bluuebunny/crossref_metadata_2025 huggingface dataset:
A Review of the Effects of Algal Blooms on Shellfish and Aquaculture
Authors: Shumway Sandra E.
Published: April 2007

Toxic algal blooms occur worldwide and in some areas they are a common and seasonal occurrence. Historically, attention has been focused on blooms of toxic dinoflagellates (e.g., Protogonyaulax tamarensis). More recently, attention has been turned to other species (e.g., Dinophysis, Aureococcus, Gymnodininum). These blooms often present problems with respect to optimal utilization of the shellfish resources, and the magnitude of economic losses can be catastrophic. Nevertheless, successful culture facilities and commercial harvests persist in areas prone to toxic algal blooms.

This paper reviews the literature available on occurrences of toxic algal blooms, discusses the means by which harvesters, managers, and industry cope with the problems associated with toxic algal blooms, and makes recommendations for the most efficient and successful utilization of resources in the face of environmental instability.
Fatty Acid Composition of Three Cultured Algal Species (Isochvysis galbana, Chaetoceros gracilis and Chaetoceros calcitrans) Used as Food for Bivalve Larvae
Authors: Napolitano Guillermo E. , Ackman Robert G. , Ratnayake Walisundara M. N.
Published: April 2007

Fatty acids of three cultured unicellular algae wldely used in aquaculture (Isochrysis galbana, clone T‐iso, Chaetoceros calcitrans, and Chaetoceros gracilis) were analyzed in detail by gas‐liquid chromatography and mass spectrometry. Fatty acid compositions of the individual species, harvested at monthly intervals during a four month period, showed a very consistent pattern. Shorter chain (C16) fatty acids accounted for more than 70% of total fatty acids in the diatoms but less than 20% in I. galbana. Medium chain (C18) and the long chain 22:6w3 unsaturated fatty acids represented more than 50% of the total fatty acids in I. galbana but less than 10% of the total In the Chaetoceros spp. However, in the latter, 20:5w3 replaced 22:6w3 at an equivalent level. Fatty acid profiles of c. calcitrans and c. gracilis were similar, except that the latter contained lower levels of 16:2w4, 16:3w4 and 16:4w1, and higher levels of 18:2w6 and 18:3w6. In particular C. gracilis contained a higher proportion of the biochemically important fatty acid 20:4w6 (arachldonic acid). One of the salient features of I. galbana lipids was the presence of the fatty acid 18:5w3. This fatty acid is not generally reported in algae or invertebrate lipid analyses, but is a typical component of I. galbana and of other marine photosynthetic flagellates. Its potential for utilization by aquatic organisms is unknown.
Maturation and Spawning of Blue Shrimp Penaeus stylirostris (Stimpson) under Hypersaline Conditions
Authors: Holtschmit Karl‐Heinz , Romero Juan Manuel
Published: April 2007

Maturation and spawning of blue shrimp Penaeus stylirostris were obtained in hypersaline and turbid water. Results indicate that number of spawnings per female and percentage of viable spawnings are similar to those reported under “standard” conditions by other investigators. However, the number of nauplii produced was 50 to 75% less. A significant correlation was observed between reproductive activity and lunar cycles, showing peak activity at three to four days following new moon. Additionally, working with records of individual females, the number of spawnings per female was found to be extremely variable, with intervals between consecutive spawnings non‐uniform. Instead, they tended to group in pairs with less than six days between spawnings, followed by a variable period of time (usually more than 12 days) before the paired spawnings were repeated.
Reproductive Response ofPenaeus stylirostristo Temperature Manipulation
Authors: Robertson Lori , Bray William , Lawrence Addison
Published: April 2007

The effect of temperature manipulation on the reproduction ofPenaeus stylirostriswas investigated as a possible method for increasing larval production. Six 3.66 m diameter black tanks were stocked with unilaterally eyestalk enucleated females and intact males. Temperature was designed to vary between 20 and 28 C at a rate of 2 C per day in the “Fast” treatment and 2 C per week in the “Slow” treatment; upper and lower temperatures were maintained for 10 days before another cycle was initiated. In the “Ambient” treatment, temperature averaged 27.8 ± 0.9 C.

During the 105 day study maturation, mating and larval production were highest in the Ambient tanks. Temperature manipulation as tested in the Fast and Slow treatments did not produce any burst of mating and spawning activity at the upper ends of the cycles to compensate for the steady production in the Ambient group. Thus, the temperature regimes examined did not afford any practical advantage.

The effect of temperature on mating was marked. In the Slow treatment which most closely mimicked natural seasonal temperature change, mating began initially when the temperature increased to 25 C. Throughout the study mating occurred more frequently at the higher temperatures, and these results suggest that the optimal temperature range was 27–29 C for reproduction. However, the shrimp did mate at all temperatures encountered. It is notable that this tropical species can successfully reproduce at temperatures as Iow as 20 C.
Feeds and Feeding Schedules for Indoor Nursery Culture of Postlarval Freshwater Prawns Macrobrachium rosenbergii1
Authors: Heinen John M. , Mensi Michael J.
Published: April 2007

