Identification of seabirds captured in New Zealand fisheries 1 July 2022 - 30 June 2023
Introduction
This is the final annual report for INT2022-02: Identification of seabirds captured in New Zealand fisheries, 1 July 2022 - 30 June 2023. Published August 2024.Download the publication
Summary
The New Zealand Exclusive Economic Zone (EEZ) supports a diverse range of seabird species. Much of the commercial fishing activity in the region overlaps with seabird foraging ranges. The accurate identification of bycatch seabirds interacting with New Zealand fisheries is vital for determining the impact of fisheries on these seabird populations.
Between 1 July 2022 and 30 June 2023, a total of 475 seabirds were reported as incidental interactions with commercial fishing vessels by on-board New Zealand Government Observers. These 475 seabirds comprised 29 identifiable at species level and 16 identified to genus level. There were 216 seabirds classed as live interactions (birds released alive) and 259 resulted in the death of the seabird. Of the 216 alive events, 206 (95%) were interaction-only (i.e., no photograph taken) and only ten (5%) were photographed interactions. Of the 259 deceased seabirds, 24 (9%) were interaction-only (i.e., no photograph taken), 87 (34%) were photographed interactions and the remaining 148 (57%) were returned for necropsy.
Of the 148 individual seabirds killed by incidental bycatch and returned for necropsy, the majority were returned in 2023; during February (n=25, 17%), April (n=21, 14%), and June (n=15, 10%).
A total of 148 seabirds comprised from 23 species were returned for necropsy, from 39 vessels. The top five most prevalent species returned for necropsy were karetai kauae mā/white-chinned petrel (n=29, 20%), toroa/Salvin’s albatross (n=27, 18%), toroa/New Zealand white-capped albatross (n=19, 13%), toroa/Buller’s albatross (n=18, 12%), and tītī/sooty shearwater (n=14, 10%). These combined species accounted for 107 (73%) of all seabirds returned for necropsy.
The birds returned for necropsy from variety of fishing methods, such as trawl (n=116, 78%), longline (n=16, 11%), set net (n=10, 7%) and purse seine (n=6, 4%). The most predominant causes of injuries identified during necropsy across all birds were: waterlogged (n=72, albatross 68% and non-albatross 32%), broken wings (n=37, albatross 89% and non-albatross 11%), and broken legs and feet (n=28, albatross 54% and non-albatross 46%).
After assessing injuries, other aspects were determined such as sex, age, and breeding status. Of the 148 birds, 131 (89%) were adults, with mostly males (n=93, 63%) returned. Of the 131 adults, the number breeding birds equated to 73 (56%), non-breeding 19 (15%), and 39 (30%) were unconfirmed breeding stage.
Stomach and gizzard contents were assessed via visual examination and discards/offal such as whole bait fish and fish ‘puree’ (n=113, 76%) appeared to represent higher amounts than naturally foraged prey in the stomach (n=64, 43%). Within the gizzard, most abundantly identified items were squid beaks (n=60, 41%), fish or squid eyeballs (n=37, 24%), fish bones and skin (n=36, 24%), and otoliths (n=30, 20%).
In addition to the seabirds that were returned for necropsy, examination of data, photographs or videos from the Ministry for Primary Industries (MPI) Central Observer Database (COD) and images provided by Government Observers identified a further 327 seabirds reported as seabird-vessel interactions or photographed (as dead or alive captures) aboard 44 fishing vessels. Over half (66%) of these were reportedly released alive. Photographs represented 97 of the 327 seabirds spread across twelve species. Reviewers noted that image quality had improved compared to previous reporting periods, but blurry or distant images continue to be provided.
Publication information
Bell, E.A. & Mclaren, D. (2024). INT2022-02: Identification of seabirds captured in New Zealand Fisheries: 1 July 2022 to 30 June 2023. Unpublished Wildlife Management International Technical Report for the Department of Conservation. 43 p.