Development of Improved Feeding Methods in the Culture of Yellow Tang,Zebrasoma flavescens

Yellow tang, Zebrasoma flavescens, are one of the most heavily traded marine aquarium fish species, with nearly 400,000 individuals collected annually from Hawaii's reefs. Despite recent success culturing this species, significant challenges in the rearing processes remain to be overcome before commercialization is feasible. This study compared two feeding regimens, an original diet treatment, which was initially used to successfully culture yellow tang, and a revised diet, which differed in the timing of the introduction of feed items and weaning periods. Both diet regimens consisted of Parvocalanus crassirostris nauplii, enriched Brachionus rotundiformis rotifers, and Artemia nauplii, followed by a transition to dry and frozen feed items. The revised feeding regimen aimed to considerably reduce the amount of copepods and rotifers needed in the rearing process. Eggs were stocked at 40/L into replicate (n = 3) 200‐L tanks for the feeding regimen trial. A follow‐up rearing study, in which eggs were stocked at 19/L in a single 1000‐L tank, tested the revised feeding method at pilot scale. Fish reared on the revised feeding regimen were observed to grow faster in body length and body depth after 2 wk in culture and transitioned more quickly to juveniles as 41% had completed their transition to juvenile coloration by 70 d after hatch. None of the fish reared under the original feeding regimen attained full juvenile coloration during the study period. Survival was not significantly different between treatments and was 0.13% ± 0.13 and 0.29% ± 0.17 in the original and revised feeding regimens, respectively. In the pilot‐scale study, growth was comparable to that of both treatments in the 200‐L scale trial, but survival was much better at 1.9%. This study successfully shortened the copepod and rotifer feeding periods for yellow tang, while not jeopardizing growth or survival. This outcome enhances the commercialization potential for this and likely other Acanthuridae species.     

Application of Marine Foodfish Techniques in Marine Ornamental Aquaculture: Reproduction and Larval First Feeding

The long-term sustainability of the marine ornamental industry is being threatened by environmental pressures that are severely degrading the health of coral reef ecosystems. There is now a compelling need to practice resource conservation through the development of 'reef friendly' aquaculture technologies as an alternative to wild collection practices and to restore degraded wild populations. The commercial culture of marine ornamental finfish is very much in its infancy, but advances can be made more rapidly using insights from years of research and development with marine foodfish species. Many of the bottlenecks and constraints to developing marine ornamental fish culture are those now being addressed with the more challenging species of foodfish being attempted. The two key bottlenecks that currently limit expansion of the marine ornamental industry are the control of captive maturation and spawning and the identification of appropriate first-feed items for marine ornamental fish larvae. This paper highlights basic principles and recent achievements in marine foodfish culture that might be applicable to rapid development of controlled reproduction and propagation techniques for marine ornamental finfish.     

胶红酵母分离鉴定及其对凡纳滨对虾幼体存活和变态的影响

用平板划线或稀释法从湛江的凡纳滨对虾、斑节对虾、翡翠贻贝、华贵类栉孔扇贝和褐蓝子鱼肠道中分离红酵母.根据形态和碳源利用特征进行分型,利用5.8S-ITS和26S rRNA基因测序分析鉴定代表菌株,通过间歇饥饿胁迫试验,比较代表菌株对凡纳滨对虾无节Ⅵ期到溞状Ⅱ期幼体存活影响,筛选出最优菌株,进而研究目标菌株从无节Ⅵ期开始...     

