How Scottish pelagic fishers and scientists are working together for a sustainable future

How Scottish pelagic fishers and scientists are working together for a sustainable future

Fishing News recently reported that Scottish pelagic fishing vessels now actively participate in gathering the biological data that inform how fisheries are managed. This new collaboration between fishers and scientists not only provides high quality data on herring, mackerel and blue whiting stocks, but also builds understanding and trust between science and industry. Here we delve into the details of how this collaboration works.

Starting as a pilot project in 2018, the Scottish Pelagic Fishermen’s Association (SPFA), Shetland UHI (SUHI) and the Marine Scotland directorate of the Scottish Government developed the voluntary scheme to go from sampling fish on the deck to entering data into the system. The aim was to supply high quality data to the International Council for the Exploration of the Sea (ICES), who carry out the stock assessments that inform fishery management. Seven pelagic fishing vessels participated in the pilot, which proved so successful that from 2021 almost all (20 of 21) of Scotland’s pelagic fishing vessels have been fully involved.

Since the 1970s, the Scottish Government has collected most of its data on pelagic catch from processers when the fish are landed. Through this new collaboration, the fish samples are collected on-board by fishers, directly from their individual hauls. Sampling in this manner provides a higher level of detail as well as collecting additional operational and environmental information.

Working together, fishers and scientists have developed logistically viable procedures to collect data at sea to supply to scientists for analysis. There are two different streams to the data collection process called ‘self-sampling’ and ‘co-sampling’.

‘Self-sampling’ means that the fishers themselves take measurements of the fish. Vessel crews take length and weight measurements from a set quantity of fish as each haul is pumped on-board. This allows the precise time and location of catch to be connected to the biological data, along with other environmental parameters. Fish are sampled from every haul of every trip, providing length and weight data at high spatial resolution, with close to full fleet coverage.

Assessing the age, sex and maturity of each fish is a more time-consuming process requiring specialist knowledge, so a different approach is needed to collect these data. This is where ‘co-sampling’ is used. Since 2020, vessel crews have been collecting fish from randomly selected trips. These samples are frozen at sea and taken to laboratories at Marine Scotland or SUHI where scientists defrost them and collect the biological information. Gaining an understanding of the age structure of fish catches is essential to assess its health and to forecast its ability to remain sustainable in future years. The numbers at age in each sample are used to estimate the numbers at age in the total catch taken in each quarter and ICES area. These estimates, along with total reported catch weights and mean lengths and weights-at-age, are provided to ICES for use in the stock assessments for each species.

Scottish pelagic fishers and scientists

From the very beginning, the project has focussed on ensuring the data collected are relevant and scientifically credible. To achieve this, the programme has worked in partnership with relevant scientific and policy institutions (national and international) to develop the specifics of the programme. Any data provided by industry has the best chance of being used when it can demonstrate that it meets the required international standards of quality and documentation, allowing it to be trusted by the institutions that use it.

Collaborations allow the distinct expertise of each partner to be recognised, combined and shared. Within this collaboration, SUHI staff manage the day-to-day implementation of the programme and work closely with the SPFA delivering training and ongoing regular communication with vessels. Marine Scotland works with SPFA and SUHI to design sampling methods, protocols, and quality assurance and control to ensure that the data collected meets required standards. The Scottish Fishermen’s Federation (SFF) is involved in the logistics of collecting and transporting samples to the laboratory. SFF is also engaged in strategic work that seeks to see how lessons from the pelagic sampling might be translated to other sectors.

There are several benefits to this collaborative sampling scheme. Collecting data directly from vessels, rather than from markets, allows catch that is usually landed abroad to also be included in the sampling. The better a sampling programme is able to reach the full scope of a fishery, the more representative the data will be. A further advantage to this new sampling approach is allowing greater control over how trips are selected for biological sampling. Random sampling of the fleet is the gold standard in sampling any fishery to produce unbiased results. In this scheme, the willingness of almost all the Scottish pelagic vessels to engage in the data collection has been key to combining random sampling with comprehensive coverage of the fishery.

A key part of the scheme is that, as owners of the data, every vessel has full access to the data they have collected. After every fishing season, summary reports and data sheets are sent to each participating vessel, providing both a summary of their results and how they compare with previous years. A summary of the anonymised results of all participating vessels is also given to each participant at the end of each year. It should be noted that for data protection purposes all data are treated in the strictest confidence and are aggregated before any reporting in the scientific community.

The success of the programme has led to the co-sampling scheme now being adopted under Scotland’s national sampling programme as the main mechanism for collecting biological data on the catches of pelagic fish by the Scottish fleet.

The information gathered through the co-sampling programme is used by ICES to make yearly assessments of the health and status of mackerel, herring and blue whiting, which are then used to make management decisions for the fishing industry for the following year. Overall, collaborative sampling is contributing to continuous improvements in science, which in turn leads to better fisheries management and more informed decision-making.
This innovative collaboration is an excellent example of how industry and scientists can work together for the greater good of fisheries and our precious marine environment. It fosters an enhanced relationship between industry and science, creating a pathway for even closer collaboration, and ensures that fishermen are at the heart of securing the future sustainability of our fisheries.

Authors: Jessica Craig, Liz Clarke & Campbell Pert (Marine Scotland Science), Chevonne Angus & Katie Brigden Shetland UHI (formerly NAFC Marine Centre, Shetland), Steve Mackinson (Scottish Pelagic Fishermen’s Association).

This graph shows yearly estimates of the number of herring at each age caught in the western North Sea. The strong age 3 cohort in 2017 can be seen progressing through the years. A strong age 2 year class is evident in 2021. Age 0 and 1 herring are generally too small to be retained in commercial nets, so are not usually seen in the catch of fishing vessels.

These age distributions feed into yearly assessments of the health and status of the stock. The stock assessments inform advice on catch limits for the following year. Replacing onshore sampling, data collected through the new co-sampling programme will now be used to estimate the age distribution of Scottish pelagic catch.