Potential feeds, feeding schedules, and feed supplements for growing M. rosenbergii postlarvae to a juvenile size of 0.5 g were evaluated. Postlarvae were grown in 69 L aquaria for 6 to 9 weeks at densities of 1.3 or 2.0/L at a water temperature of 28 C. An experimental diet (HFX‐EXD‐86X) and four commercially available feeds (Purina Trout Chow No. 2, Silver Cup Fish Feed—Salmon No. 3, Zeigler Shrimp Post Larval Granules No. 3, and MFC Clover Brand 38% Catfish Fingerling Crumbles) were tested. Prawns fed Purina Trout Chow No. 2 had the best survival and yield. Four feeding schedules were then evaluated with Purina Trout Chow No. 2 as the only food: once daily (at 1600 h), twice daily (at 0800 and 1600 h), twice daily (at 0800 and 2000 h), and three times daily (at 0800, 1600, and 2400 h). Prawns in the oncedaily treatment exhibited the best survival, final weight, yield, and food conversion ratio. A oncedaily frequency was then used to test the effects of supplementing the Purina diet with beef liver, squid mantle, codfish muscle, or cooked (scrambled) chicken egg, at 20% dry weight of the total diet. Prawns fed the beef liver supplement had the best final weight and yield.
Simulation of Short‐Term Management Actions to Prevent Oxygen Depletion in Ponds
Authors: Piedrahita Raul H.
Published: April 2007

This study examined possible changes in dissolved oxygen concentration resulting from various short‐term management actions that can be undertaken in response to cloudy conditions. The management actions were examined with a computer model of water quality in a pond, and include nutrient enrichment (fertilization, pH adjustment), water level control, and water exchange. Results of these simulations indicated that general management strategies directed at increasing nutrient availability were the least effective in counteracting the effect of the increased cloud cover. Flushing and reducing the water level in the pond were considerably more effective short‐term management actions. Areas for field research were suggested to confirm the effectiveness of the various strategies.
Effect of pH and Decapsulation on the Toxicity of Ammonia to the Brine Shrimp Artemia franciscana
Authors: Landau Matthew , Sanchez Veronica
Published: April 2007

Artemia franciscana were hatched and tested for tolerance to ammonia at pH 6.5 and 8.5 in artificial seawater with a salinity of 17 ‰. Nauplii seemed to be less tolerant of ammonia at pH 6.5 despite the fact that more of the ammonia is in the ionized form (NH4+). It is suggested that this greater sensitivity is a result of the NH4+ competing with the Na+ during gut transfer. Nauplii hatched from decapulated cysts were more tolerant of ammonia than those hatched from whole cysts, probably because of a greater energy reserve.
Evaluation of Activator Solutions, Motility Duration, and Short‐Term Storage of Paddlefish Spermatozoa
Authors: Mims Steven D.
Published: April 2007

Milt from paddlefish (Polyodon sparhula) was collected, examined for motility, and pooled. Six different solutions (dechlorinated tap water, ovarian fluid, bacteriostatic water, distilled water, 0.9% sodium chloride saline water, and milt plasma) were examined for activation and duration of spermatozoal motility. Most solutions except saline solution and milt plasma promoted activation of spermatozoa. Dechlorinated tap water was found to be the best activator with significantly longer duration of spermatozoal motility than the other tested solutions. Saline solution and milt plasma appear to be useful as carrier solutions because of their property of maintaining inactive, viable spermatozoa.

Paddlefish milt in three treatments was evaluated for chilled storage [without additives (MF); with 500 IU penicillin and 500 mg streptomycin mix in milt plasma (MP); and 0.9% saline solution (MS)]. The three treatments were stored at 2.4 ± 0.9 C in a precooled, moisture‐saturated oxygen environment and observed every 24 h for 9 d. Motility of activated spermatozoa in MS (7 d) was significantly longer than MF or MP treatments (7 d). Spermatozoa in MS had the longest chilled storage time (8 d).
IHHN Virus as an Etiological Factor in Runt‐Deformity Syndrome (RDS) of Juvenile Penaeus vannamei Cultured in Hawaii
Authors: Kalagayan Hector , Godin David , Kanna Roberta , Hagino Gerry , Sweeney James , Wyban James , Brock James
Published: April 2007

Runtdeformity syndrome (RDS) is an economically significant, frequent disease problem of cultured Penaeus vannamei. RDS is characterized by variable, often greatly reduced, growth rate of up to 30% of a cultured population and many shrimp with cuticle deformities of the rostrum, anterior appendages or other parts. The cause of RDS is undetermined.

Nursery trials comparing histologically IHHN‐positive and histologically IHHN‐negative Penaeus vannamei cultured under identical conditions were conducted at The Oceanic Institute. The IHHN‐positive populations developed RDS symptoms including increased individual size variation, reduced population growth, and high prevalance of rostrum, antennae or cuticle deformity, while the IHHN‐negative groups displayed none of these symptoms. No other diseases or parasites were identified in the IHHN‐positive populations that would account for the RDS symptoms.

A single commercialele nursery was stocked with histologidly IHHN‐positive P. vannamei and a high prevalence of RDS was observed. Shrimp growth was bimodal with a subpopulation growing normally and a subpopulation growing slowly. Significant relationships between shrimp harvest size and IHHN prevalance, selected individual organ IHHN severity grades and IHHN severity index (six organs evaluated) were found. Large, apparently normal shrimp were less severely infected with virus and did not display any cuticle deformities.

