Using prey fish species as bioindicators of anthropogenic stress and predictors of predator density and diversity on coral reefs in Bonaire, N.A.

Bioindicator species have been used to determine changes in water quality and the effect of pollution at sites of environmental concern. Increasingly degraded water quality throughout the Caribbean is leading marine park managers and scientists to use bioindicator organisms to rapidly detect differences in water chemistry by determining connections between environmental parameters and changes in reef fish communities. This study sought to determine bioindicator prey species that could provide early detection of changes as a result of anthropogenic activities in the coastal waters of Bonaire, N.A. The effects of these parameters on the density and diversity of reef fish species was compared between 4 sites of “more (MI)” and 4 sites of “less (LI)” anthropogenic impact (200 m from of coastal development, respectively). Fish communities were surveyed using a modified version of the AGRRA methodology during the morning and evening. Two 30x2 m transects at 12 m depth were used at each site to survey both prey and predator fish species. Water chemistry including nutrient, bacterial and sedimentation levels were also analyzed to attempt to determine the factor(s) driving the changes. This study revealed significantly greater densities and a higher diversity of prey and predatory fish species at MI sites versus LI sites during the morning and the evening. The species that was found at greatest densities for both LI and MI sites was Stegastes partitus, with significantly more S. partitus at MI sites during both the morning and evening. Thus, S. partitus may be a possible bioindicator of stressors on the reefs in Bonaire. The use of S. partitus as a bioindicator of anthropogenic stress may help increase the effectiveness of marine management protocols in Bonaire and provide a basis for determining bioindicator species for monitoring coastal water quality throughout the Caribbean. None of the water chemistry parameters studied differed between MI and LI sites, therefore, the driver(s) of the differences in prey species (e.g. S. partitus) may be unaccounted for in this study as a result of time lags in the coral reef ecosystem.

This student research was retrieved from Physis: Journal of Marine Science VII (Spring 2010)19: 12-20 from CIEE Bonaire.

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