Proposed Northern Shelf Ling Fisheries Management Plan

Stock Assessment and MSY

Scientific Advice

The following evidence has been collated from the most recent ICES assessment working group report (ICES 2024)^[6] and the associated ICES stock annex^[7].

As set out in Section 3.2 of the JFS and in line with the scientific objective of the 2020 Act and the TCA, the UK takes an evidence-based approach to fisheries management, making use of the best available scientific evidence. For the purpose of stock management and TAC setting, this tends to focus on the use of advice produced by ICES, although other sources of information, including data from the fishing industry, may also be used.

ICES provides biennial advice for Northern Shelf ling. ICES advice is organised according to categories, ranging from 1 (the most information available) to 6 (the least). Northern Shelf ling is a Category 3 stock which means that it is considered to have no quantitative assessment but there is a reliable indicator of relative abundance. Northern Shelf ling has seen decreases in scientific advice for TAC in recent years. There is no analytical assessment of ling in subareas 3, 4, 6-9, 12 and 14. Instead, ICES use a biomass index (derived from Norwegian longline fishery catch rates in Subareas 4 and 6) as an indicator of stock development over time, under the Category 3 approach for data-limited stocks. The biomass index is combined with a ratio of observed mean length in the catch relative to the target mean length, a biomass safeguard, and a precautionary multiplier. Finally, a stability clause may be applied to ensure the advice is within -30%/+20% of the previous value. The biomass index has shown a generally increasing trend over the last 20 years. No indicator of fishing pressure is available. This approach is considered by ICES to by consistent with the MSY approach on a precautionary basis, although it is not possible to determine MSY reference points as such.

There is no current plan for an ICES benchmark for Northern Shelf ling. The evidence base needs to be significantly strengthened before a benchmark exercise can take place, in order to ensure that a sufficient level of information is available to inform the outcomes.

Benchmark exercises are a tool used by ICES to peer-review and incorporate new science or evidence into the stock assessment process. They are part of the process which ensures that ICES advice is based on the best available scientific evidence.

Assessment of evidence

As set out above, the relevant fisheries policy authorities do not have sufficient evidence to estimate MSY reference points for the Northern Shelf ling fishery covered by this FMP, although the advice and management approach follows the ICES MSY approach under their framework for Category 3 stocks. It should also be noted that there is sufficient evidence to evaluate the likelihood of fishing below F(MSY) using a MSY proxy-based assessment. Fisheries policy authorities are therefore committed to improving the data relating to this stock, as well as considering management measures required to ensure the sustainable management of Northern Shelf ling. These steps and measures are outlined under FMP policies section.