Rationale

It has become evident that advances in the "isolated stock" methodology that has been used to assess breeding stocks A and G of the Southern Hemisphere humpback whales are necessary to handle the complexities of mixing and sub-stock structure associated with breeding stocks B and C, and D, E and F.

The purpose of the workshop is to develop such methodology to allow its ready application to data for these regions during the 2009 meeting of the Scientific Committee. Without this prior consolidation of methodology, it will not be possible within the time available at the annual meeting of the Scientific Committee to make the progress needed on agreeing both methodology and application to secure reasonable advance in the Comprehensive assessment of humpback whales in the Southern Hemisphere.

Objectives

To advance the Comprehensive Assessment of Southern Hemisphere humpback whales by the development of assessment methodology incorporating stock mixing and interchange processes to allow its ready application to data for these regions during the 2009 meeting of the Scientific Committee.

Terms of reference

The Terms of Reference of the workshop are to progress and desirably agree the following aspects of the methodology needed for the assessment of the B and C, and the D, E and breeding stocks in combination:

1. mixing of these stocks/sub-stocks on the feeding grounds;
2. allocation of past catches on the feeding grounds between stock/sub-stocks, using genetic data to estimate the proportions of such stocks/sub-stocks in different longitudinal regions at high latitudes;
3. disaggregation of population models by sex to take account of information indicating other than 50:50 sex ratios in data for catches or information relating to abundance;
4. estimation of exchange rates between sub-stocks on or near breeding grounds using capture-recapture data;
5. review results from initial simulation testing of models put forward to estimate exchange rates (see 4 above) and finalise further simulation tests to allow selection of appropriate models for this purpose on the basis of test results to be reported at the 2009 Scientific Committee meeting; and
6. clearly specify the various categories of input data needed to implement such models.

Venue and timing: Seattle 3-6 February 2009.

Steering Group: Zerbini (Convenor), Baker, Butterworth, Donovan, Double, Hammond, Jackson, Punt, Rosenbaum, Wade and Weinrich.

The following documents are available to download: