That is, how do fish get into man made lakes that are not fed by another water source, and are not purposely stocked?
My theory is that fish eggs get carried there and dropped by birds, but are there other ways?
Just a guess, but there could be a flood that carried fish or eggs there from another body of water.
Also, even if the lake is not “officially” stocked, people could throw fish in there.
I’ve always heard that birds poop the eggs into the lakes, which seconds your assumption.
There have been cases where weather phenomena have picked up eggs (the case that comes to mind involved a tornado and frog eggs) from one spot and eventually returning them to earth miles away.
If the lake receives storm sewers, there’s no telling what’s coming in that way.
If the lake is big enough to have boats, fish can be introduced when someone innocently pumps out their bilge from another lake.
More than once, people have illicitly introduced species into lakes, either accidentally or maliciously.
As for purposefully-stocked lakes, the fish come by tank trucks. They drop a large hose into the lake, open the drain valve on the tank and pour in the fish.
No way could that happen. The eggs would be long dead and dissolved after passing through a bird. Dripping off a bird… it’s possible.
I must admit I’m a little baffled by this. How do you get water to fill a lake without getting it from another source? Even if it fills with rain or ground water that is another water source.
I think you meant a water source free of fish/eggs… which would cut out irrigation water, and a lot of man-made lakes are irrigation reservoirs… so a good chunk of them are being filled with water already full of fish - even if an irrigation canal or pipe doesn’t seem like a source of wild fish.
Illegal stocking happens all the time as well. A big recreational lake only a few minutes from my place has been stocked with crayfish (which are now breeding naturally) within the past few years. A little trout pond I used to fish in was stocked with yellow perch about 15 years ago. Sometimes it’s somone who knows what they’re doing trying to establish a population of a certain kind of fish 'cause he wants to, and other times it’s ignorant people who “release” a pet fish back to nature to feel good inside themselves. There are even some religeous new year’s customs of releasing fish into water bodies in a couple cultures. All the above are/were illegal for good reasons.
These would be a distinct minority – most man-made lakes are created by modifying an already-existing stream or wetland, and thus there is at least some exchange with an extant body of water. IIRC a pure hole-filled-with-water lake with no in- or out-flow would soon become stagnant.
I have to admit I’m having a hard time thinking of a lake that is not fed by a water source that is already full of fish.
I’m having a harder time thinking of a lake that doesn’t have any overflow that would allow fish to travel into the lake form downstream.
Remember many fish will happily travel through shallow water as it flows over otherwise dry land during heavy storms. Hard to think of any lake that could be considered isolated.
There are many fishless natural lakes. High alpine lakes fed by snowmelt. In many cases (such as in national parks), these have been stocked, which can lead to problems. I wouldn’t doubt that there’s some man made lakes fed by a snowmelt as well.
Natural lakes in the Sierras have, in the past, been stocked by airplane! My guess is that most manmade lakes are deliberately, legally stocked and may be “privately” stocked at the same time.
Come on people. You can’t tell me that you have never seen a pond deep in the woods, not connected to anything and yet it has all kinds of species of fish in it. The property that I grew up on had several such ponds, never stocked and yet they all had fish in them. This was in Louisiana. Almost all, non manmade ponds near sea level have fish in them and the manmade ones will as well after several years. Many times, the fish will be something like bluegill that are almost never stocked. The fish are coming from somewhere. I was told that they were carried in birds mouths or possibly their feet from another source.
How can it not be connected to anything? Where doe the excess water go to when the pond fills up?
Well, on a friend’s property in Kentucky there are several small ponds that fit that description, assuming that what you mean is that it isn’t normally connected to any water source. During heavy rains, they’ll flood and the runoff goes into nearby streams.
As a last response to the OP, though it probably isn’t the answer in most cases, it could be a phenomenon such as the famous Maryland walking fish.
That’s what I figured had to happen. And the streams have fish and the fish swim upstream duirng raind.
Mystery solved.
There are also fish that will walk themselves to a nearby water body.
I always thought that Yokko the fish God would wave his magic wand over a large lake, do the sacred hula dance, and make all the fish we need appear :smack:
There are some man-made lakes that do not contain fish nor would allow the passage of fish into them from either inlet or overflow. Tailings ponds have specific inlets and cannot allow overflow or there’ll be big trouble; often they are built above-ground to prevent run off problems. Check out the last two pictures here.
There are also fishless natural lakes… I believe there are hundreds of not thousands in Ontario (which gets a lot of government money to stock them and modify the lake water chemistry for research). There are also all kinds of prairie sloughs and pothole/kettle lakes far from streams around these parts; we don’t get enough rain for them to overflow, and they are either kept wet by that small amount of rain or are just in low enough depressions to be into the water table.
In university I spent a week camped out next to two mountain lakes on Vancouver Island; one draining into the other. Thing was that there was an elevation difference of several hundred feet while the lakes were only a short distance apart. The fish in the bottom couldn’t have migrated up the waterfalls. Never the less we found sculpin in the upper lake (but no kokanee or cutthroat). There’s no way a sculpin could get there without help… so rare overland transfers do happen from time to time.
There are many answers. Sometimes a fisherman will release a fish he caught elsewhere. Captive fish get released into a pond (remember the Asian Snakehead Fish?) Sometimes baitfish (minnows, shiners) are dumped at the end of a fishing outing. One of my favorite lakes was drastically changed with the release of threadfin shad into the lake. Shad are food for bass, but they compete with bluegill for very small crustaceans. Now the bluegill population is permanently crippled to support the bass population.
A few people mentioned walking type fish.
Yes, there are “walking catfish” around here. There was one walking down the sidewalk in front of my house a few weeks ago after a rainstorm. There are lots of man-dug lakes around where I live, I can only assume he came from one of them, and was headed to another one. Actually, walking is kind of a misnomer, they just kind of flop back and forth to move forward.
We see people parked at these lakes fishing all the time. My wife laughs, and says they’re crazy, because there’s no fish in there. I said if there weren’t, nobody would fish there.
Ken (OP)
There are also fishless natural lakes.
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I can attest to that fact. I have spent many hours fishing these types of lakes.
There’s an area in Indiana that has dozens of “strip pits.” That is, man-made lakes resulting from coal strip-mining. Several of them have thriving fish populations. One friend of mine, though, was having a bad day on one pit, when a Dept. of Natural Resources officer hailed him from the bank.
DNR: Catching anything?
Jake: No, not a thing.
DNR: I’m not surprised. This is an acid pit, and there’s no fish here. You’re wasting your time.
There are firms that sell fish, from fingerlings to huge catfish, to pond owners, and you can get anything you want.