Journal of The World Aquaculture Society最新文献

Pham Thi, H. H., Kim, D.-H., Quach Van, C. T., Nguyen, P. T., & Nguyen T. L. (2023). Prevalence and antibiotic resistance of Aeromonas schubertii causing internal white spot disease on snakehead fish, Channa striata, in the Mekong Delta, Vietnam. Journal of the World Aquaculture Society, 54(5), 1260–1276. 10.1111/jwas.12954

The Vietnam map used in Figure 1 of the published article was incorrect. The corrected figure is shown below.

The United States has the resources to become a leader in the production of marine finfish and has developed a series of national strategic plans that include increased support for the growth of commercial marine finfish production. An economically viable hatchery phase of production is necessary to supply fingerlings needed for growout production. Published research literature, supplemented with data from U.S. redfish (Sciaenops ocellatus) commercial farms, was used to develop cost analyses of 100 hatchery scenarios. Full investment and total annual costs were estimated for seven marine finfish species (black drum, Pogonias cromis; black sea bass, Centropristis striata; cobia, Rachycentron canadum; hybrid drum, ♀Pogonias cromis x ♂Sciaenops ocellatus; redfish, spotted seatrout, Cynoscion nebulosus; and striped bass, Morone saxatilis) for which evidence was found in the literature for viable broodstock holding and fingerling production in ponds. Additional scenarios were developed for hatcheries that used only recirculating aquaculture systems (RAS) for the above-named seven species and six additional species (Atlantic cod, Gadus morhua; Florida pompano, Trachinotus carolinus; red snapper, Lutjanus campechanus; seriola, Seriola spp.; tripletail, Lobotes surinamensis; and white seabass, Atractoscion nobilis). Five production scales were modeled for each species in each production system. The models were constructed by developing and linking submodels for quarantine, broodstock holding, egg incubation and larval rearing, and larval phases of production. An additional submodel was developed to capture costs of vehicles and equipment for which it was not possible to pro-rate annual fixed costs across the hatchery phase submodels. Five of the seven species for which ponds could be used to hold broodstock and raise fingerlings were profitable, but none of the all-RAS hatchery scenarios showed profitability. The greatest costs were incurred in the nursery phase. The greatest opportunity to increase cost efficiencies and reduce costs in marine finfish hatcheries was to increase yields (kg/ha in ponds and kg/cubic meter in RAS) in the nursery fingerling production phase. For all-RAS hatcheries to be profitable, nursery yields would need to increase three to six times that of the maximum biomass values reported in the research literature. There is a strong need for well-replicated production trials in ponds and in tanks to identify stocking densities and sizes that optimize fingerling production. Such studies require ponds and tanks of sizes that effectively mirror water quality and other conditions of commercial scale production. Longer-term needs include the development of domesticated broodstock that reduce dependence on wild harvest.

Determining safe nitrite exposure limits for Penaeus vannamei in biofloc technology system (BFT) is crucial, as nitrite peaks frequently occur during BFT culture. This study evaluated the effects of chronic nitrite exposure on performance, compensatory growth, and immune response of shrimp cultured at a salinity of 25 g·L⁻¹. A 2 × 3 factorial experiment was performed with two nitrite concentrations (two- and three-fold the recommended safe level, 30.4 and 45.6 mg·L⁻¹ NO₂─N) and three “stress” exposures (7, 14, and 21 days), followed by recovery of 42, 35, and 28 days, respectively. A control was maintained with nitrite below 25% of the safe level (3.8 mg·L⁻¹ NO₂─N). After the stress phase, survival decreased in shrimp exposed to three-fold the safe level and in those exposed to two-fold levels for 21 days. Growth was reduced in the treatments exposed to high nitrite concentrations during 14 and 21 days, and the immune response was negatively affected. By the end of the recovery phase (day 49), final weight was reduced by exposures longer than 7 days, and the yield was inversely proportional to the exposure time and nitrite concentrations. Differential hemocyte count (DHC) recovered to the optimal range for healthy shrimp reared in BFT. Nevertheless, shrimp subjected to high nitrite concentration during the first phase grew at high rates again when control nitrite levels were reestablished. If exposure of animals to high levels of nitrite cannot be avoided, a maximum of two-fold the safe level of nitrite should not be exceeded for a period of up to 14 days. This will avoid productivity reduction because of mortality, and animals will return to normal growth after the stress period.

