Population Characteristics of Balanophyllia elegans in the San Juan Archipelago

Abstract

Determining predictors of Balanophyllia elegans’ population distribution and physical size is important for ecological research in the Eastern Pacific because changes in this species’ biomass, abundance, and environment could be an indication of realized impact from climate change and ocean acidification. Over the last four decades community composition has changed around the San Juan Islands, including a decline in B. elegans’ density. In this study we assessed abundance, biomass, population density, largest diameter, and surface area at 11 sites from the years 2008-2013, at depths ranging from 3 m to 27.5 m with 3 m increments, and at four flow ranks, looking for patterns and predictors. We found that all three variables (site, year, and depth) and the interaction variables ‘site + depth’ and ‘site + year + depth’ are statistically significant predictors for coral distribution, and year, depth, and the interaction term ‘year + site’ are significant predictors for oral disc surface area. These results tell us that these sites are unique, but each site has an interesting pattern that will need to be defined through further analysis for a larger sample size.