Evaluation of First-Feeding Regimens for Larval Nassau Grouper Epinephelus straitus and Preliminary, Pilot-Scale Culture through Metamorphosis

Two 10-day hatchery experiments were conducted to evaluate s-type (Hawaiian strain) and ss-type (Thailand strain) rotifers Brachionus plicatilis and cryogenically preserved oyster Crassostrea gigas trochophores as first feeds for larval Nassau grouper Epinephelus striatus. Newly hatched grouper larvae were reared at densities of 11.2–20.8/L in 500-L tanks at 36–38 ppt salinity, 25–26 C, and under a 11-h light: 13-h dark photoperiod. Beginning on day 2 posthatching (d2ph), prey were maintained at a density of 20 individuals/mL, while phytoplankton (Nanochloropsis oculata) was maintained at 500 × 10³ cells/mL. In experiment 1, survival and growth were higher (P < 0.05) for fish fed small s-type rotifers (mean lorica length = 117 μm; fish survival = 7.96%) selected by sieving than for fish fed non-selected rotifers (mean lorica length = 161 μm; fish survival = 2.13%). These results demonstrated the advantage of small prey size and suggested that super-small (ss-type) rotifer strains would be beneficial. In experiment 2, three feeding regimens were compared: 1) ss-type rotifers (mean lorica length = 147 μm); 2) oyster trochophores (mean diameter = 50 μm) gradually replaced by ss-type rotifers from d5ph; and 3) a mixed-prey teatment of 50% oyster trochophores and 50% ss-type rotifers. Survival was higher (P < 0.05) for larvae fed mixed prey (15.6%) than for those fed rotifers (9.73%) or trochophores and rotifers in sequence (2.55%), which also showed the slowest growth. Oyster trochophores, although inadequate when used exclusively, enhanced survival when used in combination with rotifers, possibly by improving size selectivity and dietary quality. In a pilot-scale trial, larvae were cultured through metamorphosis in two 33.8-m³ outdoor tanks. Fertilized eggs were stocked at a density of 10 eggs/L and larvae were fed ss-type rotifers from d2ph-d20ph, newly hatched Artemia from d15ph-d18ph, 1-d-old Artemia nauplii from d18ph-d62ph. Survival on d62ph was 1.17%, with a total of 5,651 post-metamorphic juveniles produced.     

KC1对中间球海胆幼虫变态的诱导效果

中间球海胆（Strongylocentrotus intermedius)八腕后期幼虫，在KC1添加浓度100mmol/L海水中，分别处理5，10，15min后，均变态为正常稚海胆，中间试验及生产应用结果表明，经KC1处理，幼虫的附着时间缩短了36h，附着率则分别增加了40．4％，27．75％。     

Evaluation of the Ciliated Protozoa,Fabrea salina as a First Food for Larval Red Snapper,Lutjanus campechanus in a Large Scale Rearing Experiment

ABSTRACT

One of the major challenges of culturing of red snapper, Lutjanus campechanus, is providing an appropriate food source at onset of feeding. Ciliates are abundant in marine waters but their significance as a first food for fish larvae is poorly understood as many have no lorica to facilitate their identification in the gut of a larval fish. Fabrea salina is a naked heterotrich ciliate that can be mass cultured at densities up to 84 ± 10 ciliates/mL in 7 days. Its appropriateness as a first food for red snapper larvae was evaluated in a green-water setting using 1-m³ tanks. Larvae were stocked at 10/L, 36 h post-hatch, before first-feeding commenced. Larvae were fed either (1) copepod nauplii, 20–75 μm, only from days 1 to 10; (2) copepod nauplii from days 1 to 10 plus F. salina from days 1 to 5; or, (3) F. salina only from days 1 to 3 plus copepod nauplii from days 4 to 10. Copepod nauplii were added at 2/mL and ciliates were added at 5/mL. Survival after 28 days was 0.28 ± 0.15% for larvae given only copepod nauplii and 2.39 ± 2.75% for those given F. salina and copepod nauplii. Larvae given only F. salina did not survive past 4 days post-stocking. Larvae were more actively feeding in the tanks given F. salina and copepods as first foods with 34.6 ± 8.5% mean daily reduction in copepod nauplii compared to 15.8 ± 16.2% reduction when only nauplii were provided.     

