Biotechnological advances in finfish hatchery production: a review

Abstract

It has been estimated that about 80 billion juveniles were required for the 1998 production level of 20 million metric tonnes of finfish. Increasing demand for aquaculture products has prompted researchers to produce more and better quality juveniles. This paper reviews recent relevant literature and mainly summarizes information from a workshop held in Hawaii in December 1999 to review the status of fry production and discuss current technical advances in live and inert feed production. Although hatchery technology follows similar protocols worldwide, modifications are made to meet specific needs. Feeding regimes and culture systems are modified to improve fish survival and lower production costs. Selecting appropriate feed, maintaining strict hygienic conditions versus manipulating natural conditions, and choosing a suitable water exchange system are good examples. Rotifers ( Brachionus spp.) and brine shrimp ( Artemia spp.) nauplii are the main live food items for early life stages of the major finfish species, with inert feed provided at a later stage. Superintensive rotifer culture (up to 190,000 individuals/ml) using algal paste has been studied to improve cost-effectiveness of hatchery production. While Artemia has potential use as an efficient delivery system for antibiotics, great variation in its nutritional content from different sources, the need for further studies on nutritional requirements of larvae, and decreasing supplies due to increased demand are important factors in calculating cost-effectiveness of this form of live feed. Studies on live feed production should continue, but reduced demand for live feed was recommended. In studies on larval digestive enzymes in fish and inert feed formulations, formulated feed has the potential to replace live feed earlier in the life cycle than is common in current practice. Formulated feeds used as a delivery system for substances such as hormones and vaccines would be an asset to hatcheries. Greater understanding of the roles of microbial processes in culture systems is expected to lead to major breakthroughs in hatchery production. Management of the microbial community may positively affect live feed production, larviculture, and inert feed application. Understanding changes in the microbial community in response to feed could result in dual benefits of lowering feed costs and preventing spread of diseases. Further research was recommended. Finally, there was general agreement expressed that information exchange among researchers and the aquaculture industry is essential for effective research efforts and application of these results to production.