bluuebunny/crossref_metadata_2025 huggingface dataset:
Confinement and Transport‐Induced Stress in White Bass Morone chrysops × Striped Bass M. saxatilis Hybrids: Effect of Calcium and Salinity1
Authors: Weirich Charles R. , Tomasso Joseph R. , Smith Ted I. J.
Published: April 2007

Stress induced by severe confinement in cages and by simulated transport was evaluated in reciprocal white bass × striped bass hybrids (Morone chrysops × M. saratilis) after acclimation to various calcium concentrations in freshwater (5, 10, 20, 40, and 80 mg/L calcium) and various salinities (1, 8, 16, and 24%o) at 25 C. Survival was monitored in both confinement and transport events. In confinement events, changes in plasma osmolality were used as an indicator of osmoreg‐ulatory dysfunction. After 6 h of severe confinement in cages, survival was significantly affected by treatments in both freshwater (FW) and saltwater (SW) events. Survival was greatest in 80 mg/L calcium in FW treatments and 8%o in the SW treatments. Simultaneous analysis of both FW and SW confinement data revealed that, after compensating for fish weight, survival increased as environmental ionic content increased (up to 8%o) then decreased with increasing salinity. Plasma osmolality decreased significantly from baseline levels with respect to confinement time in all FW treatments. Significant differences in plasma osmolality were observed among SW treatments: plasma osmolality of fish confined in 1%o decreased while those confined in salinities of 16 and 24%o increased. The plasma osmolality offish confined in 8%o remained near baseline levels. Almost no mortality (<5% in all treatments) occurred during (12 h) and after (5 d) transport in both FW and SW. Fish were in good condition and acclimated to transport water quality prior to transport events which may have been a major reason for high survival. Results from this study indicate that detrimental effects due to handling and transporting hybrid striped bass are reduced in FW environments that provide sufficient calcium and in SW environments which are near isoosmotic with the plasma.
Comparative Stress Dynamics of Brood Stock Striped Bass Morone saxatilis Associated with Two Capture Techniques
Authors: Harrell Reginal M. , Moline Mark A.
Published: April 2007

Mature striped bass (Morone saxatilis) were collected from the spawning reaches of the Choptank River, Maryland for the purpose of evaluating stress effects associated with capture. Two commonly used capture devices were evaluated—gillnetting and electrofishing. Results indicated that stress, as measured by changes in plasma corticosteroid and chloride concentrations, was significantly lower and recovery time quicker in those fish captured by electrofishing compared to gillnetting. By the end of the study period (48 h), those fish captured by electrofishing had recovered from the initial capture shock as evidenced by corticosteroid levels returning to near baseline levels. Conversely, at 48 h post‐capture, those fish captured by gillnetting exhibited severe hypochloremia and elevated corticosteroid levels approaching that of the initial stress associated with capture.
Measurement of Resting and Stress‐elevated Serum Cortisol in Rainbow Trout Oncorhynchus mykiss in Experimental Net‐pens
Authors: Kebus Myron J. , Collins Michael T. , Brownfield Mark S. , Amundson Clyde H. , Kayes Terrence B. , Malison Jeffrey A.
Published: April 2007

A commercially available heterogeneous, solid‐phase tube enzyme‐linked immunoassay (ELISA) was modified and validated for the measurement of serum cortisol in rainbow trout Oncorhynchus mykiss. The assay is accurate and precise. Resting and stress‐elevated serum cortisol concentrations were measured in rainbow trout with a sensitivity of 1.5 ng/ml. Fish held in net‐pens at a density of 0.4 kg/m3/cm had a resting cortisol level of 16.5 ± 3.8 ng/ml (mean ± SE). At 3 h postdisturbance, serum cortisol levels were not affected by the removal of fish from adjacent net‐pens with dip nets or by the use of 200 mg/L tricaine methanesulfonate (MS‐222) as an anesthetic for obtaining samples. However, an acute stress (60 s removal from water) elevated serum cortisol levels to 73.7 ± 9.4 ng/ml.
A Survey of Water Quality Characteristics of Effluent from Hawaiian Aquaculture Facilities
Authors: Ziemann David A. , Walsh William A. , Saphore Eva G. , Fulton‐Bennett Kim
Published: April 2007

Ten water quality parameters were measured in influent and effluent water at 11 aquaculture facilities in Hawaii. The data were grouped into four categories based on the types of organisms cultured: freshwater fish, freshwater prawn, marine fish, and marine shrimp. Within each category, concentrations of most parameters were lognormally distributed and spanned one to two orders of magnitude. Geometric mean concentrations of suspended materials, total nitrogen, total phosphorus, and pigments were highest in effluent from freshwater prawn ponds and lowest in marine fish pond effluent. Nitrate/Nitrite and total ammonia concentrations were higher in fish pond effluent than in crustacean pond effluent. Parameter concentrations were generally higher in effluent than in influent water, with freshwater fish and prawn ponds exhibiting the greatest increases in suspended materials and pigments. In contrast, nitrate/nitrite concentrations were lower in effluent than in influent waters. These data provide a basis for analyzing the environmental impacts of warm‐water aquaculture effluent discharges.
Metamorphosis to Postlarvae of Penaeus chinensis Osbeck by Removal of Heavy Metals from Rearing Systems with Polymeric Absorbent
Authors: Yuan You‐Xian , Gao Cheng‐Nian , Zhang Du‐Xi , Guo Xiang‐Ping
Published: April 2007

