Fact file: What are sea lice and should I be concerned?

TORONTO – Grocery retailer Sobeys has removed Atlantic salmon from 84
stores across the Maritimes in response to concerns that the fish was infected with sea lice.

Alexandra Morton, a B.C.-based biologist and critic of salmon farms, along with other activists posted photos of the dead fish in a series of photos on Facebook.

The activists claim sea lice was found in fish purchased at stores in New Brunswick, P.E.I and Nova Scotia.

Sobeys has not verified the complaint but says it wants to “err on the side of caution.“

Sea lice occur naturally in the marine environment and are found in both wild and farmed fish worldwide.

Global News takes a look at common questions surrounding sea lice and whether humans need to be concerned.

Are sea lice harmful to humans in any way?
There is no risk to human health associated with eating salmon infected with sea lice, say fish health experts. Fisheries and Oceans Canada says the lice usually falls off and, in most cases, is cleaned during harvesting or processing before it reaches consumers.

Farmed salmon vs. wild salmon – what is the difference?
Salmon farming involves raising the fish in containers, under water, near the shore. Experts view this as a possible solution to overfishing, which has resulted in a decline of wild fish. Critics, however, cite both health and ecological implications as serious concerns.

How do fish get infected with sea lice in the first place?
According to the Atlantic Canada Fish Farmers Association, farmed salmon enter the container or pen lice-free but because lice also travel on wild fish, ocean currents and zooplankton can move freely between both farmed and wild fish, thus infecting fish in both environments.

It can be found on wild salmon and many other species of wild fish.

Do sea lice affect the quality of the meat?
Health Canada says sea lice are only found on the outside of the fish and not in the flesh itself, thus not affecting the quality of the meat.

What treatments are available for fish that are infected with sea lice?
Health Canada has recently approved an emamectin benzoate to control sea lice numbers in Atlantic salmon farms. It is orally administrated and delivered to the fish and is said to target and eliminate sea lice in adult stages. According to Health Canada, there is no health risk associated with the consumption of fish treated with emamectin benzoate.