Preventing Sea Lice in wild fish
May 29th, 2008 by AndrewSea lice pose a huge health threat to both wild and farmed fish. Researchers have investigated the efficacy of a treatment for sea lice in wild sea trout.
Sea lice are important exoparasites of fish, both in the wild and in aquaculture.
These tiny crustaceans can lower the fitness of the fish and indirectly cause fatalities due to open lesions that prevent the fish from maintaining its osmotic, or salt/water balance. If infection rates are severe, the parasites can feed on the fish at higher than the growth rate. It follows then that developing stock are more prone to this distressing phenomenon due to their small size.
To investigate means of tackling this disease, wild sea trout were tagged with Passive Integrated Transponder tags (PIT tags). Fish are therefore identifiable and traceable using a tag scanner on recapture of the fish.
There were two groups, one treated with a prophylactic substance designed to control the parasite and the others untreated. The experiment took place in the north-west of Scotland.
It was discovered that the treatment had a significant effect on the condition factor of treated fish. Indices of condition indicated that the fish that received the prophylactic suffered less growth constraints whilst in open sea.
Possible subsequent effects on growth and survival to sexual maturity could have significant implications on stock conservation due to the direct relationship between fecundity and size in the female.
Control of this parasite is important, not only for farmed stocks, but also for wild stocks as farming situations are thought to act as sources of infection for this pest. Further research could well bring about more effective controls and superior management of our natural and farmed fish stocks.
More on this approach to sea lice control is available via this link.
Tags: EU, lice, scotland, trout
Posted in Environment. Permalink for this post: permalink.
If you are a Digg user, please 
Digg this post. If you use use Del.icio.us, then add us in: 
Del.icio.us
What do you think?
Leave a comment! Or send a trackback from your own blog.
Like to read more? Subscribe with RSS
June 3rd, 2008 at 1:04 pm
Salmon is an anadramous fish, which means that it lives its adult life in salt water, then returns to freshwater streams to spawn and die. In the spring, the eggs hatch, and the little fish start to grow and make their way out to the ocean. Wild salmon have a varied diet and along with their free roaming, their Omega 3 concentrations are high. Man-raised salmon are fed toxic fish pellets also containing unsanitary and genetically modified foods. The color of a farmed fish is gray due to its diet and confinement. To make it look pink/red, the fish are fed chemical dyes.
June 3rd, 2008 at 2:41 pm
Thanks for your input Joann. Can you assist us with any leads that might point us in the direction of potential solutions to the shortcomings that you identify?
Would you be prepared to share with us what you know about the source of the flesh colour in wild salmon?