© 1981 by The Society for Integrative and Comparative Biology
Development of Organ Systems in the Northern Anchovy, Engraulis mordax, and Other Teleosts1
National Oceanic and Atmospheric Administration, National Marine Fisheries Service Southwest Fisheries Center, La Jolla, California 92038
SYNOPSIS. Certain aspects of development that are indicative of changing functional and ecological capabilities are reviewed for six different organ systems in the northern anchovy, Engraulis mordax, and other teleosts. The six organ systems are the integument, the lateral line system, the eye, the digestive tract, the gas bladder, and the trunk musculature. The integument develops gradually but also has transient specialized cells during the larval period. The lateral line system is functional at hatching and then elaborates by recruitment proportional to growth during the larval period. The eyes are capable of photopic binocular vision when feeding starts, and later gradually develop a scotopic system. The digestive tract develops a capacity for protein digestion and filtering during the mid and late larval period. The gas bladder gradually develops an expansion capability by muscle differentiation after initial inflation. The trunk musculature differentiates and recruits two fiber types that gradually supercede the embryonic musculature during the larval period. Thus much of the development of organs in the anchovy after hatching or after feeding starts can be characterized as initial differentiation and then continued recruitment of specialized cell arrays. Behavior patterns appear to develop in conjunction with such recruitments. This may apply to fishes generally, but pattern and tempo of development must differ among species. Brief comparison of the anchovy and the Pacific mackerel, which has a more rapid and direct development, suggests that some of the differences in the two types of larvae relate to the marked difference in feeding modes of the adult stages.