After a day of fishing, a man was carrying two trout in a bucket. He was approached by a warden who asked him for his fishing license.
"I wasn't fishing," the fisherman said. "These are my pets. Every day I come down to the water, dump them in and take them for a walk to the end of the pier and back. When I'm ready to go, I whistle and they jump back into the bucket and we go home."
All the warden did was laugh.
"If you don't believe me, watch!" the fisherman said as he threw the trout back into the water.
The warden said, "OK, now whistle to your fish and show me that they'll jump out of the water and into the bucket."
"What fish?" the man replied.