Biotechnological
advances in finfish hatchery production: a review
Cheng-Sheng Lee
Aquaculture, 227(1-4): 439-458
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.
(The Oceanic Institute, 41-202 Kalanianaole Hwy.,
Waimanalo, HI 96795 1820, USA, e-mail: cslee@oceanicinstitute.org)