Journal of The World Aquaculture Society最新文献

This article aims to shed light on the recent sustainable transformation dynamics of the Norwegian aquaculture industry. Drawing on perspectives from the socio-technical transition studies this article investigates how this process has been shaped by a specific policy instrument known as development licenses (DL) launched in 2015. The article captures the DL as a transformative innovation policy instrument and shows how this has played a key role in steering the directionality of the technological innovations in the sector to instigate the sustainable transformation process of the industry. The article reveals that the DL has prompted the emergence of new challenged-oriented innovation systems through reorientation and reconfiguration processes. These processes specifically involved both the mobilization of actor-networks in the industry, including a functional reorientation by the key regulatory organ—the Directorate of Fisheries—and harnessing locally available pre-existing knowledge and skills—particularly in the Petro-maritime industry. The licensing scheme means that the industry is currently in the process of transition to becoming a sector based on multiple aquaculture production technologies. However, we suggest that addressing the long-term sustainable transformation imperatives of the sector will largely depend upon the ability to identify and support further development of promising niche aquaculture technologies.

Multiple-batch production is the most common farming strategy for raising channel catfish. Increased adoption of intensified alternative production practices has changed the cost structure of many catfish production practices including multiple-batch systems. Production efficiency in multiple-batch production can be enhanced by providing optimal stocking recommendations for fingerlings and carryover fish. Twelve 0.4-ha ponds were understocked with 20,782 channel catfish fingerlings (mean weight = 30 g/fish) at three different carryover biomass rates (3440; 4580; and 5702 kg/ha). Fish were fed once daily to apparent satiation with a 28% protein floating feed, and ponds were aerated with a 7.4-kW electric paddlewheel aerator. Gross, net, daily net yields, sub-marketable yields (<0.54 kg), growth (g/day), and survival were statistically similar among the three treatments, but yield of marketable fish yield (fish ≥0.54 kg) increased significantly with increased carryover biomass. The cost of production was reduced while net returns increased with increased carryover biomass. The lowest carryover biomass treatment (3440 kg/ha) had negative cash flow and net returns when sub-marketable fish were not assigned value. However, all three carryover biomass treatments attained positive annual net cash flows and net returns when sub-marketable fish were valued as revenue, the two higher carryover biomass treatments (4580 and 5702 kg/ha) outperformed the low carryover biomass treatment (3440 kg/ha). This study indicates channel catfish carryover biomass rates should be between 4580 and 5702 kg/ha to improve cost efficiency in intensively aerated, multiple-batch production systems.

Compared with common abalone, the orange-muscle abalone (Haliotis gigantea) has an enhanced ability to accumulate carotenoids. Feeding on asparagus (Gracilaria lemaneiformis) was critical for maintaining carotenoid contents in H. gigantea muscles. However, whether intestinal microbes play the role in carotenoid accumulation in different colored abalone, and the effects of different diets on intestinal microbes in abalone are unknown. In the study, the differences in intestinal microbiota between abalone with different colors and the effects of different diets on the intestinal microbiota of the abalone were analyzed. The results showed that (1) there was no significant difference in intestinal microbial community composition between the orange-muscle abalone and the common abalone, and (2) the intestinal microbial community composition of abalone fed on asparagus was significantly different from that of abalone fed on kelp (Laminaria japonica). At the genus level, the relative abundance of Psychrilyobacter in the intestinal tract of abalone fed with asparagus was significantly higher than that of kelp-fed groups. Stenotrophomonas and Vibrio were the dominant bacteria at the genus level in abalone fed with the kelp. This result excluded the role of intestinal microbes in different colored abalone and provided clues for further study of the coloration mechanism of abalone.

