The Fisheries Secretariat provides below our summary after The International Council for the Exploration of the Sea (ICES) released its scientific advice for Baltic Sea stocks yesterday, 31 May.
The western Baltic cod stock has not improved as expected for yet another year with a further downward revision in biomass and upward revision in fishing exploitation rate. A surprisingly good recruitment in 2016, if protected from overfishing, may help replenish this severely overfished stock.
ICES has combined the previously separate assessments for Bothnian Sea and Bothnian Bay herring into a single assessment, which also solves the ongoing issue with overlapping advice within the single EU quota-setting management area for Gulf of Bothnia herring.
The Eastern Baltic Sea cod stock has shown few positive signs of development in the last year with fish spawning at smaller sizes, and fewer small fish seen in the survey overall. For western Baltic cod, recruitment of individual fish to the fishable stock was at the highest, in contrast to the previous recruitment at a record low. The western stock is still below all biomass reference points and suffers a fishing mortality well above sustainable levels.
The larger eastern Baltic stock, close to collapse in 2002, showed signs of recovery a few years ago but the stock status now is uncertain. However, by using a new kind of model, ICES has some confidence that the relative fishing pressure in the eastern Baltic cod is well above sustainable levels, and the biomass is just above the minimum spawning stock biomass.
The bulk of Baltic herring stocks are above all biomass reference points except for herring stocks in the western Baltic. The largest herring stock, central Baltic herring, received the largest increase in advice (24%), with an overall sustainable fishing exploitation rate. All other herring stocks are experiencing some level of overfishing.
Fishing mortality on sprat has continued to decline into sustainable levels in 2016, with biomass levels above all reference points, and received a minor reduction in advice (-7%) due to normal fluctuations in the stock.
For salmon, the advice is similar to last year. Unaccounted in the advice are new preliminary data from Vattenfall in Sweden indicating a dramatic rise in M74 Syndrome, or thiamine deficiency, in returning female salmon. Thiamine deficiency is linked to extremely high mortality in juvenile salmon and is a serious issue. Vattenfall has voluntarily begun thiamine treatments in their hatcheries. Wild salmon cannot be treated for thiamine deficiency.
With regard to flatfish, ICES advises a decrease in catch for plaice, the only Baltic flatfish species under EU quota management. The stock is fished within sustainable levels, though ICES noted uniquely high discarding in 2016, 67% of the total catch, driven primarily by the Danish trawl fleet.
As for most stocks, ICES advises a total commercial catch for 2017, which is independent of management area overlaps or third country fishing effort.
The Fisheries Secretariat has produced a summary of the ICES advice which you can find in the pdf, including details about each of the stocks listed in the table below.
This table appears on page 3 of our advice summary and provides the ICES advice for total commercial catch across the Baltic fish stocks, the % difference from ICES advice for 2017, and the 2018 quota corresponding to ICES advice. The total catch for salmon is represented by a total count of individual fish.