Revealed: the deadly invader that is bleeding Great Lakes fish to death*

Aggressive virus brought in by ships devastates freshwater species - and
could spread across the continent

By Geoffrey Lean, Environment Editor
Published: 06 May 2007

Tens of thousands of fish have been bleeding to death from an aggressive
Ebola-like virus in North America's Great Lakes. Officials fear that the
plague will spread to devastate waters across the continent.

The epidemic - caused by what one US government scientist calls "the
most important and dangerous fish virus known worldwide" - is believed
to have been brought into the lakes by ocean-going ships.

It is focussing attention on the scores of alien species already
spreading uncontrolled in the lakes, which contain a fifth of the
world's fresh water. State governments are belatedly trying to introduce
measures to control this "living pollution", only to be sued by shipping
companies for "placing an undue burden" on them.

The killer - called viral haemorrhagic septicemia (VHS) - has already
affected some 37 species of fish in the lakes, including salmon, trout,
perch and white bass. Almost every species caught commercially or for
sport in the lakes' $4bn (£2bn) fishing business has been hit.

Victims bloat up and bleed from bulging eyes before dying. The
extraordinarily virulent disease is sweeping rapidly through the lakes
and is expected to start going on full rampage again within the next
couple of weeks when the water warms up to its favoured temperature.

When first discovered, just two years ago, the virus was affecting only
two species in a few patches of water, but it quickly spread to Lakes
Ontario and Erie, and Lake St Clair, on which Detroit stands. It has
recently been confirmed in Lake Huron, and is expected to reach Lake
Michigan soon.

"Updates over the winter suggest that it has spread further than we
thought, even last year", says John Dettmers, a fisheries biologist for
the Great Lakes Fisheries Commission. "As much as I'd like to say we
know exactly what is going on, we don't. We're all sitting on the edge
of our chairs waiting to see how bad it's going to be this year."

Genetic tests show that the virus probably originated in the Atlantic
off New Brunswick, Canada, right next to the start of the St Lawrence
Seaway, the shipping route which leads to the lakes. That points the
finger squarely at the 220 ocean-going ships that enter the lakes each
year as the source of the plague.

Ships take in ballast water to steady them when they are sailing without
a cargo, only to discharge it when they reach the ports where they load
up. But the water is inevitably populated by species of fish, plants and
viruses which are then given free rides around the globe. Some flourish
vigorously in their new surroundings, creating plagues.

In all, 183 such alien species have been found in the Great Lakes and a
new one is being discovered every six months. Just one - the zebra
mussel, originally from the Caspian Sea and imported in ballast water in
1988 - has already caused $3.1bn of damage, clogging up drains and vents
and damaging boats. Others include the colourfully-named bloody red
shrimp, quagga mussels, round gobies, sea lampreys, and spiny and
fishhook water fleas.

The invasion - and the spread of the virus - is fuelling an ecological
xenophobia over "creepy crawly things from foreign lands."

"How would you like to invite a bunch of strangers from other countries
to come over and go to the bathroom in your bathtub?", asked a writer on
Detroit's Metro Times earlier this year. "Sound sick and disgusting?
Sure does."

The disease does not threaten people; cooking kills the virus. But
environmentalists fear that it is only a matter of time before one
arrives that poses a danger to human health. "The lakes are vulnerable
to any pathogen getting in here", says Jennifer Nalbone of the Great
Lakes United conservation pressure group.

Scientists fear that the virus will spread throughout the continent's
rivers and lakes. "Once a species has been introduced and establishes
itself, it will continue to grow and spread, not only in the Great
Lakes, but across the waterways of North America", says Professor David
Lodge, the director of the Centre for Aquatic Conservation at the
University of Notre Dame, Indiana.

And Dr James Winton, the chief of fish health at the US Geological
Survey in Seattle - who calls VHS "the most important and dangerous fish
virus known worldwide" - adds; "Its discovery in our freshwater is
disturbing and potentially catastrophic."

Last autumn, the US Department of Agriculture banned the transport of
live fish from Great Lakes states unless they could be shown to be free
of the virus.

The State of Michigan has banned ocean going ships - known as "salties"
as opposed to the "lakers" that ply their trade within the Great Lakes
system - from discharging ballast water unless it its first sterilised.
Wisconsin, Minnesota, Indiana and other states are considering
introducing similar rules.

But nine shipping groups representing the salties are suing Michigan
saying that the law is unconstitutional, unjust and unfair. They say
that it "places unreasonable burdens on interstate commerce and is
clearly excessive in relation to the putative local benefits gained."

But Bob McCann of the state's Department of Environmental Quality
replies that the law is "Michigan's way of saying enough is enough."

The biggest freshwater lake system on Earth

* The Great Lakes - Superior, Michigan, Huron, Erie and Ontario - were
formed by glacial meltwater at the end of the last ice age

* They are the largest surface freshwater system on Earth, covering
243,000 square km

* They hold one-fifth of the world's surface freshwater supply

* They contain 35,000 islands - including Manitoulin in Lake Huron, the
largest in any inland body of water

* 183 invasive "alien" species have been found in them, and a new one is
discovered every six months

* Spread out evenly, their water would cover the 48 contiguous US states
to a depth of 9.5ft