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Summary
Protected coral species frequently occur as bycatch in commercial fisheries around New Zealand, and it is important for their protection that there is a good understanding of the species that are caught. 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. Over time, NIWA has received coral bycatch samples and images collected by Observers and has been contracted to provide expert identifications and present the results in reports.
This report, covering the second 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 2023 to 30 June 2024. A total of 39 physical specimens (in 23 samples) were collected by Observers and returned for identification during the reporting period. Ten subsamples from live-caught specimens were taken for future genetic studies. Not all specimens had sufficient live tissue for subsampling. Additionally, there were 92 historical physical specimens (86 historical samples) collected by Observers prior to 1 July 2023, for which revised higher-level identifications were made during the reporting period. Identifications for a further 46 research trawl-collected specimens in 32 samples are also reported here.
There were 765 specimens identified from 308 digital images and two digital video files that were processed during the reporting period; 706 were identified by experts as protected coral taxa. The remaining 59 specimens from images were of other, non-coral, taxa. The location of capture of all specimens from images was able to be determined (i.e. all files were able to be georeferenced) and 755 specimens were confirmed to be from within the New Zealand Exclusive Economic Zone (EEZ) (10 specimens were from Challenger Plateau, beyond the EEZ (CET)).
Corrected identifications (where the Observer identification is revised by an 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 of this report and as separate excel files.
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 from images came from SOE South East (Chatham Rise) (FMA 4) followed by SEC South East Coast (FMA 3) and AKW Auckland West (FMA 9) regions. Most were taken by bottom trawl operations targeting scampi, orange roughy, hoki and oreo. Similarly, most protected corals identified from physical specimens came from SOE South East (Chatham Rise) (FMA 4) bottom trawling, targeting scampi, although physical samples this year came from a wider range of areas and targeting a wider range of species than in previous years examined.
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 update and provide input into coral-relevant resources for Observers during this reporting period as stated in the project contract, by means of in-person refresher training, and through the improvement of Observer reference material, including revisions to the updated Coral Identification Guide and the updates to the document “Instructions to observers when carrying out at-sea protected coral data collection”.
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 this second year it was agreed with CSP that effort should focus on characterisation of genetic diversity and connectivity of gorgonian coral populations of the genus Anthothela, as an extension of taxonomic research into this group conducted by an overseas visiting expert Dr. Kirrily Moore, as part of CSP project INT2023-07. A selection of 37 individuals included bycaught and research specimens from across the EEZ, as well as representatives from international and Australian territories. Specimens were subjected to genome skimming – an economical method of obtaining DNA sequences from across the genome that works well with degraded and archival tissues. Skimming produced an average of 4.1 billion base-pairs of DNA sequence data per sample for markers that enable comparisons and combinations with past genetic and genomic approaches that have been used in CSP projects to document protected species relationships. The analysis of skimming data uncovered misidentified specimens, recovered biogeographic relationships, and identified a putative new species record of Anthothela.
Publication information
Macpherson, D., Connell, A., Bilewitch, J., Smith, L., Wood, C. R., Mills, S. (2025) INT2022-03 Identification, storage and genetics of cold-water coral bycatch specimens. Milestone 6. Final Annual Report. Prepared for Conservation Services Programme, Department of Conservation. NIWA Client Report 2025093WN. 75p.