Journal of The World Aquaculture Society最新文献

Automatic feeders are revolutionizing aquaculture by enabling precise and controlled feeding regimens that optimize growth, reduce feed waste, and enhance the overall efficiency of farming operations. Demand feeders provide some similar benefits but with feeding tailored to fish appetites and, in some cases, feed dispersal without electricity. This review explores the evolution, technological advancements, and applications of these feeders with a survey of recent research. It looks at common feeder designs and compares the pros and cons of five automatic feeder configurations in commercial use today. The article contrasts feeders and feed sizes for farmed species in different life stages and facilities, from hatcheries to ponds and offshore cages. It discusses the importance of species-tailored feeding strategies as well as impacts on fish behavior and health, nutrient delivery, and environmental sustainability. Incorporating sensors and on-site computing enables optimization in feeding algorithms that feeders then implement precisely and reliably. The review compiles results from multiple studies comparing growth rate, weight, and feed conversion ratio (FCR) outcomes from automatic feeders and demand feeders versus traditional hand-feeding regimens. The integration of feeders with real-time monitoring and data analytics is also discussed, highlighting future directions for research and adoption across the industry.

Hop acids are known for their potent antimicrobial properties and may offer significant benefits in aquaculture. As hop acids are a prominent component of spent brewer's yeast, a major byproduct of the brewing industry, their utilization in fish feed holds potential for enhancing both the economic and environmental sustainability of aquaculture operations, provided they are not detrimental to the growth and quality of the product. A 56-day nutritional trial was conducted that incorporated hop acids (Humulone and Lupulone) into the diets of Nile tilapia, Oreochromis niloticus, and assessed their effects on rearing production, lysozyme activity, and final fillet LAB color & aroma. Four experimental diets containing between 0 and 1200 mg hop acids/kg feed were formulated for the nutritional study. Ninety-six tilapias were distributed equally among twelve ~2000 L tanks (eight fish/tank) and randomly assigned a treatment diet with 3 tanks per treatment (n = 3). Fish were weighed weekly and fed daily. After the trial, various production metrics, including weight gain, feed conversion ratio, viscerosomatic index, hepatosomatic index, condition factor, and fillet yield, were assessed. Additionally, lysozyme activity was assessed in isolated serum samples. Skinned and deboned fillets were assessed for LAB color, and a sensory panel evaluated the aroma of raw and baked fillets. The study revealed the inclusion of hop acids provided no significant differences in the production metrics, except for the viscerosomatic index. While not reflected in the FCR, weekly weight measurement found that the feed treatment of approximately 300 hop acids/kg of feed had slightly higher average fish weight per tank toward the end of the feed trial. There were minor differences in color, but no significant differences in aroma between treatment and control fillets. Incorporating hop acids into the diet, even at the highest inclusion level tested, did not result in any adverse effects on the fish. While these findings do not show significant benefits of hop acid addition, there were no detrimental effects, suggesting a promising avenue for utilizing brewing waste streams or isolated hop acids as an effective supplement in fish feed formulations.

Many government regulations have improved environmental and social quality of life in the United States, but others have resulted in negative consequences that exceed their benefits to society. This study estimated the total annual cost of regulatory compliance and lost revenue for US aquaculture. The total annual regulatory cost was $196 million (in 2023 USD), which accounted for 9%–30% of total annual costs, one of the top five costs of aquaculture production. Regulatory costs result in disproportionately greater per-unit costs of production on smaller-scale farms. Total annual lost revenue was $807 million (36% of total sales value), which resulted from lost sales and thwarted expansion opportunities from regulatory actions that either closed access to existing markets, forced reduced scales of production, or prevented attempts to expand production to meet existing demand for the farm's products. Accounting for multiplier effects, lost economic contributions were $1.4 billion annually, with >8000 jobs lost nationally from farms alone, not including associated supply chain partners. Well-designed regulations made use of best available science, participatory approaches to rule-making, sunset clauses for removal of outdated regulations, and market-based approaches. Pathways identified to improve regulatory efficiency included: (1) sunset clauses for each rule; (2) reward incentives (i.e., reduced testing frequency for farms with records of compliance) (3) standardized fish health testing requirements of sample size, farm-wide rather than lot testing, testing the most susceptible species/life stages; (4) non-lethal, multi-pathogen testing methods; (5) farm compensation for reverse externalities of avian predation; (6) appropriate risk management by experts to manage aquatic invasive species and pathogens; (7) training in aquaculture science, current farm practices, and appropriate, consistent, regulatory actions; (8) engagement with independent experts and producers throughout rule-making; (9) establishment of transparent appeals processes for farmers; (10) concurrent, not sequential review of permit requests by agencies; (11) long-term aquaculture literacy programs; and (12) an efficient, streamlined permitting and regulatory framework for mariculture.

