Nutrient Flex onto the Labrador Shelf from Hudson Strait and its Biological Consequences

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Sutcliffe Jr., W. H., Loucks, R. H., Drinkwater, K. F., Coote, A. R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1983
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Newfoundland; Hudson Bay; Hudson; Hudson Strait; Labrador Shelf; atlantic cod; Gadus morhua
• Online Access: http://dx.doi.org/10.1139/f83-196; http://www.nrcresearchpress.com/doi/pdf/10.1139/f83-196

Fish abundance, based upon commercial fish catches and numbers offish-feeding birds, is shown to increase southward along the Labrador Shelf from Hudson Strait. Also, yearly abundance of Labrador Atlantic cod (Gadus morhua) using virtual population analysis is shown to be closely correlated with salinity changes at Station 27 off St. John's, Newfoundland. We suggest these observations are related to physical oceanographic events originating within Hudson Strait. Analysis of available data indicates nutrient enrichment of the surface waters through physical mixing in Hudson Strait. These waters are carried by the residual circulation onto the northern Labrador Shelf. Our interpretation of the southward increase in fish abundance is that fish production develops downstream of the area of nutrient injection due to the southward flow of the Labrador Current coupled with the time required for food chain development. The yearly variation of cod is interpreted as arising from the variation of the nutrient supply, which is itself correlated with salinity. The fresh water discharge into Hudson Bay which eventually flows out through Hudson Strait and onto the Labrador Shelf appears to suppress mixing and hence years of higher discharge would tend to decrease the nutrient supply.