Non-random reef use by fishes at two dominant zones in a tropical, algal-dominated coastal reef

Abstract

Habitat use and the processes which determine fish distribution were evaluated at the reef flat and reef crest zones of a tropical, algal-dominated reef. Our comparisons indicated significant differences in the majority of the evaluated environmental characteristics between zones. Also, significant differences in the abundances of twelve, from thirteen analyzed species, were observed within and betweensites. According to null models, non-random patterns of species co-occurrences were significant, suggesting that fish guilds in both zones were non-randomly structured. Unexpectedly, structural complexity negatively affected overall species richness, but had a major positive influence on highly site-attached species such as a damselfish. Depth and substrate composition, particularly macroalgae cover, were positive determinants for the fish assemblage structure in the studied reef, prevailing over factors such as structural complexity and live coral cover. Our results are conflicting with other studies carried out in coraldominated reefs of the Caribbean and Pacific, therefore supporting the idea that the factors which may potentially influence reef fish composition are highly site-dependent and variable.

Abundance and behavioural ecology of the blenny <em>Ophioblennius trinitatis</em> (Teleostei: Blenniidae) at an oceanic archipelago of Brazil (Atlantic)

“…As complementary evidence, during two years of field experience in the study area, O. trinitatis was never observed at low-complexity unconsolidated sites, and was very rare even at the rocky reef-sand ecotone. A similar correlation was previously observed in a small shallow reef (Medeiros et al 2010a), supporting the prominent habitat selectivity of this species.…”

“…Presence of turf algae inside the territories of these blennies is likely to be related to their feeding preferences (see below), but since this item is highly abundant at all sites (a common feature of south Atlantic reefs; e.g. Ferreira et al 2004, Floeter et al 2005, Medeiros et al 2010a), it seems not to be a limiting factor on the abundance of O. trinitatis. Instead, as mentioned above, presence of crevices is particularly more important.…”

“…Previous studies showed that Ophioblennius species contribute greatly to the overall abundance (Randall 1996, Medeiros et al 2010a) and biomass (Labelle and Nursall 1992) of site-attached fishes on both coral and rocky reefs of the Atlantic Ocean. Furthermore, given their territorial habits, which potentially influence the distribution of other fishes, and their role in linking energy from primary producers to carnivores (Labelle and Nursall 1992), they are of great ecological importance to the overall reef community.…”

Community structure of shallow rocky shore fish in a tropical bay of the southwestern Atlantic

“…Other studies within the same region, which have focused on deep reefs, tidal pools, insular and coastal coral reefs (FEITOZA et al, 2005;GODINHO & LOTUFO, 2010;MEDEIROS et al, 2010;CHAVES et al, 2010). The MDS diagram in this study presented a slight overlapping of the fish's composition between sites.…”

“…SALE (1991) observed that structuring habitat factors can differ between locations and that fish communities are not predictable. MEDEIROS et al (2010), studying Brazilian coastal reefs, found that depth and substrate composition, particularly macroalgae cover, were positive determinants for the fish community structure. According to these authors, the presence of macroalgae is one of the components that enhance habitat complexity, and thus provide shelter for small and/or juvenile individuals of many reef fish species.…”