The Fate of Deep-Sea Coral Reefs on Seamounts in a Fishery-Seascape: What Are the Impacts, What Remains, and What Is Protected?
Environmental harm to deep-sea coral reefs on seamounts is widely attributed to bottom trawl fishing. Yet, accurate diagnoses of impacts truly caused by trawling are surprisingly rare. Similarly, comprehensive regional assessments of fishing damage rarely exist, impeding evaluations of, and improvem...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2020-09-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fmars.2020.567002/full |
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| author | Alan Williams Franziska Althaus Kylie Maguire Mark Green Candice Untiedt Phil Alderslade Malcolm R. Clark Nicholas Bax Nicholas Bax Thomas A. Schlacher |
| author_facet | Alan Williams Franziska Althaus Kylie Maguire Mark Green Candice Untiedt Phil Alderslade Malcolm R. Clark Nicholas Bax Nicholas Bax Thomas A. Schlacher |
| author_sort | Alan Williams |
| collection | DOAJ |
| description | Environmental harm to deep-sea coral reefs on seamounts is widely attributed to bottom trawl fishing. Yet, accurate diagnoses of impacts truly caused by trawling are surprisingly rare. Similarly, comprehensive regional assessments of fishing damage rarely exist, impeding evaluations of, and improvements to, conservation measures. Here we report on trawling impacts to deep-sea scleractinian coral reefs in a regional (10–100s of km) fishery seascape off Tasmania (Australia). Our study was based on 148 km of towed camera transects (95 transects on 51 different seamounts with 284,660 separate video annotations and 4,674 “on-seamount” images analysed), and commercial trawling logbook data indexing fishing effort on and around seamounts. We detect trawling damage on 88% (45 of 51) of seamounts. Conversely, intact deep-sea coral reefs persist in refuge areas on about 39% (20 of 51) of the seamounts, and extend onto rocky seabed adjacent to seamounts. Depth significantly shapes the severity of trawl damage. The most profound impacts are evident on shallow seamounts (those peaking in < 950 m depths) where recent and repeated trawling reduced reefs built by scleractinian corals to rubble, forming extensive accumulations around seamount peaks and flanks. At intermediate depths (∼950–1,500 m), trawling damage is highly variable on individual seamounts, ranging from substantial impacts to no detection of coral loss. Deep seamounts (summit depth > 1,500 m) are beyond the typical operating depth of the trawl fishery and exceed the depth range of living deep-sea coral reefs in the region. Accurately diagnosing the nature and extent of direct trawling impacts on seamount scleractinian coral reefs must use stringent criteria to guard against false positive identifications of trawl impact stemming from either (1) misidentifying areas that naturally lacked deep-sea coral reef as areas where coral had been removed, or (2) attributing trawling as the cause of natural processes of reef degradation. The existence of sizeable deep-sea coral reef refuges in a complex mosaic of spatially variable fishing effort suggests that more nuanced approaches to conservation may be warranted than simply protecting untrawled areas, especially when the biological resources with conservation value are rare in a broader seascape context. |
| first_indexed | 2024-12-13T05:39:10Z |
| format | Article |
| id | doaj.art-b2fe582515204b8d8743c93f7050a24f |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-12-13T05:39:10Z |
| publishDate | 2020-09-01 |
| publisher | Frontiers Media S.A. |
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| series | Frontiers in Marine Science |
| spelling | doaj.art-b2fe582515204b8d8743c93f7050a24f2022-12-21T23:57:50ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452020-09-01710.3389/fmars.2020.567002567002The Fate of Deep-Sea Coral Reefs on Seamounts in a Fishery-Seascape: What Are the Impacts, What Remains, and What Is Protected?Alan Williams0Franziska Althaus1Kylie Maguire2Mark Green3Candice Untiedt4Phil Alderslade5Malcolm R. Clark6Nicholas Bax7Nicholas Bax8Thomas A. Schlacher9CSIRO Oceans and Atmosphere, Hobart, TAS, AustraliaCSIRO Oceans and Atmosphere, Hobart, TAS, AustraliaCSIRO Oceans and Atmosphere, Hobart, TAS, AustraliaCSIRO Oceans and Atmosphere, Hobart, TAS, AustraliaCSIRO Oceans and