Temporal variability in the condition factors of Newfoundland capelin (Mallotus villosus) during the past two decades

Abstract

Condition factors (Fulton's K and predicted weight-at-length) were determined for male and female Newfoundland capelin, Mallotus villosus (Müller), for the years 1982-1999, a time of major change in the ecosystem. Predicted weight-at-length showed the same trend as length-specific K for both males and females, so validating the use of K, even though the value of b deviated from 3. K at the population level was generally higher during the 1980s than during the 1990s. In addition, length-specific K tended to increase with length within years for both males and females. Length-specific K for males, when expressed as anomalies from the long-term mean, was higher and more variable than for females. The relationships between length-specific K anomalies and water-temperature anomalies were not significant and were a mixture of both positive and negative sign. There were weak, negative relationships between population condition for both sexes and spawning biomass, suggesting that future research should focus on density-dependent influences on K. There were no significant relationships between condition and stock productivity, expressed as recruitment and survival rate. Given the importance of environmental variability to stock productivity, as previously documented for capelin, maternal effects may be of only secondary importance. Crown Copyright © 2002 Published by Elsevier Science Ltd on behalf of International Council for the Exploration of the Sea. All rights reserved.