OUTDOORS

Mayflies, algae both part of the game for Lake Erie walleye anglers

7/6/2018

Mayflies, which in their nymph stage are buried in the sediment along the bottom of Lake Erie, provide a food source for the lake's abundant walleye population. The presence of mayflies is an indication of a healthy lake.

The Blade
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PORT CLINTON — At a time when their most precious resource is believed to be swimming in the neighborhood of unprecedented abundance, Lake Erie’s walleye anglers have been dealt a couple of wild cards, face up, but not a matched set.

On one front, the recent explosive mayfly hatch, while a nuisance of Biblical plague proportion to a few, is thought by some to have satiated the vigorous appetite of the hoard of young walleye from the 2014 and 2015 hatch classes. Stuffed on the seemingly unending supply of mayflies, the fish have throttled back on accepting the offerings of fishermen, the claims say.

In the same waters of Lake Erie’s rich and bountiful western end, the notorious algal bloom, with its colorful and destructive calling card, has returned. A contingent of anglers has expressed concerns that this early-arriving green slime signals the end of what was viewed as the summer of plenty for walleye fishermen.

Adding to the hype and mystery is the contrast — the mayfly hatch has long been considered a sign of a healthy lake, while the algal bloom is a harbinger of trouble.

The Ohio Sea Grant earlier this year cited a study by the U.S. Geological Survey that showed mayfly populations in the western end of the lake were near zero from 1959-61 when pollution levels were very high. The mayflies require very clean water to breed, and they slowly came back as the lake improved, but in 1993 biologists counted just 12 mayfly larvae per square meter of lake bottom. Those numbers are now at 300-400 mayflies per square meter, and the mayfly squadron is so vast that the insects show up on weather radar, block the light from street lamps, and cause a gooey mess on sidewalks and roads.

The algae, which in its toxic form caused the Toledo water crisis of 2014, has started to bloom in western Lake Erie, coaxed along by the stretch of sweltering heat we recently endured. Researchers report numerous algal blooms scattered across the basin. Fed by phosphorus that has streamed into the lake from runoff of agricultural fertilizers, manure spread on farm fields, and leaking septic systems, in the past these blooms have created thick mats of algae, with some of it being poisonous.

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The angling jury, never one to reach a unanimous decision, is still deliberating as to the impact of these two forces on the walleye fishery. Bob Barnhart, the owner of Maumee-based tackle supplier Netcraft and a Lake Erie walleye tournament fisherman, prefers to take the big picture view from 30,000 feet.

“The algae is there, and the mayflies were everywhere when they hatched, but it has always amazed me how this ecosystem as a whole can adapt to a wide variety of factors,” Barnhart said. “Sometimes, the fish seem to adjust to the changes a lot better than the people do.”

Barnhart said he is in regular contact with many charter captains who fish the lake every day and with the anglers on the Netcraft pro staff, and they had expressed a common concern that with the vast numbers of young walleye in the lake, would there be adequate forage to sustain all of those fish — a Lake Erie total walleye population some estimates have put at 100 million fish.

“Guys are seeing more fish than they have ever seen before, and I think that’s part of the reason we’re not catching as many big fish, because there are just so many fish from these recent hatches,” he said. “Mayflies are a big part of their diet, but there are so many fish out there eating them, I don’t think the mayflies have had any significant impact on the walleye bite. With so many 15-19 inch fish in the system, that forage is important and they hit it hard.”

Toledo native and walleye pro Ross Robertson from Bigwater Guide Service said that when the mayflies arrive, anglers just need to adjust their approach to continue to catch limits.

“You can do things different and alter your game plan, and you’ll do just fine,” Robertson said, recalling a time a few years ago when mayflies were blamed for what some considered a tough bite. “Everyone was crying that mayflies shut the bite down and it was a lost cause. We smashed the fish — and big ones — without a boat in sight the entire day. When the mayflies hit, you need to alter location and methods, just like any other time of the year.”

Captain Mike McCroskey said the walleye he has taken recently have been “loaded” with mayflies, but he is still bringing in limit catches aboard his Hawg Hanger charterboat. Captain Eric Hirzel from Erie Gold Fishing Adventures concurred, saying an adjusted approach produces walleye in the height of the mayfly hatch.

“No doubt it slows fishing, but throughout the hatches, trolling small spoons or casting mayfly rigs deeper in the water column consistently took limits through the thick of the hatches,” Hirzel said. “The upside of huge bug emergences this year is that they are providing untold tons of high-energy feed for our perch and walleye fisheries.”

On the algae front, Hirzel said the bloom appeared early and has been super-charged by the heavy rains earlier in the year flushing phosphorus into the lake and the steamy hot weather warming the water, increasing the chances for the presence of microcystin, a toxin produced by blue-green algae.

“I think for this time of year, things are pretty advanced. We've had an enormous amount of runoff and with the heat, the water temps are climbing like crazy, which points to a serious year for microcystin,” he said. “As far as catching fish in or around heavy blooms go, it doesn't appear to be a consistent advantage or disadvantage. Personally, I think it all depends where the bait is hanging out.”

Robertson said that while the algae is a huge concern as it relates to the overall health of the lake, it does not seem to impact the walleye nearly as much as it does the walleye anglers.

“I’ve fished right in the middle of the biggest algae blooms and smoked the walleye — some in algae so thick it is tough to see them in order to net the fish,” he said. “I haven’t seen any issues, except it makes the boat a mess.”

Barnhart said that on a recent holiday week outing on Lake Erie, he found the surface temperature of the lake at 82 degrees, and an abundance of algae in the water.

“It was more algae than I have ever seen at this time of year, and to me, that is clearly not good. But we trolled right through it and still got fish,” he said. “It wasn’t the real soupy stuff, but there was algae present and we were marking fish and catching fish. The algae really had zero impact on the fishing.”

Many of the charter fishermen and walleye pros expressed a belief that the optics associated with the algae are scaring off some anglers, but not the fish.

“It is absolutely stunning to hear that guys are catching fish in numbers, from West Sister Island all the way to Ashtabula, and I have never before heard of that being the case,” Barnhart said. “People overlook the fact that these fish have to eat, and with the sheer numbers of fish in the system, not every one of them has to feed every day in order for you to have an outstanding day of fishing. Despite the mayflies and the algae, the odds are in the fisherman’s corner.”

Contact Blade outdoors editor Matt Markey at: mmarkey@theblade.com or 419-724-6068.