The effect of removing heavy metal ions (copper, zinc, lead, and cadmium) with a polymeric heavy metal absorbent (PHMA) on metamorphosis of Penueus chinensis Osbeck was investigated. There was a significant (P < 0.05) reduction in metamorphosis of protozoea to mysis at concentrations more than 31.0 μg/L copper, 38.3 μg/L zinc, 32.5 μg/L lead, and 30.3 μg/L cadmium, in the absence of PHMA. At concentrations more than 61.0 μg /L copper, 68.3 μg/L zinc, 62.5 μg/L lead, and 60.3 μg/L cadmium there was a significant (P < 0.01) interaction between the absence and the presence of PHMA for metamorphosis of mysis to postlarvae. At concentrations of 12.3 μg/L copper, 45.8 μg/L zinc, 106.2 μg/L lead, and 200.2 μg/L cadmium, the metamorphosis of protozoea to mysis was blocked, but it was 51.4% in the presence of PHMA. At concentrations of 252.3 μg/L copper, 335.8 μ/L zinc, 806.2 μg/L lead and 300.2 μg/L cadmium, the metamorphosis of mysis to postlarvae was stopped, but it was 51.0% in the presence of PHMA. The toxicity of copper, zinc, lead, and cadmium to P. chinensis was reduced with PHMA.
Recovery of Serratia marcescens in Hemolymph of Macrobrachium rosenbergii from Experimentally Seeded Water
Authors: Brady Yolanda J. , Lassodela Vega Ernesto
Published: April 2007

Seratia marcescens was used as an indicator to determine if different concentrations of bacteria in water relate to concentrations in the hemolymph of Macrobrachium rosenbergii. Prawns were exposed to high (105 to 106 cells/ml), low (103 to 104 cells/ml) and control (no S. marcescens) treatments with S. marcescens inoculated in aquaria water. S. marcescens ranged from 10 to 9.9 ± 103 cells/ml from the high concentration group; a single isolate and zero S. marcescens were recovered from the low and control groups, respectively.
Experimental Collection of Pearl Oyster, Pinctada mazatlanica and Pteria sterna, Spat on a Filament Substrate
Authors: Caceres‐Martinez Carlos , Ruiz‐Verdugo Cesar A. , Ramirez‐Filippini David H.
Published: April 2007

Juveniles of Pinctada mazatlanica and Pteria sterna were collected with artificial collectors from Falsa Bay, Baja California Sur, Mexico during a 12 month experimental period. Filament substrate artificial collectors contained in 2 mm plastic mesh bags (25 ± 25 cm) were deployed from the surface to 17 m of depth, and replaced monthly. Pinctada mazatlanica had the greatest recruitment (12 juveniles/cm2) in late summer and P. sterna (5 juveniles/cm2) in winter. Maximum spat collection from September 1986 to April 1987 occurred at 10 m depth for P. mazatlanica and at 4–7 m depth for P. sterna. However, peak spatfall under 11m depth occurred from late July to August 1987. The mean prodissoconch shell height was 254 μm (SE = 0.003; N = 50) for P. mazatlanica and 313 μm (SE = 0.004; N= 50) for P. sterna. The growth equations for the first five weeks of both species, based on the prodissoconch shell height and the maximum spat height (measured from the umbo to distal edge) are presented.
Larviculture of Mediterranean Marine Fish Species: Current Status and Future Trends
Authors: Sweetman John W.
Published: April 2007

The larviculture of Mediterranean marine fish species has focused on the production of Spurus auruta and Dicentrarchus labrar. European fry production of these species has increased from 12 million in 1987 to 28 million in 1989 and is expected to rise to nearly 40 million fry in 1990.

Within differing hatchery systems, larval survival has been improved through the use of commercially available w3‐HUFA rich live food enrichment diets. This combined with the use of surface cleaning techniques has led to a standardization of larval rearing procedures enabling mass production of quality fry. Increased concern with larval hygiene has resulted in larger larval rearing batch production and regular sterilization periods in most European units.

Market pressure is stimulating established producers to diversify their species range and industrial quantities of Puntazzo puntuzzo, and Pagrus major are already being produced. Work has started on the larval culture of Dentex dentex, Pagrus pagrus and Seriola dumerilli.
A Review of Feeding Practices, Growth and Nutritional Physiology in Larvae of the Catfishes Clarias gariepinus and Clarias batrachus
Authors: Verreth J. , Eding E. H. , Rao G. R. M. , Huskens F. , Segner H.
Published: April 2007

A comparative study of larval growth in the different species of the genus Clarias in different regions revealed that in spite of strong differences in egg and larval size, the growth potential was quite similar. Differences in growth between species and regions were strongly correlated with the applied feeding strategy, the applied growth parameter and period of measuring. To evaluate feeding strategies, standardized procedures for measuring growth are needed. Recalculating the results of the mentioned study according to these standardized procedures revealed that both in India and Indonesia, the growth rate of C. batrachus larvae was too low. This is probably due to low feeding levels in India and premature weaning in Indonesia.

