| dc.description.abstract | Antarctica’s Southern Ocean hosts a large range of important species that have been the subject of
marine exploitation for about two hundred of years. Historically, whales and seals have been
overexploited and this has led to increasing efforts to establish further fishing regulations and
conservation measures by organizations such as the International Whaling Commission (IWC) and
the Commission for Conservation of Antarctic Marine Living Resources (CCAMLR). This
ecosystem hosts a complex food web that heavily relies on the world’s most abundant species in
biomass, Antarctic krill (Euphasia superbia). This species is of concern because of its central role
in the food web as a primary prey species for the majority of predator species that are of
conservation importance. The Antarctic krill population faces future challenges such as potential
increases in fishing and receding sea ice due to climate change. Changes to CCAMLR’s current
krill management regime are necessary to ensure the sustainable management of krill in the future.
This thesis aims to evaluate to what extent current CCAMLR enacted krill catch limits function in
various catch scenarios where fishing demand is variable and krill recruitment may be decreasing
due to climatic factors. Further, what changes to the fishing regime can be made to strategize for
an economically viable fishing management regime that safe-guards significant predator species
in a future with variable catches and a warmer climate where sea-ice continues to recede? We
utilize the Mori and Butterworth model to simulate krill dynamics within study area A which is
composed of CCAMLR’s statistical area 48 and 58. We use a reliance weighted index to further
understand the effect of various scenarios on predator populations. Our study finds that fixed catch
limits below 4.7 million tonnes in a fixed catch limit scenario, or variable catch limits that are
between 10% and 15% of total stock size, achieves an equilibrium state for krill and all predator
species involved when the recruitment rate is at 0.4 and when recruitment suffers a 20% reduction
in a simulated sea-ice reduction scenario. The variable catch limit is more equipped to deal with
sea-ice reduction scenarios, but it is laborious to implement for CCAMLR. Further research
regarding updates to the Mori and Butterworth model, predator inter-species dynamics,
recruitment in relation to climate change are required to derive further understanding of this
complex system. | en_US |
