Research Document - 2006/078
Redfish Catch Results from Summer 2005 Survery in Unit 2
By McClintock, J.
Abstract
To enhance the fisheries research database in Unit 2, NAFO Subdivisions 3Pn, 3Ps, 4Vn, and 4Vs, the Groundfish Enterprise Allocation Council (GEAC) has funded redfish surveys during winter 1997, and summers 1998 to 2001, 2003, and 2005. These surveys are the only available index of stock condition given the Department of Fisheries and Oceans (DFO) last conducted a Unit 2 redfish survey in 2002 and there are no plans to continue with the DFO surveys. GEAC funded and performed the surveys with scientific guidance from DFO in the design and execution of a stratified random survey and the associated sampling. The data collected during these surveys have been subsequently analyzed on behalf of GEAC and for the additional intent of providing this information to DFO, for their databases and their assessment work. This is the seventh such GEAC redfish survey in Unit 2 following on the previous 1997-2003 surveys. Catch statistics, length distribution, and stratified analysis estimates of redfish abundance and biomass, and interpretation of results are presented.
The 2005 Unit 2 total biomass estimate is 183 ktonnes which is more than double the 2003 estimate of 82 ktonnes and greater than or at least in keeping with the estimates back to 1999 which ranged from 94 to 169 ktonnes. The total abundance estimate for Unit 2 in 2005 is 298 million, an increase of 70% from the 2003 survey estimate of 175 million and is itself at least 60 to 70% of the largest estimates on record: 486 and 497 million in 1997 and 1998, and 404 million in 2001. In 2005, redfish catches were present in virtually all of the survey set locations indicating a distinctly uniform coverage over Unit 2, perhaps as pronounced as any in the survey history. Of particular note is the greater presence of catches in the northern part of the Unit (in 3Pn, the biomass estimate of 28.2 ktonnes is the largest of any survey year: the next largest being 11.1 ktonnes in 1999) and along the Laurentian Channel. In 3Ps, the biomass estimate is 60 ktonnes which is the largest since 1997. In 3Pn and 3Ps a distinct population of smaller redfish in the 8 to 10 cm range is seen in 2005 which equates about to the 2003 year class. In 4Vn, the 2005 biomass estimate of 36.7 ktonnes, is increased by more than 100% from that in 2003, and is the largest since 1998. In 4Vs, the biomass estimate is 58.6 ktonnes, almost identical to the 2005 estimate in 3Ps. While this estimate is increased almost 70% from the 2003 estimate it is generally on a par with or less than the large biomass estimates for 4Vs for the previous years. In each of the four subdivisions there continues to be a presence of fish in virtually all the 1988, 1994, and 1998 year class groupings. An exception is the absence of the 1994 year class in 4Vn and 3Pn to the north.
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