Using bioenergetic models to investigate the effect of disturbance on marine mammals

Speaker: Magda Chudzinska (CREEM/SMRU Consulting)

Abstract:

Disturbance can cause behavioural, physiological and health changes that subsequently affect an individual’s vital rates. Bioenergetic models, as recently presented by Enrico, have been used to infer how an individual’s energy stores and allocation change with behavioural state or as a consequence of disturbance.

I will present a set of dynamic energy budget models for harbour porpoises, harbour and grey seals and demonstrate how they were used to assess the effect of different levels of disturbance (corresponding to a 1-12h cessation of foraging on a day of disturbance) and residency pattern, obtained from spatially explicit movement models, on vital rates (conceptions, births, survival). I will focus on the effect of food availability, residency, in-between disturbance duration required for animals to recover and time of year of disturbance on the vital rates. I will also demonstrate how the effect of disturbance may differ for populations with different growth tendencies.

The models required values for more than 30 parameters each and taking account of the uncertainties that are associated with these values is critical. I will demonstrate how Approximate Bayesian Computation (ABC) can be used to quantify the uncertainty associated with parameters that are not directly observable and, potentially, replace expert elicitation process.