MEPS 567:109-123 (2017)  -  DOI: https://doi.org/10.3354/meps12032

ABSTRACT: Corkscrew sea anemones Bartholomea annulata are important ecologically as hubs of a mutualistic network involving cleaner shrimps and client fishes on Caribbean reefs. They also are collected for the ornamental aquarium trade, but little is known about their population dynamics to support conservation management. We quantified variation in population structure among regions of the Florida Keys and levels of human impact within region. The Upper Keys and low-impact sites supported higher population abundance and proportions of small anemones than the Lower Keys and high-impact sites. At 2 sites where we monitored anemone dynamics every 2 mo for 1 yr, individuals recruited frequently and grew rapidly to maximum body size and then remained static or shrank. Fewer than half the individuals survived all year, indicating rapid population turnover, with mortality occurring mostly among small individuals or large ones that appeared to senesce beforehand. Stasis of large individuals (or lack thereof) exerted the most influence on population size. We conclude that in Florida, corkscrew anemones experience relatively high recruitment and survival at sites with low human impact and in the Upper Keys, where summer water temperatures are cooler than in the Lower Keys. Populations are highly dynamic and appear to rely on frequent recruitment, potentially linked to the presence of resident adults at high enough abundances for fertilization of broadcast propagules. The ephemeral nature of these anemones has important implications for the dynamics of their anemoneshrimp symbionts, for reef fishes that utilize them as parasite cleaning stations, and for the conservation management of their populations.

KEY WORDS: Sea anemone · Demography · Recruitment · Mortality · Coral reef · Size-based transition matrix