A moments thought will make it very clear that all of those effects are effects on the farmed stock which don't have the option to swim away.
You assume of course that the fish would swim away if they had a choice, but clearly those wild fish caught in the fish net pens chose not to swim away. One also wonders how many swam away while they were still small enough, after staying in the pen for a few weeks? Only to pass on a few anti-bacterial resistant pathogens to their cousins? We will come back to those later.
Whether or not it was a government order is irrelevant; the farms willingly followed the fallowing program. As is so often the case with reactionary arguments, semantics are used to imply the industry wasn't fully co-operative and supportive.
So they had a choice not to follow the government order? I did not realize that. I did not say they were uncooperative and non-supportive, I merely questioned why, if they already fallowed (and I know they did) and they already developed the best practices (that I am not convinced they did) to minimize their effects on the environment (and the wild fish that use it), did the government need to order them to do so. Why were they not already fallowing during out migrations of wild fish? Obviously the timing of their fallowing, prior to the government order, was at their convenience, not the environment's. Of course they will comply when the government tells them to, they want to stay in business. I get that. However, I can not help but feel that their reasons for doing so are a little more self-serving and a lot less environmentally responsible than you suggest.
There is no question that farms contribute to sea lice numbers...
I know that. You know that. I also would also bet the farmers know that (since controlling the lice numbers is costly to their bottom line). However, the DFO apparently does not know that, as they clearly call that very fact into question on the FAQ sheet I quoted earlier. It makes you wonder whose interest they are really protecting.
It is the final outcome on which results are measured and judgments made, not the existence of some contributing factor. While disease pathogens are shed during outbreaks, the pathogens have extremely short lives in the absence of a host.
which they would find as the pens are on major migratory paths of wild salmon.
Those pathogens, should they contact a host, must also be able to overcome the immune response of the host in order to infect them. Since all the pathogens that affect farm fish come from the wild, the wild fish have been exposed and have developed immune responses. Species' disease susceptibility varies so pathogens which may harm farm fish have no effect on wild fish. Even farm fish have an immune response that wards off pathogens. A disease can take hold in a farm environment only when stress levels in the fish compromise their immune response.
And the fact that they are crowded in pens does not cause them stress?
The rapid expansion of intensive one-species aquaculture has generated severe environmental as well as socio-economic problems. . . The characteristics of one-species aquaculture, such as intensive throughput-based salmon cage-farming and shrimp pond-farming, are found to be similar to those of stressed ecosystems".
Could a farmed salmon not pick up a case of IHN, VHS, or ISA or what have you, and since they have little immunity to that disease and are stressed by their confinement to such a small area, have that disease propagate and thrive to the point of the farmers having to try to fight the disease with chemicals? Then could that farmed salmon (assuming it has survived long enough) then pass that disease to other wild salmon as they are passing the pens on their way back to the rivers to spawn (a highly stressful activity)? Then would this not increase the likelihood of those wild salmon dying from the disease? Would it not make sense to
not have these potential sources of disease on the migratory paths of wild fish already stressed to the point of collapse?
That is because the effects are indeed very minor and contained to very small areas.They have no long term effects and make no permanent changes. They are a very minor but necessary cost of obtaining the benefits that the industry provides.
You keep saying they are minor, but the research I have read says otherwise.
Like other forms of intensive food production, industrial-scale fish farming generates significant environmental costs . . .The expansion of some forms of aquaculture, particularly salmon and shrimp farms, has proven to be destructive to the natural environment and populations of aquatic animals. Industrial scale farming of salmon in netpens and shrimp in coastal ponds are the most problematic because they require the intensive use of resources and export problems to the surrounding environment.
Salmonid farms can alter the natural transmission dynamics of sea lice to wild juvenile salmon with infestation pressures four orders of magnitude greater than the natural ambient level
Four orders of magnitude greater hardly seems "very minor". Other sources claim much higher orders of magnitude (73 times) but since they do not cite specific studies we will ignore them, but a 2003/4 Norwegian study showed infection rates 3-8 times greater around farms than in an adjacent temporarily farm free area (Bijorn et al., 2011).
It is great that you assure us that all these problems the research has shown to be the results of net pen fish farming have been solved and that the the fish farmers in BC now all operate according to "best practices." However, you will forgive me if I remain as unconvinced as you are that that the dangers do not outweigh the benefits, which are going to be much smaller job-wise as the industry expands. As is true in other industrialized modes of food production, when "farming methods have become more intensive, . . . employment opportunities have declined (White et al, 2004). If you want to support fish farming, you should be supporting truly sustainable farming practices and not industrial feed lot production.