The main purpose of this report is to provide hard evidence that the shrimp parvovirus, infectious hypodermal and hematopoietic necrosis virus (IHHNV), has not resulted “in significant consequences, for example, production losses, morbidity or mortality at a zone or country level” in Thailand since at least 2010. It also reveals that no single polymerase chain reaction (PCR) test is sufficient to identify IHHNV-infected shrimp. It presents historical evidence and new evidence from 11 commercial ponds cultivating the giant tiger shrimp Penaeus monodon in Thailand. These ponds were selected because they were the ponds that gave positive PCR test results for IHHNV using two methods recommended for IHHNV diagnosis by World Organization for Animal Health (WOAH) (IHHNV-309 and IHHNV-389). However, an additional in-house “IHHNV Long-amp method” (IHHNV-LA) was also used to amplify 90% of the 4-kb IHHNV genome sequence, and it also gave false-positive test results with 2 of the 11 ponds (IHHNV-LA positive, but histological tests negative). Further tests using normal histopathological analysis for the presence of pathognomonic Cowdry A type inclusions (CAI), in situ hybridization (ISH) and immunohistochemistry (IHC) could confirm IHHNV infections in only two of the three ponds PCR-positive using all three PCR methods. In addition, positive detection of CAI alone was equivalent to ISH or IHC in confirming IHHNV infection after a positive test with any of the PCR methods used. In summary, the recommended WOAH PCR methods gave false-positive test results for IHHNV infection with 9/11 ponds (82%). All 11 ponds gave profitable harvests despite the confirmation of IHHNV in two ponds, where it was accompanied by various additional pathogens. Unfortunately, according to current practice, positive PCR test results with the WOAH methods alone sometimes leads to rejection of traded shrimp products without assurance that the test results are not false-positive results that may arise from endogenous viral elements (EVE).

Rainbow trout (Oncorhynchus mykiss) are one of the most widely farmed fish species in aquaculture both globally and in Iran. While high-altitude trout farms benefit from colder temperatures favorable to trout farming, they also face challenges due to lower dissolved oxygen (DO) levels inherent to higher elevations. The overall impact of altitude on economic efficiency (EE) remains unclear. This study aims to fill this gap by analyzing the relationship between altitude and EE in trout farming, providing novel insights through the assessment of EE while exploring the effect of altitude in selected high-altitude aquaculture systems in Mazandaran, Iran. Using primary data collected from 25 trout farms in Mazandaran, we calculated EE scores through Data Envelopment Analysis (DEA) and assessed the impact of altitude using the Tobit model. Results indicate an average EE score of approximately 43%, despite subsidies supporting foreign trout egg imports. Findings from the Tobit model reveal that altitude negatively impacts EE, as the reduction in DO levels outweighs the benefits of cooler temperatures. These findings are specific to Mazandaran and may not apply to other regions. Our results suggest that genetic improvements alone (enhancing feed conversion ratios) are insufficient to improve EE in high-altitude farms in Mazandaran. Instead, reallocating subsidies from foreign trout eggs to investments in pressure swing adsorption (PSA) technology can significantly enhance EE by ensuring adequate DO levels. Implementing subsidized PSA equipment offers a practical and policy-relevant strategy to improve EE in high-altitude trout farms in Mazandaran. Future research should also incorporate additional confounding variables—such as broader genetic traits beyond feed conversion ratios (FCR), feed quality, and husbandry practices—to more comprehensively evaluate the drivers of economic efficiency.

