You are of course right agent, it is possible these Atlantic's could transmit a disease to Pacific's but we know that hasn't happened in 40 odd years of salmon farming here on the Pacific coast. What is more likely to happen is these Atlantic's will pick up IHN from our Pacific's.
Ya, you are right dave - after 40 years - we do know some of the lack of groundtruthing, Dave. Like the lack of baseline conditions - the lack of science on the siting criteria - the lack of an environmental assessment, etc.
IHN is - as you stated - a Pacific disease. There are others - such as PRV and ISAv that were not. I am using the past tense - because we do have numerous positive PCR tests indicating ISAv is now here - and PRv is rife in fish farms - and those Atlantic couch potatoes are fed - so they can carry higher levels of PRv and not either die or get picked-off.
So - like you say - Atlantics could pick-up IHNv from Pacifics - but Pacifics can and do get more virulent introduced diseases from farmed Atlantic stocks. I don't think I would lightly dismiss the potential impacts of those diseases on wild Pacific salmon by selectively stating that: "
What is more likely to happen is these Atlantic's will pick up IHN from our Pacific's"
That goes both ways agent. If those fish were so diseased as you perceive they would be dead. keeping in mind that Atlantics are far more venerable to pacific viruses that pacific stocks.
It seems you and Dave are borrowing script from the same PR script writer, BN.
There is also a discussion that needs to be pointed-out between "vulnerable" [SIC venerable] and "virulent" - 2 very different effects. Vulnerable means "susceptible" - which may/may not include morbidity/mortality. Those effects show in "virulence" - or in how damaging the effects of getting sick might be.
Virulence of a disease-causing organism is selectively elevated where there is the situation of having a disease vector impacting on a protected host population that is fed and kept away from predators that would run down the sick ones and eat them - like in fish farms.
So fish farms genetically screen for and increase for high virulence diseases and increase virulence in viruses over time.
What that means is that there is instead increased mortality when that disease is released on naive stocks that don't have the same safeguards as farm fish.
In other words - it is worse when fish farm fish give diseases to the wild stocks.
And yes - you are of course right - then the wild stocks would either die or be picked off - and nobody would be the wiser - out of sight and out of mind for some - but one would instead wonder why so few fish came back that year.
"In summary, the scientific evidence indicates that escaped Atlantic salmon, due to their behavior and domestication, are not likely to compete on par with native salmon. Atlantic salmon do not appear to prey on native salmon and appear to make limited utilization of natural food.
except for those areas where steelhead are at low numbers...
The infectious diseases found in Atlantic salmon have originated from natural reservoirs, i.e. other fish, and are not likely to represent the threat of a new exposure to native fish.
Ya - other fish from the
ATLANTIC - which is a real problem when new diseases are released onto naive or new populations/species - like in the
PACIFIC.
