Population modelling of humpback whales in East Australia (BSE1) and Oceania (BSE2, BSE3, BSF2)

Humpback sub-stocks BSE1 (East Australia), BSE2 (New Caledonia), BSE3 (Tonga) and BSF2 (French Polynesia) show significant genetic differentiation, yet share common high latitude feeding grounds between 130E-100W and were subject to 41,871 whaling catches across this feeding ground between 1900-1978. In order to explore the population history and develop a population assessment for this region, we have constructed a two-stock Bayesian logistic ‘FITTER’ model for neighbouring pairs of breeding grounds in the South Pacific. This model allocates catches from each shared feeding ground to breeding stocks in a ratio according to annual model predicted abundance on each breeding ground. A number of 2-stock scenarios are explored: East Australia / Oceania (New Caledonia, Tonga and French Polynesia combined), East Australia / New Caledonia (shared Southern Ocean feeding ground 130E-180), Tonga/French Polynesia (shared Southern Ocean feeding ground 180-110W), and preliminary runs for a combined West Australia / East Australia / Oceania 3-stock catch allocation model. Sensitivity of models to catch allocation scenarios, CPUE and other abundance indices are preliminarily explored.

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