Autopsy report for seabirds killed and returned from New Zealand fisheries, 1 October 2006 to 30 September 2007

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Summary

Between 1 October 2006 and 30 September 2007 (the 2006-07 fishing year) a total of 324 seabirds comprising 22 taxa were killed and returned for autopsy from 50 different fishing vessels making 62 trips (ten vessels made two trips each from which seabirds were returned, and one vessel made three trips from which seabirds were returned) by on-board Government observers. Included in these totals were two unobserved trips, which returned a total of 12 seabirds. 

Birds were returned from longline vessels targeting tuna (domestic and chartered boats), swordfish and ling, from trawl vessels targeting primarily squid, hoki and scampi together with a range of other species, and from set net vessels targeting sharks. Seabirds returned during the 2006-07 fishing year were dominated numerically by two species, which combined accounted for 45% of all specimens. Sooty shearwater Puffinus griseus was the most numerous species returned (73 birds, 23% of the total). The six species which have been the most numerous historically comprised 85% of returns in 2006-07.

Of all seabird returns, 40% were from just four trips, whereas 41 trips (66%) caught only one, two or three birds. Of birds returned from all longline fisheries, 76% had injuries consistent with being hooked or entangled in the bill or throat, with albatross taxa about three times more likely to be killed in this way compared to non-albatross taxa. In contrast, of all returns from trawl fisheries combined, 70% were killed through entanglement in the net, and of these 79% were non-albatross taxa. Warp interaction was the likely cause of death in 29% of trawl specimens, of which 83% were albatross taxa. 

Mean fat scores were generally higher in birds from the 2006-07 fishing year than in most previous years, although mean fat scores were lower in 2006-07 than in 2005-06. For trawl fisheries, offal was present in 33-53% of albatross stomachs and in 33-50% of stomachs from non-albatross taxa, with a further 7-40% of non-albatross stomachs containing a mix of natural food and offal. Seabirds returned from the 2006-07 fishing year, and from trawl fisheries in particular, showed clear size-related differences in the likely cause of death, and offal appears to continue to be an attractant for many taxa.

Publication information

D.R. Thompson

DOC Marine Conservation Services Series 3

Contact

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

Email: csp@doc.govt.nz