Caribbean fish decline in the wake of coral collapse?

A new study in Current Biology (some really interesting coral related stuff being published there lately) by Michelle Paddack and colleagues (Paddack et al 2009) documents a region-wide decline in reef associated fish in the Caribbean. The authors conducted a meta-analysis on a substantial amount of fisheries-independent, time-series data on Caribbean fish densities. Fish densities seem to have been pretty stable from the mid-50s until the mid-90s, to then exhibit significant negative rates of change during the past 10 years. What is striking is the generality of the decline that has occured the past decade, across the whole region (see figure below)


Recorded declines in fish densities across five Caribbean sub-regions 1996-2007

Differences in fished and non-fished species were non-significant. This leads the authors to speculate that fishing is not the main driver of these changes (although certainly it plays a part). Rather, as has been documented in the western Indian Ocean, these changes in fish communities could be a response to the substantial losses of coral cover which have occurred in the Caribbean the past decades. A wicked problem, primarily for managers and communities dependent on fisheries, is that changes in fish communities seem to manifest themselves as a form of “degradation debt” – that is, there is a substantial time-lag between changes in the underlying benthic community and the response of fish communities.