How do fish get into lakes?

[Fat Boy]

How do fish that are not supposed to be in a lake get into a lake (other than people releasing species not indiginous [sp?] to the lake).  Any fisheries biologists or DNR folks out there that could answer this?  I heard that some fish (minnows, carp?) eggs stick to birds legs, like the great blue heron, and populate ponds that are not stocked.

What prompted this thread... someone caught a huge white perch in a small lake in PA that is not supposed to have white perch in it.  The fish was a potential state record, but the angler gave it away unknowingly.  The fish was probably released into the lake without authorization, but...

I thought that this would be an interesting topic.

[dogfish]

Ok, From Fisheries Biologist #1
 Fish can migrate through inlets and outlets.  Other animals is the main way (other than human stocking, legal or other) fish get into new bodies of water or ones where the inlets or outlets are such that fish cannot move through.

Many to most fish eggs and new hatched fry are very sticky (thus they do not roll around so much in rough water or currents).  Depending on species the eggs and fry (fry living off a yolk sac at the time) can live long periods of time in a damp condition rather than wet.  Many fish spawn in the shallows and weedy areas of a body of water and this is where you see water birds feeding, cleaning, shaking etc.   Gulls, ducks, geese and other water birds will get eggs and fry stuck within there feathers where they stay damp and out of the air.  The bird flys to a new puddle,shakes loose a fish egg or two and new fish in the pond.  Mammals such as otters and muskrats can also do the same but do not tend to cover the distance as the birds.

[Fat Boy]

Dogfish, so what species can be transported to ponds via bird/animals other than humans, all of them?  Wow, that's pretty powerful... Cool!

[dogfish]

Fat Boy
It is mostly your shallow water spawners.  Perch, Sunfish (including bass), Esosids (Pike, Pickeral and Musky), many of your minnows etc.  Tends not to include your deep water fish like Lake trout.  The biggest factor after surviving the trip is the limnology (scientific study of fresh waters) of the lake or pond moving to.  New ponds and lakes (if dug out) are often toxic to many fish due minerals and nutrients and othe compounds that were leeched down in are now exposed to water (also known in the world of chemestry as "the universal solvant") and dissolved.  This can leed to high or low Ph, metals like lead, Al and mercury, old long life herbisides and pesticides etc.   Over time the water will become habitable, amount of time depending on specific proubs. Then other times the water quality is good right off but the food chain has not yet been established so there is nothing to eat.etc, etc

[hard_waterer]

My Dad told me that this could happen