Carp remember for a year

Angling Experiments With Carp Decreasing Catchability Through One-Trial Learning
Authors: Beukema, et al
Journal: Netherlands Journal of Zoology 20(1): 81-92
Year: 1970
Where: Groningen University, Netherlands

In this Dutch experiment, scientists found that fish were able to remember, and then avoid, being caught by anglers. Carp were able to remember their terrifying experience one year later.

Incredibly, other fish were able to learn from the unfortunate experience of other previously hooked fish.

"When high proportions of the fished carp were hooked and subsequently lost, the whole populations fished for (not only the captured parts) became nearly uncatchable."

"Catchability of carp one year after being either captured or hooked and lost was some three times lower."

Fish Pain