We are pleased to share our new publication in Marine Biology with the MARMAM community: Sigurðsson, G.M., Víkingsson, G., Chosson, V., Jansen, T., and Singh, W. Spatiotemporal co-occurrence of whales and capelin on the east Greenland shelf during autumn. Mar Biol 173, 15 (2026). https://doi.org/10.1007/s00227-025-04778-2 Summary: The waters between Iceland and East Greenland have undergone considerable changes in the last 30 years, which has resulted in large scale changes to the ecosystem. Keystone species such as capelin have changed their distribution northwards and subsequently marine mammals in the region have changed their distribution to the point that the term regime shift has been raised. Hunting statistics in Greenland show marked switch from Arctic marine mammals to sub-Arctic/boreal species such as humpbacks and white-beaked dolphins. In this study we investigated the relationship between whales and capelin during these times of change. Our hypothesis was that whales previously associated with capelin would be found in greater numbers where capelin are present despite these observed changes in the ecosystem. To explore this question, we counted whales systematically using dedicated observers and measured capelin with acoustic measures during in autumn in East Greenlandic waters in 2017 and 2018. A total of 1313 baleen whale sightings and 824 tooth whale sightings were recorded in the surveys. More whales were sighted in 2018 due to larger survey area and better weather conditions. The most observed species was fin whale, long-finned pilot whales, and humpback whales in both years. Whale and capelin abundance data were then summed per statistical square (0.25° x 0.5° latitude and longitude) for statistical analysis. Whales were found at a higher frequency than expected where capelin was present, with the relationship being stronger for baleen whales than toothed whales. Further, a Generalized Additive Model (GAM) showed a weak (11% deviance explained) but significant relationship between capelin abundance and total whale abundance. When modelled separately by the most common baleen whale species, i.e. fin, minke and humpback whales, this positive relationship was stronger (49% deviance explained for minke, 27% for humpback and 14% for fin whales). The results show that whales are likely following the capelin during these changing times and likely indicate both direct predation on capelin by some of the whale species, and competition for zooplankton between capelin and some of the other whales. The next logical steps would be to confirm this with analysis of stable isotopes. The article is open access and available here: https://link.springer.com/article/10.1007/s00227-025-04778-2 All the best, Gudjon [cid:lsi-attach-effects_cc97ce66f1984e30420afd31639ac43f4d9cd39f32f747fb0a46867b.png] Guðjón Már Sigurðsson Sjávarlíffræðingur Ph.D. / Marine biologist Ph.D. Hafrannsóknastofnun - rannsókna- og ráðgjafarstofnun hafs og vatna / Marine and Freshwater Research Institute Fornubúðir 5, 220 Hafnarfjörður Sími / Tel: +354 575 2113 gudjon.mar.sigurdsson@hafogvatn.is <mailto:gudjon.mar.sigurdsson@hafogvatn.is> www.hafogvatn.is <http://www.hafogvatn.is/> Þekking - Samvinna - Þor