Hunter-gatherers introduced fish to a mountain lake 7000 years ago

> That is the only possible explanation for how fish could have populated isolated mountain lakes

isn't that a common question?

"How do fish appear in landlocked lakes/ponds/etc"?

After digging a pond and letting it fill with rainwater/groundwater, fish appear. I don't think its because people carried them there.

(don't really know the common answer though)