|The Question: Sitting beside a small lake in Massachusetts with many lily pads, we kept hearing a popping noise, almost like bubblegum snapping. What makes that sound?
Submitted by: Greg, New York, USA
The Sort of Short Answer: Full disclosure: Greg was visiting me, and we were sitting beside the lake and he asked me, “What is that popping noise?” and I had to admit that although I have often wondered about it, I didn’t know the answer. So I decided it was time to find out.
First off, here’s a recording of the sound. You might have to turn your speakers way up to hear the pops. There’s one at about two seconds, one at 11 and one at 16.
At this end of the lake, there is an area of maybe a little less than a hectare (about 2 acres) that is covered with several species of floating plants commonly called lily pads, extending out probably 50 meters (165 feet) from shore. If you listen on a good day, you’ll hear the pops every few seconds coming from the area of lily pads. My first thought was that something was falling into the water and plopping, but the pops come from the full extent of the lily pads, so too far away from the shore to be something falling from the trees that line the lake.
When I first tried to see what I could find on the web, I came up with fishing sites that say something similar to this:
“Besides looking for baitfish in the thicker weeds, Hannon tries to find signs of bluegill eating worms or grubs off the bottom of the dollar or lily pads. Holes appear in the pads when this action occurs, and one can actually hear the popping sound of the sunfish feeding.”
That explanation made some sense to me. There are certainly many sunfish in this lake, including bluegill (Lepomis macrochirus), pumpkinseeds (Lepomis gibbosus) and green sunfish (Lepomis cyanellus). And from my snorkeling, I know they often hang out in the lily pads. And in fact, as this picture shows, many of our lily pads have sunfish-mouth-sized holes in them. But to confirm this theory, I asked Dr. Tim Copeland, a fisheries scientist with the Idaho Department of Fish and Game. He also thinks sunfish are a good possibility, but isn’t willing to rule out other fish. “I used to fly fish for bluegills in lily pads and caught fish when such popping noises were present. But I also caught fish when I didn’t hear any popping noises (and vice versa of course). So in my opinion it could be any species of fish that live in weedy pond habitats. For instance, small bass might pick dragonfly nymphs from the pads. But sunfish are probably the most common.”
I also asked, Dr. Eric Dibble, who teaches aquatic science and studies sunfish behavior at the College of Forest Resources at Mississippi State University. He is more willing to bet on sunfish:
“The small sunfishes (family: Centrarchidae) i.e., bluegill (there are many other different species) are mostly insectivores and typically feed on young and adult insects. These fish have adapted to gleaning small organisms out of the water column as well as off of plants, the surface, and bottom substrate. Their mouth parts are structured is such a way to extend slightly when feeding so to create a vacuum. When they feed on the water surface, whether under a lily pad or directly off the top, a sucking sound or ‘pop’ can frequently be heard.
“I have a pond full of bluegill sunfish, and I frequently sit outside listening to the feeding in the early evening when they do much of their feeding. I also have bluegill, redear and longear sunfishes in an aquarium inside the house; and many times in the evening their feeding ‘pops’ awaken me.
I asked Dr. Dibble about the fish popping at night. Though I hear the sound most often during the day, I sometimes hear pops late into the evening as well. He said, “Generally, the centrarchids (sunfishes) have pretty good vision at night and will feed 24 hours, however much of their intensive feeding takes place during twilight hours of the day (dawn and dusk).”
So, on the basis of all those reports, I feel pretty confident to say that it is fish making the popping noises with suction feeding on lily pads. Probably sunfish, but possibly including others.
What About the Holes: The other question then, is, “Are the fish poppers making the holes in the lily pads?” I was unable to verify this in the scientific literature, but I do have a couple of clues.
One piece of evidence is that there are lily pads in a shallow marsh connected to this lake by a culvert pipe. I never see sunfish in that marsh, and the lily pads there are pristine, without the numerous holes that mark the lily pads in the open water part of the lake.