In sum, these data provide epidemiological and histopathological evidence for the hypothesis that infection by IHHN virus is the cause of RDS in cultured P. vannamei.
Use of Bagasse as a Feed Input to Semi‐Intensive Shrimp Growout Ponds
Authors: Freeman Donald W. , Duerr Eirik O. , Leber Kenneth M.
Published: April 2007

Efforts to reduce the cost of growout feeds for aquaculture have traditionally focused on the use of agricultural wastes as direct or indirect nutritional supplements to support semi‐intensive production levels. The merits of a low cost, sugar cane bagasse‐based feed for semi‐intensive production of Penaeus vannarnei were evaluated. Shrimp averaging 0.24 g each were stocked into 200 m2 earthen ponds at 20/m2 and cultured for a 12 week period. Two bagasse‐based feed treatments, a manure‐based treatment and a no‐feed input control, were compared in replicate ponds. One bagasse treatment (artificial manure) was designed to mimic manure and stimulate autotrophic and heterotrophic growth. The other bagasse treatment (bagasse alone plus inorganics) was designed to stimulate primarily autotrophic growth. Both bagasse treatments produced average growth rates of 0.78 g/wk, which were significantly greater than that of the manure treatment (0.57 g/wk). Lack of difference between the two bagasse treatments suggests that additional supplements used in making artificial manure probably were unnecessary to the nutrition of the shrimp. At harvest, bottom organics in the bagasse‐fed ponds were at least twice as great as manure‐fed ponds, and may have contributed to the lower survival associated with these treatments.
Procedural Protocol, Survival to Hatching and Plasmid DNA Fate After Microinjection into Tilapia Zygotes
Authors: Phillifs Peter C. , Kohler Christopher C. , Muhlach William L.
Published: April 2007

The plasmid vector, pBRd‐AK1‐BGH4.6.10 (pBGH), containing the bovine growth hormone sequence driven by an avian retroviral long terminal repeat (LTR) was microinjected at 0.1, 0.5, 1 or 5 ng of pDNA/20 nl of physiological saline into tilapia, Oreochromis mossambicus × O. niloticus embryos. In 24 replicates, normally 60 zygotes were microinjected with either the entire linear 8.5 kb pBGH/ClaI vector or a 3.8 kb pBGH/SalI restriction fragment. Overall mean survival to fry hatching was 7.6% in plasmid DNA‐microinjected, 15.6% in sham‐microinjected and 48.1% in uninjected control embryos. There were no significant (P > 0.05) differences in survival to hatching between those embryos microinjected with the 3.8 or the 8.5 kb restriction fragment, nor was there a trend toward decreasing survival as the plasmid DNA concentration increased from 0.1 to 5 ng. The significant (P < 0.05) increase in survival among uninjected control embryos to hatching indicates that microinjection trauma was the major cause of mortality. Large quantities of plasmid DNA were recovered from pooled‐embryo samples. Multiple bands (positive signals) were detected usually in the high molecular weight (HMW) genomic DNA regions. Position shifting of these HMW bands upon digesting with various restriction endonucleases provided evidence for plasmid DNA integration into tilapia embryo chromosomal DNA. Otherwise, these positive signah may have been end‐twnd ligations of increasingly longer plasmid DNA constructs. Putative transgenic O. mossmbicus × O. niloticus were found among eight of 27 surviving adults.
Application of High Hybridization Stringency Technology to the Analysis of Putative Transgenic Fish and Their Progeny
Authors: Paleudis George A. , Kohler Christopher C. , Muhlach William L.
Published: April 2007

Eight putative transgenic hybrid tilapia (Oreochromis mossambicus × O. niloticus) and their F, progeny were screened by Southern blot analysis for the presence of the bovine growth hormone transgene (bGH). Transgenic mice known to contain one copy of the bGH gene per genome were used as positive controls allowing for the determination of detection levels under high hybridization stringency conditions. At a sensitivity level of one copy per genome, the bovine growth hormone transgene was not detected in any of the experimental animals. The apparent lack of bGH transgene in the fish DNA at one copy per genome, coupled with no detectable levels of bovine growth hormone being found in either serum or whole blood of the original adults, indicates these fish are either not transgenic, or that they are mosaics and do not express the transgene. Results demonstrate the need for positive controls when conducting Southern blot analysis of potentially transgenic organisms. Mammalian models appear to be suitable positive controls and should be employed until transgenic piscine models are readily available. It is suggested that high hybridization stringency is necessary when analyzing for evolutionarily conserved transgenes such as those controlling growth hormones.
Dietary Lysine Requirement of Juvenile Red Drum Sciaenops ocellatus
Authors: Craig Steven R. , Gatlin Delbert M.
Published: April 2007

The dietary lysine requirement of juvenile red drum Sciaenops ocellatus was reevaluated in two separate experiments. In the first experiment, lyophilized red drum muscle was combined with an L‐form crystalline amino acid premix to yield diets containing approximately 35% protein on a dry‐matter basis. Gradations (0.25%) of L‐lysine HCl were added to the basal diet containing approximately 1.0% lysine. Each diet was fed to triplicate groups of juvenile red drum initially weighing 6–7 g for 8 weeks. Based on growth and feed efficiency data, the lysine requirement (±SE) was determined to be 1.55% (±0.079%) of dry diet or 4.430% of dietary protein. In a second experiment, the lysine requirement of red drum was investigated with diets containing 35% intact protein from zein and red drum muscle. Each of the zein‐based diets containing incremental levels of lysine was fed to triplicate groups of juvenile red drum initially weighing 1–2 g for 8 weeks. A crystalline amino acid test diet serving as a control in this experiment significantly outperformed the zein‐based diets, and palatability of those diets was questionable due to an obvious change in feeding behavior of the fish. Due to the inferior performance of the fish fed the zein‐based diets, the authors were not successful in determining a requirement with these diets. Thus, a lysine requirement of 1.55% of dry diet (4.43% of dietary protein) as determined in the first experiment is recommended for juvenile red drum.
The Intensive Culture of the Penaeid Shrimp Penaeus vannamei Boone in a Recirculating Raceway System
Authors: Reid Bart , Arnold C. R.
Published: April 2007

Recirculating raceway systems were examined for their potential as a method for the intensive culture of the marine shrimp Penaeus vannamei Boone. The systems consisted of fiberglass raceways 38 m3 (13.7 m ± 2.4 m ± 1.16 m) and 28 m3 (13.7 m ± 2.4 m ± 0.85 m) each equipped with a vertical screen biofilter, foam fractionators and an ultraviolet ozone generator. All of the systems were enclosed in a commercial greenhouse. Four preliminary growout experiments and two growout experiments with stocking densities of 970 shrimp/m3 and 2,132 shrimp/m3 were completed.

