Aquaculture has become a hot topic on the coast.
Here in the United States, farming various invertebrates—typically
oysters, clams, and mussels—has become a well-established industry with little downside;
it can even be seen as benign, as the
farms introduce large numbers of filter-feeding mollusks into areas suffering
from phytoplankton blooms, and so positively impact water quality. Recent efforts
to farm kelp are expected to bring similar benefits.
Unfortunately, finfish aquaculture has no such environmental upside,
but does pose real risks when conducted in net pens or similar facilities.
Aquaculture's best-publicized failure was probably the
2017 collapse of net pens that Cooke Aquaculture, a Canadian fish-farming
conglomerate, maintained in inshore waters off the State of Washington. As a result of such collapse, more than
250,000 non-native Atlantic salmon escaped into the waters of the Salish Sea,
where they might have further imperiled already-threatened runs of native
Pacific salmon.
An
article distributed by the University of California—Davis noted that
“Farmed Atlantic salmon can carry viruses, bacteria and
parasites such as sea lice that can infect wild salmon. The release of thousands of salmon that were
actively experiencing a disease outbreak could have huge ramifications for wild
salmon…
“While we have not seen data on the health of disease status
of the released Atlantic salmon, it was reported that they were treated for a
bacterial infection called yellow mouth in July 2016 but were believed to be
disease-free at the time they escaped.
“Without detailed disease testing data, it is difficult to know
what the potential for disease transmission could be in this most recent
release. An evaluation of the risk of
disease transmission from farmed Atlantic salmon to wild Pacific salmon
conducted over a decade ago classified the risk as low due to existing disease
testing protocols and the state’s prohibition on bringing new Atlantic salmon
stocks or eggs into Washington (which limits new diseases from entering)…
“As to whether released farmed salmon will compete with
native salmon for food and breeding or spawning space, studies have shown that
while their performance and reproductive success in nature vary, farmed salmon
are often outcompeted by wild salmon of similar size.
“…while released farmed Atlantic salmon will compete with
wild salmon for food, many also don’t make the transition from being fed
pellets in farms to catching and eating wild food.
“For those that do, though, stonefly nymphs found in the
stomachs of Atlantic salmon caught in the Salmon River (Vancouver Island)
suggest that escaped Atlantic salmon also can be predators in freshwater as
well as in the ocean…
“On balance, though, the science looking at past net pen
releases of Atlantic salmon in this region suggests that there can be negative
impacts to native salmon including disease transmission, competition for food
and breeding habitat, and the potential for long-term establishment of an
introduced Atlantic salmon run…”
Fortunately, the Cooke Aquaculture net pen collapse does not
appear to have resulted in any such negative impacts. In fact, the only significant impact the collapse
appears to have was an arguably positive one:
Legislation
that bans the farming of non-native fish in Washington waters was passed in
2018; the ban will become effective when the last of the current aquaculture
leases expires in 2025.
Elsewhere, native salmon runs have not been fortunate enough
to escape the negative impacts of aquaculture and non-native species, with both escaped fish and
introduced diseases causing harm to wild populations.
It’s not completely clear how much damage the pinks have
already done to native European salmonids, but biologists are concerned. There’s not too much information publicly
available from Russia, where the invasive salmon have been present the longest. However, research published
by a team of Russian scientists in 2015 found that
“pink salmon had a substantial negative effect on the
recruitment and abundance of the freshwater pearl mussel (Margaritifera
margaritifera) in two rivers in the White Sea basin. This was likely caused by a concurring reduction
in density of juvenile Atlantic salmon, which is the obligate host of mussel
glochidia larvae in these rivers,”
which research suggests, but does not conclusively confirm,
that pink salmon may have a negative impact on Atlantic salmon recruitment.
“Pink salmon is reported to be aggressive on the spawning
sites, which may lead to negative interactions with Atlantic salmon and brown
trout. It has been documented that groups
of pink salmon may attack Atlantic salmon that are at the spawning sites
preparing for spawning. The result is
that the Atlantic salmon move to river sections less suitable for spawning.”
The same paper considered other potential negative
impacts, ranging from rotting pink salmon carcasses leading to depleted oxygen
levels in the rivers, and so reducing the survival of larvae of later spawning
fish, to competition between pink salmon fry and that of other species, but
could draw no conclusions from the limited information available.
“Wild Atlantic salmon stocks are already under great pressure
from a variety of sources. The
introduction of novel parasites or diseases from invasive species, such as Pacific
pink salmon, could potentially represent an additional risk to the viability of
the species.
“We therefore want to better understand the immediate risk
that pink salmon could represent to our important wild salmon stocks.”
“It might be argued by some that another salmon species might
be desirable in Scotland’s rivers.
“However, the potential for negative impacts on native
species and the fact that they are the least desirable of the Pacific salmon
from an angling and commercial fishery perspective suggest that there are
unlikely to be any positives from their doing so.
“The fact that they are running up Scottish rivers is worrying
as that suggests a spawning intention – the species normally spawns from July
to October across its native range…
“It is a situation which should be closely monitored in
respect of the threat it poses to Scotland’s native salmon, given the latter’s
great socio-economic value and biological uniqueness.”
“had taken all reasonable steps and exercised due diligence
to avoid committing [the offence]”
of accidentally catching and/or retaining a pink salmon,
such actions “may be” a defense to any resulting charges. However, the words "may be" seem to offer little comfort to Scottish anglers who inadvertently find themselves with
a pink salmon in hand.
Still, given the potential threat that pink salmon could
pose to Scottish Atlantic salmon and sea trout, its understandable that the
government would want to do all that it can to assure that the invasive fish
don’t gain a foothold in Scottish rivers.
