FISHERIES_2021_MAR_SWG-PEL_10.pdf (362.1 kB)

The Penguin decline – where should most analysis effort really be focused?

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posted on 23.04.2021, 15:11 by Doug ButterworthDoug Butterworth
The impact, if any, of pelagic fishing in the neighbourhood of penguin breeding colonies on penguin population trends is unclear. Broad indications are, however, that the likely magnitude of any such impact still leaves some 90% of the recent penguin decline to be explained, and a priority for further analyses is to seek to understand the reasons for this decline better. Two hypotheses to explain this decline are summarized: shortage of food, and loss of optimal breeding habitat coupled to the large increase in abundance of a competing seal population during the previous century. These two hypotheses suggest radically different management actions to mitigate the current penguin decline. Provision of related scientifically based advice to managers in line with an ecosystem approach requires the development of tactical multi-species models, likely of the “MICE” type. This would be to evaluate and to attempt to discriminate (on a broadly defensible basis statistically) amongst those two and possibly other hypotheses for the penguin decline, so as to be in line with best practice internationally in the provision of tactical scientific fisheries management advice.

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Department of Mathematics and Applied Mathematics, University of Cape Town