Temperature, pH and salinity remained constant throughout the experiments. Unionized ammonia levels remained below 0.2 mg/L. Nitrite levels ranged from 0.1 to 1.0 mg/L. The 2,132/m2 stocking density resulted in 48% survival, food conversion ratio (FCR) of 1.8 and an average size of 10.8 g. The 970/m3 stocking density resulted in 82% survival, FCR of 2, and an average size of 14 g. Production was 11.4 kg/m3 (114 tons/ha) and 11.0 kg/m3 (110 tons/ha) for the high and low stocking densities, respectively.
Evaluation of Practical Feed Formulations and Dietary Supplements for Red Swamp Crayfish
Authors: Lochmann Rebecca , McClain W. Ray , Gatlin Delbert M.
Published: April 2007

Three 6 wk feeding trials were conducted with juvenile red swamp crayfish Procambarus clarkii in a flow‐through culture system to evaluate practical feed formulations and specific dietary sup plements. Diets were formulated to contain 30% crude protein from various practical ingredients with or without supplemental cholesterol, lecithin, astaxanthin, vitamin premix and mineral premix. Peanut meal consistently provided inferior weight gain of crayfish compared to soybean, fish and shrimp meals, and a combination of soybean meal and fish meal supported the most rapid weight gain. Supplementation of 1.0% cholesterol did not enhance crayfish weight gain compared to a basal diet, whereas supplementation of 6% lecithin improved weight gain. Astaxanthin supplementation at 13 mg/kg diet marginally improved crayfish weight gain compared to a diet containing 1% beta‐carotene. Deletion of a complete vitamin premix impaired crayfish weight gain while deletion of a trace mineral premix did not. Results from this study indicate that protein quality significantly influenced weight gain of crayfish in a flow‐through culture system, and supplernentation of a complete vitamin premix was most critical.
State of the Art of Asian Seabass Lates calcarifer Larviculture
Authors: Dhert Philippe , Lavens Patrick , Sorgeloos Patrick
Published: April 2007

Innovative techniques opened new perspectives in the larviculture of the Asian seabass in the 1980s. Induced spawning maximized egg production while sperm preservation reduced the problem of male brood‐stock supply. Studies of biometric characteristics of the fish larvae resulted in improved feeding strategies with live food. This in turn permitted a more rational use of expensive Artemia nauplii. Nutritional enhancement of the highly unsaturated fatty acid (HUFA) composition of the live food resulted in significant improvement of survival and physiological condition of the larvae at metamorphosis. A salinity stress test enabled the evaluation of the larvae's physiological status and estimation of their HUFA‐requirements during the hatchery and pre‐nursery phase.
Importance of Docosahexaenoic Acid in Marine Larval Fish
Authors: Watanabe Takeshi
Published: April 2007

Marine finfish require n‐3 HUFA such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) as essential fatty acids (EFA) for their normal growth. But it remained unclear as to which of the n‐3 HUFA, either EPA or DHA, was important. Unlike the freshwater species, the EFA efficiency of EPA and DHA may vary in marine fish. The developing eggs rapidly utilize DHA either for energy or for production of physiologically important substances like prostaglandin.

This report reveals that in marine larval fish DHA is superior to EPA as EFA. In the case of red seabream, feeding rotifers incorporating EPA and DHA or an n‐3 HUFA mixture prevented many of the ill‐effects observed when the rotifers were low in n‐3 HUFA. Apart from the best growth and survival in an activity test for the larvae fed on DHA‐rotifer, the incidence of hydrops seemed to be totally prevented dietetically by DHA. Similar results were obtained in larval yellowtail, striped jack, striped knifejaw and flounder. There seems to exist a functional difference between EPA and DHA.
Nutritional Mechanisms Involved in the Occurrence of Abnormal Pigmentation in Hatchery‐reared Flatfish
Authors: Kanazawa Akio
Published: April 2007

The mass depigmentation (albinism) in the ocular side of flatfish, which resulted from the deficiency of pigments, has widely occurred in the process of seedling production. Although many researchers have investigated the mechanisms of depigmentation, little is known in this field. The author found that depigmentation resulted from nutritional deficiencies when 10 d old larvae were fed experimental microparticulate diets. This paper suggests that the rhodopsin formation of eye retina was hindered when vitamin A, docosahexaenoic acid and phospholipid were deficient in foods, resulting in the interruption of black pigment (melanin) formation.
Nutritional Factors Affecting Stress Resistance in the Larval Mahimahi Coryphaena hippurus
Authors: Kraul Syd , Brittain Karen , Cantrell Robert , Nagao Terri , Ogasawara Amy , Ako Harry , Kitagawa Henry
Published: April 2007

Recent improvements in enriching Artemia make mahimahi culture possible without using copepods. Mahimahi survive better when cultured copepods Euterpina acutifrons are used, especially when the larvae are under stresses such as high stocking density, cold weather, or the rigors of metamorphosis. This study looked at some differences between copepods and enriched Artemia.This study tested stress resistance by holding postlarval (PL) mahimahi out of water in a hand net for varying periods of time. Recovery from this stress shock was higher in PLs whose diet was higher in docosahexaenoic acid (DHA). DHA appeared to play an important role in stress resistance. High eicosapentaenoate (EPA) or high HUFA did not confer stress resistance when DHA levels were low. Copepods contained higher levels of many essential amino acids in addition to higher levels of DHA compared with enriched brine shrimp.

