MEPS 229:173-184 (2002)  -  doi:10.3354/meps229173

Fecundity, growth rate and survivorship at the interface between two contiguous genetically distinct groups of Semibalanus balanoides

Anik Brind¹Amour1, Edwin Bourget2,*, Réjean Tremblay3

1Groupe de Recherche Interuniversitaire en Limnologie (GRIL), Département de sciences biologiques, Université de Montréal. CP 6128, succursale. Centre-ville, Montréal, Québec H3C 3J7, Canada
2Groupe Interuniversitaire de recherches océanographiques du Québec (GIROQ), Département de biologie, Université Laval, Ste-Foy, Québec G1K 7P4, Canada
3Centre aquacole marin de Grande-Rivière (CAMGR), Ministère de l¹agriculture, des pêcheries et de l¹alimentation du Québec, 6 du Parc, Grande-Rivière, Québec G0C 1V0, Canada
*Corresponding author. Present address: Vice-recteur à la recherche, Université de Sherbrooke, Sherbrooke J1R 2R1, Canada. E-mail:

ABSTRACT: On the western coast of the Atlantic, according to the literature, 2 distinct groups of Semibalanus balanoides occur with a distinct interface near the Miramichi estuary (Northern New Brunswick). On each side of this interface, the groups are characterized by clinal variations for MPI (mannose-6-phosphate isomerase) and GPI (glucose-6-phosphate isomerase). The present study was carried out to determine whether selection occurs at this interface, to establish how early in the sessile life period it occurs and to examine the selecting forces involved. Reciprocal transplant experiments of newly settled individuals to both sides of the interface were carried out. No significant differences specifically linked to source or destination were observed in growth or fecundity for the 2 groups at the sites studied for either control or transplanted individuals. However, differences in survival were observed; individuals transplanted south of the estuary showed lower survival than individuals transplanted north. An allozyme analysis of barnacle survivors for MPI and GPI, 2 enzymes whose frequencies are known to vary abruptly in this region, indicated a change of allele frequency in transplanted individuals. The transplants¹ allele frequencies came to resemble those of adults from target sites, while no change occurred in transplanted individuals at control sites. Taken together with previous results, our study suggests that selection occurs very early in the newly settled individuals (spat).

KEY WORDS: Semibalanus · Genetics · Selection · Fecundity · Growth rate · Survival

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