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

Authors: 

Rolland, R.M., Schick, R.S., Pettis, H.M., Knowlton, A.R., Hamilton, P.K., Clark, J.S. and S. Kraus

Year: 

2016

Journal/Publisher Name: 

Marine Ecology Progress Series

Publisher Address: 

Volume (Issue #): 

542

Page #s: 

265-282

Contact information: 

John H. Prescott Marine Laboratory, New England Aquarium, Boston, MA 02110, USA rrolland@neaq.org
Summary: 

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.