P. Larsson et al., PERSISTENT POLLUTANTS IN A SALMON POPULATION (SALMO-SALAR) OF THE SOUTHERN BALTIC-SEA, Canadian journal of fisheries and aquatic sciences, 53(1), 1996, pp. 62-69
Persistent pollutants in an Atlantic salmon (Salmo salar) population s
pawning in a river of southern Sweden were investigated. The populatio
n was characterized by a high growth rate. Some males reached 20-30 kg
after 3 to 4 years in the sea. The fat content of migrating salmon va
ried by one order of magnitude and was the most significant correlate
of pollutant concentrations. No relationships were recorded between fa
t content and gender, age (weight, length), year at sea, or different
measures of condition. The reasons for this may be the varied evolutio
nary strategies for maximizing reproductive output; male salmon may en
ter the spawning river as small grilse and spawn opportunely, or migra
te at a larger size, when they can hold spawning territories in the ri
ver. Females have a greater and more uniform size, and spend more ener
gy on gonadal products. The varying fat content of individual fish may
also be attributed to foraging in different areas of the Baltic and t
hereby to migration distances as well as foraging strategies. When pol
lutant levels were normalized for fat content, other factors such as a
ge (weight, length) were shown to be important for uptake; older fish
had higher levels of pollutants than younger ones.