Influence of habitat on defecation behavior of queen (Scarus vetula) and princess (Scarus taeniopterus) parrotfish

Herbivores are important structuring agents for ecosystems worldwide. While effects of grazing by herbivorous fish are well studied, their roles in organismal dispersal have only recently become a topic of interest. Location preference and range of defecation may indicate the importance of their contribution to organism spreading. This study therefore examined the distribution and frequency of defecation of the princess parrotfish (Scarus taeniopterus) and queen parrotfish (Scarus vetula) between coral reef and sand flat habitats. Observations were performed using SCUBA in Bonaire, Dutch Caribbean. Target species were observed for 20-minute trials in each habitat. Defecation frequency, bite frequency, maximum distance between defecations, and location of defecation were recorded and averaged for each species in each habitat, and compared between species and habitats through two-way analysis of variance (ANOVA). Additionally, unique food sources observed during trials were sampled and examined in the lab. S. taeniopterus individuals were found to defecate significantly less and have smaller maximum distance between defecations within the reef habitat than the sand habitat, while S. vetula did not show significant behavioral changes for any of the variables between the two habitats. Lab results also suggest that S. taeniopterus may be opportunistic omnivores. This study offers insight to behavioral plasticity and specificity to habitat type, and provides a broader understanding of dietary plasticity and ecological roles for S. taeniopterus and S. vetula.

This student research was retrieved from Physis: Journal of Marine Science XIV (Fall 2013)19: 1-13 from CIEE Bonaire.