Developing a bioenergetic model for right whales to assess population consequences of exposure to multiple stressors
Abstract
Marine mammals are increasingly exposed to a multitude of human activities, or stressors (e.g. shipping, naval activities, fisheries , oil and gas exploration and whale watching), which can have cumulative effects on targeted populations. The North Atlantic right w hale (Eubalaena glacialis, NARW), currently numbering ~356 animals, is on a trajectory to extinction, with multiple stressors (e.g. entanglement in fishing gear and reduced prey availability) hampering their recovery from whaling. The overarching aim of this proje ct is to develop a bioenergetic model for right whales to predict population consequences of multiple stressors (PCoMS). Rather than ergetic state, I will build a baseline bioenergetics model using data from populations that have been able to recover from whaling. The closely related southern right whale (E. australis, SRW) is found in the southern hemisphere and are very similar in body shape, size and life history characteristics to the NARW. My c condition (>13000 measurements from >3000 individuals), behavioural data (>100 hours of focal follows) and individual female reprod uctive histories (>1000 females) from a large number of whales from two well studied populations at the Head of Bight (HoB), Austral ia (30 years of monitoring data), and Pennsula Valds (PV), Argentina (50 years of monitoring data). While the HoB population repre sent a healthy (growing) right whale population in a pristine undisturbed environment, the PV population is exposed to both acute an (calf survival) and population dynamics. Combined, these contrasting populations offers data across the full range of possible beha viours, body condition and reproductive rates, which is necessary to build an accurate bioenergetics model for right whales. In the first work package (WP1) of this project, I will use this comprehensive data set to estimate the energetic costs of growth, maintena nce and reproduction in SRWs. In WP2, I will develop an individual based model (IBM) to simulate the optimal allocation of energy to growth, maintenance and reproduction, to maximize female lifetime reproductive success. I will validate my model predictions by fit ting the IBM to my two contrasting populations of SRWs (HoB and PV), for which long-term monitoring data on female reproductive hist ories exist. Finally, in WP3 I will build a population model of multiple IBMs, each representing an individual whale, to simulate th e population trajectory of SRWs under different disturbance scenarios to predict PCoMS. To conduct WP3, I will build a baseline mode l based on the undisturbed HoB population, which will be verified using long-term monitoring data (population size and demographics) . I will then simulate the PV population to determine how gull harassment, in combination with environmental factors (variation in p rey productivity) can affect female reproductive success (calf survival) and population dynamics. To understand how multiple stresso rs affect the behaviour of right whales, I will carry out empirical studies where I expose SRWs with varying levels of background st ress (HoB vs. PV) to an additional stressor (e.g. vessel noise from whale watching boats) to determine if multiple stressors have ad ditive, synergistic or antagonistic effects on behaviour. The outcome of this project will be a predictive model which can be used t o assess PCoMS in right whale populations (including the NARW) under different management scenarios (different levels of disturbance ). This project highly complement the objectives of the Office of Naval Research Marine Mammals and Biology program and current work by the ONR/SERDP PCoMS working group.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 22, 2021
- Source ID
- N000142112601
Entities
People
- Fredrik Christiansen
Organizations
- Aarhus University
- Office of Naval Research
- United States Navy