Chondracanthus chamissoi is a red seaweed of socioeconomic importance due to its use for direct human consumption; therefore, its cultivation is key to optimizing the production of this species and avoiding the exploitation of natural beds. In this study, a new background bottom culture technology, that is, the tree-line system, was evaluated. For this, a total of 18 tree-line systems were installed; the systems contained two types of substrates, which were inoculated with fragments of C. chamissoi: Halyard (H40 = 40 g m⁻¹); Raffia40 (R40 = 40 g m⁻¹); and Rafia80 (R80 = 80 g m⁻¹). Biomass production was recorded under three different harvest frequencies (30, 60, and 90 days). In addition, the epiphyte load found in the cultures was quantified. The results showed that both the frequency of harvesting and the type of substrate affect the amount of biomass produced. Monthly harvest did not favor biomass accumulation and, on the contrary, increased the epiphyte load. On the other hand, the treatment that was harvested only at 90 days obtained the highest biomass for substrates R40 and R80 with 916.02 ± 171.93 and 1017.84 ± 122.68 g m⁻¹, respectively, and with a low epiphytic load. These results are unprecedented and represent a substantial increase in the biomass production of this species, considerably higher than the results obtained in previous studies from different regions using vegetative propagation. With these results, a potential final biomass production of an entire tree-line system greater than 18 kg using a bottom sea area of 4 m² could be harvested after 90 days of cultivation.

Sustainable mussel farming practices are critical for maintaining production and enhancing growth of the low trophic aquaculture sector. The concept of Integrated Multi-Trophic Aquaculture (IMTA) and incorporating mussels as extractive species, holds promise for enhancing overall system efficiency, nutrient cycling, and environmental sustainability. This review delves into innovative aquaculture techniques emphasizing the synergistic relationships between Mytilus galloprovincialis and other species such as seaweeds and deposit feeders that prioritize environmental stewardship by absorbing excess nutrients, processing organic waste, and including best management practices for waste mitigation. Marine spatial planning (MSP) through IMTA development can support optimal capacity building scenarios, incorporating ecosystem services and social benefits. This review explores the different aspects of mussel biology, ecology, aquaculture, sustainability, and future perspectives on the basis of literature data, with a context of capacity building in the Atlanto-Mediterranean area. The literature data were analyzed in order to explain interactions between primary species and mussels as extractive species. We developed conceptual models at three different scales—small, medium, and large—to define the optimal growth performance of mussels in relation to their distance from the aquaculture nutrient source. The consistent trend favoring medium-scale conditions has led us to conclude that mussels predominantly extract nutrients indirectly, primarily through the phytoplankton blooms resulting from fertilization. On this basis, we recommend that the marine spatial integration of mussels must be designed according to these models to optimize production while mitigating the side effects of fish cage aquaculture.

