Millions of birds and mammals migrate into the Southern Ocean each spring-summer to feed. Climate-driven changes here have regionally specific consequences for ocean properties, sea ice, and biological productivity. There is high uncertainty about what this means for food and habitat resources upon which migrants depend. This work focuses on the East and West Australian populations of humpback whales migrating into East Antarctic feeding grounds.
We apply a relatively new approach to model behaviour-dependent habitat selection, an integrated framework which identifies behavioural states via a Hidden Markov model, and includes habitat variables to fit a step selection function and capture space use. Satellite tracking observations are used together with modelled properties from a suite of CMIP6 Earth System Models relating to ocean temperatures, sea-ice extent, and integrated primary production, now (2015-2024) and into the future (2090-2100).
We present the framework and preliminary results, highlighting challenges inherent in both reasonably representing a complex biological process, and limitations of ESMs in representing biophysical variables relevant to ecological applications for marine predators. Our projection capability will only improve, as both modelling fields continue to advance and end users drive their application towards an integrated understanding of important marine systems, and their likely future.