7 June 2022: New article on marine mammal consumption and fisheries removals in the Nordic and Barents Seas
Mette Skern-Mauritzen, Norwegian Institute of Marine Research, is the first author of an article co-authored by several other members of the NAMMCO’s Scientific Committee, recently published in the ICES Journal of Marine Science.
The study focuses on marine mammal consumption and fisheries removals in the Nordic and Barents seas ecosystems. For the first time, the prey consumption of the 22 seal and whale species present in the Nordic and Barents Seas is assessed and compared with the removals by fisheries, providing valuable information for an effective ecosystem-based fisheries management (EBFM).
Using the best available information on abundance, distribution, diet and energy requirements of marine mammals, this study quantified prey consumption by marine mammals to be between 3.1 and 8.6 times higher than fisheries removals in the study area. The study also indicated that the most common prey item consumed by marine mammals was krill and that seals and smaller cetaceans consumed more than large whales in proportion to their body mass.
The study also investigated the degree of overlap between fisheries and marine mammals in the study area, revealing differences in the trophic levels targeted by each of them. In proportion, local fisheries removed more of higher trophic levels (mostly gadoids and pelagic fish), whereas marine mammals consumed more of lower trophic levels. However, at the regional scale there were indications of overlap and hence potential competition between fisheries and marine mammals. This overlap was strongest in the Greenland and Norwegian seas and weakest in the Barents Sea.
Taken together, the results of this study suggest that marine mammals play an important role as consumers in the Nordic and Barents seas. The greatly improved understanding we have now on marine mammals supports the implementation of an EBFM approach in these high-latitude systems.
The full study by Skern-Mauritzen et al. is available here:
https://academic.oup.com/icesjms/advance-article/doi/10.1093/icesjms/fsac096/6594656?login=true