Diversification and Balanced Harvesting in Ecosystem-Based Fishery Management

Evidence is steadily emerging that highly selective fishing patterns hold important and often unintended consequences for community composition and system resilience.  Changes in demographic structure and genetic diversity, can accompany size-selective harvesting strategies that are mainstays of conventional fishery management strategies.  Spatial distribution of fishing effort  can further result in alteration in  system dynamics at the species, community and ecosystem levels. Concepts such as fishing down and fishing through food webs capture some dimensions of this problem but do not directly address the underlying issue of species-selective harvesting on community dynamics..  Here, empirical patterns of diversification in catch composition as reflected in measures of species dominance in catch histories are explored in global fishery statistics to address one aspect of this problem, the implications of species-selective harvesting patterns.  Deliberatively balanced harvesting strategies would encourage diversification in harvesting patterns with the objective of minimizing risk of marked alterations of food web structure.  These metrics are compared with the insights derived from evaluations of mean trophic level and other considerations.