[NAEP] Humans Making Wildlife Sick

[Dawn Wiseman]

The birds should be worried about us too.

-------- Original Message --------
Subject: 	Humans Making Wildlife Sick
Date: 	Fri, 17 Feb 2006 09:26:10 -0500
From: 	Suzanne.Godbout at NSERC.CA
Reply-To: 	NSERC News Letter <NSERCNEWS-L at LISTSERVER.NSERC.CA>
To: 	NSERCNEWS-L at LISTSERVER.NSERC.CA



*NSERC NEWSBUREAU BULLETIN*

*Friday, February 17, 2006*

*Under embargo until *

*Friday, February 17, 2006 at 1:45 p.m. (Eastern Time)*

*Humans Making Wildlife Sick*

Whether it's monkeys and AIDS or mosquitoes and the West Nile Virus, 
we're used to thinking of wildlife as reservoirs for emerging infectious 
human diseases. But a Canadian mathematical biologist says that it's 
time that we turned the tables - as often as not, it's humans that are 
making the wildlife sick, often to our own detriment.

It's a 180-degree turn in perspective that Dr. Mark Lewis says is 
critical to our understanding of emerging infectious diseases of both 
wildlife and humans. And, he says, in the case of at least one 
ocean-based disease outbreak, biology and math are proving to be 
powerful allies in helping stem the growing tide of an ocean plague.

"With emerging infectious diseases of wildlife today there's almost 
always some human component," say Dr. Lewis, an NSERC-funded 
mathematical ecologist in the mathematics and statistics department at 
the University of Alberta, Edmonton, Canada.

Dr. Lewis' lab group has used mathematical mapping tools, often in 
collaboration with other research groups, to document the spread of 
pests from the West Nile Virus to the Mountain Pine Beetle in Pacific 
Northwest forests.

Last year, in a landmark paper, he helped document how commercial salmon 
farms off Canada's British Columbia coast are a breeding ground for sea 
lice, a parasite that then infects young wild Pacific salmon. The 
research was the first to document the parasitic impact of commercial 
salmon farms on wild salmon in the Pacific Northwest.

Dr. Lewis and University of Alberta doctoral student Marty Krkosek, who 
led the sea lice research, are co-presenting their latest sea lice and 
salmon findings as part of a symposium called/ The Rising Tide of Ocean 
Plagues/, February 17 at the Annual Meeting of the American Association 
for the Advancement of Science in St. Louis.

Dr. Lewis is a leader in applying mathematical tools to modelling 
environmental interactions, from carnivore territoriality to risk 
analysis related to biological invaders, such as the zebra mussel in the 
Great Lakes.

When it comes to emerging infectious diseases of wildlife, Dr. Lewis 
says that public perception and policy needs to move beyond seeing 
"special cases" to seeing the constant role that people play.

"The way that people often think about emerging infectious diseases is 
that there are just a lot of special cases. That this happened here and 
that happened there, without any commonalties," notes Dr. Lewis. "But 
there's a growing sense that emerging infectious diseases are really 
important as a group. So we need the quantitative tools and mathematical 
theory to be able to study them, including being predictive and diagnostic."

In the case of sea lice, Krkosek, Dr. Lewis and biologist Dr. John Volpe 
at the University of Victoria, Canada used an innovative live-sampling 
technique to document the transfer and spreading impact of parasite 
transmission from a fish farm to wild salmon. "There's a long and 
beautiful history of mathematical models for parasite transmission that 
goes back to the 1970s," Dr. Lewis says. "But the thing that was really 
unusual here was the spatial structure."

The researchers analyzed the sea lice infection rates of more than 
12,000 juvenile wild chum and pink salmon as they headed out to sea from 
their natal rivers. The infection rates were measured in intervals 
before and for 60 kilometres after they passed a commercial salmon farm.

"Our research shows that the impact of a single salmon farm is far 
reaching," says Krkosek. "Sea lice production from the farm we studied 
was 30,000 times higher than natural. These lice then spread out around 
the farm. Infection of wild juvenile salmon was 73 times higher than 
ambient levels near the farm and exceeded ambient levels for 30 
kilometres of the wild migration route."

The researchers are now extending their work to assess how this 
increased parasite load affects the health of the young fish. There's 
already initial evidence that this human-induced parasite boost kills 
many fish. Dr. Rick Routledge from Simon Fraser University and his 
collaborators recently showed that infection rates similar to those 
documented by Dr. Lewis will kill juvenile pink and chum salmon.

But, says Dr. Lewis, there's evidence that some British Columbian salmon 
farmers aren't waiting for the final wildlife forensics report to take 
action. They're taking the researchers' sea lice numbers to heart and 
moving their salmon farms. In an unprecedented agreement, Marine Harvest 
Canada, a major fish farming company, has agreed to move adult salmon 
from its farm at Glacier Bay in British Columbia's Broughton Archipelago 
to another site further away from a major migration route of emerging 
wild juvenile salmon.

Says Dr. Lewis: "Ours is basic research, but the mathematical biology 
clearly gives key results about the contentious issue of fish farm 
impact on sea lice and wild salmon."

Both Dr. Lewis' and Marty Krkosek's research is funded by the Natural 
Sciences and Engineering Research Council of Canada.

*Contact: *

Dr. Mark Lewis
(780) 492-0197
_mlewis at math.ualberta.ca_ <mailto:mlewis at math.ualberta.ca%20> Marty Krkosek
(250) 415-7368 (cell)
_mkrkosek at math.ualberta.ca_ <mailto:mkrkosek at math.ualberta.ca>      
Arnet Sheppard
NSERC Public Affairs
(613) 859-1269*         
*
*Dr. Lewis' AAAS Presentation*
Parasite transmission from Aquaculture to wild fish
Friday, February 17, 2006
1:45 p.m. - 4:45 p.m.

Learn more about Dr. Lewis' research @ 
_http://www.math.ualberta.ca/~mlewis/index.htm_ 
<http://www.math.ualberta.ca/%7Emlewis/index.htm>