Research Document - 2001/004

The status of Monkfish (Lophius americanus) in NAFO Divisions 2J, 3K, 3L, 3N, 3O and Subdivision 3Ps.

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

Abstract

Monkfish (Lophius americanus) 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. Survey data also indicate occasional records to the north on the Labrador Shelf in deeper, warmer trenches and on the slope edge. Biomass at depth was observed to change over time. A shift to deeper waters after the mid-1980's followed by a return to shallower depths in recent years may be related to a cooling trend during the mid-1980's. 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. 3Ps and 3O, with 2/3^rds in 3O. Biomass and abundance indices fluctuated at a low in 1979, peaking in 1988. Biomass then fluctuated downward until reaching a low in 1992-93. Since then, the index has fluctuated widely, particularly from the Campelen gear. 2000 represents a year of peak abundance, almost double the previous year. Such 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. Mean monkfish weight peaked in the late 1980's in conjunction with the peak in 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 1993 to 1998 (except 1995). In 1998-2000, bycatch restrictions as per the conditions of licence is the primary limitation on effort in the monkfish fishery. Given the limited knowledge of most aspects of monkfish biology and relevant fisheries, it is difficult to determine stock health and whether the exploitation rate is appropriate. Even from a precautionary (conservative) point of view, the ratio of commercial removals and research survey biomass estimates seems to be small in recent years. Thus, there is no evidence presented here that would suggest that current levels of fishing are having a significant negative impact on monkfish. Closure due to excessive bycatch of restricted species has acted as a regulator for this stock.

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