The basic biology and nutritional physiology of the larvae of C. gariepinus have been studied extensively. At the start of exogenous feeding, the larvae have an advanced digestive system with a functional pancreas, liver and nutrient absorption capabilities, but lack a functional stomach. The advanced digestive system is further exemplified by the development of the enzymatic complex. Probably because of the rapid development of the digestive system, feeding live food organisms is mostly practiced for a few days only and is soon replaced by wet and/or dry diets. It is hypothesized that the requirement of live food or specific larval diets during the first days of exogenous feeding is related to the absence of pepsin digestion during this period. Further optimization of the feeding strategies should focus on this conclusion.
The Culture of the Rotifer Brachionus plicatilis with Chlorella vulgaris Containing Vitamin B12 in its Cells
Authors: Maruyama Isao , Hirayama Kazutsugu
Published: April 2007

The rotifer Brachionus plicatilis requires vitamin B12. Freshwater Chlorella, which is produced by traditional culture, cannot support rotifer growth under bacteria‐free conditions. However, Chlorella enriched with vitamin B12 can support rotifer growth. To attain stable mass production of Brachionus, it is desirable to develop a food that can completely support growth of the rotifers. The authors cultured rotifers at experimental and mass culture scale with concentrated Chlorella vulgaris suspension enriched with vitamin B12 in their cells.

Chlorella suspensions were prepared containing different amounts of vitamin B12 in their cells, and rotifers were then cultured in 20 ml of the prepared suspensions. The highest rotifer yield was obtained from the group cultured with Chlorella containing more vitamin B12 in their cells. The suitable content of vitamin B12 in the concentrated Chlorella suspension commercially available for mass culture of the rotifer is considered to be 200 μg per 100 g dry matter of Chlorella. The amount of vitamin B12 necessary to produce one individual rotifer is calculated at 0.32 pg.

The authors conducted mass production of the rotifer with baker's yeast and refrigerated concentrated Chlorella containing vitamin B12 Rotifer culture with vitamin B12 was more stable and showed 1.3 times higher production than with normal Chlorella.
A Comprehensive Program for the Evaluation of Artificial Diets
Authors: Bengtson David A.
Published: April 2007

The evaluation of artificial diets for marine fish larvae involves much more than feeding trials. Information on the diet in the water column (buoyancy, leaching, etc.), the digestive capabilities and requirements of the larvae, and the fate and uptake of the diet inside the larval digestive tract are all necessary to the understanding of the success or failure of a given artificial diet. Interdisciplinary teams of investigators are required to fully evaluate and formulate artificial diets.
Reproductive Quality Evaluation of Male Penueus stylirostris from a Grow‐Out Pond
Authors: Alfaro Jorge
Published: April 2007

Several male Penucus stylirostris were selected from a 3 ha commercial earthen pond and were individually evaluated for reproductive performance. Indicators measured were compound spermatophore weight, sperm count, and sperm abnormalities.

It was found that spermatophore quality was significantly better for 30–40 g shrimp than for 20–30 g shrimp (P < 0.05). The higher frequency of abnormalities measured in younger males and the inverse relationship between abnormalities and sperm count indicate that the vas deferens could be the tissue responsible for producing highly abnormal immature semen. It is proposed that male maturation has at least three independently controlled levels of organization: testes maturation, vas deferens maturation, and spermatophore synthesis.

The individual evaluation showed that each male followed a particular response in reproductive quality. Changes in spermatophore weight were not an indicator of sperm density within spermatophores.

Male reproductive tract degenerative syndrome (MRTDS) and male reproductive system melanization (MRSM) did not develop in any shrimp during these experiments.
Growth and Survival of Juvenile Orconectes virilis and Orconectes immunis at Different Temperatures1
Authors: Wetzel James E. , Brown Paul B.
Published: April 2007

Culture of orconectid crayfishes in the midwestern USA offers the potential of contributing to a year‐round supply of fresh product as summer/fall production would augment winterhpring production in the southern USA. However, relatively little basic biological information exists for this potential new aquaculture crop. In this study, the authors reared juvenile (third instar) Orconectes virilis and Orconectes immunis at either 10, 15, 20, 25 or 30 C and measured weight gain and survival over a 21 day period. Orconcctes immunis juveniles were larger than O. virilis at the third instar and gained weight more rapidly in this experimental system. Gains in weight and length for both species increased as temperature increased from 10 to 25 C. Both values were lower in crayfish reared at 30 C, though number of molts was the same in crayfish reared at 25 or 30 C. Thus, there appears to be a bioenergetic cost of rearing orconectid crayfishes in temperatures above 25 C. Further, incremental growth with successive molts was influenced by water temperature.
Bench‐Scale Evaluation of a Micro‐Computer Automated Algal Turbidostat
Authors: Rusch Kelly A. , Malone Ronald F.
Published: April 2007

A bench‐scale, micro‐computer automated algal turbidostat was constructed and its production and culture maintenance capabilities were evaluated. The computer program “Supervisor,” written in Turbo Pascal, consisted of a series of functions and procedures integrated through a core program consisting of a: 1) stack; 2) bubble sort routine; and 3) supervisor procedure. The program controlled the daily routine procedures including harvesting, feeding, monitoring and a semimonthly disinfection process. Data received from the monitoring devices were used by the computer for decision making processes concerning changes in operation. In addition to reducing labor, continuous computer monitoring insured more reliable system operation.