Atmosphere, Hobart, TAS, AustraliaCSIRO Oceans and Atmosphere, Hobart, TAS, AustraliaNational Institute of Water and Atmospheric Research (NIWA), Wellington, New ZealandCSIRO Oceans and Atmosphere, Hobart, TAS, AustraliaInstitute for Marine and Antarctic Science, University of Tasmania, Hobart, TAS, AustraliaSchool of Science and Engineering, University of the Sunshine Coast, Maroochydore, QLD, AustraliaEnvironmental harm to deep-sea coral reefs on seamounts is widely attributed to bottom trawl fishing. Yet, accurate diagnoses of impacts truly caused by trawling are surprisingly rare. Similarly, comprehensive regional assessments of fishing damage rarely exist, impeding evaluations of, and improvements to, conservation measures. Here we report on trawling impacts to deep-sea scleractinian coral reefs in a regional (10–100s of km) fishery seascape off Tasmania (Australia). Our study was based on 148 km of towed camera transects (95 transects on 51 different seamounts with 284,660 separate video annotations and 4,674 “on-seamount” images analysed), and commercial trawling logbook data indexing fishing effort on and around seamounts. We detect trawling damage on 88% (45 of 51) of seamounts. Conversely, intact deep-sea coral reefs persist in refuge areas on about 39% (20 of 51) of the seamounts, and extend onto rocky seabed adjacent to seamounts. Depth significantly shapes the severity of trawl damage. The most profound impacts are evident on shallow seamounts (those peaking in < 950 m depths) where recent and repeated trawling reduced reefs built by scleractinian corals to rubble, forming extensive accumulations around seamount peaks and flanks. At intermediate depths (∼950–1,500 m), trawling damage is highly variable on individual seamounts, ranging from substantial impacts to no detection of coral loss. Deep seamounts (summit depth > 1,500 m) are beyond the typical operating depth of the trawl fishery and exceed the depth range of living deep-sea coral reefs in the region. Accurately diagnosing the nature and extent of direct trawling impacts on seamount scleractinian coral reefs must use stringent criteria to guard against false positive identifications of trawl impact stemming from either (1) misidentifying areas that naturally lacked deep-sea coral reef as areas where coral had been removed, or (2) attributing trawling as the cause of natural processes of reef degradation. The existence of sizeable deep-sea coral reef refuges in a complex mosaic of spatially variable fishing effort suggests that more nuanced approaches to conservation may be warranted than simply protecting untrawled areas, especially when the biological resources with conservation value are rare in a broader seascape context.https://www.frontiersin.org/article/10.3389/fmars.2020.567002/fullscleractinian coralSolenosmiliaindicatorstowed-cameravulnerable marine ecosystemVME |
| spellingShingle | Alan Williams Franziska Althaus Kylie Maguire Mark Green Candice Untiedt Phil Alderslade Malcolm R. Clark Nicholas Bax Nicholas Bax Thomas A. Schlacher The Fate of Deep-Sea Coral Reefs on Seamounts in a Fishery-Seascape: What Are the Impacts, What Remains, and What Is Protected? Frontiers in Marine Science scleractinian coral Solenosmilia indicators towed-camera vulnerable marine ecosystem VME |
| title | The Fate of Deep-Sea Coral Reefs on Seamounts in a Fishery-Seascape: What Are the Impacts, What Remains, and What Is Protected? |
| title_full | The Fate of Deep-Sea Coral Reefs on Seamounts in a Fishery-Seascape: What Are the Impacts, What Remains, and What Is Protected? |
| title_fullStr | The Fate of Deep-Sea Coral Reefs on Seamounts in a Fishery-Seascape: What Are the Impacts, What Remains, and What Is Protected? |
| title_full_unstemmed | The Fate of Deep-Sea Coral Reefs on Seamounts in a Fishery-Seascape: What Are the Impacts, What Remains, and What Is Protected? |
| title_short | The Fate of Deep-Sea Coral Reefs on Seamounts in a Fishery-Seascape: What Are the Impacts, What Remains, and What Is Protected? |
| title_sort | fate of deep sea coral reefs on seamounts in a fishery seascape what are the impacts what remains and what is protected |
| topic | scleractinian coral Solenosmilia indicators towed-camera vulnerable marine ecosystem VME |
| url | https://www.frontiersin.org/article/10.3389/fmars.2020.567002/full |
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