Well, actually, sardines aren't really fish. They look like fish, but they were genetically engineered from peas and slimy salamanders as a WPA project back in the 1930s. The proto-sardines are put into the cans as larvae, the equivalent to human teenagers. They would do what teenagers do, and while the can was in shipment to the store it would be filled with the larvae's offspring. But the contraceptive linings have cut way back on the number of offspring per can.

Bet none of you knew this before, did ya?

Sardines as fish...humf. Who'd go fishing for some puny little thing like that, anyway?