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Bibliographie de l'Institut Maurice-Lamontagne

Thierry GOSSELIN

SAINTE-MARIE, B., T. GOSSELIN, T., J.-M. SÉVIGNY, N. URBANI, 2008. The snow crab mating system: opportunity for natural and unnatural selection in a changing environment. Bull. Mar. Sci., 83(1): 131-161.

[Résumé disponible seulement en anglais]
The impact of fishing as a driver of sexual selection is not well understood in crustaceans. Fishing must be viewed as acting in conjunction with, or in opposition to, natural factors, which also modify the context for sexual competition, mate choice, and sexual conflict. We review knowledge of the polygynandrous mating system of the snow crab and evaluate the likely interplay between natural and fishing forces in the process of sexual selection. The snow crab has determinate growth and two female reproductive stages (primiparous and multiparous) with discrete and disjunct mating seasons. Temperature shifts the spectrum of size at maturity in both sexes and determines female reproductive tempo, thereby altering sperm supply, egg production, and operational sex ratio. Population dynamics modulates the phenotype of receptive individuals and the direction and intensity of sexual competition over time. Fishing directed only at large males may attenuate or exacerbate some aspects of sexual conflict at primiparous mating, depending on the natural context, but otherwise it consistently promotes mating of less fecund males, reduces opportunity for female mate choice, and increases the likelihood of sperm limitation. These changes have mixed but still incompletely appreciated effects on female reproductive fitness. The long-term potential for selection against large size at maturity remains uncertain. ©2008 Rosenstiel School of Marine and Atmospheric Science of the University of Miami

GOSSELIN, T., B. SAINTE-MARIE, J.-M. SÉVIGNY, 2007. Individual identification of decapod crustaceans II : natural and genetic markers in snow crab (Chionoecetes opilio). J. Crust. Biol., 27(3) : 399-403.

[Résumé disponible seulement en anglais]
Methods for the identification of individual crustaceans are needed in many types of studies. Snow crab (Chionoecetes opilio) individuals have distinctive natural patterns of tubercles and spines on the carapace. The results of a double-marking experiment using these natural markers along with genetic (microsatellite) markers confirm that natural markings are a reliable means of recognizing individuals within groups of tens to hundreds of snow crabs. These natural markings are persistent through at least two molts. They have already demonstrated their usefulness in laboratory studies of molting and mating and could be applied to a wider spectrum of investigations. A cursory examination suggests that similar carapace features could be used to identify individuals in other crustacean species as well.©2007 The Crustacean Society

GOSSELIN, T., B. SAINTE-MARIE, L. BERNATCHEZ, 2005. Geographic variation of multiple paternity in the American lobster, Homarus americanus. Mol. Ecol., 14(5): 1517-1525 .

[Résumé disponible seulement en anglais]
We studied the frequency of multiple paternity for American lobster (Homarus americanus) at three Canadian sites differing in exploitation rate and mean adult size. The probability of detecting multiple paternity using four microsatellite loci and 100 eggs per female was in excess of 99 % under various scenarios of paternal contribution. Overall, 13 % of the 108 examined females carried a clutch sired by two or three males. Multiple paternity was observed at the two most exploited sites (11 % at Magdalen Islands and 28 % at Grand Manan Island), whereas single paternity only was observed at the least exploited site (Anticosti Island). Within populations females with a clutch sired by more than one male tended to be smaller than females with a clutch sired by a single male. Based on these and other findings, we postulate a link between female promiscuity and sperm limitation in the American lobster.©2005 Blackwell Publishing Ltd