After a fun morning of fishing and a late morning breakfast, I am sitting in our Minnesota cabin overlooking sprawling Leech Lake. JoAnn and I have been here for two weeks, upgrading our cabin property and sneaking in a little fishing.

Well, maybe more than a little fishing.

Fishing has been good. So far, JoAnn has caught the big fish of this trip, a nice seven-pound northern pike about 32 inches long. We have been fishing mainly for walleyes, so the pike was an incidental by-catch.

I have caught the biggest walleye, a 24-inch fish weighing about five pounds. Leech Lake has a slot limit, so any walleye between 20 inches and 26 inches must be released. We also released JoAnn’s seven-pound pike. It may be a nine-pound fish next summer and we may catch him again.

Thunder, lightning and pouring rain are keeping us inside the cabin for a while.

About 100 yards offshore, I am watching a flock of pelicans and cormorants.

They are displaying a unique relationship between wildlife species. Cormorants are an invasive species of duck-like water bird. They are fish-eating birds so they are disliked by fishermen because they eat lots of small game fish. Leech Lake is one of Minnesota’s largest lakes and one of the best walleye lakes in Minnesota.

Cormorants were absent when JoAnn and I lived here 45 years ago. But in more recent times, the cormorants found this lake and began devouring the young walleyes. Rafts of thousands of cormorants soon depleted most of the young walleyes and other prized game fish. As the number of game fish numbers dropped, anglers stopped coming to Leech Lake. This is major tourist area, so local businesses suffered.     

Most of 111,000-acre Leech Lake is on an Indian reservation. The tribe has a major gambling casino near the lake, so as fishing quality dropped, tourism suffered as did casino receipts. So credit the tribe with taking direct action to increase tourism by killing cormorants. Native crews destroy nests, eggs and shoot cormorants.

If Leech Lake were not on an Indian reservation, state fishery managers would probably have spent decades trying to meet all of our modern environmental laws. Tribes have much more legal latitude.  

The result was thousands of dead cormorants, better fishing quality, increased tourism and increased casino receipts. There still are lots of cormorants. While the cormorants caused problems for tourism, pelicans have learned to take advantage of the cormorants.

Cormorants have the ability to dive deeply to catch and eat small fish. Pelicans also live on a fish diet, but their large bodies do not permit them to dive deep. Their fish prey must be on or near the surface. Pelicans have learned that when cormorants dive deep to catch fish, many of these prey fish escape by swimming to the surface, away from these deep-diving fish predators. Little do they know that pelicans are waiting on the surface to devour them.

So pelicans have learned how to use their fish-eating cousins to help them catch fish to survive. I have seen similar pelican survival tricks while fishing in Canada. Pelicans have learned that human fisherman sometimes catch small fish and release them, only to have some of the released fish die. Those dead small fish are dinner for the pelicans. Frequently, I have had pelicans circle my boat, looking for dead or struggling fish.

This cormorant and pelican relationship is not rare in nature, where many species of wildlife are dependent on other wildlife species to survive.