Small marine reserves do not provide a safeguard against overfishing
Abstract Marine reserves aim to protect harvested species within their boundaries and can therefore provide insurance against the effects of overfishing. To evaluate whether marine reserves are meeting this expectation, we compiled over 40 years of rock lobster (Jasus edwardsii) monitoring data and...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2021-02-01
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| Series: | Conservation Science and Practice |
| Subjects: | |
| Online Access: | https://doi.org/10.1111/csp2.362 |
| _version_ | 1797659206946390016 |
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| author | Diana E. LaScala‐Gruenewald Roger V. Grace Tim R. Haggitt Benjamin J. Hanns Shane Kelly Alison MacDiarmid Nick T. Shears |
| author_facet | Diana E. LaScala‐Gruenewald Roger V. Grace Tim R. Haggitt Benjamin J. Hanns Shane Kelly Alison MacDiarmid Nick T. Shears |
| author_sort | Diana E. LaScala‐Gruenewald |
| collection | DOAJ |
| description | Abstract Marine reserves aim to protect harvested species within their boundaries and can therefore provide insurance against the effects of overfishing. To evaluate whether marine reserves are meeting this expectation, we compiled over 40 years of rock lobster (Jasus edwardsii) monitoring data and examined long‐term trends in three relatively small marine reserves (c.4–8 km2) in northern New Zealand, a region that has experienced large‐scale declines in the fishery over the last decade. In all three reserves, lobster density initially increased by at least a factor of three following protection. However, over the last 10 years, lobster populations have experienced large declines in all three reserves with densities now 59–80%, and spawning stock biomass (SSB) now 51–86%, below historic levels. Using peak lobster density in each reserve as an unfished reference point, current densities on fished reefs are <15% of unfished levels and SSB is currently only 3–12% of peak population biomass in reserves. These results highlight the poor state of the wider stock and declines in the reserves follow regional declines in catch‐per‐unit‐effort in the fishery, suggesting that lobster populations within these reserves are not fully protected from fishing. Adult J. edwardsii are known to undertake seasonal foraging excursions that carry them beyond the offshore boundaries of these reserves where they are susceptible to fishing‐related mortality. We propose that the observed declines are likely a result of direct harvest of individuals beyond reserve boundaries and that larger reserves which encompass both a species' longshore and offshore movements are needed. |
| first_indexed | 2024-03-11T18:10:34Z |
| format | Article |
| id | doaj.art-c881bb88a579410585e6ab90c1879286 |
| institution | Directory Open Access Journal |
| issn | 2578-4854 |
| language | English |
| last_indexed | 2024-03-11T18:10:34Z |
| publishDate | 2021-02-01 |
| publisher | Wiley |
| record_format | Article |
| series | Conservation Science and Practice |
| spelling | doaj.art-c881bb88a579410585e6ab90c18792862023-10-16T14:51:41ZengWileyConservation Science and Practice2578-48542021-02-0132n/an/a10.1111/csp2.362Small marine reserves do not provide a safeguard against overfishingDiana E. LaScala‐Gruenewald0Roger V. Grace1Tim R. Haggitt2Benjamin J. Hanns3Shane Kelly4Alison MacDiarmid5Nick T. Shears6Leigh Marine Laboratory University of Auckland Leigh New ZealandLeigh Marine Laboratory University of Auckland Leigh New ZealandLeigh Marine Laboratory University of Auckland Leigh New ZealandLeigh Marine Laboratory University of Auckland Leigh New ZealandLeigh Marine Laboratory University of Auckland Leigh New ZealandNational Institute of Water and Atmospheric Research Wellington New ZealandLeigh Marine Laboratory University of Auckland Leigh New ZealandAbstract Marine reserves aim to protect harvested species within their boundaries and can therefore provide insurance against the effects of overfishing. To evaluate whether marine reserves are meeting this expectation, we compiled over 40 years of rock lobster (Jasus edwardsii) monitoring data and examined long‐term trends in three relatively small marine reserves (c.4–8 km2) in northern New Zealand, a region that has experienced large‐scale declines in the fishery over the last decade. In all three reserves, lobster density initially increased by at least a factor of three following protection. However, over the last 10 years, lobster populations have experienced large declines in all three reserves with densities now 59–80%, and spawning stock biomass (SSB) now 51–86%, below historic levels. Using peak lobster density in each reserve as an unfished reference point, current densities on fished reefs are <15% of unfished levels and SSB is currently only 3–12% of peak population biomass in reserves. These results highlight the poor state of the wider stock and declines in the reserves follow regional declines in catch‐per‐unit‐effort in the fishery, suggesting that lobster populations within these reserves are not fully protected from fishing. Adult J. edwardsii are known to undertake seasonal foraging excursions that carry them beyond the offshore boundaries of these reserves where they are susceptible to fishing‐related mortality. We propose that the observed declines are likely a result of direct harvest of individuals beyond reserve boundaries and that larger reserves which encompass both a species' longshore and offshore movements are needed.https://doi.org/10.1111/csp2.362fishing the lineJasus edwardsiimarine protected areasmarine reserve designoffshore movementspillover |
| spellingShingle | Diana E. LaScala‐Gruenewald Roger V. Grace Tim R. Haggitt Benjamin J. Hanns Shane Kelly Alison MacDiarmid Nick T. Shears Small marine reserves do not provide a safeguard against overfishing Conservation Science and Practice fishing the line Jasus edwardsii marine protected areas marine reserve design offshore movement spillover |
| title | Small marine reserves do not provide a safeguard against overfishing |
| title_full | Small marine reserves do not provide a safeguard against overfishing |
| title_fullStr | Small marine reserves do not provide a safeguard against overfishing |
| title_full_unstemmed | Small marine reserves do not provide a safeguard against overfishing |
| title_short | Small marine reserves do not provide a safeguard against overfishing |
| title_sort | small marine reserves do not provide a safeguard against overfishing |
| topic | fishing the line Jasus edwardsii marine protected areas marine reserve design offshore movement spillover |
| url | https://doi.org/10.1111/csp2.362 |
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