Last Sunday morning my son Mitchell and I stood waste deep in a St. Joseph County marsh at the crack of dawn.
I had a suspicion that blue-winged and green-winged teal would be migrating through the night as Saturday afternoon temperatures were dropping north and northwest of us.
Teal move fast and migrate very early in the season, so any night the thermometer dips into the 50s it’s likely these little ducks will be headed south.
Stars were still showing in the sky when we pulled up to the boat ramp. I expected to be swarmed by mosquitos and was very concerned that I’d forgotten bug spray, as well as my ThermaCell. After a few minutes outside the vehicle only a couple mosquitofish showed up and it was then that I remembered this particular marsh was infested with “mosquitofish."
The lowly Western mosquitofish is very similar in appearance and behavior to the plain old guppy of aquarium tanks. This species has a native range that extends from southern Indiana and Illinois Mississippi River drainage all the way down to the Gulf Coast.
Mosquitofish have been stocked all over the world for their propensity to eat mosquito larva, thus preventing mosquito-borne illness such as malaria and West Nile virus.
According to Wikipedia, mosquitofish are considered a major factor in the eradication of malaria in South America and parts of Asia. Interestingly, in Sochi, Russia they are so revered that there is a monument dedicated to mosquitofish. While in some places mosquitofish are desirable, in other places they are considered to be invasive and compete with native species.
It’s easy to understand how things can get out of hand when you consider that these fish are incredibly prolific breeders and can withstand extremely inhospitable environs. Females become mature several weeks after being born and may give birth to live young only a few weeks after breeding. It doesn’t take many mosquitofish to populate a body of water in a relatively short amount of time.
I noticed mosquitofish a few years ago at one of my favorite hunting spots. And, it wasn’t because I actually saw them, but because I simply could not understand why there weren’t any mosquitos where I was hunting.
Everybody else was going nuts about the relentless mosquitos during the early part of the duck season, but it was a rarity to see any where I was hunting.
I started to suspect that fish were eating all of the larva. I had seen a few mosquitofish on area golf courses and assumed they were stocked to cut down on the mosquito problem but I had never seen any in other spots.
I waded around to investigate and sure enough in water only inches deep I could see hundreds, maybe thousands of tiny fish. After a little effort I was able to catch a couple with my cap and my suspicions were confirmed.
While mosquito fish eat all kinds of invertebrates they have an affinity for larva and in particular, mosquito larva. I don’t think I have to point out that we had a serious mosquito problem after flooding rains we received in the early part of August. My yard has been unbearable and just this week I noticed that the horde of biting insects has subsided to some degree.
That makes the fact that Mitchell and I were unbothered by mosquitos in a massive swamp even more amazing.
Honestly, it made me a giggle as I could see the little two-to-three-inch fish cruising the surface, scarfing down larva of all sorts. Mother Nature at her finest.
Incidentally, no teal showed up for our hunt, but we did bring a few geese home and one little snipe that made the mistake of cruising over my head.
There are other unique fish species that live in this area such as the bottom dwelling darters and unusual minnows. Right alongside the mosquitofish I could see the occasional topminnow which could have been one of a couple different species. Another fish that I see occasionally that I recall being sold at a pet store when I was a kid is the banded killifish.
These unique species of fish swim under the radar, so to speak, and it’s rare for anybody but biologists to pay attention to them. I’ve always been fascinated by them. When I was growing up in Wabash, Indiana, we’d go down to the river and catch all kinds of darters, minnows and shad after high water subsided and stranded thousands of fish in shallow river bottom pools.
It was in a small creek draining into the Wabash River that I saw my first Southern Redbelly dace in breeding colors. They reminded me of the brook trout I had caught on a fly rod in Northern Michigan. Take away the fancy colors and dace look like an awful lot like the plain old fathead minnows you buy at the bait shop for crappie fishing. When it comes to fish, beauty is often only skin deep.
If you pay attention, we have all kinds of nifty critters in our midst. It may seem insignificant to most folks, but I like the thought that there are still realms of the fish and wildlife world that exist without the ever present hand of man getting in the way. At least most of the time. While mosquitofish may have been stocked here originally, they are welcome to call our waterways home as far as I’m concerned.