Thursday, September 30, 2010

It's a bird! It's a plane! No... it's SUPER CARP!

Dust off your football and hockey equipment, because if you like boating, you may need it in the near future. As an10 invasive species biologist, I always have my ear to the ground, listening for the next high risk species to invade my area. That ear has been deafened by Asian carp.
A face only a mother could love.
There are four species of Asian carp in North America: bighead carp (Aristhythys nobilis), silver carp (Hypothalmichthys molitrix), black carp (Mylopharyngodon piceus), and grass carp (Ctenopharyngodon idella), all of which have been imported. The bighead an silver carp are two species of immediate concern to the Great Lakes.

Both were imported by catfish farmers in the 1970's to remove algae and particulate matter out of their ponds. In the 1990s, heavy rainfall resulted in large floods causing these farms to overflow. Inadvertently, these carp species were released into the Mississippi river basin. Since that time, the carp have made their way up the Mississippi River and are lurking in the murky waters on the outskirts of Lake Michigan.
The bighead and silver carp are known for their large size, voracious appetite and high reproductive capacity making them a serious threat to resident native species. Just to give you an idea of their size, bighead carp can grow up to a metre in length and weigh upwards of 45 kgs!
Once they reach Lake Michigan (yes...I intentionally did not say "if"), they will have access to the many tributaries connected to the Great Lakes. Both species are very aggressive and will compete with native fish for both habitat and food sources. Bighead carp are capable of consuming 40% of their body weight each day and both species can spawn multiple times during each season.
The Great Lakes are an ideal habitat for these invaders due to their limnological properties and lack of carp predators. The competition evoked from this invasion, will likely decrease native fish health and condition, reducing native fish populations. Ultimately, the Asian carp will have devastating effects on the Great Lakes ecosystem and a significant economic impact on the $7 billion fishery.
I also forgot to mention one small point... THEY CAN FLY! Well, not exactly, but the silver carp is well known for its aerial acrobatics. Easily spooked by motion, they can jump three meters into the air. This has spawned many problems and concerns in the recreational boating world.


Boaters have been forced to install netting and plexi-glass to prevent serious injury to themselves and their passengers. I'm not looking forward to the day I dawn hockey equipment before jumping in the Bayliner to zip over to the cottage, or have to wear padding and a face mask while water skiing. The "flying" silver carp will change the recreational boating world we know today.



Interesting tid bit: Some innovative boaters have taken advantage of the silver carp's biology to earn a little money. Littered all over the Mississippi River are silver carp bow hunting charters, where a patron pays to sit on the back of a boat and shoot jumping Asian carp with a compact bow. I've added the video below for two reasons: 1. See the hazards these fish pose to boaters and 2. To show you that I didn't make up the bow hunting portion.



You might be asking yourself: "What is keeping them out of the Great Lakes?"
Michigan, Minnesota, Ohio, Pennsylvania and Wisconsin are pressing judges to order a shutdown of the lock systems preventing the fish from moving from the Chicago area into the Great Lakes basin. However, this is not a final solution to the problem as Chicago relies on the locks to reduce river levels during storms, thus preventing floods.

A lot of focus has surrounded the Chicago Sanitary and Ship Canal (CSSC) as the main avenue for these fish to invade the Great Lakes. The U.S. Army Corp of Engineers has installed two electric barriers in the CSSC to eliminate the carp before they have a change to enter Lake Michigan (for more information http://www.ifishillinois.org/pdf/Asian_carp_FAQs.pdf).
How effective is this barrier? Well, eDNA testing at the Calumet Harbour along the Chicago shoreline found traces of silver carp DNA suggesting these fish have bypassed the $9 million dollar electrical barriers. Some will argue that this means they are in the Great Lakes already, others will stand by their multi-million dollar investment and claim an error in the tests. I challenge you, the reader, the boater, the angler, to read the literature and formulate your own opinions.
Asian carp in the Great Lakes is not a possibility, it's an inevitably.

Have we taken the appropriate measures to prevent an Asian carp invasion? Are they in the Great Lakes already? Are they going to have a noticeable impact on the Great Lakes ecosystem? Regardless of where you stand... I hope you're wearing a helmet. 

References:

Asian Carp and the Great Lakes. Environmental Protection Agency - http://www.epa.gov/greatlakes/invasive/asiancarp/
Asian carp control. Asian Carp Regional Coordinating Committee - http://www.asiancarp.org/
Asian Carp FAQ - http://www.ifishillinois.org/pdf/Asian_carp_FAQs.pdf
Chicago Sanitary and Ship Canal Dispersal Barriers. U.S. Army Corp of Engineers - http://www.lrc.usace.army.mil/AsianCarp/BarriersFactSheet.pdf
Exotic Species: Asian Carp. Great Lakes Fishery Commission - http://www.glfc.org/fishmgmt/carp.php
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