Sea lice infestations are one of the most widely
publicized issues regarding farmed fish in British Columbia.
These small invertebrates have starred in documentaries, an
advertising campaign, and even a popular US television show. But
do these small parasites warrant all this attention? Current
research reveals that Pacific salmon are less susceptible and
more resilient to sea lice than Atlantic salmon. Furthermore,
research into the actual effects of sea lice on Pacific Salmon
is, as yet, inconclusive.
What Are Sea Lice and Where are They Found?
The term "sea lice" is a generic name, often with unpleasant
connotations, use to describe a range of marine invertebrates
that are generally small, and which have, for some reason, become
part of popular culture. In southern Africa, "sea lice" is the
common name for mole crabs, from the genus Emerita, which are
innocuous burrowing crabs found on sandy, high energy shores and
used as fishing bait. In the southern US, sea lice are planktonic
organisms related to jellyfish and sea anemones. In this
incarnation they pose a serious threat to human health because
they sting thousands of swimmers every year. (There is burgeoning
industry providing suntan creams that negate the stings of these
In BC and other regions around the world where salmon are
indigenous, the term sea lice (also called salmon lice) refers to
the parasitic copepods often found on wild and farmed salmon. But
even within the communities that encounter these copepods, there
is an obvious problem of sea lice identification as there is
frequently some confusion as to what they really are. Amongst
some sport salmon fisherman and even salmon farm workers,
harmless Cumacean shrimps (closely related to copepods) have been
confidently identified to the authors as sea lice. The sea lice
identification problem is exacerbated by conflicting reports in
both the media and scientific publications on the impact of these
lice on salmon health and even wild salmon returns.