Ex situ Culture of Colonial Marine Ornamental Invertebrates: Concepts for Domestication

The worldwide market for ornamental saltwater invertebrates supplies the needs of millions of aquarium hobbyists, as well as for public exhibition (zoos, aquaria), universities, and research institutions. The large-scale continuous collection of marine organisms is responsible, in many places, for the destruction of habitats, including coral reefs. The perceived expansion of the animal trade further threatens these fragile habitats. In the present paper, several concepts for the domestication of marine ornamental invertebrates (mainly colonial species) are discussed, offering an alternative commercial approach. The major rationale is based on future ex situ propagation, not field collections; a strategy aimed to circumvent the need for wild-harvested animals. This strategy is based on: (1) collection, settlement and metamorphosis of large numbers of larvae from marine organisms or of naturally shed germ cells under aquarium conditions, where survivorship exceeds several orders of magnitude than that in nature; (2) fragmentation of very small pieces (such as the size of a single polyp in colonial corals or blood vessel ampullae in tunicates) for the production of new colonies; (3) the development of replicates and inbred-lines from chosen ornamental species; (4) the use of cryopreservation of larvae and germ cells which will support the supply of material year-round; (5) several concepts for husbandry methods. Some benefits and deficiencies associated with the strategy for ex situ cultures are discussed, revealing its importance to the future of the trade.     

Progress,opportunities and challenges for marine conservation in the Pacific Islands

1. The people of the Pacific have long relied on the ocean for sustenance, commerce and cultural identity, which resulted in a sophisticated understanding of the marine environment and its conservation.
2. The global declines in ocean health require new and innovative approaches to conserving marine ecosystems. Marine Protected Areas (MPAs) have been shown to be a highly effective means of conserving biodiversity and managing fisheries, while also restoring and preserving overall ecosystem function.
3. Traditional ecological knowledge held by many island peoples in the Pacific is critical to the development, design and implementation of contemporary MPAs.
4. Chile's offshore islands are among the few oceanic archipelagos along the west coast of South America. These islands have cultural and ecological connections to the broader insular Pacific, yet our scientific understanding of them is extremely limited.
5. Chile has created several large-scale MPAs around their offshore archipelagos. By protecting these unique ecosystems, Chile has established itself as a global leader in marine conservation.
6. Effective management and a better understanding of social–ecological interactions are currently the biggest challenges facing MPAs in the Pacific Islands.

     

Global Advances in Conservation and Management of Marine Ornamental Resources

Currently, as many as 30 million coral reef fish belonging to 1,000 species are collected annually to supply private and public aquaria around the world. In addition, over 100 species of invertebrate are used, involving hundreds of thousands or even millions of individuals. The majority of these specimens come from coral reefs and associated habitats, with about 45 countries supplying the ornamental market. Considering the many pressures currently faced by reefs it is vital that ornamental fisheries are investigated and monitored, and management strategies formulated to ensure they are sustainable. This requires research, monitoring, training, use of non-damaging collecting methods and adoption of conservation strategies for controlling catch, such as reserves, quotas and closed seasons. There are also a number of possibilities for enhancing the fishery, such as mariculture and construction of artificial reefs. This paper concentrates on some of the conservation measures that can be taken and discusses their application and effectiveness. Such measures include limiting collecting effort, establishment of species-based or overall quotas, restrictions on rare and/or endemic species, temporary closures and establishment of fisherybreak reserves.     

南美白对虾幼体和仔虾淀粉酶和脂肪酶活力的研究

以酶学分析方法测定了南美白对虾状幼体,糠虾和仔虾三个发育期淀粉酶和脂肪酶的活力。试验结果表明,糠虾期淀粉酶比活力显著高于状幼体和仔虾两期(P<0.05);脂肪酶比活力状幼体显著高于糠虾幼体(P<0.05)。在食性转化过程中,南美白对虾幼体消化酶活力与其食性相适应,不同发育阶段消化酶调节机制不同。     

Effects of Temperature on Egg Hatch,Larval Growth and Metamorphosis for Hatchery-Cultured Southern Flounder,Paralichthys lethostigma

