Estimating illegal, unreported and unregulated catch in BritishColumbia's marine fisheries

摘要

To fully understand the impact of fishing on the marine environment, it is necessary to have an estimate of total extractions from the ecosystem. In addition to nominal fisheries landings and reported discards, which are regulated and monitored, removals will include a certain amount of illegal, unreported and unregulated catch (IUU). This amount, if considered, might profoundly affect our forecasts of stock abundance and safe removal rates. Here, we present preliminary estimates of the quantity of IUU catches over time for the British Columbia salmon and groundfish fleets. Based on influences in the history of the fisheries, and on independent estimates of misreporting, our methodology employed a Monte Carlo routine to determine missing catch with an associated error range. From the 1950s to the 1980s, we estimated that between 10,000 and 20,000 tonnes of catch went unrecorded every year in the BC salmon and groundfish fisheries. IUU catch increased throughout the 1980s, and by 1990 the amount was probably closer to 30,000 tonnes per year, equivalent to 18% of recorded landings. At present, less catch is unaccounted for thanks to tighter monitoring and enforcement: about 8000 tonnes per year, or 6.6% of landings. Values calculated here, using this subjective but transparent methodology, are intended to provide a starting point for further discussion and amendment.