The system operated successfully for five months, reliably producing Chlorella minutissima. For each harvesting event, the percent volume removed from each chamber depended on the solar cell reading recorded immediately before the harvest cycle began. Significant correlations between millivolts and algal biomass concentrations allowed the use of solar cells as a reliable and inexpensive method of culture density management. Kinetic studies using Chlorella minutissima resulted in a maximum biomass concentration of approximately 190 g/m3 and an average specific growth rate of 0.66/d. Experimental data combined with a first order computer analysis projected a daily harvest of 82 g/m3/d (dry weight) based on a 38% turnover rate, the average observed harvest rate for the three chambers.
Influence of Body Weight and Food Density on Kinetics of Ammonia Excretion by the Brine Shrimp Artemia franciscana
Authors: Tanaka Yoshiaki
Published: April 2007

This study was undertaken to quantify the relationships between the rate of ammonia excretion by brine shrimp and dry weight (body size) and food density. Measurements of the rate of ammonia excretion of the brine shrimp were made at 25 C in darkness. Under these conditions, the excretion rate of ammonium‐nitrogen can be generalized as a function of body weight and food (Nannochloropsis sp.) density. The relationship between the body weight (W) and excretion rate of ammonium nitrogen (EN) is expressed as EN=α Wγ, where α is the metabolic level. The parameter α is dependent on ration, such that α=αo±αr where αo= metabolic level in starvation and αr= the metabolic level which increased with feeding or changed with the food density. In experiments in which the animal starved, the equation above becomes EN=αoWγ, and the values of α and γ were 0.22 and 0.93, respectively. The rate of ammonium excretion rose from 5.42 × 10−4 to 2.28 × 10−1μg N/animal/h as dry weight measured from 1.57 × 10−3− 1.04 mg dry weight per animal. Next, it is convenient to express αr as αr=αfmax= (1 − 10−kc), where αfmax is the maximum rate of αf at saturated level of food density, C is the mean cell density, and k is a constant defining the rate of change of the metabolic rate with cell density. Therefore, the rate of ammonia excretion by brine shrimp could be expressed as EN=αo [1 − a(l − 10−kC)]Wγ, and a =αfmax/αo.

The values of the kinetics parameters obtained from experiments where shrimp were fed were a = 2.3 and k = 0.15×10−7. Consequently, the maximum rate of ammonia excretion at a saturated food density is equivalent to 3.3 times the rate of animals that are not fed.
Response of Penaeus vannamei to Dietary Calcium, Phosphorus and Calcium: Phosphorus Ratio
Authors: Davis D. Allen , Lawrence Addison L. , Gatlin Delbert M.
Published: April 2007

Two experiments, consisting of 7 d conditioning periods and 33 d feeding trials, were conducted to evaluate the response of juvenile Penaeus vannamei to dietary calcium, phosphorus and the effects of the calcium to phosphorus ratio on growth and tissue mineralization. In both experiments, the main effects, calcium and phosphorus, and their interaction significantly affected growth and survival of the shrimp. In the absence of supplemental calcium, the basal diet containing 0.35% phosphorus was adequate to maintain good growth and survival of shrimp. In the presence of replete phosphorus, supplementation of 1.0 and 2.0% calcium to the diet depressed survival and did not appear to increase the nutritive value of the diet, indicating that a dietary calcium supplement is not required under these conditions. In the presence of 1.0 and 2.0% supplemental calcium, supplementation of 0.5–1.0% phosphorus and 1.0–2.0% phosphorus, respectively, were required to maintain normal growth of the shrimp. At high levels of calcium supplementation, poor growth was observed at the levels of phosphorus supplementation evaluated. Although the calcium and phosphorus content of the hepatopancreas and the carapace responded to dietary supplementation, there was no clear correlation of tissue mineralization to shrimp growth.
Development and Deterioration of Spermatophores in Pond‐Reared Penaeus vannamei
Authors: Alfaro Jorge , Lozano Xenia
Published: April 2007

Spermatophore deterioration in pond‐reared Penaeus vannamei was studied, and spermatophore quality was evaluated and improved. Sperm production of males collected from grow‐out ponds was increased by two techniques: eyestalk ablation using a fresh frozen maturation diet (13% body weight); and laboratory culture using a diet of the formulated feed Nicovita Plus (3% body weight/ d) and frozen squid (2%). Findings are complementary to previous reports that eyestalk ablation improves quality of spermatophores in young (25.7 g) males. The timing of eyestalk ablation for activation of the endocrine mechanism, leading to improved spermatophore quality was also explored. After eyestalk ablation, performed between postmolt and intermolt stages, 26 g males required a minimum of three spermatophore regenerations or 42 d to significantly increase spermatophore size and sperm count. On the other hand, the laboratory culture (2.5 mo) technique improved the quality of spermatophores in successive regenerations for non‐ablated males. In the present study, subadult P. vannamei produced spermatophores which, if not transferred or manually ejaculated, gradually deteriorated (successive stages are described), while a new compound spermatophore was being synthesized.
Sperm Quality of Pond‐Reared and Wild‐Caught Penaeus monodon in Thailand1
Authors: Pratoomchaat Boonyarath , Piyatiratitivorakul Somkiat , Menasveta Piamssak , Fast Arlo W.
Published: April 2007

