Research Document - 2003/100

The status of Monkfish (Lophius americanus Valenciennes 1837; Lophiidae) on the Grand Banks,
NAFO Divisions 3L, 3N, 3O, and Subdivision 3Ps

By Kulka, D.W. and Miri, C.M.

Abstract

Monkfish (Lophius americanus Valenciennes 1837; Lophiidae) is described at the northern end of its distribution. It was found to be restricted primarily to the southwest slope of the Grand Banks, closely associated with the warmest available bottom waters. Research survey data also indicate occasional records to the north on the Labrador Shelf in deeper, warmer trenches and on the slope edge. The general location of monkfish have remained constant over time (records back to the 1950s but biomass at depth was observed to change over time. A shift to deeper waters after the mid1980s followed by a return to shallower depths in recent years may be related to a cooling trend during the mid1980s. The highest densities (kg per tow) of monkfish on the Grand Banks were located where bottom temperatures exceeded 40 C. Nearly all of the biomass from Spring surveys occurred in NAFO Div. 3O and Subdiv. 3Ps; with two-thirds in Div. 3O. Biomass and abundance (less pronounced than biomass) indices fluctuated over time, peaking in 1977, declining to a low in 1979, peaking again in 1988. Biomass then fluctuated downward reaching a low in 1992-93. Since then, the index has increased, fluctuated widely. 2003 represents a year of peak abundance, almost double that of the previous year. The abrupt changes from year to year likely do not reflect dramatic fluctuations in the population. Rather, these changes suggest that there may be a catchability issue. However, there is a distinct pattern of increases followed by declines over time, the biomass having peaked 3 times in the last 33 years. Mean weight of monkfish also peaked in the mid1970s and late 1980s, in conjunction with the peaks in biomass. However, unlike the biomass, it has declined since 1996. A Canadian experimental trawl fishery for monkfish contributed to an increase in monkfish landed in 1991. A directed gillnet fishery began in 1993. In 1995-1997, a 200 metric tonne quota was instituted, but was removed in 1998. Landings increased from 1995 to 1998 then declined. In 1998-2000, bycatch restrictions as per licence conditions was the primary limitation on effort in the fishery and catch of monkfish. However, an expansion into the South Korean market and associated high price for the product has led to sharply increased (record) effort. Participant in the fishery increased from 9 in 2001 to about 80 in 2003. Total catches increased from 168 t in 2000 to 2,994 t in 2003. Correspondingly, relative F (index of exploitation) has increased by 5 times in the past two years after declining since 1998 and may now exceed a sustainable level.

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