Aquaculture feeds with optimum digestible starch levels can provide benefits but only through the continued identification and characterization of the available nutrient content of novel or lesser utilized starch sources for a larger variety of aquatic species. To address this literature gap, in vivo digestibility trials were conducted in rainbow trout and hybrid striped bass to determine the available nutrient content of commercially sourced U.S. grain sorghum hybrids. Based on digestibility data, a regression design was employed to test the replacement of wheat flour with U.S. grain sorghum in practical-type diets for rainbow trout and hybrid striped bass at four inclusion levels (0%, 5%, 10%, and 20%). All diets were formulated to contain 40% digestible protein and 18% crude lipid, and balanced to available lysine, methionine, threonine, and phosphorus to targets of 3.82, 1.30, 2.14, and 0.6, respectively, prior to cooking extrusion. For the growth trials, 10 rainbow trout (59.1 ± 0.07 g, initial weight) or 10 hybrid striped bass (27.1 ± 0.1 g) were randomly stocked into triplicate replicate tanks per diet (300 or 500 L, respectively) and fed for eight or nine weeks, respectively to assess effects on growth performance. No significant negative effects of U.S. grain sorghum inclusion on hybrid striped bass final fish weight, growth rate expressed as a percent increase, feed conversion ratio, feed intake, body condition indices, or whole-body proximate composition were observed. The effects of 20% red grain sorghum inclusion on rainbow trout final fish weight were explained by the linear model: $��\text{Final fish weigh}��\left(g\right)�=�248�-�1.0��\left(\text{Sorghum inclusion level}\right)�$. The reduced growth observed in rainbow trout at the 20% inclusion level underscores the need for additional research to examine the potential beneficial effects of further sorghum processing and optimize feed extrusion parameters when U.S. grain sorghum is used in place of wheat flour.

This study evaluated POET CFP, a corn-fermented protein derived from dry-mill bioethanol production, as a potential candidate for use in European seabass aquafeeds. The apparent digestibility coefficients (ADC) of POET CFP were evaluated and compared to soybean meal. The ADC of POET CFP protein was higher than that of soybean meal (92.7% vs. 83.9%), and the neutral detergent fiber (NDF) of POET CFP was partially digested (26%), while that of soybean meal was completely undigestible. However, the ADC of energy was similar between the two feedstuffs (70%). Two growth trials were performed to evaluate the effect on growth performance and feed utilization of European seabass for total or partial replacement of corn gluten meal (CGM) (Trial 1) or CGM and soybean meal (CGM + SBM) (trial 2) with POET CFP. For that purpose, a practical diet with 48% protein and 18% lipids was formulated to include 20% fish meal, 15% CGM, and 15% SBM (control diet). For trial 1, four diets similar to the control were formulated with POET CFP replacing CGM at 25%, 50%, 75%, and 100%. For trial 2, three other diets similar to the control were formulated, but POET CFP replaced CGM + SBM at 33%, 66%, and 100%. Triplicate groups of European seabass juveniles with 26 g were fed these diets for 85 days. Results of Trial 1 showed that total dietary replacement of CGM with CFP did not affect growth performance, feed intake, feed utilization, and whole-body composition. N retention (% N intake) was also unaffected, but energy retention (% energy intake) linearly increased with dietary CFP inclusion. Further, the histomorphological appearance of the posterior intestine was unaffected by dietary CFP inclusion. Results of trial 2 showed that total dietary replacement of CGM + SBM with CFP did not affect growth performance, feed intake, feed utilization, and N and energy retention (% intake). However, polynomial contrasts showed a significant linear trend for increased growth performance and feed efficiency with the dietary inclusion of CFP. Whole-body dry matter and lipid content linearly decreased with the dietary increase of CFP. No differences were observed between groups in the histomorphological appearance of the distal intestine. This study showed that CFP could completely replace CGM and SBM in diets for European seabass juveniles without affecting growth performance and feed utilization or adversely affecting posterior intestine morphology.

