Pike research

A pike researcher tracks radio tagged fish by boat. (Iowa DNR photos)
Pike transmitter
This radio transmitter will be surgically implanted into a northern pike. The fish needs to weigh four pounds or more.


Iowa DNR uses radio transmissions to monitor pike


By Ted Pennekamp


Iowa DNR fisheries personnel are using an innovative radio technology to monitor and improve the northern pike population in Pools 10 and 11. 

Biologist Kirk Hansen said that the Pike Project is in its second year of monitoring where pike spend their time year ‘round and how far they travel from their summertime areas to wintering areas and to spawning areas. 

Hansen said that radio transmitters are surgically placed in the body cavities of numerous northern pike which are four pounds or greater. The pike are also tagged near the dorsal fin. 

Hansen and other personnel then can track individual fish to see what conditions they prefer at various times of the year. Hansen noted that the project began in part because of big pike die offs up and down the river a couple of years ago due to high water temperatures and other factors. He said that tracking pike can identify areas that need to be dredged in order to re-establish good habitat for pike and other species. 

Much of the Pike Project has been conducted in the Sny Magill area of Pool 10 including Norwegian and Methodist lakes. Hansen said that there are numerous springs and cold water trout steams flowing into the Mississippi River in the Sny Magil area and Pool 10 in general. 

“One interesting thing we found,” said Hansen. “Was that only about 20 percent of pike seek out springs or other cold water areas in the summer. We expected that the percentage would be higher than that.” Hansen said that about two-thirds of pike that inhabit cold water areas get caught by fishermen.

Hansen said that most pike don’t travel very far from their summer haunts to spawning areas. Some travel good distances, however. He noted that one pike was found about 25 miles up the Wisconsin River from where the fish was first netted, tagged and released.  

As expected pike tend to spawn at the upper ends of lakes in flooded areas with good amounts of grass and other vegetation. 

On kind of a humorous note, Hansen said that pike can hear very well when people are walking on the ice overhead. As a consequence, he noted that large groups of pike will be on one side of a specific area, while the ice fishermen will be concentrated on the other side. He noted that successful ice fishermen going after pike are probably quieter.

Pike grow fast, said Hansen, because they are constantly eating a variety of fish, frogs and other prey. He said that researchers have caught some pike that are 7 to 9 years old in their fyke nets. 

In the past year, about 60 pike have been implanted with transmitters and floy tags. Hansen said that each individual pike has its own radio frequency and tag number. He said that anglers who catch a tagged pike should call the phone number on the tag to report where the fish was caught and other information. Also, if an angler is going to keep the fish, he or she should call so that DNR personnel can come out and recover the radio transmitter. Transmitters cost $175 each.

Hansen noted that pike are found mostly in shallow water, but some have been found in deep holes, most notably above Clayton. 

The pike population in pools 10, 11, 12 and 13 is good, said Hansen, who noted that pike monitoring identifies areas where the population is down, and thus, the stocking efforts of DNR personnel at the Guttenberg Hatchery will focus their efforts in those areas.

“We help mother nature and augment those identified areas through stocking,” Hansen said.

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