that a continual change in chemistry occurred until the larvae became 

 moribund. 



In a similar study Anraku and Azeta (6) compared cultured and wild larvae 

 and juveniles of the sea bream Chrysophrys major. They did not examine larvae 

 less than 10 mm length, but for large specimens the cultured individuals tended 

 to have a lower percentage of water, higher percentages of carbon and 

 hydrogen, and a percentage nitrogen that did not differ from wild specimens 

 until 20 mm length, when percentage nitrogen decreased in cultured 

 individuals. Differences in food of cultured and wild specimens were the 

 probable cause of differences in body chemistry. Starved individuals of sea 

 bream showed effects similar to those for herring and plaice — i.e. increased 

 percentage water and decreased percentages of carbon, nitrogen and hydrogen. 



Histological changes in laboratory -reared larvae are indicative of starvation. 

 Recent studies indicate that these criteria could be used to recognize starving 

 or poorly nourished larvae in the sea. Umeda and Ochiai (96) examined fed and 

 starved yellowtail Seriola quinqueradiata larvae, EhrHch et al (34) examined 

 herring and plaice larvae, and O'Connell (72) examined northern anchovy 

 larvae. In all of these studies there were some similar findings. Intestinal 

 epithelial cells atrophied in starving larvae and the intestine degenerated. The 

 liver also degenerated in yellowtail, plaice and northern anchovy. O'Connell 

 (72) and Umeda and Ochiai (96) examined the pancreas and found that its 

 condition was markedly deteriorated in starved anchovy and yellowtail larvae. 

 O'Connell (72) examined several other histological characters and found that 

 starved anchovy larvae also had separations of muscular fibers and little 

 intermuscular tissue, as well as notochord shrinkage. Using a discriminant 

 function analysis he was able to discriminate 90 percent of starving larvae from 

 fed larvae when four or more good histological characters were used. Ehrlich et 

 al (34) found that there were good morphological characters associated with 

 the histological changes, especially in herring larvae where severe head 

 shrinkage and gut shrinkage caused a decrease in the "pectoral angle", and an 

 increase in the eye height to head height ratio. Histological criteria as indicators 

 of impending starvation seem excellent. They are relatively time consuming 

 compared to morphometric analyses, but perhaps are more effective to 

 distinguish starvation effects. 



The concentration of prey affects larval behavior. Wyatt (100) 

 demonstrated that duration of plaice larvae activity (searching behavior) was 

 inversely related to prey concentration, and that starving larvae increased their 

 time spent searching for food. This behavior presumably is adaptive and 

 increases the probabiUty of encountering prey when it is scarce. Using vertical 

 migration as an index of activity, Blaxter and Ehrlich (20) found that fewer 

 herring and plaice larvae vertically migrated after periods of starvation, and 



186 



