The tyranny of scale and micro-management in benthic invertebrate fisheries

The field of fisheries science and assessment still reflects its origins in extensive industrial scale fisheries. In stark contrast, many, if not most, benthic invertebrate and reef fish fisheries occur in spatially complex meta-populations, comprised of multiple relatively small independent populations. These small-scale spatially complex fisheries resources pose a particular challenge for centralized top-down models of assessment and management which have an implicit scale and cost that cannot be simply resized to address the complexity, small scale, low unit value, and overwhelming number of local scale resources. A tyranny of scale exists which means that complex data-intensive stock-assessment models are an impractical solution for many fisheries. Simpler cost effective assessment and management procedures based on local indicators collected directly from the catch. This paper uses Australian studies of abalone (Haliotidae) to illustrate the tyranny of scale that occurs with local scale populations managed under regional scale management. The developing solution is described, involving local fishing communities using simple qualitative indicators of population fecundity to incrementally adjust reef scale catches and size limits until target levels of Spawning Potential Ratio (SPR) are achieved.