Antarctic fish by-catch observation during krill fishing cruise onboard polish trawler Dalmor II (March to July 2011)

Study Extent

statistical subarea 48.2;

Sampling

In order to quantify the by-catch of fish of a range of sizes, the following sorting method uses a standard sub-sampling approach that allows the user to re-sort smaller samples to ensure that small/larval fish, that may go undetected in larger samples, are recorded appropriately. 1. Ensuring all large fish removed from conveyor during this haul/time period are retained for subsequent weighing and identification. 2. Taking a 25 kg sample, remove all fish and record the total mass of each fish species. 3. Taking a 10 kg sub-sample from the remaining krill sample. 4. Sorting carefully through the 10 kg sub-sample and remove and record the total mass of each fish species. 5. Taking two 1 kg sub-samples from the remaining krill sample. 6. Sorting through each of these 1 kg sub-samples and remove and record the total mass of any remaining fish species (paying particular attention to larval fish that may be transparent).

Method steps

1. https://www.ccamlr.org/en/system/files/obsman.pdf

359 Antarctic krill catches were analysed for by-catch, it took 48.5% of observed catches and 31.3% of total catches. Fish by-catches were usual in the sector 48.1 (89.1% of cases); the most of by-caught fishes belonged to families Nototheniidae (NOX) (66.3%). Fish by-catches in the sector 48.2 were recorded in 50% examined catches; the most frequent were fishes of families Myctophidae (LXX).