Photo: Wageningen University & Research/FIS

Most target species for Dutch fisheries are healthy, significant increase in advice on catch options for sole

NETHERLANDS
Wednesday, July 03, 2024, 06:50 (GMT + 9)

The most important fish stocks for Dutch fisheries in the North Sea are doing well according to the International Council for the Exploration of the Sea (ICES). In December, the European Council of Fisheries Ministers will set the new catch quotas for 2025, in which the catch advice from ICES plays an important role.

Herring stock healthy, lower recent recruitment leads to lower catch advice

It is estimated that in 2024, over 1.4 million tonnes of adult herring will swim in the North Sea, Kattegat, Skagerrak, and Eastern Channel. The herring stock is healthy and has been above the maximum sustainable harvest (MSY) target level for more than ten years. Fishing pressure remains low and has been below the MSY target level since 1996. Based on the MSY approach, ICES advises a herring catch in these areas of 412,383 tonnes for 2025, of which 400,909 tonnes are intended for human consumption and 11,474 tonnes for industrial fishing. This decrease is a result of lower recruitment of young herring in 2022 and 2023, which now appears to be lower than estimated last year.

The new calculation method shows healthy sole stock; a sharp increase in catch advice

Last year ICES issued a historically low catch advice for sole, due to problems in the stock estimation model. The large uncertainties in the results of this estimation led to a downward correction of the stock size. Last spring the method for stock estimation of the sole stock was thoroughly evaluated in a benchmark process.

Both the data (catch statistics, natural mortality, research indices) and the calculation methods have been adjusted, which has resulted in a revision of the model. These improvements have made the need for a correction unnecessary.

The new estimate shows that the adult sole stock in the North Sea increased between 2018 and 2021, due to strong recruitment in 2018, followed by partial decline. However, since 2020 the stock has remained above the safe precautionary level. Fishing pressure has decreased significantly since 2016 and has been below the MSY target level since 2019.

ICES recommends a maximum total catch of 10,196 tonnes for 2025 based on the MSY approach. This is almost a threefold increase compared to last year, thanks to the improved status of the stock according to the new stock assessment.

Plaice stock remains very healthy and continues to grow

The plaice stock in the North Sea and Skagerrak fluctuates just below 900 thousand tonnes and is well above the MSY target level. Fishing pressure has been below the MSY target level since 2007 and has further decreased since 2019. The stock is expected to grow further in the coming years, supported by strong year classes from 2021 and 2022, together with low fishing pressure. For 2025, ICES advises a total catch of maximum 176,593 tonnes of plaice for the North Sea and Skagerrak based on the MSY approach. This is a 14% increase compared to the advice and catch quota of this year.

Bycatch species show a diverse picture

ICES also issued catch advice for a number of species that are not among the main target species of Dutch fisheries, but are valuable as bycatch in the flatfish fishery (turbot, brill, cod, whiting, sea bass). Advice is expected in October for Norway lobster (langoustines), another valuable species.

Adult turbot stock down slightly, growth expected

In 2023, the spawning stock biomass of adult turbot is slightly lower, but the total stock size is estimated to be slightly higher due to higher recruitment of juvenile fish in 2022 and 2023. This is expected to lead to future growth of the spawning stock. Since 2022, fishing pressure has been below the MSY target level. For 2025, ICES advises a maximum total catch of 2,426 tonnes of turbot in the North Sea based on the MSY approach.

Brill stocks increasing, but landings remain low

Fishing pressure on brill in the North Sea is estimated to be below the MSY target level since 2001, while the spawning stock remains healthy and above the MSY target level. ICES advises a maximum catch of 2,970 tonnes for the North Sea, Kattegat, Skagerrak and Channel.

Revised definition for cod stock; stock still below the limit level

Recent biological studies have shown that the North Sea and West of Scotland cod stock is divided into three sub-stocks: the Southern (Southern North Sea), North Western (North Western North Sea and West of Scotland) and Viking (North Eastern North Sea) stocks. These three sub-stocks are now assessed together as the Northern Shelf cod stock in a single stock assessment model. Because the three stocks intermingle and are caught together in some fisheries, ICES issues joint catch advice for these three stocks.

The southern stock is in the worst condition, with a population level below the limit level that threatens reproduction. Based on the MSY approach, ICES advises a 61% reduction in fishing pressure compared to 2024. As a precautionary measure, the same reduction in fishing pressure is applied to both the northwestern and Viking stocks in 2025, although these two stocks are healthy. This results in catch advice of 19,321 tonnes, which is 15% lower than the combined advice of 2023 and 38% lower than the established catch quota for 2024.

The whiting stock continues to grow

The whiting stock in the North Sea and the eastern part of the Channel has grown enormously over the past five years and has been well above the MSY target level for several years. Fishing pressure has been below the MSY target level for almost thirty years. Based on the MSY approach, ICES advises a total catch of 237,008 tonnes of whiting.

Sea bass remains above the limit level, but recovery has stalled

The stock of adult sea bass in the southern and central North Sea, Irish Sea, English Channel, Bristol Channel, and Celtic Sea is estimated at 13,158 tonnes. This is above the limit level, where reproductive capacity is at risk. However, the stock is still below the precautionary level for a healthy stock. Since 2013, fishing pressure has decreased significantly, well below the MSY target level, which has led to the growth of the stock in recent years. However, recruitment has been low since 2008, which has probably contributed to the slow growth. Based on the MSY approach, ICES advises a total catch of 2,776 tonnes.

Advice by ICES

ICES estimates stocks and fishing pressure each year and advises the European Commission on catch limits to achieve the objectives of the Common Fisheries Policy. The policy aims to achieve the maximum sustainable harvest (MSY), which means the highest possible long-term harvest of fish stocks.

ICES has issued advice for more than sixteen fish stocks in the North Sea. The European Commission makes catch agreements for a number of jointly managed stocks with Norway and, since Brexit, also with the United Kingdom.

On 28 June, researchers from Wageningen Marine Research will present the ICES fisheries advice to the Ministry of Agriculture, Nature and Food Quality, the fisheries sector, and civil society organizations.

Source: Wageningen University & Research

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