Tiny black “specks” prompt lake concern
When Jack Sutton noticed a dense cloud of tiny black specks along his frontage at Yellow Creek Lake in mid-May, he thought it was the start of another algae bloom on the surface of the 151-acre natural lake in southern Kosciusko County. But, the specks were different, and it turns out they weren’t even plants. They were daphnia eggs, or what biologists call ephippia.
Daphnia are microscopic animals and a favorite food of small fish. They feed on algae and are a natural part of the aquatic food chain. Daphnia can produce large numbers of ephippia in the spring when the water is clear, often when adult populations are most dense.
“I was looking outside my window and saw what looked like a film on the water,” Sutton said. “I’ve been here for 40 years and never seen anything like it.”
Sutton grabbed a water sample and contacted DNR biologist and fishery expert, Jed Pearson.
However, like Sutton, Pearson had no clue as to the identity of the tiny specks. To him, they looked like little bits of pepper.
“I thought they may have been small seeds, pollen or some form of plant,” Pearson said.
Back in the lab and under a microscope, the specks appeared to be encased in a clear protective covering. But Pearson still couldn’t identify them. So, he sent a close-up digital photo to Dr. Bob Gillespie at Indiana-Purdue Fort Wayne and Dr. Nate Bosch at Grace College.
Both requests for help in identifying the little black bits came back with the same response — daphnia eggs, or more precisely… ephippia.
When told the specks were ephippia, Sutton’s first response was: “How do you spell that?”
After hearing daphnia are a prime food item for fish, Sutton added, “No wonder a lot of fish have been hitting the top.”