Information pertaining to survival rate in salmon farms: EIR release

Information requested

To precede your request you quoted the following text for context:

“I saw you published a report about the survival rate in salmon farms, with data from 2023. The survival rate was 68.7% then. “

You then asked:

“We are looking for more recent data on the matter.

The industry group Salmon Scotland sent us their own figures - they say this shows a mortality rate of 1% in the last months. This would be a significant difference.

I guess you don’t have up-to-date data, but I was wondering if you had any indication on whether the survival rate could have increased so dramatically. Are you able to provide any figures that would show a similar improvement?"

Response

While our aim is to provide information whenever possible, in this instance the Scottish Government does not have the information you have requested. Therefore, we are refusing your request under the exception at regulation 10(4)(a) of the EIRs.

The reasons why that exception applies are explained below.

Under the terms of the exception at regulation 10(4)(a) of the EIRs (information not held), the Scottish Government is not required to provide information which it does not have. The Scottish Government does not have the information you have requested because the data on survival rates since the 2021 smolt year class has not been collected or analysed yet. The next production survey is planned to be published in October 2025 and will present survival data of the 2022 year class and there is no interim measure available.

This exception is subject to the ‘public interest test’. Therefore, taking account of all the circumstances of this case, we have considered if the public interest in disclosing the information outweighs the public interest in applying the exception. We have found that, on balance, the public interest lies in favour of upholding the exception. While we recognise that there may be some public interest in information about trends in survival rates on salmon farms between 2022 and 2024 based on the Scottish Fish Farm Production Survey, clearly we cannot provide information which we do not hold.

Additional information provided out with the EIRs to answer your question

Under regulation 9 of the EIRs (our duty to provide advice and assistance) we would like to offer you the following information that you may find helpful.

Published datasets on Scottish farmed salmon survival provide a level of information on production losses. They may be collected for specific purposes, including to fulfil a regulatory function, and may have associated constraints. They are not comparable as they do not all relate to a single production cycle nor do they include the same categories of losses.

Additional information on the data sets on which you have enquired are provided below.

Scottish Government’s Scottish Fish Farm Production Survey

Presenting the number of fish grown within a single production cycle which survive to harvest offers the best way of comparing data between production cycles and is the measure of survival published in Scottish Government’s annual Scottish Fish Farm Production Survey. It is also important to note that seasonal variability can influence farmed salmon survival rates within a calendar year.

The survival data in the Scottish Fish Farm Production Survey relates to the survival rate by specific smolt input yearclass. The survival rate referred to represents fish which were harvested for human consumption. A detailed explanation is given within the executive summary of the survey, extracted below:

Mortality is included in the number of fish not harvested for human consumption, which also consists of fish which have escaped, been culled for production reasons, removed for sampling purposes, statutory culls or selected for broodstock production.

Losses are calculated as the difference between the number of smolts input as a year class and the number of salmon subsequently harvested. Each survey covers the previous year’s complete production period (i.e. fish that were put to sea two years previously) and does not include more recent mortality.

Salmon Scotland Sector Mortality

On behalf of the Scottish farmed salmon sector, Salmon Scotland publishes site-level monthly mortality data as a percentage of all fish in production in a given month. This is a helpful measure of monthly mortality, but as it is based on different data and is calculated differently, it cannot be compared to Scottish Government’s annual Scottish Fish Farm Production Survey. This dataset does not include other losses during the month (e.g. escapes, culls etc.) which reduces comparability with the production survey.

About FOI

The Scottish Government is committed to publishing all information released in response to Freedom of Information requests. View all FOI responses at https://www.gov.scot/foi-responses.