Modelling dominance shifts of anchovy and sardine with a frame-based approach : sensitivity to the underlying sardine population dynamics

It has been shown that sardine and anchovy populations in the southern Benguela have alternated dominance during the past 50 years, and a frame based model that explores the usefulness of frames within a marine ecosystem by modelling sardine/anchovy dominance shifts in the southern Benguela has been developed in a previous study. The existing model contains a sardine population sub-model without age structure and the inclusion of age-structure allows age-related dynamics to be incorporated in the model design. In this mini-dissertation, an age-structured sardine population is implemented in the frame based model by using the sardine assessment model from the joint sardine/anchovy Operational Management Procedure, OMP-02. Methods for incorporating biological processes - such as the hypothesised school trap phenomena - that were present in the existing frame based model into the OMP-02 equations are developed, critically analysed and tested.

Grantor dc:publisher.institution

Department of Oceanography

Year dc:date.issued

2012

Author dc:creator

• Botha, Jakobus Stephanus

Advisor dc:contributor.advisor

• Jarre, Astrid

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/10261

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/10261