How can we deal with the Asian Carp invasion?

Asian carp cause injuries to boaters when the motor noise scares the fish into jumping out of the water. The Peoria carp hunters use safety nets to avoid the danger.
Screen capture Peoria Carp Hunters

Asian carp multiply so quickly and compete so successfully against native species that the fish introduced to clean southern catfish farms in the seventies are now taking over parts of American rivers. Seeing is believing, just watch what happens in this video when an electric shock makes the unseen scourge suddenly visible:

Major report proposes solutions

A major report just released reviews 8 alternatives from a multi-year study in how to up the ante in the war on invasive Asian carp species that are moving up the Mississippi River and may threaten the Great Lakes. But the technological solutions proposed have estimated construction costs of $7.8 to 18.3 billion in 2014 dollars, up to 25 billion with inflation, and annual operating costs of $140 - 220 million according to Chicago Business.

The GLMRIS report, short for Great Lakes and Mississippi River Interbasin Study report, will be presented and discussed at a series of public meetings starting in Chicago on 9 January and touring key cities along the Great Lakes and Mississipi river through St. Louis on 30 January.

Public input will be critical in guiding the next steps -- especially to support the need for government funding and to review the potential adverse or unintended consequences of the most extreme efforts, which would effectively cut off the water in the Mississippi River basin from entering into the Great Lakes without treatment to remove the invasive species.

A lot of the cost of a hydrologic separation relates to controlling the risks of flooding in areas where the natural flow of the rivers to the lakes has been inhibited. The corps of engineers claims the proposed designs can withstand a 500-year storm.

But it would also require 25 years to build: will the door close too late to keep the invasive carp out of our precious great lakes?

Louisiana Sea Grant College Program/CC BY 2.0

Can less expensive solutions succeed?


Less expensive alternatives are also reviewed in the study. One option would simply continue current electric fence barriers, but these are suspected of being ineffective as DNA tests and fish finds have raised suspicions that the carp may already be threatening Lake Michigan. Another option involves fighting the invasion with nontechnical solutions such as education, monitoring, herbicides, ballast water management. But similar efforts have not proven successful at containing other invasive species such as zebra mussels.

The GLMRIS report does overlook one obvious control option: increased predation. What better option than our planet's most successful predators: humans?

The folks at Peoria Carp Hunters have been leading the fish-hunting forces. Since we last saw their comic attempts at ninja sword fishing on skis, they have tested crazy schemes like a new sport called skarping, or netting and dunking the carp before settling on bow hunting as the preferred sportsman's approach to taking home a supper of this fish the Chinese consider a delicacy.

In fact, the silver carp seen in these videos and famous for their jumping skill feed only on plant matter, so the flesh is safer to eat than that of carnivorous species which can build up high levels of mercury and PCBs or other pollutants that concentrate in fish fat.

Certainly, turning these fish into food would help to control their numbers and should be on the table in any discussions of how to control the invasion. But the loss of native species, and the economic benefits they provide, cannot be offset by a meal of Asian carp, and the rate of their growth may outstrip harvesting, so serious consideration of additional controls must be undertaken. Check out the dates of public discussion on the GLMRIS report (scroll to bottom for dates) if you live in the upper midwest, and get involved in the Asian carp invasion solution.

Tags: Conservation | Fish | Great Lakes

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