ABSTRACT

Egg hatch, larval growth, and metamorphosis of southern flounder, Paralichthys lethostigma, were examined at 13, 17, 21, and 25°C in laboratory experiments. The experiments were separated into four developmental phases: (1) from fertilization until hatch; (2) from hatch until mouth opening; (3) from first feeding until the onset of metamorphosis; (4) from the onset until the completion of metamorphosis. Time to egg hatch were 109, 58, 39, 30 hours at 13, 17, 21, and 25°C, respectively. Size at hatch varied little among temperatures, while percent hatch was significantly higher at 17°C (P < 0.05). There was no significant difference in total length at mouth opening among temperatures (P > 0.05). However, those larvae raised at higher temperatures reached mouth opening earlier, as it took on average 7.4, 3.9, 2.8, and 2.2 days from hatch at 13, 17, 21, and 25°C, respectively. During phase three, the growth rate was optimal at 17°C, as growth rates were 0.046, 0.110, 0.106 and 0.096 mm/day at 13, 17, 21, and 25°C, respectively. Larvae in phase four completed metamorphosis sooner at higher temperatures than at lower temperatures. It took 26.4, 15.7, and 13.1 days to complete metamorphosis at 17, 21, and 25°C, respectively, while only 16% of those at 13 progressed to stage “G” within the 27 days that phase four encompassed. No difference in total length was found among treatments (P > 0.05) at the completion of metamorphosis, but fish in the 21 °C treatment had a significantly higher survival (P < 0.05). It can be concluded that southern flounder could be produced in the highest quantity and at the largest size by raising them at 17°C from fertilization until the onset of metamorphosis, and at 21 °C during metamorphosis.     

Effects of Season,Strain, and Body Weight on Testes Development and Quality in Three Strains of Blue Catfish,Ictalurus furcatus

Production of channel catfish, Ictalurus punctatus, female × blue catfish, Ictalurus furcatus, male hybrids has increased dramatically in the USA. Hybrid production requires surgical removal and maceration of blue catfish testes. Farmers report individual and seasonal variation in blue catfish testes development, and understanding the factors influencing testes development could improve hybrid catfish production. Effects of season (mid‐May vs. mid‐June), strain (D&B, Missouri, and Texas), and body weight on testes development in 5‐yr‐old blue catfish were determined. Males were measured in mid‐May and mid‐June for length, body weight, testes weight, and gonadosomatic index (GSI). Total sperm/g of testes, percent motility, and motile sperm/g of testes were determined. D&B strain males weighed more and had larger testes with more sperm than Missouri or Texas strain males in both months. Mature Texas strain males were larger than immature Texas strain males in both months. Testes were larger and had more sperm in May than in June for all strains; however, there were males from each strain with good quality testes in June. GSI, sperm/g of testes, percent motility, and motile sperm/g of testes were positively correlated. Information from this study provides a better understanding of factors influencing testes development in blue catfish.     

Blue sucker stock characteristics in the upper Yazoo River basin, Mississippi, USA

Blue sucker Cycleptus elongatus (L.) in the upper Yazoo River basin, Mississippi, USA was studied using overnight hoop net sets (n = 4093) during 1988 and 1990–1998 to determine the influence of channel dredging. There were 264 blue suckers captured, ranging from 3 to 11 years of age. Length ranged from 265 to 700 mm and weight from 120 to 4700 g. Concurrent studies with smaller mesh hoop nets failed to capture any juvenile blue suckers. Catch‐per‐unit‐effort (CPUE: fish net^?1) declined throughout the study in the Yalobusha River, a river subjected to channel dredging during 1988 and 1994. With the exception of limited hydraulic dredging in the Tallahatchie River, there was no dredging in the other Yazoo River tributaries, nor were there declines in blue sucker catch rates in these rivers. Throughout the upper Yazoo River basin, blue sucker stocks were dominated by adult fish, and there was little evidence of reproduction or recruitment. Conservation of the blue sucker in the upper Yazoo River basin should include actions that ensure the functional integrity of this floodplain river ecosystem and elimination of channel dredging throughout the basin.     

