Journal of The World Aquaculture Society最新文献

Feed conversion efficiency (FCE) is an important determinant of profitability in catfish production. Understanding factors affecting FCE at a physiological level could lead to improvement of FCE at production scale. The effect of sex, family, and size grading within family on juvenile channel catfish (Ictalurus punctatus) growth, feed consumption, feed conversion, visceral fat accumulation, and weight loss during feed deprivation was determined. In Trial 1, fingerlings from five channel catfish families were graded by weight into small, large, and random mixed-size groups, fed for 8 weeks, subjected to 2 weeks of feed deprivation, and then euthanized to determine sex. Family had a significant effect on fish growth, feed consumption, FCE, and percent weight loss during feed deprivation. Large fish had faster growth, better FCE, and lower percent weight gain than small fish from the same family. Mixed-sized fish were generally intermediate for all measured traits. In Trial 2, all-male, all-female, and mixed-sex groups of channel catfish fingerlings were subjected to the same feeding regime and then euthanized to confirm sex and weigh visceral fat. Males had a higher percent weight gain, better feed conversion, and less visceral fat than females; mixed-sex fish were generally intermediate between all-male and all-female groups. FCE was positively correlated with visceral fat percentage in the all-female treatment (i.e., fatter fish had poor feed conversion), but not in the all-male treatment. Feed conversion and weight loss during feed deprivation were generally not correlated in either trial. This is the first report that male channel catfish convert feed more efficiently than females. Future studies should investigate the relationship between fat and feed conversion in channel catfish.

Creatures grown on the island are more susceptible to genetic vulnerabilities because of their isolated nature and often limited genetic diversity. Understanding the genetic structure of these populations is crucial for effective conservation strategies, especially for the species that are commonly found in aquaculture and may inhabit islands. Bufo gargarizans and Pelophylax nigromaculatus were distributed in the Chongming Islands of Shanghai, China. We analyzed mitochondrial DNA cytochrome b (cytb) and D-loop sequences of the populations of the two species across three Chongming islands to investigate genetic diversity, phylogenetics, and infer historical demography, which indicated a lower genetic diversity in island populations compared with their mainland counterparts, reflecting a heightened vulnerability to environmental perturbations and potential extinction risks. Noticeably, a more interlaced genetic pattern was determined in P. nigromaculatus than in B. gargarizans, which was probably attributed to the differences in species' dispersal capabilities among the populations of islands and the mainland. Hence, the genetic analyses propose targeted recommendations for in situ conservation and aquaculture management.

The aquaculture industry plays a crucial role in global food production and is expected to expand in response to the increasing demand for aquatic products. To sustain this growth, aquaculturists must develop new strategies and improve existing practices to address various challenges. In Africa, the sustainable development of aquaculture could be achieved not only by intensifying and integrating breeding techniques for species like Tilapia and Catfish but also by developing and domesticating other promising species with high aquaculture potential. Identifying and understanding these species is vital for overcoming these challenges. Heterotis niloticus is one such valuable species for aquaculture in Africa, offering several advantages including its air-breathing capability, high market value, excellent meat quality, omnivorous diet, resilience to stress, ability to survive in low-oxygen water, and consumer acceptance. In captivity, it has shown significant growth, with individual mean body mass reaching 3 to 5 kg in 12 months. These findings highlight the potential of Heterotis niloticus to enhance aquaculture production, not only in Africa but also globally. However, challenges remain, such as high mortality during early life stages, the determination of its nutritional needs at various ontogenetic stages, and the development of efficient breeding practices. Further research is required in areas like nutrition, physiology, breeding technology, genetics, economics, and environmental impact to optimize the culture of this species.

This study investigates the efficacy of acid-insoluble ash (AIA) as an endogenous digestibility marker in commercial aquaculture ingredients and feeds. AIA is a naturally occurring, low-cost alternative to external markers such as chromic oxide and yttrium oxide. External markers are often impractical in the production of small batches of feed manufactured under commercial settings due to cost and logistical constraints. This manuscript is the first of its kind to quantify the AIA content of 18 commercial aquaculture feeds and 27 commercial ingredients from diverse origins, as well as the recuperation rate of pure AIA. Samples were acquired from various national and international sources based on currently available stock; all samples were analyzed in quadruplets for statistical analysis. Results indicated significant variation in AIA levels across different ingredient categories (p < 0.05), with marine-based meals and rendered animal meals exhibiting the highest AIA concentrations (up to 25.8% and 5.0%, respectively), while vegetable meals displayed the lowest AIA content (up to 0.2%). Shrimp and crab meals had particularly high AIA levels due to their mineral-rich exoskeletons (4.7% and 25.8%, respectively), and meals that had undergone certain commercial processing to increase the meal quality had lower AIA content than their regular counterparts (avian: 2.9% for high quality and 4.4% for regular quality; meat: 0.13% for high quality and 0.8% for regular quality). Additionally, a limit of quantification (LOQ) was determined to define the confidence range of the utilized AIA protocol. This study highlights the importance of considering diet composition and ingredient origin in diet formulation to ensure consistent nutritional outcomes. Furthermore, we demonstrate that a wide range of commercial diets contain a quantifiable amount of AIA. The findings suggest that AIA can serve as a reliable and cost-effective marker for in-vivo digestibility studies, aiding feed manufacturers and farm managers in optimizing production performance by rapidly assessing feed quality.

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.