Reproduction and Death in Invertebrates and Fishes

Abstract

IN NATURE some time ago (115, 155; 1925) Dr. Bidder raised again the interesting fundamental question of the cause of normal death in aquatic animals, and stated that so far as he knew there was no evidence of any marine animals dying a natural death, except those whose life is ended by the winter or the summer. Later, the same writer, after reviewing earlier discussions (Proc. Linn. Soc., 1925, p. 17), argued that we have no reason to suppose that aquatic animals, such as plaice, carp, and sea anemones, ever die except by violence. It was stated that though both man and plaice, for example, increase by approximately geometrical progression in weight until the age of puberty, man after the age of twenty-eight declines in (significant) weight and must die; whereas plaice continue to grow indefinitely by positive increments, from which fact it is deduced that life in plaice—and similar animals—may be eternal. The renewal of interest in this subject is already producing practical results, and it is worth while discussing some other aspects of the problem.