培育密度及饵料种类对四角蛤蜊幼虫生长、存活及变态的影响

在水温22.8～24.6℃,盐度24～25,pH 7.82～8.36的条件下,研究了培育密度及饵料种类对四角蛤蜊幼虫生长、存活及变态的影响.试验结果表明,不同的培育密度(5、10、15、20、30个/ml)下,幼虫的生长速度、存活率随着密度的增大而降低;30个/ml试验组幼虫不能发育至匍匐幼虫;5、10、15、20个/ml试验组幼虫的变态率随着密度的增大而降低,各阶段的发育时间随着密度的增大而增加.不同的饵料种类及投喂方式,即单独投喂金藻(J)、小球藻(Q)与混合投喂[JQ11(J:Q=1:1)、JQ12(J:Q=1:2)、JQ21(J:Q=2:1)]对幼虫的生长速度、存活率、变态率及幼虫各阶段发育时间的影响也不同,单独投喂效果较差,混合投喂效果相对较好.在四角蛤蜊苗种生产过程中,培育密度10个/ml较为合理,且混合投喂比单独投喂效果更好.     

Effects of dietary aflatoxin B1 on growth performance,body composition,haematological parameters and histopathology of juvenile Pacific white shrimp (Litopenaeus vannamei)

An 8‐week feeding trial was conducted to evaluate the effects of dietary aflatoxin B₁ (AFB₁) on growth performance, haematological parameters and histological changes in juvenile Pacific white shrimp, Litopenaeus vannamei. Six practical diets (455 g kg^‐1 protein, 78 g kg^‐1 lipid) with different levels of AFB₁ (0, 25, 50, 100, 500, 1000 μg kg^?1) were formulated. Each diet was fed to triplicate groups of shrimps (initial weight: 0.52 g). The results showed that shrimp fed with control diet (0 μg kg^?1 AFB₁) had significant higher weight gain (WG) and specific growth rate (SGR) than other groups. However, there were no significant differences in feed efficiency (FE) or hepatosomatic index (HSI) among all groups. Compared to the control diet, AFB₁ supplementation significantly changed the activities of shrimp serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total antioxidant capacity (T‐AOC) and glutathione S‐transferase (GST) and the content of cholesterol (CHO). Histological damages were identified in the hepatopancreas of shrimp when dietary AFB₁ level was over 107.6 μg kg^?1. Based on this study, it was concluded that the AFB₁ level in Pacific white shrimp diet should be <38.1 μg kg^?1.     

Rearing of the Pacific white shrimp,Litopenaeus vannamei in a biofloc system: The effects of different food sources and salinity levels

The present study assessed the effects of different types of feeds and salinity levels on water quality, growth performance, survival rate and body composition of the Pacific white shrimp, Litopenaeus vannamei, juveniles in a biofloc system. Shrimp juveniles (2.56 ± 0.33 g) were cultured for 35 days in 300 L fibreglass tanks (water volume of 180 L) with a density of 1 g/L in six treatments. Three sources of feed (100% formulated feed, mixture of 66.6% formulated diet and 33.3% wet biofloc, and 100% wet biofloc) and two levels of salinity (10 and 32 ppt) were considered in two control groups and four biofloc treatments. Water quality parameters in the biofloc treatments were significantly better than control groups (p < .05). The highest increase in growth performance and survival rate were obtained in salinity of 32 ppt and mixed feed sources. Analysing the proximate composition of body shrimp indicates an increase in lipid and ash levels in biofloc treatments, which was more evident in the salinity of 32 ppt. In addition, the proximate analysis of shrimp body showed significant differences between biofloc treatments and control groups (p < .05). The highest FCR was found in the treatment with salinity level of 10 ppt and fed only with floc. Overall, it was found that the artificial diet supplemented with biofloc at the salinity of 32 showed better performance in the juvenile stage of Pacific white shrimp.     