The early life stages of fish are critical for determining the overall productivity and sustainability of aquaculture operations. This study investigated the effects of dietary autolyzed brewer's yeast (ABY) on the growth performance and intestinal health of Nile tilapia fry (Oreochromis niloticus). A 35-day feeding trial with 480 Nile tilapia fry across 12 experimental tanks tested the effects of diets supplemented with 1, 2, and 4 g/kg of ABY, with a control diet for comparison. The results indicated that the diet which had 1 g/kg ABY supplementation (ABY1) significantly enhanced the weight gain and specific growth rate (SGR) while reducing feed conversion ratio (FCR) compared to the control diet. Intestinal gene expression analysis showed significant upregulation of immunoregulatory genes (tlr2, il10, il1β, and igm), and a tight junction gene (occludin) in the ABY1 group. Conversely, tnfα expression was significantly downregulated in the ABY1 and ABY2 groups, indicating a potential anti-inflammatory effect. Histological analysis of the mid-intestine revealed healthy morphology with no significant differences in mucosal fold length, muscularis thickness, lamina propria width, and goblet cell count among the treatment groups. The findings demonstrate that supplementing diets with ABY at 1 g/kg level enhances growth performance and modulates the intestinal immune response of Nile tilapia fry, without compromising intestinal integrity. This study offers valuable insights into using ABY as a functional feed additive to enhance Nile tilapia health and development, as well as to promote aquaculture sustainability.

Despite catfish being the dominant freshwater aquaculture product in the United States, catfish texture and sensory evaluation are understudied compared with other aquaculture species, and very few studies have been conducted to evaluate these traits in catfish. Texture, sensory, carcass yield, flavor, visceral fat deposition, gonadal development, and fillet color analyses were conducted on four size classes, small (<0.68 kg), medium (0.68–0.92 kg), large (0.93–1.75 kg), and extra-large (>1.75 kg), for channel catfish (n = 456) (Ictalurus punctatus), blue catfish (n = 78) (I. furcatus), and hybrid catfish (n = 195) (channel catfish ♀ × blue catfish ♂). Within genetic type comparisons indicated that the texture traits, hardness, and chewiness and the sensory trait toughness increased with increasing size in hybrid catfish and channel catfish but were the most pronounced in channel catfish. Overall, channel catfish had the firmest fillets based on several attributes. Blue catfish were found to have differences among texture traits between the extra-large size class and the three remaining size classes, but overall size had less of an effect compared with the channel catfish and hybrid catfish. A trend of paternal predominance was observed as the hybrid catfish was more similar to the blue catfish than the channel catfish. Hybrid catfish had the highest fillet percentage. This study is the first large-scale analysis of texture and sensory traits within two catfish species and their interspecific hybrid at different sizes and highlights the differences in commercially important texture and sensory traits.

Polyphenol-rich sugarcane extract (PRSE) is a product of sugarcane obtained from the sugar refinery industry and can potentially be used as a feed additive in farmed animals. The purposes of the current study were to evaluate the effects of PRSE on growth performance, survival, immune responses, and resistance to Vibrio parahaemolyticus and white spot syndrome virus (WSSV) infections of Pacific white shrimp, (Litopenaeus vannamei). In Experiment 1, the postlarvae were randomly divided into five groups (8 replicates/group and 80 shrimp/tank) and fed commercial feeds supplemented with PRSE at the rate of 0 (control), 0.2, 0.4, 0.6, and 0.8% of the diets four times/day for 60 days to evaluate the body weight, survival rate, and immune function. In Experiment 2, the juvenile shrimp from Experiment 1 were randomly redistributed into six groups (four treatment groups as in Experiment 1, positive control, and negative control with 3 replicates/group and 30 shrimp/tank) and challenged with either V. parahaemolyticus or WSSV via immersion (10⁵ colony-forming units/mL) and oral (feeding with infected tissues) routes, respectively, to evaluate disease resistance. Our results demonstrated that shrimp body weight for the 0.8% PRSE group was significantly greater than the other groups, and those fed 0.4%–0.8% PRSE demonstrated a significant improvement in survival, total hemocyte count, phagocytic activity, phenoloxidase activity, and superoxide dismutase activity compared with the controls. On day 7 following the V. parahaemolyticus challenges, the survival rates of the 0.4%–0.8% PRSE-fed shrimp (70%–73%) were significantly greater than the control counterpart (46%). However, shrimp challenged with WSSV suffered severe mortality regardless of the treatment groups, but those treated with 0.4%–0.8% PRSE showed delayed mortality. In conclusion, results suggested that dietary PRSE supplemented at 0.4%–0.8% diets were beneficial for improving overall health and disease resistance in shrimp culture.

