Fluctuations and forecasts in the fishery for queen scallops (Aequipecten opercularis) around the Isle of Man

The annual success of the queen scallop fishery around the Isle of Man in the northern Irish Sea is dependent on the strength of recruitment. We examined data from surveys and commercial logbooks on the annual density of spat, juvenile, and adult queen scallops in the fishery between 1982 and 2002. These were used to examine past population and fishery trends and the potential for formulating a predictive model for the fishery. The results were highly variable on both temporal and spatial scales, but there were some general trends. Density appeared to have been relatively stable during the 1980s, declined sharply from the early to mid-1990s, then recovered to produce relatively good catch rates thereafter. There was no relationship between spat settlement and the subsequent density of juveniles or adults in stock surveys or with commercial catch rates. However, within the stock surveys, there were three different significant relationships between cohort densities over time. Additionally, there was a significant relationship between the density of 1-year-olds caught on the surveys and commercial catch rates the following year. Monitoring juvenile queen scallop density would therefore allow prediction of recruitment and fisheries variations at least 1 year in advance, allowing perhaps for more effective management, including reducing the fluctuations in the fishery and helping to ensure long-term sustainability.