# How do fresh-water fish populate different basins? **URL:** \ **Category:** Factual Questions\ **Created:** [April 19, 2020, 10:21am UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117 "2020-04-19T10:21:50Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [April 20, 2020, 10:58pm UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/22 "2020-04-20T22:58:36Z")
> [@Colibri](#): > > Some primary freshwater lineages go back before the breakup of Gondwanaland, notably the lungfishes, which today are found only in Australia, South America, and Africa. (They also once occurred on the northern continents, but went extinct there long ago.) They very likely occurred in Antarctica as well until it froze over. I happened to see a rhipidistian today here in Los Angeles, although it was hard to identify because it was wearing a face mask. 😛 ---
**Author:** ![nearwildheaven](https://avatars.discourse-cdn.com/v4/letter/n/90db22/32.png) [@nearwildheaven](https://boards.straightdope.com/u/nearwildheaven)\ **Post date:** [April 20, 2020, 11:03pm UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/23 "2020-04-20T23:03:26Z")
> [@mmmiiikkkeee](#): > > anadromous Just learned a new word! TL : DR - an anadromous fish is one that lives in both fresh and salt water. ETA: Colibri beat me to it! I’m sure getting a lesson today in marine biology. Ostracods, rhipidistrian - what’s next? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 20, 2020, 11:11pm UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/24 "2020-04-20T23:11:26Z")
Birds might not transport fish very far, but it doesn’t need to be very far. I can envision an eagle catching a fish in one river, flying over a ridge, and then dropping it into another nearby river that’s a different basin. It won’t get fish into Thawed Antarctica, or across a continent-spanning desert, but it could gradually populate basins. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [April 20, 2020, 11:18pm UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/25 "2020-04-20T23:18:34Z")
> [@Chronos](#): > > Birds might not transport fish very far, but it doesn’t need to be very far. I can envision an eagle catching a fish in one river, flying over a ridge, and then dropping it into another nearby river that’s a different basin. It won’t get fish into Thawed Antarctica, or across a continent-spanning desert, but it could gradually populate basins. I doubt it very much. Fish eagles and ospreys normally fish in larger rivers and lakes, not in small streams where they could just “cross a ridge” and be in a different watershed. Kingfishers might fish in small streams, but they would be extremely unlikely to carry live fish over a ridge. ---
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [April 20, 2020, 11:47pm UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/26 "2020-04-20T23:47:24Z")
When I was young there was a small cow pond in the field behind my grandfathers house. Every Sumer it dried up. Bone, earth cracking dry. But the spring rain would always refill it. And I would always catch fish in it until it dried up again. Usually only bluegill but still… ---
**Author:** ![smithsb](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/smithsb/32/12107_2.png) [@smithsb](https://boards.straightdope.com/u/smithsb)\ **Post date:** [April 21, 2020, 12:02am UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/27 "2020-04-21T00:02:13Z")
> [@Darren\_Garrison](#): > > Turns out there has been [a study](https://phys.org/news/2018-02-dispersal-fish-eggs-birdsjust-myth.html) on the lack of studies on bird-egg dispersal. > Not fish, but I once had an above-ground basin outside my house that had filled with rain water that grew a colony of ostracods. It was pretty cool. > [@nearwildheaven](#): > > Just learned a new word! TL : DR - an anadromous fish is one that lives in both fresh and salt water. > > ETA: Colibri beat me to it! > > I’m sure getting a lesson today in marine biology. Ostracods, rhipidistrian - what’s next? Don’t just drop stuff in here people. I’ve got way more important things to do during stay-at-home than look terms up.😃 “Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders.” “The Rhipidistia, also known as dipnotetrapodomorphs (formally Dipnotetrapodomorpha) are a clade of lobe-finned fishes which include the tetrapods and lungfishes. Rhipidistia formerly referred to a subgroup of Sarcopterygii consisting of the Porolepiformes and Osteolepiformes, a definition that is now obsolete.” Now I’m going to have to work that crap into my conversations.:rolleyes: ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [April 21, 2020, 12:14am UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/28 "2020-04-21T00:14:00Z")