Sperm quality, as determined by visual examination and by reaction with “egg‐water” was not significantly different (P > 0.05) for sperm obtained by electro‐ejaculation from ablated or non‐ablated pond‐reared Penaeus monodon. Nor was sperm quality different between pond‐reared and wild‐caught prawns. Normal sperm, determined by appearance, ranged from 17.1 to 21.0%, while reactive sperm ranged from 1.5 to 3.0%. There were, however, significant correlations (P < 0.01) between spermatophore weight and prawn weight (r= 0.73, N= 434). Male prawns weighing 4150 g produced on average spermatophores weighing 22.7 mg and containing 0.8 million sperm, while prawns weighing 61‐90 g produced on average spermatophores weighing 56.6 mg with 2.5 million sperm. Ablation did not increase spermatophore size or sperm quality, although it significantly increased mortality of ablated males. Male prawns could be re‐ejaculated at about weekly intervals with no change in sperm quality. Wild‐caught female prawns artificially inseminated with spermatophores from electro‐ejaculated males produced normal spawns with 51% average egg fertilization, and 41% nauplii hatch success. Nauplii hatch success following spawning increased from >60% for newly inseminated females to near zero after 30 days post‐insemination, indicating spermatophore depletion and/or deteriorated sperm quality during spermatophore storage in the thelycum. The findings of the present study indicate that electro‐ejaculation and artificial insemination are relatively simple and practical methods for improving captive reproduction performance of closed‐thelycum prawns such as P. monodon, and that pond‐reared and wild‐caught males produced sperm of similar quality.
Dietary Carnitine and Lysine Affect Channel Catfish Lipid and Protein Composition
Authors: Burtle Gary J. , Liu Qinhua
Published: April 2007

The effects of carnitine (L‐carnitine) at 0.1% were tested at three levels of dietary lysine (L‐lysine‐HCl), 1.1, 1.4 or 1.7%, with fingerling channel caffish. Semipurified diets containing 30% protein and 3.44 kcal digestible energy/g were fed for 8 wk in flow‐through water at 26.5 ± 0.5 C. Carnitine did not significantly (P > 0.71) affect channel catflsh weight gain over this time interval. Weight gain was less when 1.1% dietary lysine was fed without supplemented carnitine than when diets contained 1.4 or 1.7% lysine. Carnitine reduced muscle lipid (P < 0.0003) and liver lipid (P < 0.0001) significantly. Percentage visceral fat was reduced with added dietary carnitine (P < 0.0001) but not with dietary lysine although there was a combined effect of carnitine and lysine (P < 0.0008). Channel catfish wholebody lipid content was reduced by supplemented dietary carnitine, lysine, or both. Protein content of channel catfish wholebody increased with added carnitine, lysine, and their interaction (P < 0.19, P < 0.003 and P < 0.001). Under these conditions, dietary carnitine improves caffish tissue characteristics by reducing fat content and increasing protein content.
Effects of Feeding Frequency and Handling on Growth and Mortality of Cultured Walking Catfish Clarias fuscus
Authors: Buurma Brian J. , Diana James S.
Published: April 2007

Two experiments were conducted to study the effects of feeding frequency on growth, and of handling stress on growth and mortality, in intensive tank culture of the walking catfish Clarias fuscus. In the first experiment, fish were grown from an initial weight of 37 g for 34 d. A fixed ration of 3.0% body weight per day was divided into either 1, 2, or 3 feedings per day, and fish were either handled weekly or left unhandled for the entire experiment. Fish given 3 feedings per day experienced 19% faster growth (P < 0.05) than fish given the same ration in a single feeding per day. These differences in growth reflect differences in assimilation efficiency, assuming all other metabolic costs were constant among treatments. Handling of individuals caused decreased growth; however, there was no effect on mortality.

In the second experiment, fish were grown from an initial weight of 78 g for 29 d. Fish were fed either 1 or 2 satiation feedings per day and were either handled weekly or left unhandled for the entire experiment. Fish fed 2 satiation feedings per day experienced 47% faster growth (P < 0.05) than fish fed 1 satiation feeding per day, which was assumed to reflect a higher level of food consumption. No effect of handling on either growth or mortality was observed for fish in experiment 2. Multiple meals per day also reduced depensatory growth among individuals in both experiments.
Induced Maturation of Striped Bass Morone saxatilis Exposed to 6, 9, and 12 Month Photothermal Regimes
Authors: Blythe William G. , Helfrich Louis A. , Libey G. , Beal W. E.
Published: April 2007

Photoperiod and temperature manipulation were used to induce out‐of‐season spawning in striped bass Morone saxatilis Maturational status of 40 age V striped bass, held in five environmental chambers exposed to compressed 6 mo and 9 mo cycles and a 12 mo reference cycle, was monitored by monthly egg and gonadal (ultrasound) diameter measurements. The primary effect of shortened photothermal and reproductive cycles was a reduction in egg and ovary diameters, and the number of ovulating females. Egg diameters were directly related to cycle length, averaging 845 μm, 946 μm, and 1,073 μm for females held on the 6, 9, and 12 mo cycles, respectively. Ovary diameters of females held on the 6 mo cycle were smaller (19.6 mm) than those held on the 9 mo (27.4 mm) and 12 mo (24.5 mm) cycles. Ovary diameter was highly correlated with egg diameter (r= 0.91). The number of ovulating females decreased with cycle length, totalling 38%, 88%, and 100% in the 6, 9, and 12 mo cycles, respectively. However, no differences in fecundity (58,452 eggslkg) or fertility (39%) were detected between photothermal treatments or tank‐spawned and strigspawned females. When held for a second 6 mo cycle, none of the females spawned repetitively. Males held on the 6 mo cycle had smaller testicular diameters (16.2 mm) than those held on 9 mo (23.6 mm) and 12 mo (19.2 mm) cycles. Testicular diameter of spermiating males (15.7 nun) was significantly larger than that of non‐spermiating males (6.9 mm) in all cycles. The low number of spawning females and small egg, ovarian, and testicular diameter offish held on the 6 mo cycle suggest that subjecting striped bass brood stock to an abbreviated cycle length (<9 mo) constrains maturation development and reproductive success.
Environmental Conditions and Channel Catfish Ictalurus punctatus Production under Similar Pond Management Regimes in Alabama and Mississippi
Authors: Hariyadi Sigid , Tucker Craig S. , Steeby James A. , van der Roeg Martine , Boyd Claude E.
Published: April 2007

