Variation in fish density, assemblage composition and relative rates of predation among mangrove, seagrass and coral reef habitats

Abstract

We tested the hypothesis for several Caribbean reef fish species that there is no difference in nursery function among mangrove, seagrass and shallow reef habitat as measured by: (a) patterns of juvenile and adult density, (b) assemblage composition, and (c) relative predation rates. Results indicated that although some mangrove and seagrass sites showed characteristics of nursery habitats, this pattern was weak. While almost half of our mangrove and seagrass sites appeared to hold higher proportions of juvenile fish (all species pooled) than did reef sites, this pattern was significant in only two cases. In addition, only four of the six most abundant and commercially important species (Haemulon flavolineatum, Haemulon sciurus, Lutjanus apodus, Lutjanus mahogoni, Scarus iserti, and Sparisoma aurofrenatum) showed patterns of higher proportions of juvenile fish in mangrove and/or seagrass habitat(s) relative to coral reefs, and were limited to four of nine sites. Faunal similarity between reef and either mangrove or seagrass habitats was low, suggesting little, if any exchange between them. Finally, although relative risk of predation was lower in mangrove/seagrass than in reef habitats, variance in rates was substantial suggesting that not all mangrove/ seagrass habitats function equivalently. Specifically, relative risk varied between morning and afternoon, and between sites of similar habitat, yet varied little, in some cases, between habitats (mangrove/seagrass vs. coral reefs). Consequently, our results caution against generalizations that all mangrove and seagrass habitats have nursery function.

Variación entre hábitats de la densidad y composición por tallas en peces de arrecife de la región noroccidental de Cuba

“…The presence of adult fish in all sampled habitats was consistent with Sheaves (2005) and Chittaro et al (2005) conclusions that the term 'nursery area' applied for mangroves and seagrass habitats should be used with discretion. Based in our results, we consider the term 'adult habitat' applied for coral reefs should be used also with discretion.…”

“…Aguilar-Perera & Appeldoorn (2007) found significant differences among habitats for S. aurofrenatum and S. viride juveniles, but not for S. iseri juveniles. The preference of S. aurofrenatum and S. iseri for reef habitats has also been reported by others (Adams & Ebersole, 2002;Chittaro et al, 2005).…”

“…Nagelkerken et al (2000) 2.5 7.5 12.5 17.5 22.5 27.5 32.5 37.5 2.5 7.5 12.5 17.5 22.5 27.5 32.5 37.5 Class marks of length classes (cm) found that L. apodus and L. griseus were more abundant in mangrove habitats and that L. apodus showed an ontogenetic shift to deeper coral reefs. Cocheret de la Moriniere et al (2002), Chittaro et al (2005), and Aguilar-Perera & Appeldoorn (2007) found that L. apodus and L. griseus showed strong preferences for mangroves over seagrass beds at all size-classes.…”

“…In other cases, several locations were sampled around a small island with a total surface of less than 200km 2 (Adams & Ebersole, 2002;Grober-Dunsmore, Frazer, Lindberg & Beets, 2007). Mumby et al (2004) and Chittaro, Usseglio & Sale (2005) studied larger spatial scales (10-100km 2 ).…”

Influence of habitat configuration on connectivity between fish assemblages of Caribbean seagrass beds, mangroves and coral reefs

“…Several studies have shown clear effects of the presence of seagrass beds or mangroves on fish assemblages on coral reefs, suggesting a high dependence of some species on these habitats, either at the scale of multiple islands , Halpern 2004 or of single islands (Serafy et al 2003, Dorenbosch et al 2004, Mumby et al 2004). However, Chitaro et al (2005) found substantial variation between sites in the abundance of juvenile fishes, indicating that not all seagrass beds and mangroves function equally as juvenile habitats. These results caution against the generalisation that all mangrove and seagrass habitats have a similar function as a juvenile fish habitat.…”