Larvae sickened by disease appeared to lose fat, including DHA, but they conserved DHA relative to other fatty acids. Even when sick, mahimahi larvae fed a copepod diet resisted stress better than larvae fed an enriched brine shrimp diet.

Optimal Artemia enrichment levels of DHA for mahimahi have not been reached and this may explain why it has been difficult for others to raise this fish consistently.

E. acutifrons is relatively easy to culture, but may not be practical for commercial hatcheries, due to low yield (less than 10 g per 100 L per week).
Marine Aquaculture in Israel with Special Emphasis on Larval Rearing
Authors: Tandler Amos
Published: April 2007

The goal of mariculture research in Israel is the development of an industry, based on available sea and brackish water, in the Arava Desert, the Gulf of Eilat and along the Mediterranean coast. Urgent progress is needed due to the shortage of fresh water for agriculture. High priced euryhaline fish like Sparus aurata and Dicentrarchus labrax are the obvious choice for development along with the more common grey mullet Mugil cephalus. The aim of this paper is to present the research and zootechnical state of the art in Sparus aurata and Dicentrarchus labrax larval rearing at the National Center for Mariculture (NCM).

Fertilized eggs are stocked in 600 L tanks and hatching success estimated from aliquot counts. Rearing continued for 32 d after which larvae are removed from these tanks with minimum mortality. Under normal rearing conditions these tanks produce 15‐35 32 d old (10 mg, ww) Sparus aurata larvae/L (20‐40% survival). Average seabass survival to 80 mg (40 d) is 35%. Tanks were continuously supplied with filtered (10 μm), temperature and salinity controlled seawater and freshly enriched food organisms through a special delivery system. This system was recently upscaled to 1,700 L tanks with equally good results for seabream larval rearing.

Live food enrichment regimes for the two species were developed to maximize their growth and survival. A microdiet is presently being used from the age of 20 d. The problems involved with using dry diets with larvae were found to be associated with both their digestibility and attractivity.

As a result of a salinity reduction from the ambient 40 to 25 ppt, swim bladders developed in 90% of seabream and 75% of seabass. In addition, growth rate of larvae improved by 15%. Finally, seabream tend to show strong aggressive behavior once size differences in the population of 32 d larvae is greater than 300%. Therefore, once seabream ended their 32 d hatchery period they are graded to three size groups of 5, 10.3 and 23 mg (ww). The graded fish are counted with a locally developed Computer Aided Fish Counter (CAFIC) and stocked separately in 5 m3 nursery tanks.
Control of Reproduction of the ShrimpPenaeus kerathurusHeld in Captivity
Authors: Luis O. J. , Ponte A. C.
Published: April 2007

The control of the reproductive cycle of the shrimpPenueus kerathurus, held in captivity from early juvenile stages without eyestalk ablation, was attempted in two sets of experimental conditions during two successive years. In the first set of experiments, light regime, sex ratio and presence of sand substratum were assessed in relation to ovarian maturation and successful mating. Examination of thelyca obtained from cast exoskeletons showed that 40–82% successful mating had taken place. A sex ratio of 2:l female/male gave a higher percentage of fertilized females than a ratio of 1:l. The induction to full ovarian development was observed for every treatment except the tank without sand substrate, where no mated females were observed.

In the second set of experiments, the role of diet, in particular the role played by a polychaeteNereis diversicolor, was assessed as a nutritive stimulator to induce maturation and spawning. With the same purpose, a parallel experiment in smaller aquaria was also conducted to assess the relative importance of mussel, squid, ragworm and crab and four composite diets consisting of two or three of the said food organisms.Nereisworm seemed to have a determinant role on the induction of shrimp ovarian maturation and spawning. The possible role of its fatty acids on shrimp reproduction is discussed. The experimental results suggest the possibility for extended control of the reproductive cycle ofP. kerathurusin a controlled environment provided that proper food is available.
Experimental and Practical Diet Evaluations with Juvenile Hybrid Striped Bass1
Authors: Brown Paul B. , Griffin Mark E. , White M. Randall
Published: April 2007

Culture of hybrid striped bass has been expanding in the United States and further growth has been predicted, however, several problem areas exist, including a lack of nutritional information. This series of studies offered reciprocal cross juvenile hybrids several of the commercially available feeds and several different types of purified experimental diets. Weight gain and feed efficiency of fish fed the commercially available feeds formulated to meet the general requirements of salmonids were better than fish fed feeds formulated to meet the nutritional requirements of catfish. Experimental diets containing casein as the primary protein source were unpalatable regardless of the level of fish oil added (6 or 12%) but were accepted if 10% menhaden fish meal was added. Addition of lower levels of fish meal resulted in decreasing degrees of acceptance. Thus, the minimum level of fish meal that elicited a feeding response appeared to be between 510% of the dry diet. A crystalline amino acid test diet was palatable, and weight gain of fish fed that diet was 65–91% of the weight gain recorded for fish fed the positive control diets. Addition of L‐arginine, L‐methionine or L‐cystine to a purified diet containing casein did not result in dietary acceptance. Whole‐body proximate composition offish revealed a general trend toward increased lipid levels with increasing levels of dietary lipid. All fish exhibited microvessicular hepatopathy, regardless of diet fed. Hepatocytes contained both glycogen and lipid in the cytoplasm.
Acute and Sublethal Effects of Ammonia on Striped Bass and Hybrid Striped Bass
Authors: Oppenborn James B. , Goudie Cheryl A.
Published: April 2007

