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The freshwater prawns of the genus Macrobrachium Spence Bate, 1868, hold major potential for sustainable aquaculture intensification and diversification. Beyond the dominant giant river prawn M. rosenbergii (De Man, 1879), successful larviculture and domestication of additional species could boost production. However, inconsistent hatchery results have hampered the wider application and commercialization of cultivation protocols. This comprehensive review aims to analyse past larviculture research efforts to advance Macrobrachium farming practices. Several published studies documenting larviculture experiments on various Macrobrachium taxa are examined. Larval developmental patterns, optimal rearing salinity and temperature ranges, stocking densities, feeding regimes, and reported survival rates are compared within and among species. Significant inter- and intraspecific variability is apparent, highlighting the need for species-specific approaches. Past studies have applied generalized techniques derived from M. rosenbergii with varying success, further motivating the analytical review of findings. Key bottlenecks impeding consistent hatchery seed production are identified. In particular, knowledge gaps regarding larval nutritional needs, biofouling prevention, and weaning method optimization present ongoing challenges. By reconciling contradictory results and emphasizing biological nuances, this review distinguishes priorities for strengthening protocol development. Priorities include standardizing assessments, disseminating optimized techniques tailored to particular target species, and outlining future research directions. With reliable hatchery production, additional Macrobrachium species could be incorporated into polyculture or mono-crop systems, supporting livelihood diversification and sustainable intensification of aquaculture. [ABSTRACT FROM AUTHOR]

The goal of this study was to test a commercial scale larval rearing tank with a self-cleaning mechanism to improve larval rearing success for marine fish. Four trials were conducted to compare the performance of a self-cleaning tank (SCT) to a control (CON) larval rearing tank. Two trials were conducted using California yellowtail (CYT; Seriola dorsalis) and two were conducted using white seabass (WSB; Atractoscion nobilis). Metrics collected for each trial included, larval growth, survival, bacterial colony counts (Vibrio spp.), total suspended solids concentrations, and labor (time spent siphoning the tanks). There were no differences in growth between tanks for either species. CYT survival in Trial 1 resulted in better survival in the CON tank (56.8%) than in the SCT (32.8%). WSB survival in both Trial 1 and 2 was higher in the SCT than in the CON tank (35.5% versus 26.9% and 15.8% versus 10.1%, respectively). We suspected that the cleaning arm was likely causing early mortality in both species (between 0 and 16 days post hatch; dph), therefore, Trial 2 involved only cycling the arm twice per day for one hour until the larvae were 16 dph. This modification yielded improved survival in the SCT (60.5%) than CON tank (47.1) but only for the CYT. Total suspended solids were higher in the CON tank for both species (up to 8.0 mg/L). Bacteriology results showed higher CFU counts for CYT in the CON tanks from 8 to 24 dph, and at 24 dph counts were higher in SCT. CFU counts were higher for WSB in the CON tank at 9 and 13 dph but otherwise there were no differences over time. Perhaps most notable was that the SCT tanks yielded a fourfold reduction in labor when compared to CON tanks due to more efficient siphoning.

This study aims to estimate the welfare gains of the Philippine milkfish industry in establishing local fry hatcheries to reduce imports from Indonesia and Taiwan. It also seeks to identify the industry stakeholders who gain from this import substitution endeavour. The economic surplus model was used to estimate the welfare gains from the commercialization of the hatchery-bred milkfish fry in the fishery sector. Specifically, the changes in consumer and/or producer surplus per stakeholder were compared to determine who the biggest gainers are. Results of the study showed that the consumer surplus from the milkfish fry industry was larger than its producer surplus. On the other hand, the reverse was true for the grow-out industry. It is interesting to note that the consumers in the fry industry and the producer in the grow-out industry were the same set of stakeholders, i.e., the milkfish grow-out operators, who gained the most from this development. The study also showed that commercializing the local milkfish hatchery technologies can bring about more benefits to the country than importing fry and fingerlings. Hence, the development of local hatcheries for other aquaculture species can be expected to bring similar welfare gains. More importantly, the technical and financial assistance that were extended by the government’s fishery institutions through the GAINEX project as pioneered by DOST-PCAARRD can serve as an effective catalyst to prospective hatchery operators in reducing the risks, especially when setting-up a new enterprise like the hatchery-bred fry for an emerging aquaculture species in the country.

The European seabass/seabream industry presently is at the maturation phase in its evolution as an industry. Profit margins have been strongly compressed, and ex-farm prices in Greece have decreased, from 14 Euro/kg in 1989 to 4.56 Euro/kg in 2000. New aquaculture strategies have been applied, targeting the economies of scale, the diversification of farmed species, and the improvement of the quality of the farmed species. The production levels may increase up to 20% in the next decade, while the production cost has to decrease more than 5% per year. This will occur with better management of the living resources, as well as with continuous improvement of feed technology and better husbandry. [ABSTRACT FROM AUTHOR]