Reproduction

Abstract

If a fish is to be represented genetically in the next generation, at some time in its life it must begin to allocate resources to reproduction. Its reproductive success will depend on where and when it reproduces and on the resources it allocates to reproduction. Consequently, a study of the ecology of reproduction will include analyses of these problems in relation to the effects of environmental factors: where and when does spawning take place and what resources are allocated to reproduction as opposed to maintenance and growth? The problem of timing raises two sets of questions. The first set asks at what age does a fish becomes sexually mature and what factors determine this age? The second set asks what factors determine when in the year reproduction takes place? The problem of allocation also has two basic components: what portion of available resources is allocated to each reproductive attempt; and of the material resources that are allocated to reproduction, what portion is allocated to each individual offspring? This chapter explores each of these questions, where possible in relation to the effect that environmental factors have on their resolution.