Project
Is the aberrant plaice maturation visible in young fish?
During the plaice age exchange (2020) and follow-up workshop (WKARP2 online workshop in December 2021) the age distributions for plaice in the Demersal Younf Fish Surveys (DYFS) were discussed. Small fish has been taken into account in the workshop, and especially in 0- and 1-year olds from in- and offshore areas a discussion has taken place on the winter ring. The conclusion of the KBWOT project on maturation of plaice and sole (report) showed that plaice maturation development seems to be aberrant from the expectation, especially in the southern North Sea, indicating spawning activity. Incidental spawning activity in summer for plaice in the southern North Sea is in line with the signals from the Dutch North Sea beam trawl survey. During WGBEAM 2022 the Belgian representative confirmed that -in that same area- also spawning plaice was encountered quite regularly in the Belgian North Sea beam trawl survey. Plaice is one of the main commercial flatfish species in the Netherlands. A changed spawning pattern will probably affect the stock assessment, even if the change is only regionally. Furthermore, the day rings analyses will improve understanding the importance of the nursery qualities, for plaice North Sea coastlines. This may provide a basis which can be used for future management and conservation policies.