This study was conducted to compare water quality and channel catfish production in earthen ponds located in two dissimilar physiographic regions of the southeastern United States and supplied with water of disparate quality. Ponds at Auburn, Alabama are on acidic Piedmont soils and filled with poorly mineralized runoff water; ponds at Stoneville, Mississippi are on slightly alkaline alluvial clays and filled with groundwater of high total alkalinity and hardness. Channel catfish were stocked at 8,750 fish/ha, fed daily, and provided nightly aeration in 0.04‐ha ponds at both sites. Ponds were managed as similarly as possible. Minimum daily water temperatures and pH were higher at Stoneville than at Auburn, and there were greater concentrations of suspended clay turbidity, dissolved inorganic phosphorus, total ammonia‐nitrogen, and nitrite‐nitrogen at Auburn than at Stoneville. The taxonomic composition of the phytoplankton community was broadly different between the two sites. Taste tests revealed off‐flavor in fish at both sites, but there were no significant differences (P > 0.05) in flavor scores between sites. The quality of flavor was somewhat different between sites, and these differences in quality were thought to result from observed differences in the taxonomic composition of phytoplankton communities. All differences in water quality seemed to be directly or indirectly related to the dissimilarity in the quality of the water supply and soils at the two locations. Although some water quality variables differed between sites and changed over time at both sites, environmental conditions never deteriorated enough at either site to cause serious stress or mortality in fish. There were no significant differences (P > 0.05) in average net fish production, survival, weight of individual fish at harvest, or feed conversion ratios. Average net fish production and feed conversion ratios, respectively, were 4,905 kg/ha and 1.27 at Auburn and 5,286 kg/ha and 1.27 at Stoneville. The results of this study demonstrate the need for site‐specific investigations when conducting certain types of aquaculture research.
Analyzing Production Feasibility and Market Potential For Florida Aquaculture Catfish Products
Authors: Clancy Colleen M. , Spreen Thomas H. , Zimet David J. , Olowolayemo Surajudeen O.
Published: April 2007

A spatiotemporal linear programming model (GAMS) was constructed to simulate the catfish production and marketing system in the U.S. in order to study the economic feasibility of Florida entering the aquaculture catfish industry. Evaluation of base model results and sensitivity analysis were used to identify constraints to the potential expansion of the catfish industry in Florida. Results indicated production and processing costs were more important in determining the locus of production and processing than were processing capacity, storage costs and capacity, and transportation costs. Thus, existing industry geographic concentration is likely to continue, but small new processing plants could develop proximate markets for fresh product.
The Nitrogen Budget of a Tropical Semi‐Intensive Freshwater Fish Culture Pond
Authors: Acosta‐Nassar Marco V. , Morell Julio M. , Corredor Jorge E.
Published: April 2007

Nitrogen inputs, outputs and compartamentalization were quantified in a freshwater fish pond stocked with hybrid Oreochromis throughout a production cycle. The budget accounts for 91% of the nitrogen added to the system. Feed addition accounted for 87% of the nitrogen input and an additional 11% was attributable to nitrogen fixation, mainly in the water column. The balance of the nitrogen input was contained in the source water for the pond. Commercial‐size fish accumulated 17.5% of the nitrogen added to the system. Most of the nitrogen was eventually deposited in the sediments. Nitrification constituted a major pathway for nitrogen transformation, but only 1% of the nitrogen input was lost through denitrification.
Spawning by Captive Serranid Fishes: A Review
Authors: Tucker John W.
Published: April 2007

The current available information on spawning by serranid fishes in captivity is reviewed. Much work has been done on members of the family Serranidae because of their value as food or ornamental fish. At least 31 species have been induced to ovulate with hormones, and at least 23 species have spawned voluntarily (without chemical treatment) in captivity. Typically, a serranid female with fully‐yolked oocytes will ovulate within 24–72h (usually 36–50h) after the first of 1–3 injections of 500–1,000 IU human chorionic gonadotropin/kg body weight. Similar results have been obtained for several species given 1–3 injections of 10–50μg luteinizing hormone‐releasing hormone analog/kg body weight. Voluntary spawning has occurred mostly with well‐fed uncrowded fish during the natural spawning season under conditions of ambient temperature and partial or total natural light. The necessary temperature range for spawning varies among species, and daylength seems to be a less important stimulus than temperature for serranids.
A Comparative Study on the Use of Different Preparations of Decapsulated Artemia Cysts as Food for Rearing African Catfish (Clarias gariepinus) Larvae
Authors: Pector R. , Tackaert W. , Abelin P. , Ollevier F. , Sorgeloos P.
Published: April 2007

African catfish (Clarias gariepinus) larvae were fed on five preparations of decapsulated Great Salt Lake Artemia cysts: 1) dried (35C, 6h) and UV‐irradiated cysts; 2) heated cysts (80C, 10 min); 3) brinedehydrated and UV‐irradiated cysts; 4) micro‐bound diet 1 (with intact decapsulated cysts used in diet preparation 1); and 5) micro‐bound diet 2 (with crushed and shited decapsulated cysts used in diet preparation 1). The larvae were fed from the first day after yolk‐sac resorption (fourth day after hatching). After a 14‐d rearing period, larvae fed on dried or heated decapsulated cysts yielded significantly higher mean weights than the groups fed on brine‐dehydrated decapsulated cysts or micro‐bound diet 1. Feeding micro‐bound diet 2 resulted in a significantly lower average gain in weight as compared to the other groups.
Chemistry of Sediment Pore Water in Aquaculture Ponds Built on Clayey Ultisols at Auburn, Alabama
Authors: Masuda Kiyoshi , Boyd Claude E.
Published: April 2007

