INTRODUCTION 
Fishes are large and conspicuous members of marine communities. They 
have important commercial and recreational value, and their abundance can 
fluctuate widely in response to environmental variability or heavy exploitation. 
Fluctuations in abundance of fishes usually are caused by large annual 
differences in recruitment, which are related to mortality experienced by a 
cohort during the larval stage (28, 29). It has been difficult to evaluate 
potential factors that could affect recruitment in studies carried out on natural 
populations at sea because of the problem in estimating egg or larval 
abundances over extensive ocean areas, and because of an unpredictable 
environment whose effects cannot be controlled. During the past 15 years a 
capability has been developed by several laboratories to routinely culture 
marine fish larvae beyond embryonic and yolk-sac stages to the juvenile stage. 
Experiments on these laboratory cultured species has resulted in significant 
advances in our understanding of how environmental factors affect survival and 
growth of larvae. 
Several papers recently have reviewed aspects of marine fish larvae culture 
(42, 50, 64, 65, 67). Although May’s (67) evaluation of the critical period 
hypothesis, and Iwai’s (50) review of feeding by fish larvae, included 
discussions of both laboratory and field-oriented studies, they did not 
specifically make conclusions about larval requirements based on experimental 
research. Blaxter’s (14) general review of egg and larval development of fishes 
did summarize results of laboratory studies. We review some important results 
of recent experimental research on marine fish larvae and make conclusions 
about effects of environmental factors based on laboratory studies. Emphasis is 
on studies of species that have typical, pelagic larvae and includes the period 
from initiation of feeding until transformation to juvenile. Research on embryo 
and yolk-sac stages, aquaculture-oriented studies, and work on non-pelagic or 
non-typical larvae are not emphasized, although important contributions have 
been made in recent years. 
Two major areas of research are reviewed and discussed. These are 1) the 
role of the food supply, the ability to feed, and the effects of predators; and 2) 
the role of physical and chemical variables, other than those due to man’s 
impact on the environment. In addition, new techniques that hold promise for 
advancing environmental research on fish larvae are outlined and discussed. 
FOOD REQUIREMENTS 
The most important advance in larval culture technology during the past 1 5 
years has been the determination of kinds and concentrations of living prey 
that give predictable survival and growth rates. The ability to undertake 
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