Sargassum-associated fish communities are stable over time and feature low levels of parasitism

Sargassum-associated fish communities are stable over time and feature low levels of parasitism

Sargassum mats are common features of South Florida coastlines. Consisting of pelagically drifting clumps of brown algae (usually of the genus Sargassum), these mats are critical nursery habitat for many fish species, providing surface shelter in otherwise exposed open ocean areas. However, the ecology of Sargassum mat communities remains unstudied. This project addressed two key knowledge gaps. First, the long term stability of Sargassum community structure was assessed in samples collected over an 8-year period. Overall 9 fish species were collected (N=150). Individual Sargassum mats typically harbored 2.6 ± 0.7 fish species which were equally abundant in any given sample (Pielou’s evenness 0.7 ± 0.2). Although cluster analyses distinguished two distinct groups of co-occurring species, overall community structure was stable across samples and did not vary as a function of collection month, season, or year (ANOSIM; 0