EU request for a technical service on unavoidable bycatches in various Baltic fisheries

ICES is not in a position to assess whether Baltic Sea sprat fisheries can be operated without any bycatch of herring or whether Baltic flatfish fisheries can be operated without any bycatch of cod. Analysis of 2022 landings composition data by métier and country suggests that the fisheries can control the degree of mixing but that even in very targeted fisheries there is some marginal bycatch of other stocks.

Central Baltic pelagic fisheries - The level of mixing of herring and sprat in landings is variable and depends on a given country’s quota shares of both stocks. Countries which in proportion have much larger sprat quotas have clean sprat fisheries with low levels of herring bycatch. On the contrary, countries which in proportion have larger central Baltic herring quotas show more mixing of herring and sprat in the landings. Additionally, when using small mesh sizes (16–31 mm), cleaner sprat landings can be achieved.

Gulf of Bothnia pelagic fisheries - In the Gulf of Bothnia most métiers target herring with incidental sprat bycatch. The amount of bycatch depends on the migration of sprat into the gulf, which varies depending on the year.

Herring fisheries in subdivisions (SDs) 22–24 - Herring catches from SDs 22–24 are considered to be taken in a directed fishery for herring, with only a few as bycatch in a directed sprat fishery.

Demersal fisheries in SDs 22–24 - More than 75% of the cod catch in SDs 22–24 comes from bottom otter trawlers of 12–18 m length and gillneters and trammelnet vessels < 12 m. Cod is caught in a mixture with other species. Bottom otter trawls catch cod principally together with plaice, flounder, and dab. Gillnet fisheries catch cod in addition to plaice, flounder, dab, brill, and turbot while Danish gillnet fisheries also catch sole together with cod.

Demersal fisheries in SDs 25–32 - More than 75% of the catch in SDs 25–32 is taken by bottom otter trawlers with mesh sizes > 120 mm and vessel length 12–14 m and gillnetters with mesh sizes of 110–156 mm and vessels < 12 m. Cod is mainly caught together with flounder and plaice. The exception is the Finnish gillnet fishery, which has pure cod catches.