Research Document - 2005/086

Witch Flounder in NAFO Subdivision 3Ps

By Maddock Parsons, D.

Abstract

Landings from this stock over the last 20 years have fluctuated between 300t and 1000t. From 1986-1993 landings were relatively stable averaging around 1000t annually. During the past five years landings averaged just over 500 t but were as low as 250t in 1996. The main directed fishery is prosecuted by offshore otter trawlers complemented by a nearshore Danish seine fishery. However, in recent years it appears to be a mixed American plaice and witch flounder fishery by otter trawlers. During 2000-2003 American plaice catch rates in the otter trawl directed witch flounder fishery ranged from 72-143% of the witch catch, compared to less than 6% by Danish seiners. In 2004 by-catch of American plaice in the otter trawl component of this fishery declined to about 50%. Although survey stock size indices since 1983 have been highly variable, the survey biomass index during recent years suggests that the biomass is on average about 75% of the 1983-1990 average when catches were around 800t. The age and size structure observed in this stock since the early 1980s also appear to have remained stable with little change in growth pattern. Geographic distribution has not changed appreciably since 1983 except during the early to mid 1990s when fish disappeared from the 83-193m depth zone coincident with extremely cold sea bottom water temperatures. In recent years the distribution appears to be returning to a more normal pattern. No measurable change in recruitment has been observed over the past 20 years.

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