Researchers at Saint Mary's University led a research team, consisting of numerous collaborators in Canada and the Unites States, that has just published a peer-reviewed paper in the Royal Society Open Science on the effects of inbreeding on reproduction in the endangered North Atlantic right whale.
The population of North Atlantic right whales (Eubalaena glacialis) is currently represented by only ~356 individuals. The species faces ongoing threats from human activity (i.e. vessel strikes and entanglement in fishing gear), but they also are not reproducing as often as would be expected. With extremely low levels of genetic diversity, limited options for mates, and variation in reproductive success between females within the population, researchers wanted to understand if inbreeding is contributing to their poor reproductive performance.
This study quantified reproductive success in female North Atlantic right whales using reproductive history information collected over decades of field observations. Researchers also used genome sequencing to investigate how inbred each female was, and assessed if and/or to what degree inbreeding accounted for this variation in reproductive success among females.
The researchers found that inbreeding did not explain the variance in reproductive success currently observed in females. However, combining these results with prior studies suggests that inbreeding is impacting which fetuses survive to term, and therefore is likely limiting reproductive success of the species as a whole.
This process is likely a double-edged sword. On the negative side, this process is likely lowering the overall reproductive performance of the species, and therefore limiting recovery. However, on the positive side, it also means that those calves that are born have higher levels of genetic diversity (are less inbred) than expected, which could be key in allowing the species to recover in the long-run, if we can reduce mortalities.
OVERALL RESEARCH PROJECT
This study builds on ongoing long-term research on North Atlantic right whales taking place at Saint Mary's University and elsewhere. This specific work was partially supported by Genome Canada, Genome Atlantic, and Research Nova Scotia through a Large-Scale Applied Research Project (LSARP) award. The $6-million, four years international collaboration is managed by Genome Atlantic in partnership with Saint Mary's University, the New England Aquarium, Fisheries and Oceans Canada, the National Oceanographic and Atmospheric Administration, the Canadian Whale Institute, the Georgia Department of Natural Resources, and Duke University.
Project partners at Saint Mary's include Carla Crossman, PhD candidate and Dr. Tim Frasier, professor of Biology and Forensic Science.
The paper is available here: https://royalsocietypublishing.org/doi/10.1098/rsos.240490