Surface disinfection of Pacific threadfin, Polydactylus sexfilis, and amberjack, Seriola rivoliana, eggs

The effects of exposing the eggs of Pacific threadfin and amberjack eggs (AEs) to different concentrations of hydrogen peroxide for 5 min on hatch rate and survival were assessed in a series of experiments using a petri dish model rearing system. Despite significant inter‐batch variation in hatch rate, it was shown that eggs of both species could be safely exposed to up to 11 340 mg L⁻¹ H₂O₂ for 5 min. Exposure to 34 230 mg L⁻¹ H₂O₂ for 5 min was shown to be lethal to AEs at a late stage of development. In two further experiments, it was demonstrated that Pacific threadfin eggs were resistant to all tested concentrations of a range of polyvinylpyrrolidone iodine (PVP‐I) concentrations and contact times (up to 1000 mg L⁻¹ PVP‐I for 10 min). The level of bacteria adhering to the eggs of both species was highly variable. Where eggs were heavily colonized (>10⁴ cfu egg⁻¹), hydrogen peroxide concentrations of at least 11 340 mg L⁻¹, or PVP‐I concentrations higher than 500 mg L⁻¹ for 10 min, were required for effective sterilization. In less colonized batches, rinsing in sterile seawater or exposure to lower (550 mg L⁻¹) concentrations of H₂O₂ was sufficient to result in high apparent levels of surface sterility (<1 cfu egg⁻¹).     

Essential Fish Habitat and the Effective Design of Marine Reserves: Application for Marine Ornamental Fishes

Extensive and unregulated harvest of marine ornamental fishes can lead to localized depletion of target species and habitat degradation from inappropriate collecting techniques. One potential solution to these problems is the creation of marine reserves where fishing is prohibited. Marine reserves have been shown to increase fish abundance and protect ecosystems from habitat destruction associated with fishing. If protective areas are to be effective, they must include the diversity of habitats necessary to accommodate the wide range of fish species that are of interest to the marine ornamental fish trade.Fish assemblages with high diversity and abundance are often associated with habitats of high structural complexity. A relationship between fish size and reef complexity suggests the importance of shelter as a refuge for certain fishes in avoiding predation. Many species tend to aggregate to spawn in structurally complex habitats to reduce their risk of predation. Closing of spawning areas during aggregation periods has been shown to be a highly effective management strategy for these species. The limited home ranges and high degree of habitat specificity associated with many marine ornamental fishes should make marine reserves a highly effective strategy for managing these resources.     

Pond Culture of Larval and Juvenile Cobia,Rachycentron canadum,in the Southeastern United States

Abstract

The potential of growing larval and juvenile cobia, Rach-ycentron canadum, in ponds was investigated. Larval cobia, obtained from tank spawning of wild-caught adults, were stocked 48-72-h post-hatch at a rate of 700,000/ha into three fertilized 0.25-ha ponds. At one week post-stocking (WPS), fish were observed consuming formulated feed. Growth was rapid, with specific growth rates (SGR) ranging from 12.5-19.2% body weight/day. At harvest (5 WPS) fish reared in two ponds weighed 7.9 and 9.3 g and total length (TL) was 118.9 and 129.3 mm, respectively (all fish reared in remaining pond died the night prior to harvest due to aerator failure). Feed conversion ratio (FCR) was 3.8 for both ponds and survival was 5.3 and 8.5%. Low survival rates were thought to be due primarily to cannibalism. Immediately after harvest, fish were restocked into two 0.25-ha ponds at a stocking rate of 14,400/ ha. Fish were fed formulated, pelleted feeds. Growth was rapid up to ～9 WPS, after which pond water temperatures declined. Ponds were harvested at 13 and 15 WPS, respectively. Final weight of fish was 309.9 and 362.5 g. Final TL was 343.1 and 355.7 mm. FCR was 3.8 and 4.5 and survival was 27.5 and 30.5%. Major losses of fish were associated with avian predators and possibly a toxic algal bloom. Results of trials indicate that cobia larvae and juveniles can be reared in pond-based culture systems, however additional research is needed to refine this approach.