UC San Diego
An observational assessment of feeding behavior and preferences of reef fishes : : quantifying the driving forces of herbivore foraging
- Author(s): Simonsen, Cara Marie
- et al.
Coral reefs have undergone major phase shifts in the past three decades resulting in algal dominance. Herbivorous fish are the main force removing algae from Caribbean reefs since the die-off of Diadema antillarum. This study looks to determine the elements controlling herbivorous fish populations on Caribbean coral reefs and their ability to remove turf and erect macroalgae. We asked whether the foraging rates and behaviors at a species, family and guild level changed with context. Over a three- month period, focal observations were conducted on five common herbivorous fish species, three Scarids and two Acanthurids, at nine sites on Curaçao that varied in benthic composition and fish populations. Bite rates, benthic composition and fish assemblages were quantified at each site. The three driving forces of foraging behavior of reef fishes are preferred bite rates, species abundances and diversity, and food availability. An increase in any of these factors increases the foraging intensities. I also found that herbivores have an overwhelming preference for turf algae at every site, regardless of the benthic makeup. Variations of density, estimated bite rates and selectivity all decreased along an inverse taxonomic gradient. These findings suggest that analyzing foraging behavior and intensity at a guild level is the most beneficial to understanding impact of herbivory on coral reefs. The total amount of bites taken on a reef can determine how the herbivorous fish guilds affect both the overall benthic composition and coral reef functionality