Unfortunately, the threat posed by introduced and aquacultured
fish isn’t limited to pink salmon, Europe, or competition in the spawning
rivers. Here in North America, aquacultured
Atlantic salmon appear to have transmitted a virus to native chinook (also
known as “king”) salmon stocks in British Columbia.
From
what scientists could tell, such transmission has been going on for a very long
time—probably more than thirty years.
But the disease that's callled Piscine orthoreovirus-1, or PRV-1, and
causes heart and skeletal muscle inflammation in the farmed Atlantic salmon, manifests
itself very differently in the wild chinooks, which incur fatal liver and kidney
damage. Since
about 97% of all farmed Atlantic salmon in British Columbia contract the virus
by the time that they are 18 months old, and since the virus is believed to
have been introduced into British Columbian waters in 1989, after the farms imported
infected eggs from Europe, wild chinook salmon have been extensively and
continually exposed to PRV-1, which is spread when the farmed salmon’s feces are
released into the water.
“Both are genomic and epidemiological
methods independently came to the same conclusion, that salmon farms act as a
source and amplifier of PRV transmission…
“The study’s genome sequencing clearly
indicates that PRV is not native to [British Columbia] waters—it originated in
the Atlantic Ocean and has been spread around the world through salmon
aquaculture.”
In response to that finding, Dr.
Andrew Bateman, of the Pacific Salmon Foundation, who was a co-author of the
study, advised that
“The PRV findings, in particular, support
calls to transition from open-net salmon farming towards farming technology
that doesn’t allow disease transfer between farmed and wild salmon.”
Of course, salmon aren’t the only
fish that suffer from viruses, nor are they the only fish which are raised in
open-net pens. Dr. Bateman’s advice has
much wider application.
Anglers here in the United States
ought to be paying particular attention, because encouraging open-water
aquaculture has become a national priority, and right now, it appears that fish
farming in federal waters may be conducted with very little control.
Back
in 2016, the National Marine Fisheries Service issued regulations for permitting
and regulating aquaculture operations in the Gulf of Mexico. A consortium of environmental, commercial
fishing, recreational fishing, and food-safety groups brought suit to challenge
such regulations, arguing that the Magnuson-Stevens Fishery Conservation and
Management Act’s definition of “fishing” did not include aquaculture, and that NMFS
lacked the authority to issue permits for offshore aquaculture operations.
The decision had unintended
consequences.
While the plaintiffs brought the
action hoping to prevent the construction of offshore aquaculture facilities in
the Gulf of Mexico, and probably elsewhere off the United States coast, the appellate court's decision did not further that goal.
Instead, it
merely removed NMFS, the agency with the greatest expertise with respect to marine
fish and related issues, from the permitting process, leaving all permitting up
to agencies such as the Environmental Protection Agency, which would only have
jurisdiction over the discharge of pollutants, and the Army Corps of Engineers,
which promotes marine conservation in about the same way that the tobacco
industry promotes respiratory health. NMFS’
role is now limited to consultation on matters such as protected species
interactions and impacts on essential fish habitat.
“The goal of the project is to show to the
Florida fishing and boating community that offshore aquaculture can be
something that they can learn to love and embrace.
“Our goal here is to set up a very small-scale
single cohort, one batch of fish, only 20,000 fish, which that’s [sic] about
one percent of what the size of a commercial farm might be, and then
grow those fish through to harvest size.
[emphasis added]”
Right now, there are quite a few
people who don’t yet “love and embrace” the proposed project, and might be
expected to have an even colder reaction to the sort of “commercial farm” that might
keep 2,000,000 fish penned up in a small expanse of ocean. One
op-ed, written by an angler and professor at Florida Southwestern State College,
which appeared in The [Cape Coral] News-Press, objected to an aquaculture
facility
“smack dab in the middle of the red
snapper and grouper grounds of recreational anglers in Southwest Florida and
from all over the country,”
and expressed concern over
“20,000 almaco jack fish packed like
cattle, in an oversized bait ball of synthetic feed, waste, and pharmaceuticals,”
fearing that it would
“alter the ecology and pollute and deform
Florida’s natural, heretofore, uncorrupted west coast.”
“Ocean Era’s facility will feed harmful algae
blooms, present dangers to the genetics of native species if the fish escape
and degrade the nearby ecosystem by polluting the Gulf with fish waste and
pharmaceuticals.”
Ocean Era, of course, disagrees,
but in April, an EPA administrative judge acceded to such concerns by delaying
action on the required pollution discharge permits. Final action is expected this Tuesday, June
1.
Should the permits be granted, it
is likely that other would-be offshore aquaculture operations will soon be
seeking permits for other facilities, some of which will probably seek to
culture species that, unlike Almaco jacks, are not native to the area. Should such facilities be developed, it will probably
only be a matter of time until the same problems currently facing salmon aquaculture—pollution,
the escape of invasive, non-native species, and the transmission of disease to
wild fish stocks—will erupt in the ocean as well.
At the same time, people want to
eat fish, and as the population expands, wild stocks will probably be unable to
supply their needs. Well over a century
ago, the market hunters who once supplied elk, deer, and waterfowl, along with
such other now-extinct species as passenger pigeons and Eskimo curlew, to urban
markets were replaced by meat produced on terrestrial farms. It is only reasonable to expect seafood to
follow the same path.
And, in the end, following exactly the same path is probably
the right answer. For the ideal
aquaculture operation should exist not in the open ocean, but on terrestrial
farms, where water can be cleaned and recycled, and fish can be raised
without any fear of them escaping, of polluting local waterways, or of spreading
disease to wild populations.
Land-based farms are also—at least
for now—more expensive to run, and produce a more costly product.
Balanced against such costs is
the question: What price are we willing
to pay for healthy and abundant wild stocks of fish. Because, as experience already shows, wild stocks
will always be at risk when fish pens are nearby.