ABSTRACT
All species of the order Mysidacea lay their eggs in a brood pouch thus allowing direct study of the development of young from oviposition to attainment of the juvenile stage. In recent years increasing interest has been focused on the development of young and its ecological and physiological demands and implications. This has been accompanied by increasing efforts and success in experimentation and the culture of the animals. Besides their traditional rôle in fisheries biology and in food chain studies, mysidaceans have recently become important as test organisms in work on the ecological and physiological effects of pollutants (see review by Nimmo & Hamaker, 1982). The present review is mainly concerned with the ecophysiological importance of incubation in mysidaceans. This importance may be direct or indirect; it may reflect the effects of certain factors on incubation or the implications of incubation for other ecological or biological processes. In fact, it is shown in the following that the duration of incubation bears more and stronger implications on reproductive and population ecology than was previously thought. The incubation period appears to be a key factor for the understanding of variations in the length and timing of the breeding season, age at maturity, frequency of broods, numbers of young per brood, egg size, and adult body size. This review may initiate search for similar relationships in other groups of brood-protecting marine poikilotherms. These relationships are of fundamental importance to the whole complex of reproductive and population ecology. In this way the present study may give valuable background information for almost any kind of study dealing with biology, population ecology or ecophysiology in mysidaceans.
