Brain coral bleaching and disease effects on goby population dynamics in Bonaire, Netherlands Antilles

Certain goby species, including the Peppermint Goby (Coryphopterus lipemes), Sharknose Goby (Elacatinus evelynae), Glass Goby (Coryphopterus hyalinus), and Bridled Goby (Coryphopterus glaucofraenum) are known to dwell on brain coral species Colpophyllia natans, Diploria labyrinthiformis, and Diploria strigosa. Coral degradation (eg. bleaching and disease) can have adverse effects on coral-dwelling fishes, such as these goby species. The purpose of this study was to display how coral bleaching and disease affect the goby populations that live on brain corals. Goby abundance was compared between healthy and bleached specimens for each observed species and specimens in total. Amongst all the coral species, healthy or bleached, the greatest number of gobies was observed on healthy C. natans individuals (64 gobies). In total, there was a greater number of gobies dwelling on the bleached corals than healthy corals (71 and 67 gobies, respectively). Goby density was calculated by dividing the number of gobies dwelling on a brain coral by the surface area of each coral head. Average goby density on bleached coral heads (0.0038 ± 0.0040) was found to be significantly greater than average goby density on healthy coral heads (0.0011 ± 0.0006) (t-test; d.f.=12; p=0.0178). Although statistically significant, this result may not be biologically significant. The results imply that gobies can persist on moderately degraded brain corals. This suggests that gobies are resistant to early stages of degradation due to bleaching.

This student research was retrieved from Physis: Journal of Marine Science XVIII (Fall 2015)19: 70-76 from CIEE Bonaire.