High variability in spawning migration of sea trout,Salmo trutta,in two northern Swedish rivers

Abstract Telemetry was used to examine spawning migration of sea trout, Salmo trutta L. (n = 126), in two rivers in northern Sweden. The spawning areas defined by radio‐tagged fish differed between the river systems. In the River Vindelälven, sea trout spawned in the main stem and 80% of tagged individuals returned to areas where hatchery‐reared juveniles had been previously stocked. In the River Piteälven, 74% of tagged sea trout ascended tributaries for spawning. Tagged fish were categorised into three groups of migratory pattern. cart (classification and regression tree) analysis indicated that distance from tagging location to spawning site (S_dist) explained the migratory patterns. Large S_dist separated fish with stepwise upstream migration from those with up‐ and downstream migrations and one‐directional direct migration. Fish tagged early in the season migrated the longest distance to spawning areas. Stocking locations and sex explained the large search behaviour up‐ and downstream in the rivers. The findings are important for the sustainable management of sea trout in the Gulf of Bothnia.     

IMAGING DIAGNOSIS—ENOSTOSIS-LIKE LESION IN THE FEMUR OF A HORSE

An enostosis-like lesion was diagnosed in the left femur of a Swedish Warmblood horse that had a left hindlimb lameness of 3 weeks duration. With scintigraphy using technetium 99m-hydroxymethylene diphosphonate (^99m Tc-HDP) a marked regional focal increase in radioactivity was identified in the medullary cavity of the left femur. Radiographically there was a corresponding focal increase in bone opacity in the middiaphysis of the left femur. Histopathologically, a 5 cm area of bone matrix was present in the diaphysis of the left femur and confirmed as an enostosis-like lesion. Enostosis-like lesions should be considered as a source of pain in horses with difficult to localize, moderate to severe chronic lameness.     

Four Cases of Congenital Malformation of the Heart in a Litter of Eleven Dogs

Abstract—Four cases of congenital malformation of the heart in a litter of eleven dogs are reported. In one case the only defect to be found was a patent ductus arteriosus. In the other three cases there was an unusual malformation of the tricuspid valve giving rise to pronounced stenosis. These three dogs had a right to left shunt on the atrial level and in one dog it was possible to demonstrate that the main vascular supply to the lungs was through the bronchial artery. The litter was the result of inbreeding and this could be the reason for the familial incidence of the malformations. Résumé—Quatre cas de malformations congénitales du coeur, dans une portée de onze chiens, sont rapportés. Dans un cas seulement, le seul défaut trouvéétait un canal artériel. Dans trois autres cas, il s'agissait d'une malformation peu commune de la tricuspide produisant un rétressissement prononcé. Ces trois chiens avaient une communication inter-auriculaire, et, chez un chien, on démontra que l'apport du sang vers le poumon se faisait par une artère bronchiale. Cette portée était le produit de croisements consanguins, ce qui pouvait expliquer la fréquence de malformations. Zusammenfassung—Vier Faelle werden berichtet von congentialer Missbildung des Herszen in einem Wurf von elf Hunden. In einem Fall war der einzige Defekt, der gefunden werden konnte, ein offener ductus arteriosus. In den drei anderen Faellen war eine ungewoehnliche Missbildung der Tricuspidalklappe, die zu einer erheblichen Stenose fuehrte. Diese drei Hunde hatten eine (Blut-) Stromablenkung von rechts nach links im Vorhof-Niveau, und in einem Hund war wes moeglich zu zeigen, dass die hauptsaechliche Gefaessversorgung zu den Lungen durch die Bronchialarterie ging. Der Wurf war das Ergebnis von Inzucht und diese koennte die Ursache sein fuer das vererbungs-bedingte Auftreten der Missbildungen.     

Phenotypic and genetic parameters of body and compositional traits in Arctic charr, Salvelinus alpinus (L.)

Abstract. Phenotypic and genetic parameters of body and compositional traits were estimated for a population consisting of 327 two-year-old Arctic charr, Salvelinus alpinus (L.), from 21 full-sib groups. Heritability estimates for body traits, such as fork length, gutted weight, condition factor and visceral weight, were all of intermediate magnitude (0·24–0·45). Heritabilities for carcass component traits, e.g. fat, protein, dry matter and astaxanthin contents, were low to medium (0·0–0·28). Genetic and phenotypic correlations were high between astaxanthin content and body traits, whereas they were medium to low between astaxanthin content and carcass compositional traits such as fat, dry matter and protein contents. The genetic variation in fat and dry matter contents was closely associated with variation in body weight. Selection for higher body weight at 2 years will probably lead to small, but positive, correlated changes in fat content. Our findings suggest that it should be possible to select for higher astaxanthin content in Artic charr to improve their flesh coloration.