Quantitative risk assessment of salmon louse-induced mortality of seaward-migrating post-smolt Atlantic salmon

Publication date: June 2018Source: Epidemics, Volume 23Author(s): Anja Bråthen Kristoffersen, Lars Qviller, Kari Olli Helgesen, Knut Wiik Vollset, Hildegunn Viljugrein, Peder Andreas JansenAbstractThe Norwegian government recently implemented a new management system to regulate salmon farming in Norway, aiming to promote environmentally sustainable growth in the aquaculture industry. The Norwegian coast has been divided into 13 production zones and the volume of salmonid production in the zones will be regulated based on salmon lice effects on wild salmonids. Here we present a model for assessing salmon louse-induced mortality of seaward-migrating post-smolts of Atlantic salmon. The model quantifies expected salmon lice infestations and louse-induced mortality of migrating post-smolt salmon from 401 salmon rivers draining into Norwegian coastal waters. It is assumed that migrating post-smolts follow the shortest path from river outlets to the high seas, at constant progression rates. During this migration, fish are infested by salmon lice of farm origin according to an empirical infestation model. Furthermore, louse-induced mortality is estimated from the estimated louse infestations. Rivers draining into production zones on the West Coast of Norway were at the highest risk of adverse lice effects. In comparison, rivers draining into northerly production zones, along with the southernmost production zone, were at lower risk. After adjusting for standing stock biomass, estima...

Source: Epidemics - July 5, 2018 Category: Epidemiology Source Type: research