The composition of sediment pore water was determined for ponds constructed on clayey Ultisols at Auburn, Alabama. Pore water was anaerobic and contained much higher concentrations of ferrous iron (Fe2+), soluble reactive phosphorus (SRP), total phosphorus (TP), total ammonia‐nitrogen (TAN), and sulfide (S2−) than surface or bottom waters. Concentrations of SRP and TP in pore water were higher in ponds with high soil phosphorus concentrations than in a new pond with less soil phosphorus. Increased concentrations of organic matter in soil or larger inputs of feed to ponds favored greater microbial activity in soils and higher concentrations of TAN in pore water. The pH of pore water was 6.5–7.0, and pH was apparently controlled by the equilibrium:

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Movement of Fe2+, SRP, and S2− from pore water into pond water apparently was prevented by the oxidized layer of soil just below the soil‐water interface. Pond managers should concentrate on maintaining this oxidized layer to reduce the tendency for toxic substances to diffuse into the pond water.
Preliminary Observations on the Marketability of Saltwater‐Cultured Florida Red Tilapia in Puerto Rico
Authors: Head William D. , Zerbi Alfonso , Watanabe Wade O.
Published: April 2007

A preliminary assessment of the marketability of saltwatercultured Florida red tilapia was conducted at a farm outlet store and at nine restaurants in Puerto Rico. Florida red tilapia were grown in six 0.2‐ha ponds at 22.7 ± 1.2 (mean ± SE) ppt salinity by a commercial aquaculture enterprise in Dorado, northeastern Puerto Rico. Customers purchased 4,683kg of dressed‐out fish (gilled, gutted and scaled) at $7.70/kg and 826kg of whole fish at $6.60/kg from a retail outlet store located at the aquaculture farm, and nine restaurants purchased 1,071kg of dressed‐out fish at wholesale prices ranging from $4.96 to $5.18/kg. Farm outlet customers and restaurants preferred dressed‐out fish between 454–567g and 567–580g, respectively. Prices paid per serving by restaurant customers for red tilapia ($7.00–$25.00) were similar to that paid for silk snapper Lutjanus vivanus, a popular marine food fish in Puerto Rico. Market surveys of customers at these outlets showed that 75–81% of the respondents were new consumers of red tilapia and that they rated red tilapia highly in taste, texture, freshness, and presentation and equal to or better than silk snapper. There was no effect (P > 0.05) of age group or economic level on consumer responses. Survey participants stressed the need for product promotion, including a more markehriented name that emphasized the red color and that it was farm‐raised in saltwater, to distinguish it from darkcolored, wild‐caught freshwater tilapia. Local saltwater production of Florida red tilapia could help supply the market demand for fresh, marine fish in Puerto Rico if producers can meet the demand for quality, availability and price.
Effect of Total Water Hardness and Chloride on Survival, Growth, and Feed Conversion of Juvenile Red Drum Sciaenops ocellatus
Authors: Pursley Michael G. , Wolters William R.
Published: April 2007

Juvenile red drum Sciaenops ocellatus were tank‐reared in two, separate 30‐d trials to assess effects of total water hardness and chloride concentratlon on growth, survival, and feed conversion. Two levels of total hardness and chloride were used in 2 × 2 factorial designs to obtain total hardness and chloride levels in trial one of 100 and 200mg/L CaCO3 and 125 and 250mg/L Cl−, and hardness and chloride levels of 100 and 400mg/L CaCO3 and 150 and 500mg/L Cl− in trial two. In trial one, average daily growth and feed conversion were significantly (P≤ 0.05) improved at 100mg/L hardness levels compared to 200mg/L at both chloride levels. Average daily growth was 0.11 ± 0.02g/d at 100mg/L hardness and 125mg/L Cl− compared to 0.06 ± 0.01g/d at 200 mg/L hardness and 125mg/L chlorides. No significant (P≥ 0.05) difference in survival could be attributed to levels of total hardness or chloride. In trial two, 500 mg/L Cl− treatments produced significantly (P≤ 0.01) better growth, survival and feed conversion than 150mg/L Cl− at either level of total hardness (100 and 400mg/L). Survival at 150mg/L chloride and 100mg/L hardness was 48.8 ± 18.7%, while at 500mg/L chloride and 400mg/L hardness survival increased to 96.6 ± 2.1%. Growth also increased from 0.14 ± 0.03 to 0.27 ± 0.01g/d and feed conversion improved from 5.77 ± 1.56 to 1.87 ± 0.06 at the same levels. No interactions between levels of hardness or chlorides were shown to affect red drum growth, survival, or feed conversion in either trial.
Egg Quality Determinants in Finfish The Role of Overripening with Special Reference to the Timing of Stripping in the Atlantic Halibut Hippoglossus hippoglossus
Authors: Bromage Niall , Bruce Mike , Basavaraja Ngappa , Rana Krishen , Shields Robin , Young Carl , Dye John , Smith Peter , Gillespie Malcolm , Gamble John
Published: April 2007

