Some comments on the suggested use of the “one third for the birds” measure as a pelagic OMP performance statistic threshold

Butterworth, Doug S

Some comments on the suggested use of the “one third for the birds” measure as a pelagic OMP performance statistic threshold

Working Paper

2015

Publisher

University of Cape Town

Department

Marine Resource Assessment and Management Group

Faculty

Faculty of Science

Abstract

Although Cury et al. (2011) provide valuable insight into seabird population dynamics, their suggested application of a “one third for the birds” threshold is considered premature for a number of reasons. Further research remains needed to develop population models for the seabird populations considered, to utilise the assessments of their prey species to infer their abundance distributions in the absence of harvesting, and to take account of size structure effects. Such thresholds are not pertinent when Management Procedures (MPs) are used to provide management advice; there the relevant performance statistics relate to projected seabird abundance trends. The role of analyses such as those by Cury et al. (2011) in such circumstances is to inform the specification of the predator-prey models included in the operating models used for testing those MPs.