Space partitioning among damselfishes in the Caribbean coast of Panama: the role of habitat preferences

Abstract

This study aimed to assess abundance and habitat use by juvenile and adult damselfishes, as much as the benthic cover of different reefs on Isla Colon, Bocas del Toro, Panama. Reefs were selected considering different levels of wave exposure and depths. Damselfish and benthic communities were distinct between reefs. The most abundant species in the sheltered deeper reef was Stegastes planifrons followed by S. leucostictus, and they were also recorded in the sheltered shallower reef. Low densities of S. partitus and S. variabilis were also observed in the sheltered deeper reef, as these species are apparently restricted to higher depths. Additionally, these reefs presented patches with high cover of live and dead massive coral. Shallow depths presented high abundances of S. adustus, indicating a preference of this species for shallow habitats and exhibiting a two-fold increase in abundance at higher wave surge. Also, Microspathodon chrysurus reached higher numbers in shallow depths. Furthermore, the exposed reef presented a high cover (%) of algae groups and the fire-coral Millepora alcicornis, acknowledged as a preferred habitat for M. chrysurus and other reef fish. In this study, distinct habitat uses were observed, with patterns regulated by depth and/or wave exposure levels and/or availability of specific benthic cover. For site-attached species as damselfish, habitat specialization, competition and/or non-random recruitment patterns have been found to rule distributional patterns. Similar results for damselfish relative abundances were found compared to studies conducted within Panama and other reefs throughout the Caribbean region over three decades ago, indicating strong habitat affinity for the most abundant species. However, severe reductions of habitat availability following coral mass-mortality events may have disrupted their distributional patterns.