Life in the Slow Lane: Ecology and Conservation of Long-Lived Marine Animals

When Are There “Too Few” Newborns in a Small Population of Marine Mammals?

Solange Brault

doi: https://doi.org/10.47886/9781888569155.ch8

Abstract. —A suite of stage- and age-classified models are constructed to determine whether an apparently unusual event is the result of external, environmental causes in a small population. These models are used as a baseline, or null hypothesis, that such an event may result from population structure and demographic stochasticity. An observed multiyear reproductive delay in a pod of killer whales Orcinus orca is used as an example of this process. All models, regardless of their complexity, give the same qualitative result: the observed reproductive delay could not be explained by pod composition and demographic stochasticity; external causes have to be sought to explain this phenomenon.