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How did freshwater fish species spread from one drainage basin (river system) to another?
I can't imagine a flood or a course change crossing a watershed consisting of a ridge of high ground (which many are). Transport by people has probably only happened in fairly recent years.
I'm asking specifically about trans-watershed transport, rather than things like isolated ponds getting flooded by a nearby river.
Egg transport by birds sounds probable: is there evidence it happens?
3 Answers
- ?Lv 75 years agoFavorite Answer
o as eggs on bird feet?
o otherwise carried by birds?
o squirmed across land (there are a couple of species of fish that actually do this)?
o swam from one to the other during a time of flood?
o carried by people (including "stocked")
o the land has shifted in recent millenia. At one or more times those rivers shared a common source (possibly ice-age repeated inundation).
- ?Lv 75 years ago
Stream capture, flooding, and trips through saline water from river mouth to river mouth
- Cal KingLv 75 years ago
Mostly through floods. Some fish can also move over dry land. Rivers will also change courses and they may join and disjoin.