Egg quality, those characteristics of the egg that determine its capacity to survive, is a significant problem for many species of fish currently being farmed. Little is known about the determinants of egg quality and there is little agreement regarding reliable methods for its assessment. To be of practical benefit, assessments should be simple to perform and should be carried out as early in development as is possible. Fertilization rates are often used as measures of quality. For the Atlantic halibut Hippoglossus hippoglossus, fertilization rate and assessments of cell symmetry at early cleavage stages provide reasonable indicators of quality. Regardless of assessment method, it is strongly recommended that performance data from all batches of each broodfish be examined when surveying the overall quality of a stock. The misleading effects of pooling such information are demonstrated for a rainbow trout Oncorhynchus mykiss broodstock. Although a large number of factors have been implicated as possible determinants of egg quality, only 1) bacterial colonization of the eggs, 2) nutritional status of the broodfish and, 3) overripening, the process of aging that occurs when eggs are retained within the broodfish after ovulation, have been clearly shown to affect egg quality.

The effect of overripening on fish egg quality is discussed in detail. Species‐specific differences in the time scale of overripening are pointed out and related to spawning strategy and water temperature. Rainbow trout eggs and those of other salmonids should be fertilized within approximately one week of ovulation. Overripening proceeds much more rapidly in warm water species, e.g., tilapia eggs must be fertilized within an hour or so of ovulation. Egg viability also decreases rapidly for batch spawning species. Fertilization data are presented for Atlantic halibut demonstrating that egg quality decreases 4–6 h after ovulation. The rate of overripening was comparable for eggs held in vitro in ovarian fluid to those retained within the ovarian lumen. These halibut data, combined with information from other marine and freshwater fish, indicate that overripening is a significant determinant of egg quality for many if not all fish.
Egg Quality in Wild and Broodstock Cod Gadus morhua L.
Authors: Kjørsvik Elin
Published: April 2007

Problems concerning egg viability or egg quality have received increasing attention, in relation to cultivation as well as to the assessment of reproduction of wild fishes. One important aspect of this paper is to discuss the use of cell morphological characteristics as indicators of egg quality in cod. Early cellular malformation rates in egg batches show a positive correlation with their later egg and larval survival, and can be used as a rough prediction of normal development and mortality rates.

The natural mortality rate offish eggs is not well understood, and observed egg viability of captive cod is are discussed in relation to egg viability in the wild. Results from recent work indicated that approximately 10% of naturally spawned cod eggs from both wild fish (planktonic samples) and from a broodstock had abnormal cleavages at the 2–128 cell stage. Eggs with observed early abnormal cell‐cleavage showed very poor survival and hatching rates. For broodstock cod, egg viability was highest during the peak of the spawning season.

The North Atlantic cod may provide a good model species for studies of egg viability variations in wild and captive individuals, as its reproductive biology is well studied. It is now documented that the egg production in cod is dependent on fish age, nutritional status, batch number, and stress factors.
Effects of Fasting on Fatty Acid Composition of Muscle, Liver, and Abdominal Fat in Channel Catfish Ictalurus punctatus
Authors: Webster Carl D. , Tidwell James H. , Goodgame Laura S. , Yancey Daniel H.
Published: April 2007

Channel catfish Zctalurus punetatus were fasted for 20, 40, 60, and 80 d. Proximate and fatty acid composition of liver, abdominal fat, muscle, and viscera were determined. Percentage moisture, protein, and lipid of viscera showed little change during the period of fasting. Percentage protein in muscle decreased (P < 0.05) after 20 d of fasting from time 0 (control), while percentage lipid increased (P < 0.05). Fish fasted for 0, 40, 60, and 80 d were not different (P > 0.05). In the liver, percentage lipid was higher in fish that were not fasted (0 d) than in fish fasted 20, 40, 60, and 80 d (P < 0.05). while percentage moisture was lower in control fish compared to all other treatments (P < 0.05). Fatty acid composition of muscle and liver indicated that docosahexaenoic acid (DHA), 22:6(n‐3), was conserved in these tissues during fasting, while oleic acid, 18:1(n‐9), concentration decreased during fasting. Fatty acid composition of abdominal fat indicated that a high percentage (>50%) of the total lipid was composed of oleic acid and there was little change in levels of individual fatty acids in abdominal fat during 80 d of fasting.
Digestive Characteristics of the Sea‐Urchin Lytechinus variegatus (Lamarck) (Echinodermata: Echinoidea) Fed Prepared Feeds
Authors: Klinger Thomas S. , Lawrence John M. , Lawrence Addison L.
Published: April 2007

Lytechinus variegatus were fed two prepared feeds identical in composition except one contained only soybean protein and the other contained equal concentrations of fish and soybean protein. Feeding rate, defecation rate, passage time through the gut, apparent dry matter digestibility of protein and carbohydrate, and the production of gut tissue did not differ significantly (P > 0.05) with feed type. Individuals about 50 mm in diameter and 60% wet body‐weight consumed about 3‐g wet weight of feed per day. Feeding rate decreased during the experiment, but defecation rate did not. The throughput rate was two days with considerable mixing of feed in the gut. Fecal production ceased two days after cessation of feeding. Only trace amounts of feed remained in the gut three days after feed was not available. The apparent dry matter digestibility was 62% for soluble protein and 35% for soluble carbohydrate for both feeds. The apparent dry matter digestibility of ash was 19% for the feed with soybean meal alone, and 11% for soybean and fish meal. The apparent dry matter digestibility calculated by the use of chromic oxide is greater than that calculated by the use of ash.