Seabirds on the menu

August 10, 2011

Dragonfly staff attended the New Zealand Marine Sciences Society conference, held in Oban on Stewart Island from 5-8 July.

Getting to the island entailed travelling through Bluff, one of the few places where sooty shearwater pies may be bought for lunch.

The population of Stewart Island is only 360 in the winter, so the arrival of 150 scientists was noticeable around the township.

Muttonbirds (sooty shearwater or titi) are a local delicacy and around 350,000 are customarily taken from their burrows each year, when the chicks are almost fledged. Sooty shearwaters are also caught in trawl fisheries, and their numbers are now in decline. The sign advertising muttonbird pies for sale in Bluff emphasizes the multiple threats that seabirds face.

The conference was an intense three days of marine science. “It was also good to have a yarn with the local blue cod fishers in the pub, and they were keen to give us their views about things, including seabird interactions, commented Edward.

"We went on a charter trip with Squizzy, on the Lo Loma, and had a good crowd of mollymawks and albatrosses hanging around waiting for scraps."

“We also went over to Ulva Island, a pest-free bird sanctuary, and saw yellowheads, tree creepers and lots of weka on the beach, says Yvan, Dragonfly's keenest birder.

“Finlay and I went out looking for kiwi a couple of times. Unfortunately those two nights we got soaked but saw nothing. Then when I went out with Edward, we saw one wandering across the rugby field just on the edge of town.”

The conference aimed to investigate opportunities to increase the understanding of New Zealand’s marine environment and apply new knowledge to its management and conservation.

Dragonfly staff gave the following presentations:

Edward Abraham - Seabird bycatch in New Zealand fisheries.

An overview of the current status of knowledge of seabird bycatch in New Zealand fisheries was presented. In recent years there has been an increased focus by government and by the fishing industry on reducing seabird bycatch in New Zealand fisheries.

This has included the use of a range of mitigation devices, an increase in observer coverage in poorly observed fisheries and work aimed at understanding the impact of fisheries bycatch on seabird populations. The efficacy of measures aimed at reducing bycatch and directions for future research was discussed.

Yvan Richard - Risk of commercial fisheries to seabird populations

within the NZ EEZ. New Zealand is a global centre of seabird diversity, and some studies estimate a high number of seabirds are captured in commercial fisheries within the Exclusive Economic Zone (EEZ). The impact of these captures on species viability depends on demographic parameters such as population size, survival, and productivity.

The risk from bycatch in commercial trawl and longline fisheries for 64 New Zealand seabird species were examined. The black petrel (Procellaria parkinsoni) clearly stood out as the species most at risk from commercial fishing activities within the Exclusive Economic Zone.

Finlay Thompson - Common dolphin bycatch in New Zealand mackerel

trawl fisheries. Observer coverage of the mackerel trawl fishery in New Zealand waters between 1995 and 2009 allowed evaluation of common dolphin bycatch on the North Island west coast. Observer data were used to develop a statistical model to estimate total captures and to explore covariates related to captures.

Over the 14-year study period, there were 108 common dolphin captures reported by observers, with capture events frequently involving more than one individual. In the 2008-09 season, an estimated 25 common dolphins were captured in the mackerel trawl fishery.