Highly specialized development of the digestive system in piscivorous scombrid larvae

Abstract

Scombrid fish generally display a unique early development characterized by large head, fast growth, and early piscivory. Development of the digestive system, which is a crucial element for feeding and growth, was examined using laboratory-reared larvae of 5 scombrid species: Japanese Spanish mackerel Scomberomorus niphonius, striped bonito Sarda orientalis, bluefin tuna Thunnus thynnus, yellowfin tuna T. albacares, and chub mackerel Scomber japonicus. Compared with common marine fish larvae, the digestive system appeared to develop precociously in all the scombrid larvae examined, but, the timing varied with the species. Differentiation of the juvenile-type digestive system corresponded to the appearance of piscivory and acceleration of growth rate. © 2002, The Japanese Society of Fisheries Science. All rights reserved.