At its 2010 meeting, the Scientific Committee agreed that a time series of recruitments from a well- designed survey in the Ross Sea could be a useful input into the stock assessment model and requested members develop a pre-recruit survey design. A preliminary proposal for a pre-recruit survey was presented to the 2011 meeting of WG-SAM. In this paper we provide an update of the preliminary proposal by taking into account the comments of WG-SAM. It provides the scientific rationale and background for the research proposal for a longline survey of pre-recruit toothfish in the southern Ross Sea, which has been submitted as a paper to the Scientific Committee.
We consider here the objectives of the survey, the target fish age and length classes to be monitored, appropriate survey strata size and location, the number of sets in each stratum required to achieve target c.v.s, and associated sampling methodologies. As a result of this review, we propose that the first survey be a pilot, with two main objectives:
(i) To establish the feasibility of developing a time series of longline surveys to monitor pre-recruit (<100 cm TL) toothfish in the south of SSRUs 881.J and 881.L in the southern Ross Sea using standardised gear in a standardised manner; and
(ii) To carry out experimental depth-stratified fishing in 400–600 m depth adjacent to the survey boundaries to establish the most appropriate depth strata for future annual surveys.