02 September 2015
UK fisheries survey logbooks from the 1930s to 1950s have been digitised for the first time, revealing how cod responded to changing temperatures in the last century. Scientists at the Centre for Environment, Fisheries and Aquaculture Science (Cefas) and the University of Exeter found that at the time, the warm seas experienced around Norway benefitted the cod, similar to the conditions there today.
Most cod eaten by the UK comes from northern seas including the Barents Sea around Norway, because the stocks there at the moment are at record highs. Cod stocks were also big in the middle of the last century, and this new research, published in PLOS ONE, reveals that the environmental conditions at the time contributed to the change. Cod diet data reveals that their food preferences each year, between capelin, herring, crustaceans and cod cannibalism, were also affected by their environment.
Cefas holds many records from historical survey cruises, many of them in the form of paper log books. A recent programme of work concentrated on cataloguing and digitising these documents, where possible, to ensure that they are not lost and can be made freely available. More of Cefas’ data, with the exception of data owned by industry, will continue to be made available over this year, as announced in June by the Environment Secretary, Elizabeth Truss.
The Barents Sea surveys were mainly carried out by the steam vessel RV Ernest Holt, which was commissioned especially to withstand Arctic conditions. These newly rescued data allow scientists to understand how fisheries in the region have responded to temperatures all the way from the 1930s to the present day.
The scientists at the time knew that the cod were being affected by their environmental conditions, but digitising this data has meant that much more modern techniques can be used to really delve into the responses of cod to changes in their environment and diet.
Cefas’ Marine Climate Change Scientist Bryony Townhill said:
“Historical data such as this are so important in understanding climate change and variability. We know from anecdotal evidence that fisheries have varied in the past but it is rare to have such comprehensive datasets going back to the early 20th century. These logbooks, along with others still held by Cefas, reveal unique insights into the state of fish stocks and the environment in the past century, and enable us to put more recent changes into context.”
Dr Steve Simpson, Senior Lecturer in Marine Biology & Global Change at the University of Exeter said:
“To predict how future climate change will affect crucial fish stocks, we can learn by looking back in time. This historic survey was conducted when Barents Sea was relatively warm and cod populations were booming. Painstaking efforts to convert scribbled notebooks into modern digitised data have provided new evidence on how warmer temperatures affect cod diet and cod populations."
1. The article can be found at:http://dx.plos.org/10.1371/journal.pone.0135418
2. The full dataset referred to in this research is available from https://www.cefas.co.uk/publications-data/fish-stomach-records/.
3. Cefas is one of the world’s longest-established marine research organisations, dating to 1902. Cefas holds historical records of fish catches, stomach contents, fish tags, fish otoliths, scales, vertebrae and shellfish, along with environmental and oceanographic data including temperature, salinity, currents and water clarity. The Barents Sea data described here represents only a small part of the data which is being digitised to ensure the longevity of these valuable data.Lists of Cefas' open data are being routinely published via the MEDIN and data.gov.uk portals. Whilst this data is currently mainly available on request, current work is progressing on making online view and download options available in the near future. This project was funded by Cefas Seedcorn research project “Trawling Through Time”.
4. The Centre for Environment, Fisheries and Aquaculture Science (Cefas) is a world leader in marine science and technology, providing innovative solutions for the aquatic environment, biodiversity and food security. We are the UK’s most diverse centre for applied marine and freshwater science and research, covering an unrivalled breadth of specialist areas to provide a fully integrated, multi-disciplinary approach to all our customers’ needs. For more information about Cefas visit www.cefas.co.uk and follow @CefasGovUK
5. The University of Exeter is a Russell Group university that combines world-class research with very high levels of student satisfaction. Exeter has over 19,000 students and is ranked 7th in The Times and The Sunday Times Good University Guide league table, 10th in The Complete University Guide and 9th in the Guardian University Guide 2015. In the 2014 Research Excellence Framework (REF), the University ranked 16th nationally, with 98% of its research rated as being of international quality. Exeter was The Sunday Times University of the Year 2012-13. The University has invested strategically to deliver more than £350 million worth of new facilities across its campuses in the last few years; including landmark new student services centres - the Forum in Exeter and The Exchange on the Penryn Campus in Cornwall, together with world-class new facilities for Biosciences, the Business School and the Environment and Sustainability Institute. There are plans. www.exeter.ac.uk
6. Photo caption: “N Reynolds. UK scientist on board the RV Ernest Holt in the Barents Sea.” Crown Copyright.