Seasonal aggregations of Canadian east coast pollock as inferred from the commercial fishery and hydroacoustic observations

Data from an otter trawler fleet fishing on the Scotian Shelf combined with year‐round hydroacoustic data indicated that the locations of aggregations of pollock Pollachius virens did not change appreciably from month to month. The proportion of pollock mass compared with total catch mass in individual trawl catches, however, tended to be higher from September to February. The period of highest catch rates was shown to be the December to January period. This period coincided with the period when pollock had the least affinity with the seabed based on information from hydroacoustic observations, a behavioural consideration for acoustic survey design. Based on these observations, it was concluded that the optimal time to conduct an acoustic survey was during the December to January period.