July 2023
This is the final annual report for INT2019-04: Identification and storage of cold-water coral bycatch 1 July 2021 - 30 June 2022.


Many protected coral species occur as bycatch in commercial fisheries around New Zealand. The Conservation Services Programme (CSP) of the Department of Conservation (DOC) recognise that Government Fisheries Observers on commercial fishing vessels are not always able to identify this bycatch at sea with high precision (especially to species level), with the confirmation of species requiring identification from a coral taxonomist in many cases. For this reason, a research project “Identification and storage of cold-water coral bycatch specimens” was initiated in 2016 (previously INT201503 - DOC16307, currently INT201904 - DOC20303), to determine, through the examination of returned coral specimens and specimen images, the taxon and the provenance of corals bycaught in New Zealand fisheries.

This report, for the third and final year of the Project (2022/23), summarises the sample and image identifications of all observed coral bycatch collected under the project during the period 1 July 2021 to 30 June 2022. A total of 54 physical specimens in 48 samples were collected by Observers and returned for identification during the reporting period. Sub-samples from each live specimen were taken for future genetic studies (n=32) not all specimens had sufficient live tissue for subsampling. Additionally, there were four historical physical samples (five specimens) collected by Observers with revised higher-level identifications made during the reporting period. A total of four research trawl-collected specimens in four samples are also reported here. Corrected identifications (where the Observer identification is revised by a coral expert), have been made where necessary in the COD database, with both the original and amended identifications retained. All raw data extracts are provided in the Appendices and as separate excel files.

There were 290 specimens identified from digital images of catch reported as coral during the reporting period; 170 were protected coral taxa, and while Observers provided a label showing trip and tow number information for only 88 of the 273 processed images, all images were able to be georeferenced. The remaining 120 specimens were of non-protected corals or other non-coral taxa.

Data summaries of protected coral by-catch occurring in New Zealand region fisheries are presented by Fisheries Management Areas (FMA), fishing method, and target fishery. The greatest number of protected coral specimen counts by images came from the South-East (SOE, FMA4) and South-East Coast (SEC, FMA3) regions. Most were taken by bottom trawl operations targeting the deep-sea species orange roughy and hoki. Similarly, most protected corals identified from physical specimens came from Auckland West (AKW, FMA9) bottom trawl operations targeting orange roughy.

While no formal analyses of accuracy have been carried out during this reporting period, between Observer and NIWA expert identifications, brief non-statistical summaries of accuracy are provided to help inform Observers.

NIWA have continued to provide information to brief Observers and give input into coral guide resources, including the updated and revised Deepsea Coral Guide, to help improve overall accuracy of protected coral species identification at-sea. As in previous reports, NIWA stresses in the recommendations, Observers use of labels when images are taken, and consistency in specimen label and benthic form recording processes.

Publication information

Mills, S., Connell, A., Macpherson, D., Tracey, D. 2023. Identification and storage of cold-water coral bycatch specimens. INT2019-04 final annual report prepared for Conservation Services Programme, Department of Conservation. NIWA Client Report 2023073WN. 51 p.


Conservation Services Programme
Department of Conservation
PO Box 10-420
Wellington 6143


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