Herring in the Firth of Clyde being within safe biological limits: EIR Release

Information requested

Can you please supply copies of all supporting evidence and information used to conclude that this population is currently within 'safe biological limits'. In particular how you have concluded that this population is exhibiting a population age and size distribution that is indicative of a healthy stock.

Response

All of the information you have requested is available in the consultation document which can be found on the Scottish Government website, in particular in section 6.

Under regulation 6(1)(b) of the EIRs, we do not have to give you information which is already publicly available and easily accessible to you in another form or format. If, however, you do not have internet access to obtain this information from the link above, then please contact me again and I will send you a paper copy.

Under regulation 9 of the EIRs (our duty to provide advice and assistance) we would like to specifically address your request by providing an overview of the scientific analysis undertaken by the Marine Directorate. As stated in the report, we accept that data regarding the Clyde herring fishery are not comprehensive. We would reiterate our request from the consultation for any relevant additional data that fishers, research organisations, universities or other stakeholders may hold on this stock which may be considered in the evidence base during 2025. For further details on the requirements of the data, please refer to the consultation document.

Herring in the Firth of Clyde was historically one of the most economically important species to fishers during the first half of the 20th century. This importance has decreased significantly in recent years, and since 2013 there have been no landings from the Clyde, apart from 2021 when there was a single landing of 180 tonnes (although this was landed into Belfast and hence no samples were available). Consequently, due to a lack of landings, an absence of recorded discards (none since 2019), and no acoustic survey since 2018, the available data are limited, and there has been no analytical assessment of Clyde herring since 1990. These are the reasons why we note that the Clyde herring data are not comprehensive, and certainly are more sparse than in previous eras.

In this situation, our indication of stock dynamics is dependent on the ongoing West Coast bottom trawl surveys, a type of survey which, while not ideal for herring, has been used successfully elsewhere to produce indices of herring abundance (see, for example, the use of the IBTS Q1 survey to indicate abundance of 1-ringers for North Sea herring: ICES. 2023. Herring Assessment Working Group for the Area South of 62° N (HAWG). ICES Scientific Reports. 5:23. 837 pp. https://doi.org/10.17895/ices.pub.22182034). The current time series from these surveys runs from 1986 to 2023 for Q1, and from 1997 to 2022 for Q4. Therefore, the length of this time series allows us to get a reasonable indication over time of trends in the herring biomass. The plot found in Annex 1 (Figure 12, page 13 of consultation document) shows that, within the confidence limits of the data, there are no significant trends in the time series from 1986 to 2023, and furthermore it also appears to be stable in recent years. Stocks are not considered to be within safe biological limits if the spawning stock biomass is at a level where recruitment is impaired and fishing mortality is at a level which would give rise to a high probability of recruitment failure. The evidence from the current surveys suggests the extant stock consists primarily of younger fish, which could indicate good recruitment, or migration of older fish away from the area. It has been hypothesised that the fish found in the Clyde could also originate from a number of local and neighbouring areas. The data would suggest that, overall, there are no significant indications of a decrease in Clyde herring populations during the last year.

With the current data, it is not currently possible to determine MSY-based reference points, of the type that would be determined by ICES for a more data-rich stock. However, our scientific advisors believe, given all of the available data on current stock dynamics mentioned above and in the consultation document, they are showing a stock that is likely to be within safe biological limits.

Our goal is to be responsible fisheries managers, but also to be responsive to the evidence we have available, as well as that which may come in the future. This includes maintaining the population at a safe biological level which was a key principle considered when forming the basis of the precautionary Scottish Government recommendation to maintain the Total Allowable Catch (TAC) at the same level as 2023.

As you will be aware, we offer the opportunity to all stakeholders to engage during the consultation period to discuss their views and any questions they may have. We would encourage you to reach out to discuss any queries ahead of any future TAC considerations so they can be fully considered during the consultation process.

We hope this explains the evidence behind the proposal given in the consultation and subsequent TAC recommendation made to the Secretary of State.

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EIR 202400425322 - Information Released - Annex

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