Two Buddies Fishing

...but they haven’t caught anything all day. Just then another fisherman walks by with a huge load of fish. They ask him "excuse me, but where did you get all those fish"?

The other fisherman replies, "If you just go down the stream until the water isn't salty, there are a ton of hungry fish".

Both mates thank him and go start to walk further up the stream.

Twenty minutes later, the first fisherman says to his mate "fill the bucket up with water and see if the water is salty".

Second mate dips the bucket in the stream and drinks some and says "Nope. Still salty".

Thirty minutes later the first mate asks his mate to check again.

Second mate says "Nope, still salty".

An hour later first mate asks to check again.

Second mate says "Nope. Still salty".

First mate says "I don't understand this at all, we have been walking for almost two hours, and the water is still salty"!

Second mate says "I know, I can't understand it either and the bucket is almost empty"!