An aquaponic system which is an integration of hydroponics with aquaculture is sustainable, ecologically friendly, and uses non-renewable resources with very high efficacy. The increasing trend in aquaponics research demonstrates a growing recognition of its potential to address critical global issues such as food security, water conservation, and sustainable agriculture, particularly in regions vulnerable to climate change and resource limitations. It has witnessed remarkable advancements in recent years, with various methods and variations emerging to enhance its functionality and productivity. The purpose of this review is to unify fragmented research on aquaponics and provide a comprehensive resource that emphasizes its potential for broad adoption and successful implementation in varied environments. This review focuses on recent innovations in aquaponic system designs for various climates and examines key advancements in critical areas, including microbial communities, biofiltration, feed management, water quality, and nutrient cycling, emphasizing the interdisciplinary nature of aquaponics. Coupled systems suit moderate climates with high resource efficiency, while decoupled systems offer flexibility across diverse climates by allowing independent control of each component. Innovations such as sandponics, algaeponics, and saline aquaponics address challenges like water scarcity and nutrient efficiency. Smart technologies like IoT and AI are integrated into aquaponics, automating monitoring and nutrient management for better productivity. Emerging areas, including vermi-aquaponics and flocponics, offer new solutions for nutrient cycling, making aquaponics more efficient, adaptable, and resource-conserving globally. This paper also examines the sustainability aspects of aquaponics, emphasizing its economic, social, and environmental dimensions. Despite high setup costs and nutrient complexities, aquaponics offers significant potential for sustainable food production by minimizing water use and reducing synthetic fertilizers. Its scalability in both urban and rural areas, along with innovations like vertical systems, presents promising solutions for enhancing agriculture and food security across diverse environments.

Aquaculture generates less greenhouse gas emissions compared to other agriculture practices due to its limited land-use changes, improved feed conversion rates, and reduced methane emissions from animals' digestive systems. The aquaculture carbon emissions come from various production stages, including feed production, farm operations, processing, transportation, and so forth. This review illustrates the theories, calculation methods, and practical applications of the carbon footprint in fisheries and aquaculture, as well as the challenges and strategies for emission reduction. The factors influencing the carbon footprint of fishing and manufacturing aquaculture are also discussed. Further research should focus on refining carbon footprint assessment techniques, promoting green technologies and sustainable aquaculture practices. Managing aquaculture's carbon footprint though is crucial for mitigating environmental impacts and supporting sustainable development.

Feed formulations low in fish meal and fish oil can decrease feed intake and nutrient digestibility. Dietary application of lecithins could improve growth performance and nutrient digestibility; however, knowledge about specific lecithins and their effects in post-juvenile fish is lacking. This study evaluated the effects of a commercially available rapeseed lecithin mixture on growth performance, feed intake, and nutrient digestibility of post-juvenile rainbow trout (77.1 ± 12.1 g). A commercially based diet low in fish meal served as the control, while in the remaining three diets, fish oil was replaced with lecithin by 50%, 100% with lecithin, or 100% with a mixture of equal amounts of lecithin and rapeseed oil. Fish were fed to apparent satiation twice per day for 56 days. At the end of the trial, growth parameters, health parameters, nutrient digestibility, and filet coloration were assessed. Overall growth and feed intake were significantly elevated in all lecithin diets compared with the control group. The nutrient digestibility of all diets containing lecithin was similar to the control, and no differences in health parameters were detected. Filet coloration was significantly improved in diets of 100% fish oil replacement. Rapeseed lecithin can act as a feed attractant in fish meal and fish oil-reduced diets.

Crab stocking densities in brackish water ponds can influence crab growth rate, survival, and production volume. This study aimed to determine the optimum grow-out stocking density for Scylla tranquebarica crablets reared in lined ponds to supply the soft-shell crab industry. Three stocking density treatments (1, 4, and 8 ind./m²) were applied to crablets reared in lined ponds for 90 days. The crablets were fed low-value fish (Leiognathus equula) at an initial rate of 100% of total body weight for two weeks, reduced to 3% toward the end of the study. Crablets stocked at 1 and 4 ind./m² had a significantly (p < 0.05) higher net growth (NG) and daily growth rate (DGR) than crablets stocked at 8 ind./m². Deformed crabs were also most common at the highest stocking density. The intermediate stocking rate achieved moderate survival and feed conversion rates, with the highest crab production volume (19.65 ± 0.10 kg/100 m²) and net income (6845.60 US$/Ha/2 crops/year). Based on these findings, a stocking rate of around 4 ind./m² is recommended for the grow-out of S. tranquebarica crablets in lined ponds.