Inferring Atlantic salmon post-smolt migration patterns using genetic assignment.

Understanding migratory patterns is important for predicting and mitigating unwanted consequences of environmental change or anthropogenic challenges on vulnerable species. Wild Atlantic salmon undergo challenging migrations between freshwater and marine environments, and the numbers of salmon returning to their natal rivers to reproduce have declined over several decades. Mortality from sea lice linked to fish farms within their seaward migration routes is proposed as a contributing factor to these declines. Here, we used 31 microsatellite markers to establish a genetic baseline for the main rivers in the Hardangerfjord, western Norway. Mixed stock analysis was used to assign Atlantic salmon post-smolts caught in trawls in 2013-2017 back to regional reporting units. Analyses demonstrated that individuals originating from rivers located in the inner region of the fjord arrived at the outer fjord later than individuals from middle and outer fjord rivers. Therefore, as post-smolts originating from inner rivers also have to migrate longer distances to exit the fjord, these data suggest that inner fjord populations are more likely to be at risk of mortality through aquaculture-produced sea lice, and other natural factors such as predation, than middle or outer fjord populations with earlier exit times and shorter journeys. These results will be used to calibrate models estimating mortality from sea lice on wild salmon for the regulation of the Norwegian aquaculture industry.

[Hemoglobins, XLII: Studies on the hemoglobin of the greylag goose (Anser anser). The primary structures of the alpha- and beta-chains of the main component (author's transl)]. / Hämoglobine, XLII: Untersuchungen am Hämoglobin der Graugans (Anser anser). Die Primärstruktur der alpha- und beta-Ketten der Hauptkomponents.

The alpha- and beta-chains of the main component of hemoglobin of the greylag goose (Anser anser) were isolated. For determination of the primary structure of hemoglobin, the chains were cleaved and the cleavage products isolated. The chains and peptides were degraded automatically in the sequenator: the complete primary structure of the alpha-and beta-chains was obtained and compared with the human adult hemoglobin. Comparison with human sequences show 1 substitutions in the alpha-chain and 44 in beta-chain. The mutations are discussed. The alpha-chains contain no tryptophan, only one methionine and two cysteines. Seven alpha 1 beta 1-contacts and one alpha 1 beta 2-oxy- and deoxy-contact are altered. In the beta-chains two acidic amino acids are eliminated. This is probably the reason for the more basic character of the greylag goose hemoglobin. The contact points of the allosteric effector (inositol pentaphosphate in case of birds, 2,3-diphosphoglycerate in case of mamals) with the beta-chains are identical in chicken and greylag goose, two more than in the human beta-chains. Six alpha 1 beta 1-contacts and one hem-contact are changed. This work forms a basis to allow comparison of the functions of several bird hemoglobins and for further studies of bird hemoglobins and for further studies of evolution and systematics of birds.

[Ontogeny and function of rank order in a sibling group of greylag geese (Anser anser L.)]. / Ontogenie und Funktion der Rangordnung innerhalb einer Geschwisterschar von Graugänsen (Anser anser L.).

Between the siblings of a family of greylag geese (Anser anser L.) a rank order is established by fighting during the first days after hatching, and also by other, more complex interactions. The position of each goose in the rank order can be defined by three groups of behaviour patterns (aggressive behaviour, "greetings", escape responses). A clear-cut ranking relation between two individuals is a prerequisite for their close cohesion. The survival function of rank order lies in diminishing the intensity and frequency of agonistic interactions, in diminishing social stress situations and in guaranteeing the close family cohesion.