How did fish get into lakes in the first place?

Question

This question is being asked scientifically. I'm not really interested in hearing that God put them there. Although if that's what you believe I respect that.

Answer 1

Only a couple of the answers you received were correct...from David C and Elephas. The others all have flaws. Some assumed that fish swam from the oceans up the rivers and into lakes. That ignores the fact that fish in oceans tolerate only salt water, while those in rivers and lakes tolerate only fresh water. With the exception of a few types (like salmon), most fish living in one kind of water would be repelled by the other type.

Other respondents mentioned that water once covered areas of land that are dry today, and when water levels receded, the lakes and rivers were formed. That's basically true, but again you have the salt water/fresh water problem. In short order, those salt water lakes would become fresh water as rainfall diluted them, so any salt water fish would have died off. Even if they started out as fresh water, by now each lake and river system would have its own species of fish and mollusks, very different from those in the next system. That's because each system is separated by land from the next, and that isolation over millions of years would have allowed the species in one system to evolve differently from those in another. Of course, that has happened to an extent, but the fact that you can find the exact same species in widely separated river systems indicates that something else is going on. The best explanation is the one given by Darwin: the eggs of these creatures were carried from one river and lake system to another by mobile creatures, such as birds. Problem solved!

Answer 2

I suppose that depends. There are fish that can swim up freshwater rivers from the ocean and into lakes for a while. Certain sharks can do that. Some fish probably just got into a bay which, millions of years ago, closed in around them do to tectonic plate movement. As the salt seeped out, so did the fishe's need for it. And then from that lake sprouted a river which led to a large natural bowl formation and turned into a lake. Then fish swam in between the two and a landslide cut the fish in lake A from the fish in lake B.

Answer 3

At one point the water level was highter so a lot of lakes were connected. The fish can come up from the ocean in a river and then the river would lead to a lake, the fish would stay in the lake. Then there would be a lot of rain and the lake would flood and lead to puddles where the fish would get or it would connect to another lake. Then modern man came along and now fish can get in the lakes by people.

Answer 4

Most lakes, unless manmade, are fairly recent in origin and were once part of a river etc. But your question is relevant for some lakes, such as those in areas of volcanic lava.

Let's see what Charles Darwin has to say on the matter in his 'Origin of the Species':

"When ducks suddenly emerge from a pond covered with duck-weed, I have twice seen these little plants adhering to their backs; and it has happened to me, in removing a little duck-weed from one aquarium to another, that I have unintentionally stocked the one with fresh-water shells from the other. But another agency is perhaps more effectual: I suspended the feet of a duck in an aquarium, where many ova of fresh-water shells were hatching; and I found that numbers of the extremely minute and just-hatched shells crawled on the feet, and clung to them so firmly that when taken out of the water they could not be jarred off, though at a somewhat more advanced age they would voluntarily drop off. These just-hatched molluscs, though aquatic in their nature, survived on the duck's feet, in damp air, from twelve to twenty hours; and in this length of time a duck or heron might fly at least six or seven hundred miles, and if blown across the sea to an oceanic island, or to any other distant point, would be sure to alight on a pool or rivulet."

So fish's eggs could potentially get stuck to birds who have recently visited one lake and be deposited in the next. Well traveled little fish!

Answer 5

Water once existed everywhere on earth before it pooled up in oceans, seas, lakes or got frozen into glaciers at the poles. Fish got caught in any number of places. Do you know that some areas which now are not submerged have a fossil record of fish?

Answer 6

People stocked the lakes with male and female fish. The fish continued to reproduce so there became lots of fish in the lakes and stuff. But in the beginning God created fish so He had something to do with it.

Answer 7

Most inland fish lay eggs. And the eggs are usually deposited on plant matter. It's easy for the plant matter to be "transported" to lakes and other water bodies. So all fishes in lakes are actually from larger water bodies like rivers and larger lakes.

Answer 8

Tides. Got abandoned in the Great Flood of 47 I reckon. Other animal excreta.Eggs,hatchlings can end up anywhere. Flower pollen has been found in aircraft engines ie miles up.It could have rained fish.....look it up..whirlpools etc.Hold on ...it was the fish that ....

Answer 9

They were either stranded there as ocean waters receded and it became freshwater, or they have hopped up a river or stream to the next body of water. Some could have been introduced there by humans.

Answer 10

some african cat fish walk from lake to lake, and eels from the sea swim up rivers and then slither like snakes if they want to cross land to other waters. so they get flown, they get dumped, they swim, they get flooded, they get left behind, they walk, they slither