> [@Lucas\_Jackson](#): > > When I was young there was a small cow pond in the field behind my grandfathers house. Every Sumer it dried up. Well, it’s understandable that fish can repopulate it, given 4000 years. ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [April 21, 2020, 12:20am UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/29 "2020-04-21T00:20:39Z")
This is sort of a specialty niche, but there are fish that “walk” between different bodies of water, i.e. the walking catfish\* that plagues part of the American South (and similar fish in Australia). \*never pick up a hitchhiking fish holding a sign that says “Next Swamp Or Bust”. ---
**Author:** ![whc.03grady](https://avatars.discourse-cdn.com/v4/letter/w/a6a055/32.png) [@whc.03grady](https://boards.straightdope.com/u/whc.03grady)\ **Post date:** [April 21, 2020, 3:56am UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/30 "2020-04-21T03:56:25Z")
Yellowstone Cutthroat Trout and [possibly Lake Trout](https://billingsgazette.com/lifestyles/recreation/yellowstone-fisheries-chief-suspects-invaders-got-to-lake-on-their/article_cac59446-828d-54d7-b1a5-b96fd292fb4b.html) are thought to have crossed over the Atlantic-Pacific (i.e., the Great) Divide at the [Parting of the Waters](https://en.wikipedia.org/wiki/Parting_of_the_Waters) in Wyoming. (Wyoming has at least one other “either” hole in the Great Divide, Isa Lake, and one “neither” hole, the Great Divide Basin.) How many other oddities like this might’ve existed over geological time, across many different basins? In the last few years I vaguely recall reading about a fish tagged in Montana but caught in Idaho; it was suspected that a bird caught it and dropped it, still living, into a different drainage. I might have the details or even the facts entirely wrong, though. I’ll keep looking and update if I find anything. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [April 21, 2020, 4:42am UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/31 "2020-04-21T04:42:23Z")
> [@smithsb](#): > > Don’t just drop stuff in here people. I’ve got way more important things to do during stay-at-home than look terms up.😃 > > “Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders.” I dug up [a photo of mine](https://imgur.com/a/gNKdZtT). It is better than I remember, and actually not too bad for their tiny size and a 2001-model digital camera. ---
**Author:** ![JasmineOlive](https://avatars.discourse-cdn.com/v4/letter/j/e99b99/32.png) [@JasmineOlive](https://boards.straightdope.com/u/JasmineOlive)\ **Post date:** [April 21, 2020, 6:04am UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/32 "2020-04-21T06:04:59Z")
It depends, since different kinds of freshwater fish have different levels of tolerance to saltwater. ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [April 21, 2020, 8:38am UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/33 "2020-04-21T08:38:31Z")
> [@Darren\_Garrison](#): > > I dug up [a photo of mine](https://imgur.com/a/gNKdZtT). It is better than I remember, and actually not too bad for their tiny size and a 2001-model digital camera. Congratulations, you have excellent eyesight! And thank you and all the others for very interesting links and observations, you are helping me greatly. 🙂 ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [April 21, 2020, 8:59am UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/34 "2020-04-21T08:59:14Z")
> [@mmmiiikkkeee](#): > > It also depends how long you are talking about for fish to get into new fresh water habitat. You’re not gonna get true fresh water fish if they can’t migrate through salt water over just a few hundred years. But if you have millions of years and the new habitat remains then a few salt water species will eventually evolve into fresh water fish, which is where we got our fresh water species today from. > > [This](https://whyevolutionistrue.wordpress.com/2012/02/16/nearly-all-marine-fish-came-from-freshwater-ancestors/) page talks about a study from a while back suggesting that most of the salt water fish today are descended from fresh water species, who of course originally evolved in salt water. So the longer you have, the more ways to get fresh water fish into previously unavailable habitats. In North America I am talking about tens of thousands of years, that is, since the last glaciation: what has happened so far. But for Antarctica I am talking about all the time left in the future after the continent melts, if it ever does (and I guess it will, as it has done so in the remote past and humans are warming the Earth): whatever might happen in the future. Thanks for the link, I did not expect that modern marine fishes are mostly freshwater fishes who went back. Nice! ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [April 21, 2020, 9:00am UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/35 "2020-04-21T09:00:55Z")
