Use of trophic structure as an indicator of reef fish assemblages in areas open and closed to fishing
The change in the mean trophic level of fish assemblages can be used as an indicator of fishing pressure. To gain a more detailed understanding of changes in trophic level, trophic spectra can be derived using a 3-point moving average technique. The mean trophic level was used to determine differences between reef fish assemblages inside and outside fish protected areas (FPAs) around Bonaire, Dutch Caribbean. Additionally, mean trophic levels of reefs spanning the entire Caribbean were calculated to enable comparison based on their level of degradation by anthropogenic disturbances. No difference was seen between the mean trophic level of sites inside and outside the FPAs, possibly due to the fact that the FPAs have only been in place for 4 years. Differences in mean trophic levels across the Caribbean were significant but did not correspond to estimated reef health, implying that mean trophic level may not be a good indicator of reef health. Reef fish assemblages seem to be affected by a variety of factors, not simply fishing pressure or reef health.