MEPS 400:267-276 (2010)  -  doi:10.3354/meps08426

Sex-specific survival in the humpback whale Megaptera novaeangliae in the Gulf of St. Lawrence, Canada

Christian Ramp1,2,*, Martine Bérubé3, Per Palsbøll3, Wilhelm Hagen2, Richard Sears1

1Mingan Island Cetacean Study, 285 rue Green, St. Lambert, J4P 1T3, Quebec, Canada
2Marine Zoologie (FB2), Universität Bremen (NW2), Postfach 330 440, 28334 Bremen, Germany
3Department of Genetics, Microbiology and Toxicology, Stockholm University, 106 91 Stockholm, Sweden

ABSTRACT: Sex-biased adult mortality is commonly observed in the animal kingdom. In mammals, a predominantly male-biased mortality is found in species with a polygynous mating system, while in monogamous taxa, female-biased mortality prevails. In the largest of all mammals, the Mysticeti, no sex-specific mortality has been found so far apart from that found in biased whaling data. We estimated sex-specific survival rates using an Akaike Information Criterion (AICc)-based model selection of 18 yr of mark-recapture data from a North Atlantic humpback whale feeding aggregation, the Gulf of St. Lawrence, Canada. We found a significantly higher survival rate for females (0.992; 95% CI 0.985–0.999) than for males (0.971; 0.943–0.985). Humpback whales are a typical polygynous species, with males competing intensively for mates while females bear the costs of pregnancy and lactation. However, the existing data did not allow us to test if differential costs of reproduction are causing the skew in mortality. We could not preclude stock-specific differences, such as contamination levels, migratory distances, and reproductive parameters (e.g. calving intervals, age at sexual maturity), and further data are needed to investigate the underlying reasons.


KEY WORDS: Sex-specific survival · Mark-recapture models · Humpback whale · Gulf of St. Lawrence · Mating strategies


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Cite this article as: Ramp C, Bérubé M, Palsbøll P, Hagen W, Sears R (2010) Sex-specific survival in the humpback whale Megaptera novaeangliae in the Gulf of St. Lawrence, Canada. Mar Ecol Prog Ser 400:267-276

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