Metabolism plays a crucial role in the growth rate of species. Proteomics serves as a potent tool to explore these metabolic changes. Herein, we investigated the metabolic growth differences in Gymnocypris przewalskii (GP) and Gymnocypris ecklon (GE). After 9 months of culture, the growth rate of GP was slower than that of GE (p < 0.05), while there were no significant differences in survival rates (p > 0.05). To understand the metabolic changes underlying growth superiority, we conducted a proteomic analysis of GP and GE. The metabolic pathways mainly include glycolysis (gluconeogenesis), the pentose phosphate pathway, pyruvate metabolism, amino sugar and nucleotide sugar metabolism, oxidative phosphorylation, and protein digestion and absorption. The study also identified some differentially expressed proteins related to metabolism, such as creatine kinase, glutamate–cysteine ligase, 4-aminobutyrate aminotransferase, hexokinase, pyruvate kinase, L-lactate dehydrogenase, fumarate hydratase, carbonic anhydrase, and cytochrome oxidase. These findings are the first to reveal the molecular mechanism of GP and GE at the protein level. Notably, the expression of proteins related to metabolism may be a factor contributing to the slower growth of GP than GE. The study thus provides important information for genetic breeding and improvement of G. hybrid (GP and GE) for aquaculture production.

Beluga sturgeon (Huso huso) is a valuable fish all over the world to produce caviar and meat. It is a good candidate for aquaculture due to its acceptance of formulated diets and high resistance to stressors from increased density during farming. This study evaluated three groups of sexually unknown farm-raised Beluga sturgeon populations that differed by age to understand differences in growth rate, nutrient utilization and microbial community by gut sections. Weight, length, and liver samples were collected to determine growth parameters. Proximate compositional and histopathological analyses were conducted. Luminal samples from the stomach and midgut and hindgut sections were collected for 16S rRNA gene characterization. The results showed that fish weight differed by age group (p < 0.05). The condition factor ranged from 0.61 to 0.78 for all the age groups. Fillet fatty acid compositions showed that erucic acid (monounsaturated) was significantly different (p < 0.005) between the three age groups, but not for other fatty acids and amino acids. The gastrointestinal section was a stronger factor than age modulating the microbial compositions in beluga (p < 0.05), and their compositions and diversity varied between stomach, midgut, and hindgut sections. The abundance of Lactococcus and Lactobacillus genera increased in the hindgut section of the gastrointestinal tract and differed by age group. Proteobacteria correlated positively and significantly with the essential amino acids (p < 0.05). The genus Haloimpatients from phylum Firmicutes showed a positive correlation with phenylalanine and threonine in the Beluga stomach (p < 0.05). A similar trend was found between Staphylococcus and histidine in the hindgut. More studies should be directed to address the functionality of the microbiota highlighted in the gut sections in this study and their involvement in the metabolism of essential amino acids to improve the conditions and optimal nutrient requirements of farm-raised Beluga sturgeon.

Acidifiers serve as effective feed additives that enhance fish growth and welfare. This study investigates the effects of a mixture of lactic acid, citric acid, and potassium sorbate (denoted as OA, in a 1:1:1 ratio) on common carp (Cyprinus carpio) for the first time. A total of 240 fish, each weighing approximately 18.5 grams, were randomly assigned to four treatment groups, each consisting of four replicates containing 15 fish. The fish were fed diets supplemented with varying levels of OA: 0 g/kg (Control), 2.5 g/kg (A-2.5), 5 g/kg (A-5), and 10 g/kg (A-10) for a duration of 56 days. Growth performance, calcium and phosphorus levels in vertebrae and muscle, intestinal antioxidant status, bacterial populations, gene expressions, as well as immunological parameters in skin mucus and blood plasma were analyzed at the end of the experiment. The results indicated a significant (p < 0.0001) increase in the abundance of Lactobacillus sp. in the OA-treated groups compared to the Control group. Conversely, the intestinal populations of Vibrio sp. (p < 0.0001) and Aeromonas sp. (p = 0.010) significantly decreased in the OA-treated groups, particularly in the A-10 treatment. Moreover, significant (p < 0.0001) up-regulations were observed in the expression of intestinal tumor necrosis factor-alpha (tnf-a), interleukin-1 beta (il-1b), heat shock protein 70 (hsp70), and mucin-2 (muc-2) across all OA-treated groups when compared to the Control group. All OA-treated groups, especially the A-5 treatment, exhibited significant (p < 0.0001) increases in the expression of intestinal lysozyme (lys), mucin-5 (muc-5), and beta-defensin (b-def) relative to the Control group. Furthermore, intestinal levels of reduced glutathione (GSH) significantly increased (p = 0.0003), while malondialdehyde (MDA) levels decreased (p = 0.002) in all OA-treated groups, particularly in the A-5 treatment. Notably, plasma lysozyme (p = 0.002), alternative complement (AC; p = 0.022), skin mucus protease (p = 0.011), lysozyme (p = 0.002), and alkaline phosphatase (ALP; p = 0.001) showed significant increases in the A-5 and/or A-10 treatments compared to the Control group. Dietary supplementation with OA significantly enhanced muscle and vertebral ash, phosphorus, and calcium levels, particularly in the A-5 treatment. Additionally, growth performance and feed efficiency significantly improved in the A-5 treatment when compared to the Control group. In conclusion, dietary supplementation with 5 g/kg of OA proved beneficial for common carp by enhancing intestinal health, humoral and mucosal immune responses, calcium and phosphorus retention, as well as overall growth performance.

