Herding Carp

By: Bill Bartodziej

Super bowl commercials make you laugh with it and best-selling books have used the title, so why can’t we make reference to herding carp, oh I mean herding cats? Although there seems to be some similarities with carp and cats, we are making progress with carp management in the Phalen Chain of Lakes. With the continued assistance of the U of MN Sorensen Lab and a commercial fisherman, we had another successful netting of common carp in Lake Gervais. On February 25th, 825 adult carp were removed from this lake system.       

Overall, the main goals of this management program are to 1) reduce the adult common carp population to less than 100 lb per acre, and 2) keep substantial numbers of juvenile carp from entering the Phalen Chain of Lakes. Research points to 100 lb per acre as being the threshold where carp negatively impact lake water quality.

So what progress have we made? In 2009, the initial carp population estimate was just over 8,000 adults in the Phalen Chain. This amounts to roughly 180 lb per acre of carp. Below is a summary of the carp removal since the inception of the carp research and management program:

Date	Lake	Removal Method	Adult Carp Removed
1.14.10	Gervais	Netting	100
2.16.11	Gervais	Netting	1,505
2.24.11	Gervais	Netting	732
2.22.12	Gervais	Netting	71
9.28.12	Kohlman	Boxnet trap	551
10.3.12	Kohlman	Boxnet trap	69
10.8.12	Kohlman	Boxnet trap	2
2.25.13	Gervais	Netting	825

                                                                                                             TOTAL =            3,855



The seine net being placed under the water.

Nettings are done in the winter using a large seining net attached to small robotic submarines that ‘herd’ the carp to an opening in the ice. In the summer, the U of MN research team uses a baited ‘boxnet trap’ to capture carp. A boxnet involves a 71-foot square net placed on the lake bottom with the sides down. For a two week period, the middle of the net is baited with dried corn. Once the carp become comfortable with the free meals and school over the net, the sides are quickly raised to catch the feeding carp.

Interested onlookers watch as the fishermen wrestle
thousands of pounds of carp.

As of March 2013, 3,855 adult carp have been removed from the Phalen Chain. The research team estimates that this is close to fifty percent of the overall carp population. Carp weight, or biomass, has declined from 180 lb per acre to roughly 90 lb per acre. Although estimates put us just under the 100 lb per acre threshold, we will still continue to reduce the population. This year, we will set more boxnets in Kohlman, and likely conduct another winter netting in February, 2014. Please stay tuned as we continue to make progress in herding the common carp in the Phalen Chain.

Carrie and Nicole (RWMWD staff and Green Corps intern)
look for tagged carp and count the catch.



A musky caught in the carp net was safely released
back into Lake Gervais.