Bioassays in static water (mean ± SD; temperature, 20–22 C; pH, 8.2–8.4; alkalinity, 205 ± 10 mg/L CaCO3; total hardness, 220 ± 10 mg/L CaCO3) were used to determine median lethal concentrations (LC50) of un‐ionized ammonia (NH3‐N) for striped bass Moronc saxatilis and hybrid striped bass M. saxatilis × M. chrysops. The 96 h LC50 for striped bass was 1.01 ± 0.24 mg/L NH3‐N3 and was significantly higher than the LC50 for hybrid striped bass (0.64 ± 0.05 mg/L NH3‐N). The effects of sublethal ammonia were evaluated after fish were exposed for 96 h to 0.0, 0.25, or 0.5 mg/L NH3‐N or to additional exposure to oxygen depleted water (about 2.0 mg O2/L). Plasma ammonia of striped hass did not change as sublethal ammonia increased, but exposure to oxygen depletion caused a decrease in plasma ammonia. In contrast, plasma ammonia of hybrid striped bass increased as environmental ammonia increased, and increased further after exposure to oxygen depletion. Plasma cortisol levels of striped bass were significantly higher and more variable than cortisol levels of hybrid striped bass; additional exposure to oxygen depletion increased this variability, but these responses may be due to the stress of handling and confinement. Mean differences also existed between species for hemoglobin and hematocrit, while differences in variability occurred for osmolality and oxygen depletion rates. Striped bass tolerated ammonia better than hybrid striped bass but were more susceptible than hybrid striped bass to the additional stress of oxygen depletion. Most changes in physiological characteristics were relatively independent of environmental ammonia, but they were affected by oxygen depletion challenge.
Growth Trial with the American Oyster Crassostrea virginica Using Shrimp Pond Water as Feed
Authors: Jakob Greg S. , Pruder Gary D. , Wang Jaw‐Kai
Published: April 2007

This study was conducted to quantify the potential of Crassostrea virginica biculture using marine shrimp pond water. It was envisioned that this biculhre could avoid cost and reliability problems associated with the mass production of algae as oyster feed. Such problems contributed to the failure of previous attempts to commercialize oyster culture.

Oysters were reared in each of two flow through 310 L tanks receiving shrimp pond water from selected commercial semi‐intensive shrimp ponds. In each tank, pond water was delivered to the upper trays and flowed downward through each of two seven tray stacks. For both tanks, mean oyster growth rate (2 g/wk) and survival (79%) from seed (0.04 g) to market size (55.0 g) compared favorably with previous reports and for the first time approximated the growth projected in a 1968 engineering study by American Cyanamid (Calbo et al. 1968).

Oyster growth within and between tanks indicated a relationship between biomass and exchange rates. During a 65 d controlled monitoring period mean oyster growth rates of 3.7 g/wk were achieved in upper trays of both tanks. Data are provided to estimate optimum pond water flow rate and oyster biomass relationships. The prospects for shrimp and bivalve co‐culture appear promising.
Production of Channel Catfish Ictalurus punctatus in Flowing Agricultural Waters in Arizona
Authors: Budhabhatti Jennifer , Maughan O. Eugene
Published: April 2007

Catfish were cultivated in 0.3 m3 site‐specific cages built for fish culture in irrigation ditches. Poor growth (239 g ± 4.2) in 1989 was probably due to velocity of water and variability of fish size at stocking. Addition of baffles to the cages and hand grading of fish eliminated these problems in 1990. A power failure near the middle of the 1990 growing season forced the brief move of the fish from the ditch to a pond. Catfish reached an average weight of 465 g in 1990 over roughly the same growing season as in 1990. Before the cages were moved, fish at lower densities had significantly higher growth (588 ± 3, 515 ± 3) than those at higher densities (396 ± 4.6, 334 ± 4). However, at the end of the experiment, growth was not significantly different between densities (P > 0.05). Perhaps stress to fish caused by moving cages obliterated the previous density differences in growth.
Preliminary Studies on the Suitability of a Fairy Shrimp Streptocephalus dichotomus as Live Food in Aquaculture
Authors: Prasath Ethiraj Balaji , Munuswamy Natesan , Abdul Nazar Abdul Khudus
Published: April 2007

A preliminary growth study was conducted with juvenile Oreuchromis mossambicus using a live‐food Streptocephalus dichotomus. Experimental fish showed better growth, survival and food conversion ratios, as well as a significant increase in protein (12%), free sugars (34.4%) and protein bound sugars (101%). However, there was a decline in the lipid content (‐3.99%). Energy budget analysis revealed that about 90% of the consumed energy (as live‐food) was assimilated by the experimental fishes. It is likely that the fish used 45% of the total energy assimilated for metabolic activities associated with growth.
Golden Shiner Notemigonus crysoleucas× Rudd Scardinius erythrophthalmus Hybrids: Gonad Histology and Spawning Trials
Authors: Goodwin Andrew E. , Grizzle John M. , Tave Douglas , Gibson Mike D. , Barnett Jimmy , Fiegel Don H. , Beavers Berry F.
Published: April 2007

