University of Cape Town
FISHERIES_2020_JAN_SWG-PEL_09rev.pdf (1 MB)

Updated implementation of the Algorithm recommended by the Panel for the 2016 International Stock Assessment Workshop for assessing whether or not to continue with the penguin island closure experiment

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posted on 2021-02-10, 13:50 authored by Andrea Ross-GillespieAndrea Ross-Gillespie, Doug ButterworthDoug Butterworth
The analysis conducted late in 2016 to apply the algorithm recommended by the international Panel to evaluate the results of the island closure experiment is extended to include the further data now available, as well as to incorporate results further response variables for which data have been provided, making for a total of seven variables in all. For Dassen Island, all the response variables except for chick survival give little to no indication of a biologically meaningful negative impact of fishing on the penguin population. For Robben island, two of the data sets (chick condition and fledging success) provide evidence for a meaningful negative impact of fishing; the other response variables give little indication of such an impact. For all the variables not currently reflecting such an impact (except for chick survival at Robben island), at least an additional 20 years’ data would be required before there is an 80% probability of detecting such an impact, if it is indeed present.



Department of Mathematics and Applied Mathematics, University of Cape Town