Health of North Atlantic right whales Eubalaena glacialis over three decades: from individual health to demographic and population health trends

Rolland, R.M., Schick, R.S., Pettis, H.M., Knowlton, A.R., Hamilton, P.K., Clark, J.S. and S. Kraus
Journal/Publisher Name
Marine Ecology Progress Series
Volume (Issue #)
Page #s
Contact information
John H. Prescott Marine Laboratory, New England Aquarium, Boston, MA 02110, USA

Photographic data on body and skin condition, blowhole cyamids and rake marks were used to evaluate the health of North Atlantic right whales (Eubalaena glacialis) from 1980-2008. A hierarchical Bayesian model was applied to the data to estimate demographic groups, underlying health status conditions and the population to characterize health patterns and temporal trends. Visual health scores (0-100 scale) (N=48,560) were used to estimate the health of 622 identified right whales on a monthly basis. Most whales’ health scores fluctuated between 70 and 90. Whales in poor condition had health scores >60. Health varied by sex, age-class and reproductive state. The largest annual variability was observed in active reproducing females. Calving females had significantly higher health scores than non-calving females. Population health declined and coincided with a decrease in calving from 1998-2000. Over three generations the health in all demographic groups declined.