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Thom Cmar’s Blog

Canadian Asian Carp Study Ups the Ante: Fewer Than 10 Pairs of Carp May Be Enough to Overrun the Great Lakes

Thom Cmar

Posted July 12, 2012 in Curbing Pollution, Saving Wildlife and Wild Places

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Today the Canadian Department of Fisheries and Oceans released a long-awaited risk assessment of the likelihood of Asian carp surviving and spreading in the Great Lakes should they successfully infiltrate Lake Michigan through the Chicago Area Waterway System (CAWS).  Much that was released today simply reinforced what we have known for a long time:  there is a serious, imminent threat that Asian carp will invade the Great Lakes through the CAWS and spread throughout the system, threatening the vitality of native fish species (and the ecosystem itself) as they spread.

But there is one key finding that is new in today’s report:  with a population of 10 females and 10 males or fewer there may be as big as a 50% chance of a breeding Asian carp population establishing.  Those are very low numbers, which stand in stark contrast to federal officials’ past estimates that a population of several hundred carp was probably need for there to be a significant risk.

What the Canadian study emphasizes is that even small number of Asian carp getting into Lake Michigan may put the Great Lakes at risk.  This is why the latest positive environmental DNA (eDNA) results for silver carp within 6 miles of Lake Michigan are significant:  if those tests are indicators of live fish being present that close to the Lake, that should cause serious alarm that current efforts to stop the carp need to be accelerated and strengthened.

Unfortunately, federal officials have continued to downplay the eDNA results, suggesting that because we can’t say with certainty that there are live Asian carp present in the CAWS that we should assume the negative:  that current efforts are working fine and buying time to study long-term solutions.

This is false confidence that borders on hubris.  As John Rogner of the Illinois DNR pointed out in yesterday’s public meeting in Chicago, trying to catch an Asian carp in an area where they are present only in small numbers is like trying to catch a needle in a haystack.  There is consensus among scientists who know the Asian carp’s behavior well that it is very difficult to catch using conventional methods when present only in small numbers.  We can’t afford to rely on the Feds’ inability to catch a live fish as a reason to believe that this threat is under control.

Today’s Canadian study reinforces this.  Can we really say with certainty that 10 females and 10 males won’t be able to slip into Lake Michigan, given the repeated positive eDNA results we’ve seen and the well-documented weaknesses in the Army Corps’ electrical barrier?  No, we can’t, and anyone who says otherwise is not telling the truth.  And if that happens, then there may be a 50% chance that a thriving population takes off? 

I’m not a betting man, but I don’t like those odds.

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Comments

Amy EckardtJul 13 2012 01:14 PM

I attended the meeting to spread the word that the only way to rid the Illinois waterways of the Asian Carp is to harvest it a.k.a fishing. Scientists want to poison the environment which ultimately will poison a mass of people. Top officials understand the dilemma yet have not made the move to employ more fishermen. As it stands now only 10 fishermen are employed at the Starved Rock area this simply is not enough fishermen. The call to action is for the Federal government to employ more fishermen not more scientists.

George J.Jul 13 2012 11:02 PM

Here is the bottom line.

Asian Carp were randomly caught in nets in Lake Erie between 1995 and 2002. In order for them to be randomly caught when fishermen were not even looking for them, there would have had to have been at least 100s, if not 1000s, of Asian Carp in the Lake the study claims would be most conducive to their survival. In addition, they were caught in western Lake Erie, not too far from the Maumee River which is theoretically one of the rivers that would support Asian Carp reproduction.

And yet, after 17 years from when the first Carp were caught in Lake Erie we find that they did not reproduce in Lake Erie or the Maumee River and eventually died off. However, the Canadian study claims that by now all five Great Lakes should be infested with Asian Carp. So, the “science” behind the “study” could not even predict what we know has already happened!

Obviously the Canadian study is flawed and Asian Carp are not, in reality, a threat to the Great Lakes.

So why is the Canadian study so irrelevant?

Because it offers nothing but a mathematical prediction based on a compilation of opinions from other papers that we now know were flawed. In fact, I remember seeing those same charts and tables in a paper released several years ago.

What the Canadian study does not have is any new science or research. Particularly research on live Asian Carp that would support their claims.

This study is only 12 pages long and acknowledges that:

“Predictions and risk assessment on species that are currently not established in the Great Lakes are based on best available information. Research that is underway where results were not available, or research noted as a critical knowledge gap, may in the future, provide more information that would change the results of the risk assessment.”

Doesn’t sound very convincing, does it?

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Switchboard is the staff blog of the Natural Resources Defense Council, the nation’s most effective environmental group. For more about our work, including in-depth policy documents, action alerts and ways you can contribute, visit NRDC.org.

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