The dead fish floating in the pond last week appeared suddenly and disappeared almost as quickly. While the causes of both may never be known for sure, experts suggest it is all natural and the pond is safe to open for the season.
A week ago Tuesday, after a DPW worker found numerous dead fish at the town beach, and others reported seeing them elsewhere around the pond, Bare Hill Watershed Management Chair Bruce Leicher, Health Agent Ira Grossman, and the Parks and Recreation Commission began looking at evidence to determine the cause of the fish kill and make a decision about keeping the pond and town beach open for Memorial Day weekend.
The E-coli samples taken by Grossman after the event tested normal at the Nashoba Boards of Health.
A natural spawning event
After questioning Leicher, Richard Hartley, who is responsible for investigating fish kills for the state Department of Fish and Wildlife, concluded the dead fish were the result of a natural spawning event that didn’t warrant further testing.
Leicher said Hartley had told him that had a toxin been present in the pond, multiple species would have been affected, rather than just the blue gills that pond committee consultant Wendy Gendron had identified. When large numbers of fish congregate in shallow water to spawn, the water’s oxygen concentration may not be sufficient to support them all, especially after a long dry spell like the one earlier in the month. Recent rain was expected to have increased the pond’s oxygen levels.
The pond committee will continue to monitor the pond for water clarity and keep an eye out for increased algae activity.
Leicher found a fish in his backyard, about 150 feet from the pond, in an area where a resident fox is teaching its kits to hunt, he told the Press in an email. He said he learned from Mark Mattson, the state Department of Environmental Protection official who monitors Bare Hill Pond, that spring fish kills like the one last week can provide a food source for mink, otter, and fox young and breeding birds of prey.
