Factors that Influence Population Density of Galapagos Damselfish



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In this study, we focused on the distributions of the yellowtail damselfish (Stegastes arcifrons), the ringtail damselfish (Stegastes beebei) and the pencil sea urchin (Eucidaris galapagensis). Species abundance across locations and habitat types, as well as algal distribution may convey insights into trophic interaction as well as specific niches. The purpose of this study was to quantify the abundance and distribution of S. arcifrons, S. beebei, and E. galapagensis in several bays of San Cristóbal, Galapagos. Three filmed transects of about three minutes each were surveyed in three bays of San Cristobal, while participants counted both species of fish in real time. Afterwards, species abundance, habitat type, and algal cover were evaluated in video freeze frames. We found that there is a positive correlation between S. arcifrons, rocky habitats, and higher average algal cover, while S. beebei had no discernible correlation with any of these factors. There is also a fairly strong negative correlation between S. arcifrons and E. Galapagensis.