Finlay N Thompson & Edward R Abraham
Thompson, F. N., & Abraham, E. R. (2009). Six monthly summary of the capture of protected species in New Zealand commercial fisheries, summer 2007–08. New Zealand Aquatic Environment and Biodiversity Report No. 35.
A summary is presented of captures of seabirds and marine mammals in trawl and surface longline fisheries within the New Zealand Exclusive Economic Zone (EEZ), for the first half of the 2007–08 fishing year (1 October 2007 to 31 March 2008, inclusive). Data from other fisheries, such as bottom longline and set-net, were not available for the period covered.
Ministry of Fisheries observers report captures of protected species when they occur, and these data are presented here. Observers in trawl fisheries recorded 177 bird captures in the first half of 2007– 08, an increase from 124 bird captures in the first half of 2006–07. The most frequently caught birds in trawl fisheries were 65 sooty shearwater (Puffinus griseus), 45 white-chinned petrel (Procellaria aequinoctialis) and 30 white-capped albatross (Thalassarche steadi). Other captures included eight Salvin’s albatross (Thalassarche salvini), three Buller’s albatross (Thalassarche bulleri), and single captures of Campbell albatross (Thalassarche impavida) and southern royal albatross (Diomedea epomophora). One black petrel (Procellaria parkinsoni) was caught in a scampi trawl, and was confirmed by necropsy. A Westland petrel (Procellaria westlandica) was reported caught alive by an observer, but the identity could not be confirmed as it was released.
There were 25 New Zealand fur seals (Arctocephalus forsteri) observed caught in trawl fisheries, 21 of them south of 48◦ south. Seven New Zealand sea lions (Phocarctos hookeri) were caught, four of them in the Auckland Islands squid fishery and three in the southern blue whiting fishery to the east of Campbell Island. There were 20 dolphins, identified by the observers as common dolphin (Delphinus delphis), caught in the jack mackerel fishery on the west coast of the North Island. This was twice as many as were observed caught in the first half of 2006–07. No other species of marine mammal were observed caught, and there were no marine mammals caught in surface longline fisheries. No turtles were caught in either trawl or surface longline fisheries.
Between the first half of 2006–07 and the first half of 2007–08 the total trawl effort decreased from 54 500 to 48 300 tows. In contrast, the number of observed tows increased from 3884 to 4436. Most bird captures were in the squid trawl fishery. There was a small increase in the number of observed tows in the squid fishery, from 1075 to 1194. Observed captures rose from 89 to 136 birds, and the capture rate increased from 8.3 to 11.4 birds per one hundred tows. However, across all trawl fisheries, observed captures of white-capped albatross decreased from 42 to 30 birds. Observed captures of other albatross species increased slightly from 12 to 14 birds. Of the 30 white-capped albatross caught in the first half of 2007–08, only eight were caught on trawl warps. Coverage of inshore trawl fisheries remains low. During the first half of the 2007–08 fishing year 97 inshore trawls were observed, 0.3% of the fishery. During these trawls two birds were caught, a cape petrel (Daption capense) and a white-capped albatross.
There were seven birds observed caught in surface longline fisheries, compared with 85 in the first half of 2006–07. All birds were caught by domestic vessels. The species caught were two flesh-footed shearwaters, two Buller’s albatross, one Salvin’s albatross, one Gibson’s albatross (Diomedea gibsoni) and one unidentified petrel. The large decrease in the total observed captures can be attributed to the absence of charter surface longline vessels fishing operating in the first half of 2007—08. Although observer coverage in the domestic longline fishery was low (only 3.4% of hooks were observed), there was a decrease in the seabird capture rate within this fishery, from 3.8 to 3.2 birds per 10 000 hooks.