Preliminary estimates of biological and yield characteristics of deep-water witch flounder (Glyptocephalus cynoglossus) in the Georges Bank - Mid-Atlantic bight region

Abstract

The existence of a deep-water (greater than 366 m) resource of witch flounder (Glyptocephalus cynoglossus) along the northeastern U.S continental slope and adjacent abyssal plain is suggested by several lines of evidence including: 1) egg and larval distribution patterns; 2) by-catch rates in deep-water surveys for red crab (Chaceon quinquedens) and monkfish (Lophius americanus); and 3) various special deep-water studies conducted as far south as Virginia. Nothing is known regarding the abundance, biology, and production rates of these fish, nor their affiliation to witch flounder in shallower shelf waters. Recent opportunistic sampling at depths ranging between 367-914 m has provided a limited number of samples for the preliminary estimation of growth and maturation rates. When compared to witch flounder of the shallower regions of the Gulf of Maine and Georges Bank, growth rates for deep-water fish are considerably lower and maturation occurs at an older age. Production rates (yield-per-recruit) are calculated for deep-water witch flounder and compared with those for the exploited Gulf of Maine resource (NAFO Div. 5Y). Implications for the management of a potential future fishery for currently unexploited deep-water witch flounder are discussed.