Orange roughy (Hoplostethus atlanticus Collett 1889) in the Northwest Atlantic

Abstract

New Northwest Atlantic records of Orange roughy (Hoplostethus atlanticus) are reported, consisting of 506 specimens from 219 commercial fishing sets conducted from 1982 to 2000 with bottom otter trawls and gillnets. Percent of observed trawl sets in the study area with orange roughy was <3 sets in 1 000 observed, lower in other gears, indicating that the species is uncommon there. Most specimens were taken off Baffin Island at 63°N. The others were from the Northeast Newfoundland and Labrador Shelf, Grand Banks, Flemish Cap, Scotian Shelf and the Corner Seamounts south of the Grand Banks at about 35°N. Virtually all captures were at 285-1330 m and predominantly deeper than 800 m. The only exception was a record of four specimens at 70 m but the specimens were not available to the authors for verification. Average long-term bottom temperatures where captures occurred were 2-9°C, but primarily from 3 to 4°C. A sample of 27 specimens was examined in detail and, based on these, data on meristics and morphometrics, size composition, reproductive stages and food composition are provided. It is not possible, based on present data, to establish whether the species reproduces in the Northwest Atlantic. However, water temperatures in the north, where most specimens were caught, are not conducive to survival of orange roughy eggs and larvae. A possible hypothesis is that the Northwest Atlantic occurrences represent the western fringe of distribution of Northeast Atlantic populations.