Anglers say that fish congregate around blooms. Scientists have found levels of a liver toxin in fish
Even though algae blooms are often said to smell bad and look bad, Eric Hirzel and Matthew Hehn say they help them catch more fish in Lake Erie.
Both have been charter fishing captains for a long time. They fish in the western basin of the lake, mostly for walleye (pickerel) and yellow perch.
Algae blooms happen when too many nutrients, like phosphorus or nitrogen from fertilizer, run off into water systems. This makes it easy for algae to grow quickly.
In 2017, there was one of the biggest algal blooms ever seen in western Lake Erie.
Hirzel, who is from Ohio, says that when the blooms get big enough, they make enough shade that fish often gather under the green slime, which makes it easier to catch them.
Hirzel said, “Sometimes, it’s not like we’re trying to get away from these flowers.”
“Most of the time, we go straight to them. It isn’t very nice to look at. It doesn’t always smell good, but the fish are definitely busy under it.”
Hehn, who is from Michigan, agrees. He says that it is “kind of a running joke” in the charter fishing business and in the group that he fishes with.
“At that time of year, it’s almost like the walleye are wearing sunglasses, and then there’s a flat day with the algae bloom… Hehn said that the bites were still very good.
“But if we don’t have that algae bloom and the water flattens out and there’s a lot of sun, the bite usually slows down a lot.
Can eating fish that have been around algae blooms make people sick
Hehn said that, in his experience, fish don’t usually eat algae on the water’s surface.
“From what I’ve heard from the Michigan DNR and the Great Lakes Fisheries Commission, algae doesn’t affect the quality of the meat or anything like that.”
What do scientists say, though?
The director of Ohio Sea Grant and Ohio State University’s Stone Laboratory says that algae blooms can make fish flesh toxic.
But Chris Winslow says that research from universities and government agencies doesn’t show levels of toxins in fillets that are high enough to warrant more warnings for fear that eating them will make people sick.
Winslow said, “There is already a warning about eating fish from Lake Erie, and it’s mostly because of mercury.”
“But what we’ve found is that the toxins in the fish tissue don’t outweigh the mercury consumption advice. As long as you follow the advice that’s been around since the 1970s, those toxins haven’t made it worse.”
Are the algae blooms in Lake Erie bad for the fish
René Shahmohamadloo has written a research paper about how algal hepatotoxins don’t make Lake Erie fish unsafe to eat, but he’s also worried about the fish’s health.
The ecotoxicologist and postdoctoral scientist said he hopes his work can speak up for a population of “voiceless” fish.
“What about the fish that have to swim in these baths that could be very poisonous?” Shahmohamadloo, a professor at both Washington State University and the University of Guelph, said this.
“It’s interesting to me that we can look at this story because it shows how focused on people we’ve become… If it doesn’t matter to us as a species, then let’s keep living.”
Shahmohamadloo said that after two rounds of sampling, their study shows that the levels of concentrations could hurt the growth and development of fish populations.
He said that some fish had unhealthy levels of a liver toxin called microcystins before, during, and after big algae blooms.
“It looks like it might be a problem for their growth, development, and population dynamics.”
Shahmohamadloo said that it’s possible that the fish are gathering under the blooms because they’re scared.
“It’s easy for us to catch them, but there could be a serious biological reason, like cyanobacteria, for the fish to gather in that way. When we think about these flowers, we need to be careful.”
In contrast, Winslow said he needs to see more “definitive” research to support the idea that fish are being affected by the toxins.
“We don’t seem to see that it’s killing fish and we don’t even seem to think that it’s affecting their behaviour or their growth to date.”
How have blooms been so far this summer on Lake Erie
The National Oceanic and Atmospheric Administration (NOAA) continues to predict a low to moderate-sized bloom across the western Lake Erie watershed this summer.
On a scale of 1-10, the U.S. federal agency expects a severity level range of 2 to 4.5 because of a dry spring and low phosphorus loads into the lake.
As of July 24, the current bloom in western Lake Erie has an approximate area of 620 square kilometres, with scum likely showing up nearshore around parts of Michigan and Ohio.
Rajesh Bejankiwar said even though they don’t change the severity of algae blooms, wind and wave action can impact them across the western basin of Lake Erie.
The International Joint Commission scientist said they can alter how blooms spread, and collect at beaches and local shorelines.
“If you have a big amount of algae and if there is a wind from south to north, obviously the blooms will move towards the north shore of Lake Erie and then we’ll see more on our shoreline, on the Ontario side,” Bejankiwar said.
Sandy Bihn lives at the mouth of the Maumee River and Lake Erie — an area widely viewed as a main source of phosphorus load into the lake from livestock manure.
She’s also the executive director for an advocacy group called Lake Erie Waterkeeper — with a focus on algal blooms.
Bihn said she expects the bloom to be bigger in August and September because of the recent rainfall we’ve seen.
“These blooms are caused by usually six to eight major events in a year,” Bihn said.
“The waters are a little cooler this year. Water levels are down this year from what they’ve been a little bit. How much that factors in temperature certainly does play a role in it, but I suspect we’re going to have a large bloom in August and September.”
The health of Lake Erie is “immeasurably important” to Pelee Island, according to its mayor.
And so far, Cathy Miller said there’s nothing notable to report along Canada’s southernmost shoreline.
“Our main industries of agriculture and tourism are both reliant on a healthy lake — as is most of mainland Ontario,” said Miller.
“Tourism has been negatively impacted in years where massive blooms have impacted water quality.”
She said the island consistently tracks algae bloom reports from a handful of agencies, adding despite algal blooms affecting small communities like Pelee Island first, that it’s an “international issue that ultimately could affect us all.”
“It is my perception that Ontario’s 12-point plan to address this issue has been effective.”
Everyone who draws on Lake Erie for drinking water could be impacted by high levels of algae and algal blooms, added Miller.
“Residents draw from personal wells, small drinking water systems, sand points and the municipal water system. The municipal water system is heavily monitored and regulated to ensure safety.”