Community Consequences of Fish Stock Diversity

Genotypes are variable among fish stocks, and these limit potential niche. In turn, realized niche is further constrained by the interaction of abiotic and biotic environmental factors, together with fishery exploitation. Selection pressures by these three factors provide feedback on genotypes, modifying potential niches. The steady-state consequence of this process is a harmonic community of co-evolved stocks. Using community size structure as one of our criteria, we trace the effects of the major classes of perturbation on harmonic communities, and discuss their management implications.Key words: harmonic community, co-evolution, fish stock, management, genetics, biotic and abiotic environmental factors, niche