Our favourite anti-salmon farming activist is now trying to suggest that the VHS virus, which has been killing wild fish for millions of years and which was observed long before salmon farms, is now magically spreading from salmon farms and killing herring by making them bleed out their eyes.
This protest sign has finally come true!
How about we cut the crap and look at the science, shall we?
A study was just published which is “the first comprehensive analysis of the genetic diversity and epidemiology of VHSV isolates from the marine waters of BC since the first
detection of the virus in Pacific herring in 1993.”
The study, titled “Molecular epidemiology of viral haemorrhagic septicaemia virus (VHSV) in British Columbia, Canada, reveals transmission from wild to farmed fish” by Garver, et al, was published in May.
Along with a lot of detailed genetic analysis of the virus and its transmission, it provides ample proof that VHS virus observed in farmed fish only comes from wild fish passing by or through the net pens.
Shedding rates of VHS diseased herring have been estimated to be in the order of 1.8 to 5.0 × 108 plaque-forming units fish−1 d−1 (Hersh berger et al. 2010). Thus, it is conceivable that if large numbers of herring residing in or around a net-pen undergo a VHSV epizootic then the farmed salmon may be subjected to high concentrations of waterborne virus.
Great Scott! That’s 500 million viral particles PER FISH PER DAY! If 3,000 infected herring are in a farm, they are shedding 417 million viral particles per second!
The farmers should be outraged! After all, didn’t Morton prove to all of us that salmon farms shedding viral particles will fill up ocean channels and kill fish in apocalyptic proportions? Wouldn’t that mean that herring shedding millions and millions of viral particles would fill up ocean channels, too?
Heyyyy… shouldn’t Morton et al be outraged that these horrible herring are shedding billions of viral particles in the ocean where our precious wild salmon swim? Because if viral particles shed from salmon farms will survive to decimate wild salmon, won’t viral particles from herring also survive to decimate wild salmon? Where’s the anti-herring outrage?
Hang on, there’s that pesky thing called context.
What Morton fails to mention every time she uses this “viral particles” example (aside from her not being sure if it’s 650 billion particles per hour or 65) is that viral particles do not spread very far without hosts. In fact, floating around in seawater without hosts, many viruses quickly lose their ability to infect. VHS virus is most unstable in seawater and will not survive long without a host, let alone retain its ability to infect new hosts.
For one group of fish to infect another, a large amount of one group would have to be infected to have enough viral load to infect the other. They would also have to spend some time in proximity.
That’s what happens when VHS-infected herring hide inside salmon farm pens to escape predators. The herring infect the farmed salmon.
However, even then, the problem is minimal for farmers. There are very few farm mortalities related to VHS virus. That’s because farmed salmon are healthy, and kept resistant through good husbandry and handling processes.
But this context is all white noise to Morton and friends, who will continue to spin the wheel of fish to see what new outrage they can whip up next.
Well, let ’em keep on spinning. Because all they’re doing each time they carry on with this nonsense, is picking the box.