Depth and habitat determine assemblage structure of South Africa’s warm-temperate reef fish
- Heyns-Veale, Elodie R, Bernard, Anthony T F, Richoux, Nicole B, Parker, Daniel M, Langlois, T J, Harvey, E S, Götz, Albrecht
- Authors: Heyns-Veale, Elodie R , Bernard, Anthony T F , Richoux, Nicole B , Parker, Daniel M , Langlois, T J , Harvey, E S , Götz, Albrecht
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/456035 , vital:75477 , xlink:href="https://doi.org/10.1007/s00227-016-2933-8"
- Description: 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 may exclude deep habitats essential to exploited populations. To ensure MPA efficacy at the design, uptake and management levels, baseline data on fish populations associated with deep nearshore reefs are needed. This study employed baited remote underwater stereo-video systems to investigate fish habitat associations at shallow (11–25 m) and deep (45–75 m) reef sites in the Tsitsikamma National Park MPA, South Africa. The compositions of fish assemblages at shallow and deep reef sites were significantly different. Specifically, rare species, juveniles and low trophic level species dominated the shallow reef, while deep reef assemblages were characterised by large, sexually mature and predatory fish. The body size of abundant species was also correlated with depth, with larger individuals being more abundant on deeper reefs. Habitat types were identified according to a habitat classification system established in a previous study, which resulted in four broad depth separated habitat types (defined by macrobenthos and environmental variables). Canonical analysis of principle coordinates (CAP) indicated that habitat type was a good categorical predictor of the observed fish assemblages. The CAP analysis determined that 86 % of the samples were correctly assigned to the habitat type from which they were collected, indicating that specific fish assemblages were associated with distinct habitat types. This study highlights the importance of protecting both shallow and deep reefs, not only to ensure the conservation of particular fish assemblages, but also to provide protection for all stages of the life cycle of fish species.
- Full Text:
- Date Issued: 2016
- Authors: Heyns-Veale, Elodie R , Bernard, Anthony T F , Richoux, Nicole B , Parker, Daniel M , Langlois, T J , Harvey, E S , Götz, Albrecht
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/456035 , vital:75477 , xlink:href="https://doi.org/10.1007/s00227-016-2933-8"
- Description: 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 may exclude deep habitats essential to exploited populations. To ensure MPA efficacy at the design, uptake and management levels, baseline data on fish populations associated with deep nearshore reefs are needed. This study employed baited remote underwater stereo-video systems to investigate fish habitat associations at shallow (11–25 m) and deep (45–75 m) reef sites in the Tsitsikamma National Park MPA, South Africa. The compositions of fish assemblages at shallow and deep reef sites were significantly different. Specifically, rare species, juveniles and low trophic level species dominated the shallow reef, while deep reef assemblages were characterised by large, sexually mature and predatory fish. The body size of abundant species was also correlated with depth, with larger individuals being more abundant on deeper reefs. Habitat types were identified according to a habitat classification system established in a previous study, which resulted in four broad depth separated habitat types (defined by macrobenthos and environmental variables). Canonical analysis of principle coordinates (CAP) indicated that habitat type was a good categorical predictor of the observed fish assemblages. The CAP analysis determined that 86 % of the samples were correctly assigned to the habitat type from which they were collected, indicating that specific fish assemblages were associated with distinct habitat types. This study highlights the importance of protecting both shallow and deep reefs, not only to ensure the conservation of particular fish assemblages, but also to provide protection for all stages of the life cycle of fish species.
- Full Text:
- Date Issued: 2016
Depth-related distribution patterns of subtidal macrobenthos in a well-established marine protected area
- Heyns, E R, Bernard, Anthony T F, Richoux, Nicole B, Götz, A
- Authors: Heyns, E R , Bernard, Anthony T F , Richoux, Nicole B , Götz, A
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457230 , vital:75618 , xlink:href="https://doi.org/10.1007/s00227-016-2816-z"
- Description: Effective marine resource management requires knowledge of the distribution of critical habitats that support resource populations and the processes that maintain them. Reefs that host diverse macrobenthic communities are important habitats for fish. However, detailed information on macrobenthic communities is rarely available and is usually limited to SCUBA diving depths. To establish depth-related distribution patterns and drivers that structure reef communities, the macrobenthos situated in a warm-temperate marine protected area (MPA; 34°01′24S; 23°54′09E) was sampled between 2009 and 2012. Comparison of shallow (11–25 m) and deep (45–75 m) sites revealed significantly different communities, sharing only 27.9 % of species. LINKTREE analysis revealed a changeover of species along the depth gradient, resulting in four significantly different assemblage clusters, each associated with particular environmental variables. High light intensity supported benthic algae at shallow depths, and as light availability decreased with depth, algal cover diminished and was eventually absent from the deep reef. Upright growth forms and settled particulate matter were positively related to depth and dominated the deep reef. Reduced wave action and currents on the deep reef can explain the increased settling of suspended particles. Under such conditions, clogging of feeding parts of the encrusting species is expected, and upright growth would be favoured. Considering that most MPAs are restricted to shallow coastal habitats and that macrobenthic communities change significantly with depth, it is probable that many unique deep reef habitats are currently afforded no protection.
- Full Text:
- Date Issued: 2016
- Authors: Heyns, E R , Bernard, Anthony T F , Richoux, Nicole B , Götz, A
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457230 , vital:75618 , xlink:href="https://doi.org/10.1007/s00227-016-2816-z"
- Description: Effective marine resource management requires knowledge of the distribution of critical habitats that support resource populations and the processes that maintain them. Reefs that host diverse macrobenthic communities are important habitats for fish. However, detailed information on macrobenthic communities is rarely available and is usually limited to SCUBA diving depths. To establish depth-related distribution patterns and drivers that structure reef communities, the macrobenthos situated in a warm-temperate marine protected area (MPA; 34°01′24S; 23°54′09E) was sampled between 2009 and 2012. Comparison of shallow (11–25 m) and deep (45–75 m) sites revealed significantly different communities, sharing only 27.9 % of species. LINKTREE analysis revealed a changeover of species along the depth gradient, resulting in four significantly different assemblage clusters, each associated with particular environmental variables. High light intensity supported benthic algae at shallow depths, and as light availability decreased with depth, algal cover diminished and was eventually absent from the deep reef. Upright growth forms and settled particulate matter were positively related to depth and dominated the deep reef. Reduced wave action and currents on the deep reef can explain the increased settling of suspended particles. Under such conditions, clogging of feeding parts of the encrusting species is expected, and upright growth would be favoured. Considering that most MPAs are restricted to shallow coastal habitats and that macrobenthic communities change significantly with depth, it is probable that many unique deep reef habitats are currently afforded no protection.
- Full Text:
- Date Issued: 2016
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