Hybrid fish were produced in ponds by crossing golden shiners × rudd (Notemigonus crysoleucas×Scardinius erythrophthalmus) and rudd × golden shiners. Histologically, testes from the hybrids contained spermatocytes that resembled those of the parental species, but no sperm were observed. Lack of sperm in hybrids could have been a seasonal effect. The ovaries of both types of hybrids contained variable numbers of morphologically normal, vitellogenic oocytes and numerous abnormal oocytes in the chromatin nucleolar stage. Abnormal oocytes were necrotic or had irregularly shaped nuclei and clumped chromatin. Many oocyte nests contained infiltrating macrophnges. Spawning trials with F1 hybrids did not result in spawning behavior or production of F2 generation fish. Colden shiner × rudd hybrids are of reduced fecundity, but sterility was not conclusively demonstrated.
Use of Plant Proteins in Catfish Feeds: Replacement of Soybean Meal with Cottonseed Meal and Replacement of Fish Meal with Soybean Meal and Cottonseed Meal
Authors: Robinson Edwin H. , Li Meng H.
Published: April 2007

Plant protein sources were evaluated in 32% protein grow‐out feeds for channel catfish (initial weight: 180 g/fish) stocked at high densities (24,700 fish/ha) in 0.04 ha earthen ponds. Each of the eight practical‐type feeds was assigned for five replicate ponds. The fish were fed to satiation once daily for 170 d. Specifically, cottonseed meal and cottonseed meal plus supplemental lysine were evaluated as replacements for soybean meal. Soybean meal, a combination of soybean meal and cottonseed meal, or a combination of soybean meal and cottonseed meal plus supplemental lysine were evaluated as a substitute for animal protein sources. Based on weight pin, feed conversion ratio, body composition, percentage visceral fat, and dressed yield, the data indicated that cottonseed meal plus lysine can be used as a total substitute for soybean meal in catfish feeds. However, it is not recommended that more than 30% cottonseed meal be used in catfish feeds until additional data are available on the effects of gossypol on reproduction in catfish. Also, data indicated that plant proteins can be used as a total replacement for animal protein without detrimental effects. Reduced weight gain was observed in fish fed a feed that contained 68% of the established available lysine requirement. However, fish fed feeds estimated to contain only 76 or 82% of the available lysine requirement did not show reduced weight gain. This suggests that lysine may be more highly available from cottonseed meal than previously estimated, or that natural food organisms in the pond contributed nutrients including lysine, or that fish were able to consume enough of the marginally deficient feeds to meet their requirement for lysine. This study was conducted with large catfish fed a 32% protein feed to satiation once daily. If smaller fish, a lower protein fed, or a restricted feeding regimen had been used, the results may have been different.
Cage Culture of Hybrid Striped Bass in Indiana and Evaluation of Diets Containing Three Levels of Dietary Protein1
Authors: Swann D. LaDon , Riepe Jean R. , Stanley John D. , Griffin Mark E. , Brown Paul B.
Published: April 2007

Culture of hybrid striped bass Morone saxatilis × M. chrysops has been increasing in selected regions of the United States. Because of their thermal tolerance, hybrids may have potential as a new commercial aquaculture species in the Midwest. In these studies, hybrid striped bass were reared in cages located in southern, central and northern Indiana and offered one of three practical diets. Diets contained either 32, 36 or 40% crude protein. Additionally, a preliminary 8 wk laboratory experiment was conducted in which fish were offered the same diets. All diets were formulated to meet the established dietary lysine requirement; optimal levels of other essential amino acids in the diet were predicted by the whole‐body essential amino acid profile of hybrid striped bass. In the laboratory experiment, weight gain of fish fed 36% crude protein was significantly higher than those fed either other level of dietary protein. After 205 days, final average weight gains of fish in the field experiment were not significantly different and ranged from 233 to 426 g with an overall average daily gain of 1.6 g/fish/d. Overall survival was 89.1%. Dress‐out percentages were 81.2, 69.8, and 34.9% for eviscerated, eviscerated and headed, and fillets, respectively. Those values were not significantly different among dietary treatments or sites. Lipid content of fillets from fish fed 32% dietary crude protein was significantly higher than in fish fed 36 or 40% crude protein.
A Comparison of Black Drum, Red Drum, and their Hybrid in Saltwater Pond Culture
Authors: Henderson‐Arzapalo Anne , Colura Robert L. , Maciorowski Anthony F.
Published: April 2007

Hybridization has been used in aquaculture to produce fish that exhibit improved growth and survival over parent species. Previous studies produced an intergeneric hybrid by crossing female black drum Pogonias cromis with male red drum Sciaenops ocellatus. In the present study, the two parent species and their hybrid were simultaneously cultured in ponds for 9 mo. Two‐ to three‐day‐old larvae of each type were initially placed into three separate 0.1 ha ponds. After about 41 d, fingerlings of each type were transferred from the larval culture ponds to six 0.2 ha ponds. Two ponds each received 3,000 black drum, red drum or hybrid fingerlings. Fish were fed a commercial feed and harvested after about 230 d. At harvest, mean weight, mean total length, and production for the hybrids was 190 g, 245 mm, and 10.7 kg/ha/d, respectively; red drum averaged 142 g, 236 mm, and 7.0 kg/ha/d; and black drum averaged 144 g, 214 mm, and 10.6 kg/ha/d. Black drum survival was 94%, red drum survival was 63%, and hybrid survival was 72%. Hybrid growth was more rapid than either parent. A taste panel failed to identify differences in flavor between the three fishes. With similar flavor and faster growth, hybrid drum have potential for commercial mariculture.
Indoor Spawning and Egg Development of the Red Claw Crayfish Cherax quadricarinatus
Authors: Yeh Hsin‐Sheng , Rouse David B.
Published: April 2007

In 1991 and 1992, indoor hatchery experiments were conducted with red claw crayfish Cherax quadricarinatus a large tropical crayfish from northern Australia. Six fiberglass tanks were stocked with 40–190 g mature red claw crayfish at 10/m2 and a 1:2 male to female ratio. Water temperature was maintained at 28 ± 1 C. Photoperiod was provided by natural daylight in 1991 and controlled lighting in 1992.

