Mine was trapping muskrats on frozen sloughs by Alexandria MN when I was 15.My father came along for a 3 day trip.I had a sled with a box built on it loaded with traps and stakes.I was setting in houses and feedbeds.I had begged and borrowed as many suitable traps as I could.I checked traps twice a day with my father helping.We had a family dog,a black cocker named Candy.She always came along trapping.We caught 324 muskrats in 3 days.Candy caught 3 muskrats by there holes out on the ice.My father was from San Francisco and never had been trapping until his kid started.The sloughs hadn't been trapped in years.There were rat houses everywhere.My uncles slough had most of the vegetation( reeds and cattails) cut down by muskrats.I sold the rats frozen on the carcass to one of Marv Koep's sons that was buying fur.He paid the same price as put up rats then. I used the money to buy a Browning A 5 12 ga.We talked about that trip for years and years after that.I never saw rat populations like that again.