Population Studies of the North Atlantic Right Whale


Hal Caswell and Christine Hunter, Biology Department, WHOI

Awarded:  May 2004

Population models contribute to conservation in four ways: by assessment of population status, diagnosis of the causes of poor performance, prescription of management interventions, and prognosis of population viability. These tasks all require estimates of the vital rates and the construction and analysis of population models, especially analysis of population growth, sensitivity to perturbations, and environmental fluctuations.

This research program will produce a new generation of population analyses of the right whale. It will require advances in mark-recapture estimation of the vital rates and powerful new analyses of population models. Our previous work applying mark-recapture analysis to the right whale photo ID catalog provided striking insights into the right whale population (Caswell et al. 1999, Fujiwara and Caswell 2001, 2002a,b, Fujiwara 2002). It showed that survival, especially of females with calves, has been declining since the 1980s, that inter-birth intervals have increased, and that these trends (especially the first) have reduced population growth rate from positive to negative values.

As is so often the case in science, each step in the analysis has opened up new questions. Fortunately, the development of new analytical and modeling methods has kept pace; they make it possible for us to answer these questions.  Our overall goal is to increase - dramatically - our understanding of right whale population dynamics (is the population increasing or declining? how fast? in response to what kinds of environmental fluctuations? how much heterogeneity is there in the population?) and our ability to focus management activities (what is the relative importance of changes in survival and reproduction? of survival of different stages in the life cycle? how much must survival or reproduction improve to affect persistence?). Here we document the overall directions of the analysis and specify goals for Phase 1.