Hi Joyster,joyster wrote:as a salmon farm employee of 27 years let me dispell some of the dross that is sometimes presented as fact by the press and some other "authorities" on the subject.
all salmon farms do their utmost to eradicate sea lice on our fish as a lice infestation can cause a 30% reduction in feeding and the introduction of infections caused by the lice.
in the critical spring period when salmon and sea trout smolts go to sea all farms are inspected on a 2 week basis to count the number of lice on the fish.the permitted numbers of oviderous females per fish is .5 per fish.if this number is exceeded thn the marine institute will tell the farm to do a treatmtnt.
the most widely used treatment at the moment is hydrogen peroxide, this is a oxidising agent which literaly lifts the lice off the fish whilst the peroxide itself bio degrades in 20 minutes in sea water.
salmon smolt when they migrate to sea do not hang around the bays and do in fact move out to sea at a very fast rate, a smolt that was micro tagged in the screeb fishery in connemara was recovered in a mackerel trawl off the mull of kintyre 8 days later.
in conclusion , salmon farms do their utmost to rid their fish of lice as it causes them large financial costs, they have a legal obligation to do so ,they also have an envoirnmental obligation.
lastly, there are no organicaly certified in feed treatments for sea lice treatment,but you will have to check with the 3 organic certification authorities that certify the fish that we produce to verify this.
The fact remains, regardless of what alleged efforts you state that salmon farmers go to eradicate lice from their fish, lice problems persist. Lice problems which didnt exist in the vicinities of farms prior to their introduction. My first hand experience relates to a farm which was introduced exactly 22 years ago this month. 22 years into the operation and there are still sea trout being encountered with grossly excessive lice infestations to the point of being fatal. Several generations of sea lice on individual fish. It didnt happen before salmon farming was in the area, it is completely unnatural and it is killing wild fish.
A juvenile salmon can swim as fast as it likes away from the coast, if it swims through a high density of salmon louse nauplii it is doomed, speed of travel wont save it. Whats more, salmon smolts navigate by the coastline before heading off into the deep ocean as your example of a Screebe smolt being caught 8 days later off the Mull of Kintyre demonstrates. That fish has navigated the length of Ireland by its coastline and was very likely going to carry on northwards along the west of Scotland coastline, travelling through salmon farm occupied Scottish water en route. So your in attempts to argue that smolts are not vulnerable to salmon farm nurtured lice infestations, you have actually achieved the complete oppositte. Thanks for pointing out something we were all aware of initially- salmon smolts navigate by coastlines, ie salmon farm territory.
Even if salmon farms did their utmost to eradicate lice infestations on their own fish it still doesnt alter the fact that farms are permanent salmon louse breeding reservoirs which are not supposed to be there, evolution didnt plan for them. Farms dont have to have problematic infestations on their individual fish for there to be an absolutely giant lice production being released into the natural environment. Even if the number of egg bearing female lice is as low as 0.5 per farmed fish in a farm containing lets say 500,000 fish, thats still 250,000 egg releasing adult lice in a specific coastal ecosystem which shouldnt be there. The number of lice on your individual fish is irrelevent. Its the combined number of egg producing female lice on your stock which is the problem. Thats the reason I am catching sea trout on an annual basis with sickening infestations of sea lice present. The worst one Ive seen involved 18 fully grown adult lice and 293 immature transparent lice. The fish was a very disturbing sight, emaciated from the dorsal fin region rearwards. Thats the actual real result of salmon farming whether you like it or not, regardless of whether you attempt to control lice ot not. The fact is, you cannot control lice. You cannot prevent lice occuring on intensively farmed fish and you cannot prevent them from reproducing. Their offspring infest the wild fish's environment in densities which cannot possibly happen without the presence of salmon farming.