Estuarine and Diadromous Fish Metapopulations

TL;DR: This chapter charts the metapopulation of diadromous fishes, a group of fish that regularly migrate between the sea and freshwater and those species that live in estuaries for much of their lives and may spawn in the sea or estuary but are estuarine dependent during important life stages.

Abstract: Publisher Summary Diadromous fish regularly migrate between the sea and freshwater. These fish include the anadromous species that spawn in fresh water but spend much of their lives in the sea, the catadromous species that spawn at sea but spend most of their lives in freshwater, and those species that live in estuaries for much of their lives and may spawn in the sea or estuaries but are estuarine dependent during important life stages. This chapter charts the metapopulation of these fishes. The application of the metapopulation concept in diadromous fishes requires the understanding of how their life histories affect population structure, and begs a clear understanding of the concept. The dichotomy of naturally evolved versus fragmentation-induced metapopulations emphasizes the role that evolutionary genetic adaptation will have in the response of the metapopulation to change and stress. In a naturally evolved metapopulation at equilibrium, the population will have surmounted the problems of genetic load and inbreeding depression, and, potentially, small population size. The application of metapopulation theory differs fundamentally between marine and terrestrial systems. The revitalization of the theory in ecology was in the context of habitat fragmentation of species that were wide ranging, in efforts to stop their decline to extinction