The tropical sea cucumber, Holothuria scabra, plays an important economic and ecological role. Aquaculture of this species has been developing rapidly, and an increasingly effective and efficient system for juvenile production is required. Nursery is a crucial process, as it involves the transition of rearing methods from indoor hatcheries to outdoor environments. This study determined the influence of various nursery sites within earthen pond systems on the growth and survival of juvenile H. scabra. Juvenile H. scabra with a mean wet weight of 1 g (n = 50) were held in replicate floating hapa units over 84 days across four nursery sites: reservoir pond (RP), stirred pond (SP), non-stirred pond (NSP), and main inlet sluice (MIS). Sea cucumbers in MIS exhibited significantly higher weight gain (6.95 ± 0.90 g), growth rate (0.08 ± 0.01 g day⁻¹), and specific growth rate (2.36 ± 0.15% day⁻¹) than all other treatments. Survival did not differ significantly among treatments, ranging from 64.00% ± 2.37% to 74.80% ± 5.82%. The MIS exhibited the highest growth rate for juvenile H. scabra, presumably supported by favorable environmental conditions and effective water exchange. These findings highlight the importance of water circulation and nursery site selection indicating that strategically positioning hapa units close to inlet zones may improve juvenile performance in commercial aquaculture.

Small indigenous fish species, such as mola carplet (Amblypharyngodon mola), play a crucial role in the diets of fish-dependent populations in India due to their rich micronutrient content. Recognized as a key species for promoting nutrition-sensitive aquaculture, mola has recently been successfully bred in hatcheries using standardized induced breeding and mass seed production protocols. This study assesses the economic viability of integrating mola seed production into an existing carp hatchery in Odisha, India. A comprehensive financial analysis, including cost-return assessment, bankability, economic performance, break-even analysis, and sensitivity testing, was conducted. The proposed model has a production capacity of 1 million seeds per cycle, with 24 cycles annually. The total investment required is INR 4,12,932 ($4975), comprising capital expenses of INR 2,56,650 ($3092) and annual operational costs of INR 1,56,282 ($1883) considering the loan component. The business model demonstrates strong profitability, with an operational profit margin of 53.57% at a selling price of INR 1000 ($12) per 100,000 hatchlings. The break-even point is achieved at 17 production cycles per year and INR 885 ($10) of per unit of seeds price. Financial indicators confirm high viability, with a benefit–cost ratio of 1.67, a net present value of INR 2,28,233 ($2750), and an internal rate of return of 32.94%. The model is also bankable, evidenced by a debt service coverage ratio of 1.63, and remains profitable under various sensitivity scenarios. These findings highlight the potential for integrating mola seed production into existing carp hatcheries, offering a scalable and sustainable approach to strengthening small indigenous fish farming and advancing nutrition-sensitive aquaculture in India.

In the pond culture production process, culture patterns and conditions have important impacts on the feeding, growth, metabolism, behavior, physiology, biochemistry, and immune responses of aquatic animals. These interact with the ecological environment to jointly determine the production outcome of pond culture. Both of Acanthopagrus schlegeli and Apostichopus japonicus are high economic value mariculture animals. This study investigated the effects of pond monoculture and integrated culture patterns as well as different culture densities, water depths, and background colors used in the integrated culture pattern on the growth performance, survival rate (SR), and biochemical composition of A. schlegeli and A. japonicus. Finally, the suitable conditions for integrated pond culture of A. schlegeli and A. japonicus were obtained. Under the patterns AB (integrated culture of A. schlegeli and A. japonicus), A (A. schlegeli monoculture), and B (A. japonicus monoculture), differences in final body weight (W_t-final), specific daily growth rate (SGR), secondary production (P), and SR were not significant (p > 0.05). However, the overall growth of cultured animals in AB was better than in A or B. The differences in proximate composition between A. schlegeli and A. japonicus were not significant among different culture patterns (p > 0.05), nor were the differences in superoxide dismutase (SOD) activity of A. schlegeli between AB and A (p > 0.05). However, the SOD activity of A. japonicus in AB was significantly higher than in B (p < 0.05). Based on the statistical analysis and actual production situation, density bc (A. schlegeli: 36 ind. m⁻³, A. japonicus: 5 ind. cage⁻¹) would be the most suitable combination for integrated culture of A. schlegeli and A. japonicus. The optimal water depth for integrated culture of A. schlegeli and A. japonicus would be 2 m, and white would be the best background color. Our study results provide useful scientific data for the pond culture production and management of A. schlegeli and A. japonicus.