With natural lighting, monthly spawning rates (% of females spawning/month) ranged from an average of 15% during months with less than 12 h of light per day to over 35% in months with more than 12 h of light per day. Peak spawning occurred from May to July, too late to obtain juveniles for spring stocking. During the second year, photoperiod was increased from 10L:14D in December to 14L:10D in February and maintained at this level until July. Red claw spawning increased with increasing day length. Peak spawning rates of 50% per month and higher occurred from March to May. Spawning rates decreased dramatically after May, even though photoperiod and temperature remained constant. Eggs per spawn increased with an increase in female size. Fecundity average 7.3 juveniles per gram of body weight for females from 40 to 190 g, regardless of size. Egg color was useful for predicting stage of development.
Effects of Environmental Factors on Egg Development and Hatching of Pacific Halibut Hippoglossus stenolepis
Authors: Liu Han Wu , Stickney Robert R. , Dickhoff Walton W. , McCaughran Donald A.
Published: April 2007

Eggs of Pacific halibut were incubated under various environmental conditions. Optimum hatching occurred over a temperature range from 6 C to 8 C, whereas temperatures of 3, 10, and 11 C were lethal. Development time from fertilization to 50% hatching varied from 250 h (9 C) to 320 h (6.5 C). Salinity effects on hatching were not as critical as temperature, as long as eggs were floating during the incubation period. Light intensity between 5 and 15 lux did not affect hatching success, but high light intensity (15 lux) and red and blue light (5 lux) produced high levels of larval abnormality. Simulated transport of unfertilized eggs indicated that the eggs can be safely moved and that fertilization rate is acceptable during the first 12 h after collection.
Profit‐Maximizing Stocking Rates for Channel Catfish in Cages
Authors: Duarte Sergio A. , Nelson Robert G. , Maser Michael P.
Published: April 2007

A production function for catfish in cages was estmated by combining data from a survey of producers in Alabama with data from experimental studies in Texas, South Carolina, and Alabama. Explanatory variables in the quadratic model included cage stocking density, fingerling size, length of growing season, feed conversion rate, squared and cross‐product terms, and dummy variables for data sources. Model R2 was 87%. Profit‐maximizing stocking densities were calculated for varying levels of growing season duration, fingerling size, fingerling price and market price. Optimal stocking density was shown to be most sensitive to length of growing season.
Effects of Dietary Mycotoxins Produced by the Mold Fusarium moniliforme on Channel Catfish Ictalurus punctatus1
Authors: Li Meng H. , Raverty Stephen A. , Robinson Edwin H.
Published: April 2007

Channel catfish Ictalurus punctatus (initial weight: 6.1 g/fish) were fed eight diets containing the mold Fusarium moniliforme‐cultured corn supplying 0.7, 2.5, 5, 10, 20, 40, 80, or 240 mg of the mycotoxin, fumonisin B1 (FB1)/kg diet under laboratory conditions for 12 wk. Fish fed diets containing FB1 levels of 40 mg/kg and above showed reduced growth, feed consumption, and feed efficiency, but fish fed FB1 concentrations of 20 mg/kg and below did not. The minimum level of FB1 that depressed growth appeared to be between 20 and 40 mg/kg. Hematocrit was significantly lower for fish fed diets containing 80 and 240 mg FB,/kg than for fish fed diets containing lower levels of FB1. Fish fed diets containing 40 mg FB1kg and above had increased liver glycogen, increased vacuolation in nerve fibers, and perivascular lymphohistiocytic investment in the brain compared to fish fed diets containing lower levels of fumonisins. Results from this study indicate that FB1 levels below 20 mg/kg diet are not a problem in commercial catfish feeds. However, it is prudent to screen for fumonisins in feed ingredients.
Chemical Characteristics of Bottom Soils from Freshwater and Brackishwater Aquaculture Ponds
Authors: Boyd Claude E. , Tanner Margaret E. , Madkour Mahmoud , Masuda Kiyoshi
Published: April 2007

Soil chemical analyses were conducted on samples from 358 freshwater fish ponds and 346 brackishwater shrimp ponds. Freshwater ponds were located in Honduras, Rwanda, Bhutan, and the United States. Ponds in the United States were in Alabama, Georgia, Mississippi, Florida, and South Carolina. Brackishwater ponds were in Thailand, Ecuador, Philippines, and Venezuela. Soils of freshwater and brackishwater ponds did not differ greatly in average concentrations and concentration ranges for carbon, nitrogen, calcium, and pH. Concentrations of copper and barium tended to be higher in freshwater soils than in brackishwater ones. All other measured chemical constitutents tended to be more abundant in the soils of brackishwater ponds than in those of freshwater ponds. For the most part, ranges of pond soil chemical properties were similar to those of terrestrial soils, with freshwater pond soils resembling terrestrial soils from humid areas and brackishwater soils being similar in many respects to soils of arid regions. However, some brackishwater pond soils were highly acidic, acid‐sulfate soils. Data were arranged into concentration categories (very low, low, medium, high, and very high) to facilitate comparisons of the present data set with other data on soil chemical properties for aquaculture ponds. All ponds included in the present study were used for aquaculture, showing that it is possible to rear fish and shrimp across an extremely wide range of soil chemical properties.