Atlantic Fisheries Research Document 1996/006

Status of Newfoundland and Labrador snow crab

By E.G. Dawe; D.M. Taylor; P.J. Veitch; H.J. Drew; P.C. Beck; P.G. O'Keefe

Abstract

Data on catch rate, size (carapace width, CW) and molt status (chela allometry) from various sources were presented and used to infer resource status. Trap survey data from commercial grounds in each of three management areas in NAFO Div. 3L were available since the early 1980's, based on sampling with both large-meshed (commercial) traps and small-meshed traps. A model was developed for each area which uses the survey catch rate of legal-sized crabs (including 'soft' crabs) to provide an indication of the commercial catch rate in the following year. The commercial catch rates in all three areas remained high in 1995, as had been predicted from the 1994 surveys. For both trap types, the 1995 survey catch rates indicated that commercial catch rates should generally remain high in Div. 3L in 1996. The survey catch rates of two size groups of prerecruit crabs have been declining over the past 3-4 years especially for small-clawed crabs (which will continue to molt and may begin to recruit in 2-3 years). This suggests that recruitment is declining in Div. 3L. Data from Div. 3K trap surveys, in area 3B (White Bay) in 1994 and 1995 showed no clear difference between years in the catch rates of legal-sized or prerecruit crabs.

Data from the fall NAFO Div. 2J3KLNO bottom trawl survey agreed with those from the trap surveys, for Div. 3L, in suggesting that abundance of prerecruits, relative to that of legal-sized crabs, was low in that division. The trawl data also suggested that crab abundance was low in Div. 2J and 3K. Abundance of prerecruits appeared to be particularly high in virtually unexploited Div. 3N. First estimates of minimum trawlable biomass were generated using STRAP, recognizing that the catchability of the survey trawl for snow crab is unknown. Legal-sized crabs were not caught in deepest trawl sets on the Div. 3KL slope or in shallow areas near the Labrador coast (Div. 2J) and on the Grand Bank (Div. 3LNO). Prerecruit and female crabs extended into shallower areas than did commercial crabs.

Data from sampling by observers aboard commercial vessels were presented for 1994 and 1995. Comparison between years was hampered by yearly differences in distribution of sampling effort by trap type among management areas. However it appeared that catch rates were lowest in Labrador and on the West Coast of the Island.

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