IMIS

Submarine canyons are common features of continental margins off both coasts of North America. The Sable Gully is a submarine canyon located approximately 40 km east of Sable Island on the eastern Scotian Shelf that separates Banquereau Bank and Sable Island Bank. It is unique among canyons on the eastern Canadian continental shelf because of its depth, steep slopes and extension far into the shelf. It can be divided into two general areas, the trough and the canyon. The trough is a wide (30 km x 70 km) shallow basin at the inshore end of the canyon that links this feature with the inner Scotian Shelf. The canyon is a narrower feature (10 km x 40 km) extending from the shelf break into the continental shelf that is characterized by steep sides extending to depths greater than 2000 m. Plankton tows were carried out during two multidisciplinary oceanographic missions to the Gully in 2006 and 2007. The first of these was onboard the CCGS Hudson (18HU06008) and took place between April 17, 2006 and May 7, 2006. The second was also on the CCGS Hudson (18HU07033) and took place between August 2, 2007 and August 9, 2007. Zooplankton were collected at a series of stations in the Gully by vertical tows using a 3/4m diameter ring net (202 micron mesh). Most tows were between 100m and the surface, with a few deeper casts. A detailed description of the sampling and analysis methods is given by Greenan et al. (2010). Field sampling and laboratory analyses were carried out following the Atlantic Zone Monitoring Protocols (AZMP) protocols. The OBIS collection is a subset of this dataset containing species distribution information. Results from analysis of data on circulation, current variability, cross-shelf exchange, tides and low frequency variability of hydrographic properties suggest that circulation in the Gully may play a role in localized retention of materials as well as larger scale cross-shelf transport. However, many conclusions from previous reports have depended solely on computer simulations of the circulation in the Gully. Data collected during these cruises will be used to test the models and provide new insights into the circulation of this area.