of 1.31, 1.15 and 0.31 g N/m2d‐1. The PT provided arranonia removal of only 0.25, 0.32 and 0.14 g N/m2d‐1.Dissolved oxygen, nitrite, nitrate, pH, alkalinity and chemical oxygen demand analysis was also performed.
ABSTRACTThe rotifer Brachionus plicatilis is widely used in aquaculture, but problems remain with its utilization. It is often difficult to synchronize rotifer production with larval demand, year‐round culture maintenance is a technical nuisance, and cross‐strain contamination is a persistent problem. Rotifers produce resting eggs that are thick‐walled encysted stages which can remain dormant for extended periods. These resting eggs are analogous to Artemia cysts and could be used in a similar fashion in aquaculture. The mass production of rotifer resting eggs depends upon our ability to manipulate the rotifer life cycle in mass cultures. This paper examines several factors regulating the rotifer life cycle and identifies environments that promote resting egg production. Depending on the rotifer strain used, the strongest mictic response occurs at moderate temperatures and salinities. A mixed diet of Chlorella and baker's yeast promoted the greatest resting egg production. The RUS B. plicatilis strain exhibited the strongest mictic response in all environments tested and was 5 times that of any other strain. Success in manipulating the rotifer life cycle for resting egg production will depend upon a thorough understanding of sexual reproduction and how it is integrated into the life cycle. The major problem currently limiting resting egg production in laboratory populations is fertilization rate. The prospects for the controlled mass production of rotifer resting eggs are nonetheless good, but they are not imminent.
ABSTRACTPolyculture, the culture of two or more aquatic species in a single culture unit, has proven ecologically sound and practical. However, when cultured organisms have different physical needs or have antagonistic (competitive or predator‐prey) relationships, successful polyculture becomes unlikely. To remove the constraints without loss of the advantages of polyculture, an alternative system of “integrated pond culture” has evolved. The antagonistic species are cultured in discrete ponds which maintain contact only through the flow of nutrients and food organisms. By simple engineering and proper coordination of the ponds, this system shows promise for conserving water, energy, and especially nutrients. This is reflected in reduced operating cost in stocking, feeding and harvesting. Comparisons are made of polyculture and integrated pond culture with regard to aspects of management, engineering, economics and ecology.
ABSTRACTCarangid fishes of the genus Trachinotus have received much attention as mariculture candidates. Foremost among these is the Florida pompano (T. carolinus), which drew considerable research attention in Florida and Alabama that culminated in several business‐sponsored, intensive but uneconomical attempts to commercially culture pompano in south Florida and the Dominican Republic from the 1960's through the mid‐1970's. These attempts, however, demonstrated the biological feasibility of rearing pompano. Recently renewed interest has developed in commercially culturing pompano and two related species, Atlantic permit (T. falcatus) and palometa (T. goodei). Research on Trachinotus spp. in Martinique, Venezuela and Miami, Florida, is summarized, together with problems and prospects for commercial culture of these species.
ABSTRACTGrowth, feed digestibility (apparent total dry‐matter digestibility), and proximate body composition of juvenile Penaeus vannamei and Penaeus monodon were evaluated at dissolved oxygen (DO) levels of 1, 2, 3, and 4 ppm at a mean temperature of 28°C. The four different W levels were obtained by aerating different rates of nitrogen gas countercurrent to a constant flow of seawater. A standard formulated diet containing the marker material Cr2O3, and a mean 280% exchange of 30 to 32 ppt seawater per day were used. Initial wet weights of shrimp were 60.2 and 55.5 mg for P. vannamei and P. monodon, respectively. Final mean wet weights for shrimp maintained at 1, 2, 3, and 4 ppm DO level after a 16‐day growth trial were 0.24, 0.40, 0.42, 0.46 g, and 0.16, 0.26, 0.29, 0.29 g for P. vannamei and P. monodon, respectively. For both species, a significant reduction in growth and in the instantaneous growth rate (k) was obtained at the lowest Do level. No significant differences were observed for apparent feed digestibility in either shrimp. Laboratory analysis revealed no differences in moisture and lipid content for both species, while protein content was found to differ only in P. monodon grown at different DO levels. A description of the experimental system and a discussion of the significance of the data to the production of shrimp in ponds is presented.