I got another tantalizing clue as I sat in a canoe, floating in the middle of lily pads, trying to record the pops, I heard one just to my right. When I looked in that direction, there was a lily pad jiggling wildly, as if something were in fact, pulling on it from underneath. When the movement stopped, I paddled over and discovered, as this photo shows, that the lily pad had what looked like a new hole. Notice that the edges of the center hole are freshly ragged and not browned, like the other holes.
This doesn’t qualify as proof, but I believe this hole was made in connection with the pop I heard. I suspect it’s all connected. The popping noise comes from fish sucking tasty treats off the bottom of the lily pads, and the noise itself probably occurs when the leaf snaps, releasing the suction and creating a hole. That’s why, after a long summer of feeding, the lily pads are pocked with holes.
And now, when guests ask me “What is that popping noise?” noise, I’ll have a better answer.
I have heard this too, attributed it to the flowers on the pads opening in the morning.
Dale, I hear the noise most in the early evening. But maybe I just notice it more then because the normal daytime activity and noises are reduced.
Can anyone explain why you hear popping noises in a saltwater marsh at low tide? It is not fish as there is barely any water on the mud flat. Maybe something to do with gasses escaping fiddler holes?
Christian, where is the marsh you are talking about? Can you take pictures and record the sound? If so, email them to me at firstname.lastname@example.org. Thanks.
I like your discussion. I suspect whether the leaf tears or not, the suction feeding can make a popping sound as the tension is released. To me it sounds like a soft slap. The holes you see are not to be confused with the massive damage caused by hailstorms (a relatively rare occurrence) or the often severe feeding damage from Galerucella nymphaeae, the waterlily leaf beetle. On our lake at Stockton, the beetles often defoliate the spatterdock, sometimes twice or more a summer.
Thanks for your comment, Dr. Cromartie. Do you concur that the popping is probably sunfish, or other similar fish? What does the Galerucella nymphaeae damage look like?
We have a lot of sunfish nests nearby, so we think that’s the most likely.
I have bluegill in my pond and have witnessed them striking the lilies , the pop, and the resultant hole. I do not feed them often but am wondering if it would lessen the damage to the lilies if I were to feed them regularly. Any thoughts?
I’m generally against feeding wild animals. Also, feeding them might not stop them from eating bugs off the lilies, if they like the bugs better. Lastly, although the lily pads end up a little ragged by the end of the summer, the damage doesn’t seem to kill them, so my recommendation would be to just observe an interesting phenomenon.
Hello, found your site as I too have “popping” on a small retention pond, but have no lily pads, but probably blue gills. I hear the popping sound all the time. My theory is this: The pond has lots of algae produced from the many fertilized lawns surround the pond, as this algae dies it sinks to the bottom where it then degrades, produces some kind of gas which travels up towards the water surface and bursts making the sound. I can see the water surface being disturbed and it produces small wave rings all over the pond but mainly near the shore where its shallow. I can see lots of cloudy, green/gray matter floating just above the floor of the pond but yet still under the water.
Hi Kathleen, that’s interesting. Can you make a recording of the popping? The popping I hear is far too loud to be bubbles. But maybe you’ve got something different going on. Thanks, Tom
I googled “popping noises when bluegill feed” and this came up. We do not have lily pads in our pond but hear the bluegill making the popping noise when we feed them. The crackle-ly poppy sounds stop when the food is gone.
That’s interesting. So maybe the lily pads aren’t necessary for them to make a snapping sound when they suck up food from the surface.
I have observed the popping and lily holes in our local Rhode Island pond, which is loaded with pumpkinseeds. I figured they were nibbling little insect larvae off the bottoms of the leaves. Thanks for confirming!
I live in upstate NY and I have seen bluegills bite the Lilly leaves from under the water. I also can say after catching a mess of bluegill and when I’m cleaning them I see a lot of green matter digesting in their stomachs. II have a lot of dragonflies and damselflies on the pond and suspect might be eating the larvae along with a piece of leaf.
I know bluegill make a perfectly round bite because I have been bitten a number of times while swimming. They seem to target my moles. They do draw blood but it’s not that bad. It’s startling when they bite usually when I’m not moving around.