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Summary
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 (INT201503 – DOC16307), continued in 2020, (INT201904 – DOC20303), and 2022 (INT2022-03 – DOC23303), to determine, through the examination of returned coral specimens and specimen images, the taxon, provenance and, for the current project, the genetics of corals bycaught in New Zealand fisheries.
This report, covering the first year of a three-year contract, summarises the sample and image identifications of all observed coral bycatch collected under the project during the period 1 July 2022 to 30 June 2023. A total of 12 physical specimens in 11 samples were collected by Observers and returned for identification during the reporting period. Sub-samples from each live-caught specimen were taken for future genetic studies (n=9) not all specimens had sufficient live tissue for subsampling. Additionally, there were 49 historical physical samples (67 specimens) collected by Observers with revised higher-level identifications made during the reporting period. A total of 20 research trawl-collected specimens in 19 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 are provided in the Appendices and as separate excel files.
There were 2854 specimens identified from 382 digital images of catch reported as coral during the reporting period; 2595 were identified by experts as protected coral taxa. The remaining 259 specimens in images were of other non-coral taxa. Observers provided a label showing trip and tow number information for 172 of the 382 processed images and all except one of the remaining images were able to be georeferenced.
Data summaries of protected coral bycatch 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 orange roughy and scampi. Similarly, most protected corals identified from physical specimens came from South-East (SOE, FMA4) 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.
We have continued to provide information to brief Observers and give input into coral guide resources, including the updated and revised Deepsea Coral Guide, and MPI’s new Benthic Materials Observer training module to help improve overall accuracy of protected coral species identification at-sea. We stress in our recommendations to Observers the use of labels when images are taken, and consistency in specimen label and benthic form recording processes.
An additional objective of this project was to assess the utility of genetic or genomic methods of identifying and discriminating both known and undescribed protected corals. In the first year it was agreed with CSP that effort should focus on determining the relationship of a tentative new family of gorgonian octocorals that was first discovered in CSP project BCBC2020-26 Octocoral bycatch diversity on the Chatham Rise. All eight available specimens of this unknown taxon were DNA-sequenced using genomic methods, to produce a genealogy that demonstrated that they belonged to a unique group that was distinct from morphologically similar gorgonians, including the bamboo, golden and primnoid corals. A comparison of these results to the literature indicates this taxon either belongs to a new family or to a described family that has not been reported from New Zealand. A morphological analysis of the eight specimens is required before either scenario can be definitive.
Publication information
Connell, A., Macpherson, D., Mills, S., Bilewitch, J., Wood, C. (2024). INT2022-03 Identification, storage and genetics of cold-water coral bycatch specimens (1 July 2022–30 June 2023). Milestone 3. Final Annual Report. Prepared for Conservation Services Programme, Department of Conservation NIWA Client Report 2024096WN. 64p.