Fishing!

As I was leaving a cove well-known for its fishing I was stopped by a game warden today with two ice chests full of fish.
The game warden asked the me, 'Do you have a license to catch those fish?'
'No, sir' I replied. 'I haven't got a license. You must understand, these here are my pet fish.'
'Pet fish?'
'Yeah. Every night, I take these here fish down to the lake and let 'em swim 'round for awhile. Then, when I whistle, they jump right back into these here ice chests and I take 'em home.'
'That's a bunch of hooey! Fish can't do that.'
I looked at the warden for a moment and then said, 'It's the truth Mr. Government Man. I'll show ya. It really works.'
'Ok.', said the warden. 'I've got to see this!'
I poured the fish into the lake and stood and waited.
After several minutes, the warden says, 'Well?'
'Well, what?' I say.
The warden says, 'When are you going to call them back?'
'Call who back?'
'The FISH'!, replied the warden.
'What fish?' ...