Do Scottish and Norwegian salmon farmers face different challenges in controlling sea lice?

Readers will be aware that the issue of sea lice infection and control is a problem that affects farms in most salmon-producing areas. However, when discussing the problem or its solution with reference to other countries it is important to understand the major differences as well as similarities involved. In earlier Fish Farmer articles we have described the recent Scottish experience with reference to Lepeophtheirus salmonis and Caligus elongatus. This article will compare these data to the outcomes from a Norwegian study conducted over a similar time period (1997-1999). The less significant sea lice parasite in Scotland, C. elongatus, is even less of a feature on Norwegian salmon farms and so this article deals only with the more prevalent louse, L. salmonis.