Recent trends in finfish by-catch from the krill fishery in Area 48

Trends in finfish by-catch from the krill fishery using data reported from the fine-scale catch and effort (C1) data from 2010 to 2021 are characterized. Finfish by-catch in relation to annual reported weight, species composition and trawl technique, by subarea and Small Scale Management Units (SSMUs) is examined. The reported finfish by-catch and species composition was variable throughout the time series, though has increased in recent years with increasing krill catches in Area 48. Chionodraco rastrospinosus, Champsocephalus gunnari, and Lepidonotothen larseni, were the dominant by-catch species for Subareas 48.1, 48.2, and 48.3, respectively. The increase in the quantity of finfish by-catch recorded in the krill fishery is particularly significant in the South Orkney Islands West (SOW) and South Orkney North East (SONE) SSMUs, where there has also been a substantial increase in krill catches in recent years. Factors that may influence these trends are discussed. A recommendation for the inclusion of an additional field in the C1 data to indicate whether the information on by-catch was collected by the fishing crew or scientific observer on a haul-by-haul basis is provided. Given the uncertainties in data quality of finfish by-catch, it would be useful to identify certain years in the C1 dataset that are deemed unsuitable for analysis.