dc.contributor.author |
Tuck, Ian |
en |
dc.contributor.author |
Williams, JR |
en |
dc.contributor.author |
Fenwick, M |
en |
dc.contributor.author |
Roberts, CL |
en |
dc.date.accessioned |
2018-10-08T23:23:46Z |
en |
dc.date.issued |
2017 |
en |
dc.identifier.isbn |
978-1-77665-688-2 |
en |
dc.identifier.issn |
1179-5352 |
en |
dc.identifier.uri |
http://hdl.handle.net/2292/39665 |
en |
dc.description.abstract |
A dredge survey of sea cucumbers (SCC), targeting Australostichopus mollis (Echinodermata: Holothuroidea), was conducted in May 2017 in SCC 3, off the north Canterbury coast. Catches of SCC as bycatch of trawl fisheries have exceeded the Total Allowable Commercial Catch (TACC) in this area in recent years. The objective of the survey was to estimate sea cucumber biomass within key areas of SCC 3, to inform fisheries management on sustainable harvest limits. A greenweight to split-weight conversion relationship was also estimated on the basis of catches aggregated to the station level. The survey extent was informed by trawl survey bycatch, fisher knowledge, MPI observer reports and MBIE/MPI-funded habitat survey work, and covered a depth range of 60–120 m, and an area of 3816 km2. The survey was stratified by depth and latitude, with priority given to the deeper and northern area, where existing data suggested that SCC catch rates would be higher. Raising survey catches to the area covered by the survey provided a total population abundance estimate of 23.8 million SCC (16% CV), with a green weight of 3207 tonnes (13% CV) and a split weight of 1329 tonnes (14% CV). Considering only SCC with a split weight of 63 g or greater (on the basis of a previously estimated marketable SCC selectivity curve) led to a commercial SCC biomass of 619 tonnes (17% CV). Estimating the biomass with non-parametric resampling of SCC within stations, and stations within strata, did not markedly change the estimates: total split-weight biomass was 1326 tonnes (95%CI = 1005 – 1700 t), and 63 g or greater split-weight biomass was 622 tonnes (95%CI = 446 – 837 t). These estimates may be conservative because they assume 100% dredge efficiency. The TACC for SCC 3 is currently 2 t, but landings have consistently exceeded this in recent years. Average SCC 3 landings (since 2011–12) represent 1.2% of the lower 95% CI of estimated commercial SCC biomass for the survey area. Given the large size of the SCC 3 stock area, it was not possible to estimate the biomass at the stock-wide level within this project. Yield estimation and assessment methods for sea cucumbers, and recommendations for longer term monitoring and biological studies, are discussed. |
en |
dc.publisher |
Ministry for Primary Industries |
en |
dc.relation.ispartofseries |
New Zealand Fisheries Assessment Report |
en |
dc.rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obtained from https://www.mpi.govt.nz/about-this-site/mpi-copyright/ |
en |
dc.rights.uri |
https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm |
en |
dc.rights.uri |
https://creativecommons.org/licenses/by/4.0/ |
en |
dc.title |
Dredge survey of sea cucumbers in SCC 3, 2017 |
en |
dc.type |
Report |
en |
pubs.volume |
2017/53 |
en |
dc.rights.holder |
Copyright: Ministry for Primary Industries |
en |
pubs.author-url |
https://fs.fish.govt.nz/Page.aspx?pk=113&dk=24497 |
en |
pubs.commissioning-body |
Ministry for Primary Industries |
en |
pubs.place-of-publication |
Wellington |
en |
dc.rights.accessrights |
http://purl.org/eprint/accessRights/OpenAccess |
en |
pubs.subtype |
Commissioned Report |
en |
pubs.elements-id |
684373 |
en |
pubs.org-id |
Science |
en |
pubs.org-id |
Statistics |
en |
pubs.record-created-at-source-date |
2017-10-06 |
en |