Population Trends and Status of Two Exploited Northwest Atlantic Grenadiers, Coryphaenoides rupestris and Macrourus berglax
Jennifer A. Devine and Richard L. Haedrich
Abstract.—Roundnose grenadier Coryphaenoides rupestris and roughhead grenadier Macrourus berglax are well known slope species in the North Atlantic. Dramatic population declines in both species in Canadian waters of the Northwest Atlantic raised the question: was the decline a result of environmental changes or exploitation? Min–max autocorrelation factor analysis and dynamic factor analysis, two types of time series analysis, showed that a combination of factors acting on different temporal scales explained the trends in both species. Those in Macrourus were best explained by environmental factors operating on long time scales; those in Coryphaenoides were related to exploitation. Our results support the view that an unregulated deep-ocean fishery, as experienced by Coryphaenoides, has serious consequences for species that are slow-growing, long-lived, and late-maturing.