Distribution, Growth and Food Habits of the Atlantic Wolffish (Anarhichus lupus) from the Gulf of Maine-Georges Bank Region

Abstract

The spatial and temporal distribution patterns of the Atlantic wolffish (Anarhichas lupus) from the Gulf of Maine-Georges Bank region were examined based on bottom trawl survey data from 1963 to 1989. Age composition, growth and food habits were also evaluated from 1983 to 1989. Catches of wolffish were distributed throughout the region, but highest concentrations occurred along the 100 m depth contour of the Gulf of Maine-Georges Bank.Statistical analyses of the depth occurrences revealed a seasonal shift in depth distribution from shallow water (<120 m) in spring to deeper water in autumn. Further analyses showed that the large (>50 cm) wolffish migrate to these shallow waters in spring and return to deeper waters in autumn.The oldest wolffish aged was 22 years. Mean length-at-age ranged from 4.7 cm total length for age 0 to 98.0 cm total length for age 22 in spring. Growth was modelled best by the Gompertz function. Bivalve molluscs (primarily Placopecten magellanicus) dominated the diet, followed by echinoderms, gastropods and decapods.

Spring feeding of Atlantic wolffish (Anarhichas lupus) on Stellwagen Bank, Massachusetts

“…For instance, in spring in the GOM, predominantly larger fish have been found at depths of 5-40 m, and the largest fish was 98 cm TL and 22 years old, supporting the theory that Atlantic wolffish occupy deeper, warmer waters until they are sexually mature (Keats et al, 1986;Nelson and Ross, 1992). In this study of shallow (27-46 m) SBNMS waters, Atlantic wolffish ranged from 59 cm TL (age 7) to 130 cm TL (Fig.…”

“…Our age data for older fish may be more accurate than data from previous studies. Nelson and Ross (1992) aged whole, polished otoliths, which can be difficult to read because they grow thicker in older fish; whereas, we aged sectioned otoliths. It is possible that slightly younger fish were present in the SBNMS group but, because of gear selectivity, were excluded from the catch.…”

“…In the GOM-GB region, there is some evidence of size-segregated, seasonal movements of Atlantic wolffish, likely linked to spawning, from shallow (<10 m) to deep (274 m) waters in fall and then the reverse in spring (Albikovskaya, 1982;Nelson and Ross, 1992;AWBRT 3 ). For instance, in spring in the GOM, predominantly larger fish have been found at depths of 5-40 m, and the largest fish was 98 cm TL and 22 years old, supporting the theory that Atlantic wolffish occupy deeper, warmer waters until they are sexually mature (Keats et al, 1986;Nelson and Ross, 1992).…”

“…An estimated 4-5 months before spawning, these typically solitary fish begin courting and form bonded pairs (Johannessen et al, 1993); inshore migrations into shallower water may occur at this time (Nelson and Ross, 1992). Spawning is believed to occur from September through October in the GOM, but there is no conclusive proof of this spawning period (Pavlov and Moksness, 1994;Rountree, 2002).…”

“…Atlantic wolffish range from Greenland to Cape Cod, occasionally as far south as New Jersey (Rountree, 2002;Keats et al, 1986), and inhabit waters from 5 to 240 m depending on fish size, age, and season (Nelson and Ross, 1992). According to trawl surveys in U.S. waters, abundance south of Canada is highest (<1.5 kg [3.3 lb]/tow) in the Gulf of Maine-Georges Bank (GOM-GB) region, especially in the southwestern portion at depths of 80-120 m (AW-BRT 3).…”