Abstract

Management of Caribbean coral reef fishes would benefit from the use of simple indicators of the state of exploited reef fish communities. This would facilitate monitoring and help improve communication across different stakeholder groups. Monitoring fishpot catches and conducting underwater visual censuses (UVC) are two conventional survey approaches that can be used to obtain data on simple fish metrics (i.e. fish biomass, fish density, average fish body size) to inform about trends in fish communities. However, the data provided by each approach will be subject to different sampling biases, raising questions about the validity of comparing fish metric trends between approaches. In this study, we surveyed six shallow fringing reefs along a fishing pressure gradient on the west coast of Barbados using both fishpots and UVC concurrently. We then compared spatial trends in the aforementioned fish metrics at different levels of data aggregation (i.e. species, family, trophic status, and community levels) between the two survey approaches. Overall, we found low consistency between approaches for most metrics, except for fish biomass at the trophic and community levels (with moderate consistency) and fish biomass, density, and average fish size of parrotfishes at the family level (with high consistency). Further, in both approaches, family-level average parrotfish size exhibited the strongest association with the fishing pressure gradient. These findings suggest that simple metrics derived from the entire parrotfish community are the most comparable between fishpots and UVC, while highlighting the value of average parrotfish size as an indicator of fishing effects irrespective of approach.

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