Research Document - 2010/056
The Fall 2007 NAFO Subdivision 3Ps GEAC Survey: Catch Results for Atlantic Cod (Gadus morhua), American Plaice (Hippoglossoides platessoides F.), Witch Flounder (Glyptocephalus cynoglossus L.), and Haddock (Melanogrammus aeglefinus)
By J. McClintock
Abstract
To enhance the fisheries research database in Northwest Atlantic Fisheries Organization (NAFO) Subdivision 3Ps, under contract to the Department of Fisheries and Oceans (DFO), the Groundfish Enterprise Allocation Council (GEAC) completed a fall survey in 2007 directed at groundfish, with specific interest in cod, American plaice, witch flounder, and haddock. GEAC had previously completed fall surveys to 3Ps from 1997 to 2005. The 2007 survey represents a new starting point for this information: both a new survey vessel and new fishing gear were employed as well the survey area was expanded. In this analysis, catch statistics, length and age distribution, and stratified random survey analysis estimates of biomass, including age distribution estimates, are presented. The results were presented during the regular zonal stock assessment meetings in St. John’s (February 2009).
The largest catches of cod were located at the southern entrance to the Halibut Channel and on the western portion of St. Pierre Bank with a few on the eastern side of the mouth of Placentia Bay. The estimated total number of cod for 3Ps is 18.1 million and the estimated total cod biomass is 13.1 ktonnes. For an estimated 8.7 cod per standard 15 minute tow the greatest numbers are at ages 1 (3 fish per tow) and 3 (2.5 fish). From the cod abundance index at length estimates there are two peaks at lengths 16-22 cm and 34-40 cm.
The largest catches of American plaice were located at the southern entrance to the Halibut Channel. The estimated total number of plaice for 3Ps is 127 million. The estimated total plaice biomass is 22.3 ktonnes though there is large variance and hence uncertainty in the estimates. The total mean number of plaice per tow is 58.3 with about 10 fish each at ages 2, 3, and 4. At ages 5 through 8 there are from 4.5 to 5.4 fish per tow. Lesser numbers are at ages 9 (3.2 fish) and 10 (2 fish). The majority of sampled plaice are in the 12-30 cm range.
Witch catches were located at the southern entrance to the Halibut Channel and also on the western portion of St. Pierre Bank both west of St. Pierre et Miquelon and on the Laurentian Channel slopes. The estimated total number of witch for 3Ps is 34.8 million. The estimated total witch biomass is 7.2 ktonnes. The total mean number per tow is 16.7 with the greatest numbers estimated at ages 5 (2.7 fish per tow), 7 (2.5 fish) and 6 (2.4 fish). Of the sampled witch there is a peak in the length distribution at 33 cm with the majority of samples in the 26‑43 cm range.
Haddock were caught in only 7 of the 75 successful survey trip sets. The estimated total number of haddock for 3Ps is 2.8 million and the estimated total haddock biomass is 5.8 ktonnes though there is large uncertainty in these estimates due to the few sets reporting haddock: the within-stratum variance being an important factor as well. Seventy-one percent of the total abundance estimate and 91% of the total biomass estimate are for the 51-100 fathom regime.
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