It's fish fly season

Ragman

Veteran Expediter
Retired Expediter
Is it the calm before the swarm? Heavy rains likely to affect fish fly invasion

12:17 AM, Jun. 11, 2011

BY PEGGY WALSH-SARNECKI

DETROIT FREE PRESS STAFF WRITER

They swarm. They invade. They mush on your windshield.

The annual invasion of fish flies is coming, and scientists say the storms and rains of spring are likely to affect the annual fish fly hatch -- but no one's sure exactly what that will mean.

Either the stormy spring will mean a late hatch and we'll see a record number when they all come out at once, or the weather churned up the water so much it will kill off much of the larvae while they're still in the water -- meaning we'll see fewer of the little buggers.

"It seems it could go either way," said Don Schloesser, fishery biologist with the U.S. Geological Survey's Great Lakes Science Center in Ann Arbor. "It's going to take three or four days of relatively calm water, and these critters will come out."

They may be commonly called fish flies in this area, but they're really mayflies, Schloesser said -- classified within the genus hexagenia, if you want to get technical about it. At one time, they were called Canadian soldiers because a northeast wind would appear to send them marching in from Canada.

And while they can be found in many places, the relative shallowness of Lake St. Clair and western Lake Erie, coupled with currents that wash pollutants downstream, make southeast Michigan one of the great fish fly spots.

So what are all those fish flies doing when they're landing in your hair?

They're mating. They spend the first two years of their lives in the underwater sediment and only come to the surface when it's time to reproduce. They mate within the first 48 hours of coming up for air, lay their eggs, and that's pretty much it for a mayfly's life.

Whether it's going to be fish fly feast or famine this year, folks from Lake St. Clair to western Lake Erie are sure to view the annual rite with mixed emotions.

To some, they're pests that ought to be called dead-fish flies because that's what they smell like. They're a nuisance and travel in such thick swarms that they have to be hosed off windows and walkways. And it can be, well, just yucky to have to walk through clouds of them.

River Farrell remembers when she moved from Traverse City to Detroit's east side. She thought she had seen fish flies up north, but she hadn't seen anything like those in southeast Michigan.

They turned to mud under her windshield wipers. And one time they were so thick on her car, the sidewalk and the windows of a pizza shop she was headed to, she decided she wasn't hungry after all.

"I started to get out of my car and I couldn't," Farrell said. "It was a horrible experience."

On the other side are those who rejoice in the annual hatch because the flies are a sign of a healthy lake environment.

"As annoying as they are, don't hate them," Schloesser said. "They're a good indicator. People want to know their environment is better; that people spent all that money for good reason" in cleaning up the region's lakes and rivers.

So, annoyance or sign of a healthy lake, most folks around here just take them as one more phase of summer.

"First we have the twirly birds, then we have the white fuzzies, then we have the fish flies -- and they're all a pain in the you-know-what," said Mary Kaminski of New Baltimore.

Contact Peggy Walsh-Sarnecki: 586-826-7278 or [email protected]
 

layoutshooter

Veteran Expediter
Retired Expediter

"Either the stormy spring will mean a late hatch and we'll see a record number when they all come out at once, or the weather churned up the water so much it will kill off much of the larvae while they're still in the water -- meaning we'll see fewer of the little buggers."


That article was poorly written though. All the rain in the world will not affect the "larvae" since it is NOT the larvae that hatches each spring but rather a "nymph" that has lived UNDER the mud in Lake Erie for at least two winters.

These "journalists" should do a bit of research prior to putting out their stories. This is a prime example of why I DON"T trust our "press" and "media" Far too many times when I read a story that I know something about I find them either wrong or worse.






Hexagenia limbata is one of the most geographically widespread mayflies in North America. It is found from coast to coast as well as from Florida to Canada and often constitutes an important part of the food chain in clear water lakes and slow moving streams. In suitable habitats Hexagenia nymphs may reach populations densities of nearly 500 per square foot of lake bottom. The high densities and productivity rates of these mayflies may constitute a significant component of nutrient and energy cycling within their aquatic habitats and adjacent terrestrial systems. This would be especially true for Florida, where almost one quarter of the state’s land is swamps. In certain Great Lakes and Mississippi River areas Hexagenias hatch in such great number as to become a public nuisance and in some cases have to be bladed off of roads to prevent traffic hazards. In Oregon and Washington Hexagenia hatch in a few small lakes and slower sections of streams. Most notable of these are certain Cascade Lakes and portions of the Williamson River.

Female Hexagenia and most other mayflies deposit their eggs directly on or in the water. Individual Hexagenia females release as many as 8,000 oval eggs, each less than 1/2 mm long, which sink to the lake bottom. After several days to several months (dependent partly on the water temperature), a tiny nymph hatches from each egg. It immediately burrows into the lake sediment to feed on particulates and to construct a U-shaped burrow, with two openings at the sediment surface. The nymph continually enlarges its burrow as it grows, so that the burrows of mature nymphs can be as much as 5 inches deep. By undulating its body and moving its feathery abdominal gills in sweeping motions, the nymph keeps the burrow oxygenated.