ABSTRACTBlack drum (Pogonias cromis) and spot (Leiostomus xanthurus) were cage cultured in a cooling lake of a power plant near Baytown, Texas, from June through September 1978 and June through November 1977, respectively, to determine the effects of varying feeding rates on the dynamics of growth. Temperature, salinity, pH and dissolved oxygen were monitored daily and fish were measured and weighed either monthly or at two‐week intervals to determine growth rates.Survival was poor for spot due to handling stress, and excellent for black drum. Instantaneous growth rates were correlated to temperature, salinity, fish size, and feeding rate. Mean food conversion efficiency (FCE) was correlated to size and feeding rate. Maximum growth rates occurred at temperatures between 27–30°C. Growth rates increased with increasing salinity, and large fish grew faster at higher salinities than small fish. Growth rates increased with increasing feeding rates up to and slightly beyond the maximum daily ration, then declined. FCE decreased curvilinearly with increasing ration up to the maximum daily ration, then remained stable. Growth rates and FCE declined curvilinearly with increasing fish size.
ABSTRACTReported diseases of juvenile clams (Mercenaria mercenaria) are reviewed. A summary of disease problems experienced by hard clam hatcheries and seed purchasers of juvenile clams during a ten‐year period is presented. These include poor growth, poor seed quality and poor survival due to both chronic and acute mortalities. External fouling of juvenile cultured clams by bacteria, protozoans (including algae), molds, sponges, entoprocts, ectoprocts and others, are sometimes detected by microscopic examination of the external surface of the juvenile; however, the effects of external fouling and undetected diseases of the internal organs are not apparent on gross or microscopic examination of the entire juvenile clam. Histological studies are required to evaluate the health and presence of disease, including retrograde changes and atrophy of internal organs of the juvenile during culture. Suggestions for health evaluation of the cultured juvenile clam in order to increase productivity for hatcheries, and to assure quality control for clam seed purchasers, is presented.
Journal of the World Mariculture SocietyVolume 16, Issue 1-4 p. 386-386 THE EFFECT OF pH AND THE IMPROVEMENT OF WATER QUALITY BY Chondrus crispus IN AN Ostrea edulis NURSERY Catherine T. Enright, Catherine T. Enright Atlantic Research Laboratory, National Research Council, Halifax, Nova Scotia B3H 3z1 Canada.Search for more papers by this authorJames S. Craigie, James S. Craigie Atlantic Research Laboratory, National Research Council, Halifax, Nova Scotia B3H 3z1 Canada.Search for more papers by this authorGary F. Newkirk, Gary F. Newkirk Biology Department, Dalhousie University, Halifax, Nova Scotia B3H 4J1 Canada.Search for more papers by this author Catherine T. Enright, Catherine T. Enright Atlantic Research Laboratory, National Research Council, Halifax, Nova Scotia B3H 3z1 Canada.Search for more papers by this authorJames S. Craigie, James S. Craigie Atlantic Research Laboratory, National Research Council, Halifax, Nova Scotia B3H 3z1 Canada.Search for more papers by this authorGary F. Newkirk, Gary F. Newkirk Biology Department, Dalhousie University, Halifax, Nova Scotia B3H 4J1 Canada.Search for more papers by this author First published: March 1985 https://doi.org/10.1111/j.1749-7345.1985.tb00219.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume16, Issue1-4March 1985Pages 386-386 RelatedInformation
Journal of the World Mariculture SocietyVolume 16, Issue 1-4 p. 101-103 AMINO ACID DIGESTIBILITY IN RAINBOW TROUT: INFLUENCE OF TEMPERATURE, MEAL SIZE AND TYPE OF FOOD Benoît Hudon, Benoît Hudon Centre de Recherche en Nutrition and Département de Biologie Université Laval Québec, Canada, G1K 7P4Search for more papers by this authorJoël de la Noüe, Joël de la Noüe Centre de Recherche en Nutrition and Département de Biologie Université Laval Québec, Canada, G1K 7P4Search for more papers by this author Benoît Hudon, Benoît Hudon Centre de Recherche en Nutrition and Département de Biologie Université Laval Québec, Canada, G1K 7P4Search for more papers by this authorJoël de la Noüe, Joël de la Noüe Centre de Recherche en Nutrition and Département de Biologie Université Laval Québec, Canada, G1K 7P4Search for more papers by this author First published: March 1985 https://doi.org/10.1111/j.1749-7345.1985.tb00192.xCitations: 4AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume16, Issue1-4March 1985Pages 101-103 RelatedInformation
ABSTRACTTriplicate ponds (0.07‐ha) were stocked with either a single size group (11–12 cm) or mixed size groups (either smalls 7–8 cm, mediums 11–12 cm or larges 15–16 cm) of all‐male tilapia hybrids of female Tilapia nilotica x male T. hornorum. After 140 days, smalls, mediums and larges gained 1.89, 3.10 and 2.59 g/day in mixed stocking, respectively, while mediums in single stocking gained 2.59 g/day. In mixed stocking, growth of smalls was depressed due to competition with mediums, larges, or both. Larges apparently expended mre energy on nest building and guarding, thus allowing mediums to maximize their food intake and growth. Lack of a predetermined hierarchy under single stocking resulted in depressed growth.
