Habitat specialization in tropical continental shelf demersal fish assemblages
MetadataShow full item record
The implications of shallow water impacts such as fishing and climate change on fish assemblages are generally considered in isolation from the distribution and abundance of these fish assemblages in adjacent deeper waters. We investigate the abundance and length of demersal fish assemblages across a section of tropical continental shelf at Ningaloo Reef, Western Australia, to identify fish and fish habitat relationships across steep gradients in depth and in different benthic habitat types. The assemblage composition of demersal fish were assessed from baited remote underwater stereo-video samples (n = 304) collected from 16 depth and habitat combinations. Samples were collected across a depth range poorly represented in the literature from the fringing reef lagoon (1–10 m depth), down the fore reef slope to the reef base (10–30 m depth) then across the adjacent continental shelf (30–110 m depth). Multivariate analyses showed that there were distinctive fish assemblages and different sized fish were associated with each habitat/depth category. Species richness, MaxN and diversity declined with depth, while average length and trophic level increased.The assemblage structure, diversity, size and trophic structure of demersal fishes changes from shallow inshore habitats to deeper water habitats. More habitat specialists (unique species per habitat/depth category) were associated with the reef slope and reef base than other habitats, but offshore sponge-dominated habitats and inshore coral-dominated reef also supported unique species. This suggests that marine protected areas in shallow coral-dominated reef habitats may not adequately protect those species whose depth distribution extends beyond shallow habitats, or other significant elements of demersal fish biodiversity. The ontogenetic habitat partitioning which is characteristic of many species, suggests that to maintain entire species life histories it is necessary to protect corridors of connected habitats through which fish can migrate.
This article is published under the Open Access publishing model and distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0/ Please refer to the licence to obtain terms for any further reuse or distribution of this work.
Showing items related by title, author, creator and subject.
Heyns-Veale, E.; Bernard, A.; Richoux, N.; Parker, D.; Langlois, T.; Harvey, Euan; Götz, A. (2016)Depth and habitat are important predictors of fish assemblage structure, yet current no-take marine protected area (MPA) networks are generally limited to providing refuge for fish species that inhabit shallow waters and ...
McIlwain, Jennifer; Harvey, Euan; Grove, S.; Shiell, G.; Al Oufi, H.; Al Jardani, N. (2011)The coastal shelf of the Gulf of Oman experiences periodic upwelling events during the summer months that are driven by the southwest monsoon. It is unclear what role these events play in the spatial and temporal distribution ...
Dorman, S.; Harvey, Euan; Newman, S. (2012)Baited underwater video techniques are increasingly being utilised for assessing and monitoring demersal fishes because they are: 1) non extractive, 2) can be used to sample across multiple habitats and depths, 3) are ...