Hex nymph picture from:
HATCH GUIDE FOR LAKES
by Jim Schollmeyer

Nymphs are found from just a few inches to fifty feet deep. Depending on the topography of the lake bottom, most Hex nymphs will be found at depths of two to ten feet. Where the water is clear enough to see the lake bottom, it is easy to spot areas where colonies of these nymphs live as their burrows will be easily seen.

The nymphal life of Hexagenia lasts from about one year in warm climates and usually two years or more in colder regions. It is believed that Hexagenia nymphs remain in Lake Erie over two winters before they mature. This is the common cycle in Pacific Northwest lakes as well. As with all insects, they grow by shedding their exoskeleton or "skin" in a process called molting. Hexagenia nymphs undergo perhaps as many as 20 to 30 molts. When the nymph is ready for its final molt, it leaves the burrow at dusk or soon after and rapidly swims to the lake surface, where its exoskeleton splits lengthwise down its back. From the raft-like exoskeleton emerges a fully winged subimago or (dun), which after only a few minutes takes flight. The winged Hexagenia is the only stage in the insect's life cycle that most people see.

Although the dun may appear at first to be an adult mayfly, it is not fully developed sexually, and its color is usually opaque than the adult. During the night or the following day, male and female duns molt a final time, leaving behind a subimaginal exoskeleton. They are now sexually mature imagoes or (spinners - adults). Neither the duns nor spinners eat, because their mouthparts are not completely developed. At dusk or at night, female spinners fly into a large swarm of male spinners. The males and females mate in flight during darkness. Within minutes of mating, the female spinner settles down to the lake surface, extrudes her eggs, and dies. This is called a spinner fall.

In the Oregon Cascades there is strong evidence that more than one specie of large burrowing nocturnal may fly may inhabit some lakes. Several color variations and at least two distinctly different sizes of may flies may emerge in a single evening.
The large yellow may fly pictured at the top of this page is common to the three local lakes we fished during summer of 2000. It ranges up to 1.7" from head to the base of its tails. The two variations pictured here are also present in large numbers in all three lakes but rarely exceeds 1.2". One variation
has dark smokey colored wings. On this insect the tails and the under side of the legs are dark brown. The other insect is pale creamy yellow with very light brown markings. The tails and under side of legs are creamy colored. Males and females have been observed in both color phases.

When fish a Hex hatch, there is no need to get to the water before late afternoon. This is the perfect situation for the angler who wants to do some fishing after the work day is done. The angler will usually see a very few duns around 7:00 o'clock. This is a false hatch. Unless there is dense cloud cover the real hatch starts about 8:30 or 9:00.
(For a useful list of Hex patterns: click here.)
The angler should start fishing over Hex beds with a sinking line around 7:00 o'clock with a Silvey's Hex Nymph. The sink rate of the line you choose is dependent on the depth of the water. You should let the fly sink to within a foot of the bottom and retrieve with fairly rapidly. 3X tippet is advisable. Some of the best fish will be encountered at this level.

As the hatch progresses both the fish and the nymphs will start to concentrate near the surface. You should carry two rods, one with a floating line and the other with a sinking line. When there is sufficient surface action switch to the nymph on the floating line.



Hexagenia Mayflies, Stillwater Fly Fishing Super Hatch

Giant Michigan Mayflies
 

Moot

Veteran Expediter
Owner/Operator
There have been a few years where MNDOT used snowplows to clear mayflies from the Wakota Bridge, I-494 over the Mississippi near Stockman's Truck Stop.

I had a great weekend of walleye fishing in northern Minnesota during a mayfly hatch. Every walleye we caught was full of mayflies yet they were still biting on minnows!
 

layoutshooter

Veteran Expediter
Retired Expediter
There have been a few years where MNDOT used snowplows to clear mayflies from the Wakota Bridge, I-494 over the Mississippi near Stockman's Truck Stop.

I had a great weekend of walleye fishing in northern Minnesota during a mayfly hatch. Every walleye we caught was full of mayflies yet they were still biting on minnows!

The walleye shut down on Lake Erie when they are out. You can SOMETIMES get them to hit on a brown and gold crawler harness LARGE blade, pulled SLOW so it just "thumps" a bit. Other than that, two weeks of wasted time out there.
 

Moot

Veteran Expediter
Owner/Operator
The walleye shut down on Lake Erie when they are out.
Conventional wisdom would say that applies everywhere. I was amazed that walleye would bite on minnows when all that hook free food was available. These fish were stuffed full of mayflies yet still had room for a minnow. It's all in the presentation! On Minnesota lakes the mayfly hatch only lasts for 2 or 3 days.
 

layoutshooter

Veteran Expediter
Retired Expediter
Conventional wisdom would say that applies everywhere. I was amazed that walleye would bite on minnows when all that hook free food was available. These fish were stuffed full of mayflies yet still had room for a minnow. It's all in the presentation! On Minnesota lakes the mayfly hatch only lasts for 2 or 3 days.

It is a LONG two weeks out on Lake Erie. The fly hatch is magnificent!! There are "rafts" of nymph shucks out the that are hundreds by hundreds of yards in size and there are hundreds of those!!

I once caught a wild brown trout, in Scotland, it took a tiny size 22 nymph. It had a rat's tail hanging out of it's mouth. Sometimes you can overcome. It was around 15lbs. Small by their standards but a good fish. It was released to fight again.
 
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