Newton Creek Fish Kill Attributed to Rapidly Changing Water Temperatures, Bacteria


A spokesperson for the New Jersey Department of Environmental Protection says water chemistry in the lake is normal. Camden County authorities are testing the water quality as well.

By Matt Skoufalos | March 19, 2024

Dead Bluegill in Newton Creek. Credit: Matt Skoufalos.

State officials say that a fish kill at Newton Lake is most likely the result of rapidly changing water temperatures, and not a sign of a larger environmental issue.

On March 5, the New Jersey Department of Environmental Protection (NJDEP) received a report of a significant number of fish having died off in the waterway, according to NJDEP Press Officer Vincent Grassi.

Staff visited the site two days later, where they observed an estimated 20 to 30 Bluegill and six adult Gizzard Shad floating in the lake.

“Given the small number of fish found, this would be considered a very minor kill,” Grassi wrote in an e-mail.

“Most of the fish appeared several days old; however, two Bluegill suitable for testing were collected and frozen for further examination.”

After testing, New Jersey Fish and Wildlife staff “found the water chemistry to be normal and able to readily support aquatic life,” Grassi reported, with “no foreign odors or chemical slicks” observed onsite.

Because fish kills have been reported in the lake previously, NJDEP staffers surmise that the die-off likely is related to bacteria outgrowth “as a result of the rapid change in water temperatures,” he said.

Representatives from the Camden County Haz-Mat team also investigated the site, and didn’t find any issues, according to Camden County Communications Director Dan Keashen. Those crews likewise did not see a chemical sheen, or identify any suspicious odors onsite, and a cursory water quality test came back without any concerns.

The Camden County Municipal Utilities Authority (CCMUA) also is testing water from the site, and will have expanded results in a few days, Keashen said. He likewise pointed to sudden temperature changes as likely contributing to the oxygen deprivation that can affect the fish.

Authorities believe these Bluegill that died in Newton Creek are not a signifier of broader environmental concerns. Credit: Matt Skoufalos.

Naturalist Keara Giannotti of Collingswood said that heavy rains can also contribute to issues with dissolved oxygen in the water, which is a key environmental factor for aquatic life.

“We still have a lot of plant matter in the lake because of fertilizer runoff; that causes an overgrowth of plants, which then decay, and that’s when the dissolved oxygen gets used up by bacteria and fungi that are eating the plants,” Giannotti said.

She also pointed out that the fish that died off in the lake also had survived the harshest temperatures of the winter, making them more susceptible to diseases, viruses, or changes in the dissolved oxygen levels. Bluegill prefer warmer climates, and New Jersey is among the northernmost geographic reaches of their observed range.

Fish kills can offer early warnings about the environmental health of a body of water because of their sensitivity to change. NJDEP recommends that members of the public report them when observed.

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