Overview of Sea Lice

Sea lice is the common term used for one group of parasitic caligid copepods which occur naturally on fish world-wide Copepods are crustaceans found in both marine and freshwater environments. Most are planktonic, while others are found living in the sediments.

The recognition that the expansion of salmon and trout farming in Europe, Canada and Chile has been accompanied by increasing infestations of sea lice, prompted Merck Animal Health to develop and manufacture an antiparasitic drug known as SLICE*

  • Lepeophtheirus salmonis and Caligus elongatus, Caligus teres and Caligus rogercressyi are the most important species affecting farmed fish. Other species of parasitic copepods are becoming a problem as fish farming expands world-wide and more species of fish are being cultured

  • Some species are specialized to live as parasites, on or in host organisms at some stage in the lifecycle, although one or more stages are free-living as plankton in the water, usually during the early stages of development.

  • Under intensive salmon farming conditions where fish are kept in close proximity, sea lice numbers can increase rapidly and cause serious problems as a result of the opportunistic response of lice to the high density of available hosts.

SLICE* feed premix contains emamectin benzoate in a 0.2% formulation that has proven to be highly effective against the world's most damaging species of copepods infecting salmon.

Effective control of all parasitic stages of sea lice [i.e. chalimus, pre-adults, and adults including gravid females] by SLICE* enables farmers to maintain optimum fish health throughout the entire salmon production cycle.

* Trademark


Disease reprinted courtesy of OIE Diagnostic Manual for Aquatic Animal Diseases, OIE (World Organisation for Animal Health), Paris, France.