Research Document - 2007/027

Exploitation and movements of Atlantic cod (Gadus morhua) in NAFO Division 3KL: tagging results from the reopened fishery in 2006

By Brattey, J. and B.P. Healey

Abstract

The directed fishery for cod in the inshore of NAFO Div. 2J+3KL was reopened during 2006, resulting in reported landings totaling 2,679 t from commercial, recreational, sentinel and by-catch fisheries combined (2,373 t from 3KL). Approximately 5,000 cod were tagged and released in the inshore of 3KL during 2006 prior to the re-opening of the fishery. Tag returns were used to estimate exploitation rates in three inshore areas that accounted for most of the landings (3Ki, 3La, 3Lb). The tagging study incorporated estimates of tagging mortality, tag loss, and reporting rates using methods we have described previously. Single tag reporting rates estimated from a high-reward tagging study were approximately 50%, much lower than the rate (76%) estimated for the period 1997-2002. Based on recaptures of tagged cod >50 cm fork length and released in 2006, exploitation rates (% harvested) were high (25-35%) for cod released in 3Ki in the Twillingate area compared to those tagged about 50 km away southeast of Fogo (10%); reported landings from 3Ki during 2006 were only 573 t. Cod tagged further south in 3La (Bonavista Bay) and 3Lb (Trinity Bay) were much larger (mostly >65 cm) and exploitation estimates were 5% for cod tagged in Bonavista Bay and 10% for those tagged in Smith Sound, Trinity Bay. The distribution of recaptures was similar to that from our previous (1997-2002) experiments. Overall, the results are consistent with our previous conclusion indicating a resident inshore component of northern cod that remains within an area bounded by the 3Kd/3Ki border in the north and the 3Lb/3Lf border to the south.

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