Inter-Research > MEPS > v689 > p179-189  
MEPS
Marine Ecology Progress Series

via Mailchimp

MEPS 689:179-189 (2022)  -  DOI: https://doi.org/10.3354/meps14040

Larger females have more calves: influence of maternal body length on fecundity in North Atlantic right whales

Joshua D. Stewart1,7,*, John W. Durban2,3, Hollis Europe2, Holly Fearnbach4, Philip K. Hamilton5, Amy R. Knowlton5, Morgan S. Lynn2, Carolyn A. Miller6, Wayne L. Perryman2, Brandon W. H. Tao2, Michael J. Moore6

1National Research Council Postdoctoral Fellow for Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla Shores Drive, La Jolla, CA 92037, USA
2Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla Shores Drive, La Jolla, CA 92037, USA
3Southall Environmental Associates, Inc., Soquel Dr., Aptos, CA 95003, USA
4Marine Mammal Research Program, SR3, SeaLife Response, Rehabilitation and Research, S 216th St., Des Moines, WA 98198, USA
5Anderson Cabot Center for Ocean Life, New England Aquarium, Boston, MA 02110, USA
6Department of Biology, Woods Hole Oceanographic Institution, Woods Hole Rd., Woods Hole, MA 02543, USA
7Present address: Marine Mammal Institute, Department of Fisheries, Wildlife, and Conservation Sciences, Hatfield Marine Science Center, Oregon State University, Newport, OR 97365, USA
*Corresponding author:

ABSTRACT: North Atlantic right whales (NARW) are critically endangered and have been declining in abundance since 2011. In the past decade, human-caused mortalities from vessel strikes and entanglements have been increasing, while birth rates in the population are at a 40 yr low. In addition to declining abundance, recent studies have shown that NARW length-at-age is decreasing due to the energetic impacts of sub-lethal entanglements, and that the body condition of the population is poorer than closely related southern right whales. We examined whether shorter body lengths are associated with reduced fecundity in female NARW. We compared age-corrected, modeled metrics of body length with 3 metrics of fecundity: age at first reproduction, average inter-birth interval, and the number of calves produced per potential reproductive year. We found that body length is significantly related to birth interval and calves produced per reproductive year, but not age at first reproduction. Larger whales had shorter inter-birth intervals and produced more calves per potential reproductive year. Larger whales also had higher lifetime calf production, but this was a result of larger whales having longer potential reproductive spans, as body lengths have generally been declining over the past 40 yr. Declining body sizes are a potential contributor to low birth rates over the past decade. Efforts to reduce entanglements and vessel strikes could help maintain population viability by increasing fecundity and improving resiliency of the population to other anthropogenic and climate impacts.


KEY WORDS: Photogrammetry · Cetacean · Reproduction · Anthropogenic impacts


Full text in pdf format
Supplementary material 
Cite this article as: Stewart JD, Durban JW, Europe H, Fearnbach H and others (2022) Larger females have more calves: influence of maternal body length on fecundity in North Atlantic right whales. Mar Ecol Prog Ser 689:179-189. https://doi.org/10.3354/meps14040

Export citation
Mail this link - Contents Mailing Lists - RSS
Facebook - - linkedIn