MIGRATION OF PRESPAWNING CAPELIN (MALLOTUS-VILLOSUS) AS RELATED TO TEMPERATURE ON THE NORTHERN GRAND BANK, NEWFOUNDLAND

Associations between average temperature (°C) from 0-75 m and the size distribution of capelin (Mallotus villosus) on the northern Grand Bank (≈46°N 52°45′W-49°10′N-49°30′W) were explored, using information from research vessel surveys conducted during May from 1985 to 1992. Immature capelin were generally distributed in the northern part of the survey area while mature capelin were distributed in the south. Mature capelin are believed to migrate to the southern area in the spring, prior to onshore migration. Distribution of mature capelin was not associated with temperature on relatively small spatial (≈2000 km2) and temporal (within years) scales, but was on larger spatial (≈90 000 km2) and temporal (among years) scales. Assuming a link between maturation rate and migration, we propose that temperature is not used as a proximate cue during capelin migration, but that seasonal temperatures moderate offshore capelin migration patterns through regulating growth, maturation, and food abundance and distribution. Capelin are growing and migrating on a biological cycle but research surveys are conducted on a chronological cycle. Consequently, biomass acoustic estimates may be underestimated in cold years if spring migration into the survey area is delayed. © 1994 International council for the Exploration of the Sea.