> [@Colibri](#): > > Thanks for that. That idea has so generally been accepted that I was not aware that it wasn’t based on any actual studies. > > There has, however, been a recent study showing that [swans can transport viable fish eggs through fecal matter.](https://www.smithsonianmag.com/smart-news/these-fish-eggs-can-travel-through-swans-digestive-system-and-emerge-intact-180972426/) (I will say that killifish are among the most durable life forms on the planet. They were common in a creek in my neighborhood in the Bronx that I think must have been nearly half petroleum.) It’s also worth considering that in longer periods of time, less normal events will occur - such as a water fowl being killed by a predator on arrival in the shallows of a new body of water, and that event emptying the bird’s crop into the water, for example - improving the survival chances of anything that happened to be in there. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 21, 2020, 12:49pm UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/36 "2020-04-21T12:49:16Z")
There are plenty of places where a lake of significant size is very close to the edge of its basin. Yellowstone Lake is within an eagle’s flight of multiple divides (including the Great one), and even before the Chicago River was reversed, Lake Michigan was very close to the Mississippi basin. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [April 21, 2020, 1:40pm UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/37 "2020-04-21T13:40:45Z")
> [@whc.03grady](#): > > In the last few years I vaguely recall reading about a fish tagged in Montana but caught in Idaho; it was suspected that a bird caught it and dropped it, still living, into a different drainage. I might have the details or even the facts entirely wrong, though. I’ll keep looking and update if I find anything. A bird doesn’t have to drop a live fish either, it could be full of roe. I’ve never thought the bird theory was good for crossing oceans though. A bird could cross a continental divide, crossing an ocean with fish or eggs that will live doesn’t seem so likely. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [April 21, 2020, 3:21pm UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/38 "2020-04-21T15:21:05Z")
> [@TriPolar](#): > > A bird doesn’t have to drop a live fish either, it could be full of roe. Most fish have external fertilization, so without milt they won’t develop. And the eggs of freshwater fish usually need to be deposited in the right environment. Even if the bird opens the fish and dumps the eggs in the water, it’s unlikely they would develop. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [April 21, 2020, 3:24pm UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/39 "2020-04-21T15:24:51Z")
> [@Colibri](#): > > Most fish have external fertilization, so without milt they won’t develop. And the eggs of freshwater fish usually need to be deposited in the right environment. Even if the bird opens the fish and dumps the eggs in the water, it’s unlikely they would develop. Ah right. Doh :smack: ---
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [April 21, 2020, 8:30pm UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/40 "2020-04-21T20:30:07Z")
> [@Ludovic](#): > > Well, it’s understandable that fish can repopulate it, given 4000 years. Sorry I’m not understanding your meaning. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [April 21, 2020, 8:36pm UTC](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117/41 "2020-04-21T20:36:22Z")
> [@Lucas\_Jackson](#): > > Sorry I’m not understanding your meaning. He was punning on the fact that you misspelled summer as [Sumer](https://en.wikipedia.org/wiki/Sumer) in your post. It was an exceedingly obscure joke, and this being the Dope I am compelled to nitpick and point out it should have been 6000 years, not 4000 (no doubt the source of your confusion.)😃 I would instead have assumed you were using the [Middle English spelling.](https://en.wikipedia.org/wiki/Sumer_is_icumen_in) [Previous page](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117.md?page=1) [Next page](https://boards.straightdope.com/t/how-do-fresh-water-fish-populate-different-basins/852117.md?page=3)