Biogeographic patterns of reef fish community structure in the northeastern Arabian Peninsula

Abstract

Burt, J. A., Feary, D. A., Bauman, A. G., Usseglio, P., Cavalcante, G. H., and Sale, P. F. 2011. Biogeographic patterns of reef fish community structure in the northeastern Arabian Peninsula. – ICES Journal of Marine Science, 68: 1875–1883. This study provides the first large-scale comparison of reef-associated fish communities in the northeastern Arabian Peninsula, with 24 sites spanning >3000 km of coastline in the southern Persian Gulf, the western Gulf of Oman, and the northwestern Arabian Sea, each with its own unique environmental conditions. Multivariate analyses revealed three distinct community types that were represented mainly by sites within each major water body, with >70% dissimilarity in community structure between each. Persian Gulf communities had low species richness, abundance, and biomass of reef fish compared with the other subregions, with communities dominated by herbivores and generalist predators that had little association with live coral. Reef fish biomass in the Gulf of Oman and Arabian Sea was comparable, and communities were dominated by fish with moderate coral association. However, there were relatively more herbivores and larger fish in the Arabian Sea than in the Gulf of Oman, where communities were dominated by planktivores. Species richness was highest in the Arabian Sea when differences in abundance among regions were accounted for. The influence of distinct environmental and oceanographic conditions on reef fish community structure in each of these areas is discussed.

Environmental Extremes Are Associated with Dietary Patterns in Arabian Gulf Reef Fishes

“…While our results show that sponges are consumed by P. maculosus throughout the year in the Arabian Gulf, sponges are generally a minor component of the P. maculosus diet (16% overall) relative to coral (75% overall). Sponges are relatively rare in this region (<1% of reef benthos, Burt et al, 2011a), perhaps due to the extreme nature of the environment and/or as a result of overgrazing due to the unusually high abundance of P. maculosus on these reefs (>400 ha −1 in the southern Gulf, Burt et al, 2011b). Regardless of the cause, P. maculosus in the sampled region have focused their diet toward corals, and this is consistent across all individuals and seasons we examined.…”

“…For example, our results show that P. maculosus in the Arabian Gulf is feeding primarily on coral, but coral is known to have low nutritional value (Tricas, 1989;Aeby, 2002) and it is unknown whether its focus on corals-rather than the expected sponge/algae diet-has an energetic cost that translates into lower performance at the individual or population level. Additionally, over the long-term the degree of corallivory by the hyper-abundant P. maculosus and the very common P. aquilus and P. trichrourus populations on these reefs (Burt et al, 2011b) may contribute to the further depletion of corals that are already under pressure from recurrent bleaching events and localized development activities (Sheppard et al, 2010;Sale et al, 2011). Further research is needed to examine the broader implications of the unique feeding habits of coral reef fishes living in this extreme environment.…”

“…Three reef-associated fish species were collected from Saadiyat reef in Abu Dhabi, UAE (N 24.59900 • E054.42150 • ): the Arabian angelfish, P. maculosus, the dark damsel, P. aquilus, and the pale-tail damsel, P. trichrourus ( Figure 1A). These species are among the most abundant coral reef fishes in the southern Arabian Gulf, and among the most important species driving reef fish community divergence from those in adjacent seas (Feary et al, 2010;Burt et al, 2011bBurt et al, , 2013.…”

“…As a result of these extreme conditions, coral reefs in the Gulf are less structurally complex and less diverse than in most other parts of the IndoPacific (Coles, 2003), with benthic communities distinct from those in even the biogeographically connected Indian Ocean (Sheppard et al, 1992;Bauman et al, 2012). As a result of this extreme environment as well as variation in habitat structure and food resources, reef fish assemblages in the Arabian Gulf are also structurally and functionally distinct from those in more benign reef environments (Feary et al, 2010, with trophic guild structure that differs markedly from even adjacent seas (Feary et al, 2010;Burt et al, 2011b;Hoey et al, 2016), and broader ranges of food consumed in at least some guilds (Pratchett et al, 2013).…”

“…Other than studies of diet-related pollutant accumulation in commercially important fish species (e.g., SaeiDehkordi et al, 2010;Monikh et al, 2012Monikh et al, , 2013, only a few other studies have explored reef fish feeding ecology in the Arabian Gulf. Pratchett et al (2013) used in situ observations of feeding habits to discern selectivity and rates of feeding in corallivorous butterflyfishes, while Burt et al (2011b) inferred the trophic structure of reef fish communities based on field surveys and literature reviews. Both of these studies suggested that reef fish feeding activities in the Arabian Gulf were distinct from that of less extreme reef environments.…”