DOES STARFISH PREDATION DETERMINE SPAWNING SEASONALITY IN THEWHELK BUCCINUMUNDATUM IN THE GULFOF ST LAWRENCE?

The common whelk Buccinum undatum is an abundant predatory and scavenging gastropod that is widely distributed on both sides of the North Atlantic, from Canada to New Jersey in North America and from Svalbard to France in Europe. The species range extends to 708N along the western shores of Greenland and fossil shells (late Pliocene formation of Kap København) have been found as far north as 828300N (Global Biodiversity Information Facility, 2013). It occurs on various substrates in coastal areas from low tide level to 200 m and sometimes deeper, but shows a preference for waters of about 20–30 m depth (Weetman et al., 2006; Włodarska-Kowalczuk, 2007; Heude-Berthelin et al., 2011). The biology of this important commercial species has been relatively well studied throughout its range, and includes studies of the seasonality of reproduction. In the eastern Atlantic the species spawns during October to December from northern France to the Shetland Islands, em-bryogenesis takes 3–5 months and the young hatch between January and May. During this incubation period, temperature