ABSTRACTTwo studies each consisting of a growth and digestibility trial were carried out to evaluate the nutritive merit of four cereal grains (corn, milo, wheat and barley) in diets formulated forMacrobrachium rosenbergii. In the first growth trial four isonitrogenous, isolipidic and isocaloric (gross energy) diets differing in their grain source were fed to prawns with an initial mean weight of 7.3±0.1 g. After 12 weeks the barley based diet produced greater growth than the wheat based diet. No significant differences in feed conversion ratios, protein efficiency ratios, or feed consumption were observed. The same diets containing 1% chromic oxide were fed to larger animals (40–50 g) to determine apparent digestibility of protein and energy. Apparent digestibility of dietary energy ranged from 76.8% to 79.1% for the four diets tested and was significantly lowest in the wheat diet. Apparent digestibility of protein ranged from 84.1% to 88.9% and did not vary significantly among diets. In the second growth trial prawns with an initial mean weight of 4.1±O. l g were fed six isolipidic, isocaloric diets varying in protein level (20%, 30% or 40%) and grain source (wheat or barley). Growth at 12 weeks was significantly different among treatments. The wheat and barley 30% and 40% protein diets supported greater growth than the 20% protein wheat diet. The 40% protein wheat diet and 30% protein barley diet supported greater growth than the 30% protein wheat diet. Higher feed consumption was observed with the higher protein diets. No differences between feed and protein conversion ratios were observed among diets. In the second digestibility trial, apparent digestible protein was not significantly different among treatments, however, digestible energy was significantly different among treatments. It appears from the results that feed consumption and apparent digestible energy contributed to the growth response observed in the two growth trials. At the 30% dietary protein level, barley appears to have been more efficiently utilized than wheat, effectively reducing the level of required dietary protein.
ABSTRACTA negative relationship was found between damselfly nymph population density and final shrimp population density in ponds. The importance of damselfly nymphs as potential predators of post‐larval shrimp and the effect of shrimp size, salinity, and substrate type on this predatory relationship were evaluated by a series of laboratory experiments. When 5–10 nymphs and 15 post‐larval shrimp were stocked in tanks with a 0.96 m2 bottom area and containing 150 liters of water, each nymph averaged killing 1.7 shrimp per day at 10 ppt salinity and 0.6 shrimp per day at 20 ppt. Damselfly predation rates were inversely related to the three shrimp sizes (average 8.55, 12.89, and 17.30 mm). Presence or absence of a natural muddy substrate had no effect on shrimp mortality caused by nymphs. The results of these experiments strongly suggest that predation of damselfly nymphs on post‐larval shrimp, when they occur together in ponds, may be a serious problem for the culturist.
ABSTRACTThe costs and returns of hybrid bass aquaculture were evaluated based on experimental production data in South Carolina. The market potential for hybrid bass was examined based on market price and volume of striped bass on the East Coast during the past two decades. This preliminary assessment indicates that the economic outlook of commercial aqua‐culture of hybrid bass in estuarine waters appears promising. With current technology, prices in the $5.50/kg or higher range would generate some profits for aquafarms. However, the major concern at present is legal restrictions on commercial production and marketing of hybrid bass in South Carolina.
Five kinds of artificial seawater with similar salinity, pH and osmolarity were prepared with different concentrations of calcium and magnesium ions. The five seawaters in this study are: complete seawater, calcium-free seawater, half calcium-free seawater, magnesium-free seawater, and half magnesium-free seawater. Dolphin fish (Coryphaena hippurus) spawn in captive tanks without hormone induction. Eggs with developing embryos were removed from the incubation tank prior to hatching and incubated in the media with different concentrations of calcium and magnesium. Survival and hatching percentages of embryonic eggs in different media were recorded and compared. The results showed that both calcium and magnesium are essential for normal development. Reduction or elimination of either of these ions has different effects, resulting in embryonic abnormalities and/or reduced hatching and larval survival.
ABSTRACTProduction technology for soft‐shelled red swamp crawfish (Procam barus clarkii) was investigated. Immature trapped crawfish molted when placed under intense (100/m2) short‐term culture at a rate of 3.8% of the population/day when provided a diet of floating trout pellets. Other diets (carrots, cracked corn and milo, and low protein duckweed) yielded daily molting rates of 2, 1.6 and 1.4%, respectively. Pre‐ and postmolt weights of crawfish were not different. Processing by (1) removal of rostrum and gastroliths; (2) removal of internal organs, plus (1); and (3) removal of carapace plus (1) and (2) yielded 92, 79 and 72% edible product. Crawfish collected by seining yielded a greater number of molts over a 10‐day period than trapped crawfish.
