Dear MARMAM community,

My coauthors and I are pleased to announce the publication of our paper, ‘Genetic identifications challenge our assumptions of physical development and mother–calf associations and separation times: a case study of the North Atlantic right whale (Eubalaena glacialis)’ in a special issue of Mammalian Biology.

Philip K. Hamilton, Brenna A. Frasier, Lisa A. Conger, R. Clay George, Katharine A. Jackson, Timothy R. Frasier

You can find the article here.

While photo-identification is an effective tool to monitor individuals in wild populations, it has limitations. Specifically, it cannot be applied to very young animals before their identifying features have stabilized or to dead, decomposed animals. These shortfalls leave gaps in our understanding of survival, parentage, age structure, physical development, and behavioral variability. Here we report on 13 case studies of North Atlantic right whale, Eubalaena glacialis, calves that required genetics to track their life history data. These case studies revealed unexpected variations in mother–calf associations and separation times, as well as calf physical development. Prior to this study, calves were assumed to have died if their mothers were always alone on the feeding ground in the calf’s birth year. Using genetics and photo-identification, four such calves were discovered to be alive; two of the four possibly weaned earlier than expected at 7.5–8.0 months. To put these early separations in context, photo-identification data were queried and revealed that mothers and calves are seen apart from each other on the feeding grounds in 10–40% of all spring/summer sightings; previously, there were no published data on how often pairs are seen apart in the calf’s birth year. Two dead whales initially logged as calves of the year were discovered to be juveniles, thus allowing skewed survival estimates for calves of the year to be corrected. Genetically sampling animals early in their lives before they disperse or separate from their mothers provides an important means of individual identification at a time when photo-identification is not reliable.

 

The data behind this paper took years to collect and required the collaboration of many individuals and organizations along the east coast of North America. It serves as an excellent example of the power of working together.

 

Philip

 

Philip Hamilton

Senior Scientist

Kraus Marine Mammal Conservation Program

Anderson Cabot Center for Ocean Life

New England Aquarium

Central Wharf

Boston, MA 02110

(617) 973-5253

(802) 387-5277