Potential of dynamic ocean management strategies for western Pacific leatherback sea turtle bycatch mitigation in New Zealand
Western Pacific leatherback sea turtles (Dermochelys coriacea) are a priority bycatch mitigation concern due to the projected extinction of the population before the end of the 21st century. The species regularly occurs as bycatch in gillnet and surface longline fisheries. Here, we explore the poten...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2024-02-01
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| Series: | Frontiers in Marine Science |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2024.1342475/full |
| _version_ | 1797303312825974784 |
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| author | Zachary A. Siders Campbell Murray Charity Puloka Shelton Harley Clinton Duffy Christopher A. Long Robert N. M. Ahrens T. Todd Jones |
| author_facet | Zachary A. Siders Campbell Murray Charity Puloka Shelton Harley Clinton Duffy Christopher A. Long Robert N. M. Ahrens T. Todd Jones |
| author_sort | Zachary A. Siders |
| collection | DOAJ |
| description | Western Pacific leatherback sea turtles (Dermochelys coriacea) are a priority bycatch mitigation concern due to the projected extinction of the population before the end of the 21st century. The species regularly occurs as bycatch in gillnet and surface longline fisheries. Here, we explore the potential for dynamic ocean management in an emerging hotspot of leatherback sea turtle bycatch in the New Zealand pelagic longline fishery. We compared spatial areas of different sizes built from single oceanographic covariates as well as built from a composite risk surface developed through ensemble random forests. We found that, individually, the Okubo–Weiss parameter, sea surface temperature (SST) anomaly, SST, moon phase, and distance to the SST front were important oceanographic covariates for leatherback sea turtle bycatch. However, the spatial areas built from the composite risk surface were the most effective at discriminating sets with and without bycatch across a range of risk cutoffs. When we also considered implementation metrics of spatial area and coherence as part of performance, the area derived from the composite risk surface with a risk of interaction per set greater than 52% performed best. This spatial area was ephemeral, occurring 1 or 2 weeks each year, and localized, occurring along the north coast of East Cape in the North Island of New Zealand. The apparent presence of discrete spatial areas with elevated risk may be useful to inform future management in the area. Considering implementation metrics in defining utility was useful for identifying tradeoffs between the total size and the underlying covariates delineating a spatial area. As such, we recommend these types of metrics to be included when designing spatial bycatch mitigation strategies elsewhere. |
| first_indexed | 2024-03-07T23:51:03Z |
| format | Article |
| id | doaj.art-5b93c3be097e4f889c217c1d6b72d321 |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-03-07T23:51:03Z |
| publishDate | 2024-02-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-5b93c3be097e4f889c217c1d6b72d3212024-02-19T04:49:31ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452024-02-011110.3389/fmars.2024.13424751342475Potential of dynamic ocean management strategies for western Pacific leatherback sea turtle bycatch mitigation in New ZealandZachary A. Siders0Campbell Murray1Charity Puloka2Shelton Harley3Clinton Duffy4Christopher A. Long5Robert N. M. Ahrens6T. Todd Jones7Fisheries and Aquatic Sciences, School of Forest, Fisheries, and Geomatic Sciences, University of Florida, Gainesville, FL, United StatesFisheries New Zealand, Ministry for Primary Industries, Wellington, New ZealandFisheries New Zealand, Ministry for Primary Industries, Wellington, New ZealandFisheries New Zealand, Ministry for Primary Industries, Wellington, New ZealandMarine Species Team, Department of Conservation, Wellington, New ZealandFisheries and Aquatic Sciences, School of Forest, Fisheries, and Geomatic Sciences, University of Florida, Gainesville, FL, United StatesPacific Islands Fisheries Science Center, NOAA Fisheries, Honolulu, HI, United StatesPacific Islands Fisheries Science Center, NOAA Fisheries, Honolulu, HI, United StatesWestern Pacific leatherback sea turtles (Dermochelys coriacea) are a priority bycatch mitigation concern due to the projected extinction of the population before the end of the 21st century. The species regularly occurs as bycatch in gillnet and surface longline fisheries. Here, we explore the potential for dynamic ocean management in an emerging hotspot of leatherback sea turtle bycatch in the New Zealand pelagic longline fishery. We compared spatial areas of different sizes built from single oceanographic covariates as well as built from a composite risk surface developed through ensemble random forests. We found that, individually, the Okubo–Weiss parameter, sea surface temperature (SST) anomaly, SST, moon phase, and distance to the SST front were important oceanographic covariates for leatherback sea turtle bycatch. However, the spatial areas built from the composite risk surface were the most effective at discriminating sets with and without bycatch across a range of risk cutoffs. When we also considered implementation metrics of spatial area and coherence as part of performance, the area derived from the composite risk surface with a risk of interaction per set greater than 52% performed best. This spatial area was ephemeral, occurring 1 or 2 weeks each year, and localized, occurring along the north coast of East Cape in the North Island of New Zealand. The apparent presence of discrete spatial areas with elevated risk may be useful to inform future management in the area. Considering implementation metrics in defining utility was useful for identifying tradeoffs between the total size and the underlying covariates delineating a spatial area. As such, we recommend these types of metrics to be included when designing spatial bycatch mitigation strategies elsewhere.https://www.frontiersin.org/articles/10.3389/fmars.2024.1342475/fullensemble random forestsmachine learningmarine reptilesfisheries bycatchprotected speciesthreatened species |
| spellingShingle | Zachary A. Siders Campbell Murray Charity Puloka Shelton Harley Clinton Duffy Christopher A. Long Robert N. M. Ahrens T. Todd Jones Potential of dynamic ocean management strategies for western Pacific leatherback sea turtle bycatch mitigation in New Zealand Frontiers in Marine Science ensemble random forests machine learning marine reptiles fisheries bycatch protected species threatened species |
| title | Potential of dynamic ocean management strategies for western Pacific leatherback sea turtle bycatch mitigation in New Zealand |
| title_full | Potential of dynamic ocean management strategies for western Pacific leatherback sea turtle bycatch mitigation in New Zealand |
| title_fullStr | Potential of dynamic ocean management strategies for western Pacific leatherback sea turtle bycatch mitigation in New Zealand |
| title_full_unstemmed | Potential of dynamic ocean management strategies for western Pacific leatherback sea turtle bycatch mitigation in New Zealand |
| title_short | Potential of dynamic ocean management strategies for western Pacific leatherback sea turtle bycatch mitigation in New Zealand |
| title_sort | potential of dynamic ocean management strategies for western pacific leatherback sea turtle bycatch mitigation in new zealand |
| topic | ensemble random forests machine learning marine reptiles fisheries bycatch protected species threatened species |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2024.1342475/full |
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