Seedstring cultivation is a fundamental method for Pyropia yezoensis aquaculture, as it provides an artificial substrate for the attachment of P. yezoensis spores and growth of gametophytes. This method has been widely used in the P. yezoensis aquaculture all over the world because of its convenience for seaweed management and harvest. However, the composition and types of seedstrings vary in different countries. Little is known about the effect of different seedstrings in terms of spore attachment and early development of gametophytes in P. yezoensis. In this study, four types of commercially available seedstrings from Korea (KR), China (CN), and Japan (JP1 and 2) and three new seedstring types developed by W.L. Gore & Associates, Inc. (Gore A, B, and C) were compared in terms of seeding density, growth rate, and biomass yield. Our results show that the Gore C seedstring had the highest seeding density and yield among all seedstrings. The Gore B had the lowest seeding density and yield. The Gore A and B seedstrings had the highest growth rate at early stages in development. The CN and KR seedstring showed lower growth rates than the other seedstring types. A comprehensive evaluation shows that the Gore C seedstring type had the best performance among all seven seedstrings under laboratory conditions. Future studies are needed to test the performance of the seedstrings on Pyropia farms.

Climate change has driven global temperature increases, resulting in severe heat waves, altered precipitation patterns, and extreme weather events. In April 2024, a massive die-off of hybrid catfish larvae and fry occurred in Thai aquaculture farms, coinciding with elevated temperatures of air (37–41°C) and freshwater (30–32°C). This study aimed to investigate the correlation between elevated temperatures and abnormal embryonic development in hybrid catfish. Controlled mating of male North African catfish (Clarias gariepinus) and female bighead catfish (Clarias macrocephalus) was conducted in May and June 2024. We examined the effects of water temperature changes in hybrid catfish, focusing on fertilization, hatching, yolk sac absorption, and mouth morphology, while keeping the conditions of water quality, feeding, and disease management constant. The fertilization rate was 67.7% at 29°C, whereas it significantly decreased to 59.0% at 32°C. The hatching rate decreased from 43.4% at 29°C to 26.6% at 32°C. Survival rates plummeted, with no larvae surviving beyond 72 h post-hatching (hph) at 32°C. Yolk sac absorption was notably accelerated at 32°C, being completely absorbed by 48 hph. Mouth morphometry revealed that a gap in the mouth started to develop 12 hph, and the opening size of the mouth increased out to 72 h. These findings indicate that higher temperatures (32°C) lead to faster yolk absorption, causing embryos to deplete yolk reserves rapidly, potentially before full development and independent feeding. This results in a smaller body size and lower survival rates. Present study provides crucial insights for enhancing breeding practices and creating management protocols for hybrid catfish hatcheries during the period season of high temperature in the context of climate change.