Dear MARMAM-ers On behalf of the team I am pleased to announce a recent publication on hybridization between Fin and Blue whales in Evolutionary Applications<https://onlinelibrary.wiley.com/doi/10.1111/eva.13091> Evidence of unidirectional hybridization and second‐generation adult hybrid between the two largest animals on Earth, the fin and blue whales Christophe Pampoulie; Davíð Gíslason; Guðbjörg Ólafsdóttir; Valérie Chosson; Sverrir Daníel Halldórsson; Stefano Mariani; Bjarki Þ. Elvarsson; Marianne H. Rasmussen; Maria R. Iversen; Anna Kristín Daníelsdóttir; Gísli A. Víkingsson Abstract Biodiversity in the oceans has dramatically declined since the beginning of the indus-trial era, with accelerated loss of marine biodiversity impairing the ocean's capacity to maintain vital ecosystem services. A few organisms epitomize the damaging and long-lasting effects of anthropogenic exploitation: Some whale species, for instance, were brought to the brink of extinction, with their population sizes reduced to such low levels that may have caused a significant disruption to their reproductive dynam-ics and facilitated hybridization events. The incidence of hybridization is neverthe-less believed to be rare, and very little information exists on its directionality. Here, using genetic markers, we show that all but one whale hybrid sample collected in Icelandic waters originated from the successful mating of male fin whale and female blue whale, thus suggesting unidirectional hybridization. We also demonstrate for the first time the existence of a second-generation adult (male) hybrid resulting from a backcross between a female hybrid and a pure male fin whale. The incidence of hybridization events between fin and blue whales is likely underestimated and the observed unidirectional hybridization (for F1 and F2 hybrids) is likely to induce a re-productive loss in blue whale, which may represent an additional challenge to its recovery in the Atlantic Ocean compared to other rorquals The paper is available for open-access download: https://doi.org/10.1111/eva.13091 Please correspond to: christophe.s.pampoulie@hafogvatn.is<mailto:christophe.s.pampoulie@hafogvatn.is> Christophe Pampoulie Marine and Freshwater Research Institute Fornubúðir 5 220 Hafnarfjörður Iceland -- Sverrir Daníel Halldórsson líffræðingur, hvalarannsóknum Uppsjávarsviðs Hafrannsóknastofnun - rannsókna og ráðgjafastofnun hafs og vatna Fornubúðir 5, IS 220-Hafnarfjörður Ísland