Feasibility of trawl surveys to estimate abundance of juvenile toothfish in Subarea 88.1

This report presents results from a desktop study to determine the feasibility of conducting trawl surveys for juvenile toothfish in Subarea 88.1 (Ross Sea). Potential problems including a largely unknown juvenile distribution, variable ice cover, large survey area, and rough bottom topography, were considered using data from published and unpublished literature, the exploratory longline fishery and previous research cruises.
The major limitation on a trawl survey in the Ross Sea is ice cover. On average over the last three years, 63% of the seabed area from 0–600 m depth was not fishable in January–February because of ice. Ice cover varied greatly between years, with the untrawlable area ranging from 31% in 2002 to 89% in 2002. Less than 10% of the potential trawl survey area was fishable in all three years.