Wave energy and spatial variability in community structure of small cryptic coral reef fishes

Abstract

The distribution and abundance of small cryptic reef fishes were quantified among microhabitats and reef zones at both exposed and sheltered sites at Lizard Island, Great Barrier Reef. A total of 1042 individuals from 44 species in 8 families were sampled. Marked variation in abundance, species numbers, size-class distribution and species composition were displayed among reef zones at exposed sites; in contrast, comparatively little variation was found in sheltered sites. The exposed, wave-swept front flat reef zone was clearly the most depauperate and species-poor zone with calmer back reef, lagoonal and reef base zones containing the highest numbers of individuals and species. Larger, heavier individuals predominated in exposed wave-swept reef zones whereas smaller, lighter individuals were commonly found in calmer waters. Sheltered sites exhibited little variation among zones. In these sites, microhabitat appeared to play a much greater role in shaping community composition. Overall, 68.5% of all individuals (70.1% at exposed and 65.4% at sheltered sites) were collected from sand/rubble microhabitats as opposed to 31.5% from open reef microhabitats. Assemblages at exposed and sheltered sites exhibited little taxonomic overlap, even of highly abundant species. These results indicate that wave energy plays a significant role in structuring small cryptic coral reef fish communities, with microhabitat type playing a key role in the absence of wave energy.KEY WORDS: Cryptic · Distribution · Reef fish · Habitat · Community ecology · Gobiidae · Blenniidae · Wave exposure Resale or republication not permitted without written consent of the publisher

Distribution and factors influencing on structure of reef fish communities in Nha Trang Bay Marine Protected Area, South-Central Vietnam

“…Some authors found that amount of living hard coral cover was positively related with fish species richness (Carpenter et al 1981;Bell and Galzin 1984;Cadoret et al 1999) whereas others recorded no such relationship (Luckhurst and Luckhurst 1978;Roberts and Ormond 1987;Lecchini et al 2003). Most recently, the spatial structure and distribution of fish assemblages have been related to water depth (Russ 1984a;Fowler 1990;Friedlander and Parrish 1998;Cadoret et al 1999;Lecchini et al 2003), exposure (Williams 1982;Victor 1986;Depczynski and Bellwood 2005), reef zone (Lecchini et al 2003;Depczynski and Bellwood 2005), distance from the shoreline to offshore waters (Williams 1982;Green et al 1987;Adjeroud et al 1998;Lecchini et al 2003) and geographical location (Travers et al 2006). In general, findings from previous studies on relationships between the spatial distribution and structure of reef fish communities and environmental factors have provided conflicting conclusions.…”

Spatial variation of reef fishes and the relative influence of biotic and abiotic habitat traits

“…Adding to the small-scale variation, previous investigations have detected a considerable proportion of variance in the distribution of reef fishes at scales comparable to that of the present sites. This was often explained with spatial changes of hydrodynamics [95], the relative availability of algae playing different functional roles [30,84,96,97], or a combination of biotic and abiotic processes [32,98,99]. Such differences, instead, were unlikely to occur in the present system, where all sampled reefs and sites were chosen as being comparable in terms of wave exposure and general occurrence of macroalgal beds and might have critically contributed to the smaller variation at these scales compared to the transect scale.…”

“…This could be the case, for example, of the here common 'European sea bass' , Dicentrarchus labrax, which has high mobility and releases pelagic eggs [61], but may depend on within-reef occurring spawning grounds [100]. In a system, such as the present one, lacking marked among-sites differences in potentially relevant factors, including wave exposure [95], position relatively to the coast [101] and fishing pressure [102], smaller-scale variation might logically predominate irrespectively of fish life-histories relying on obvious local or larger-scale processes. Nonetheless, the general lack of among-sites significant variation should be interpreted with caution since the present impossibility to tease apart spatial and temporal variation likely increased the among-reefs variation, potentially masking, at least in part, among-sites differences.…”

Cryptobenthic fish assemblages across the coral reef−seagrass continuum in SE Sulawesi, Indonesia

“…Many cryptobenthic fish species have specific microhabitat preferences (Mun day et al 1997, Depczynski & Bellwood 2004, Her ler 2007, though it is unclear to what extent habitat partitioning occurs. Although most research on cryptobenthic fish assemblages focuses on 3 or 4 primary microhabitat types (Depczynski & Bellwood 2003, 2005, the present study distinguished 7 different microhabitat types. Further research investigating distribution patterns and factors structuring cryptobenthic fish assemblages will ultimately provide a better understanding of the ecological role of these fishes in tropical coastal ecosystems.…”

“…However, the strength of cryptobenthic fish−microhabitat associations has been shown to be influenced by properties of the physical environment such as wave action (Depczynski & Bellwood 2005, Santin & Willis 2007 and habitat degradation (Bellwood et al 2006). The present study investigates other potential factors that may influence cryptobenthic fish microhabitat associations by examining assemblages in key microhabitats across the coral reef−seagrass continuum.…”