For more than 50 years, many species of fish were unable to move into Smelt Brook in Sullivan due to the presence of a dam. Scientists on Tuesday announced that just months after that dam was removed, spawning Atlantic tomcod have been found upstream from the former dam site at the head of Frenchman Bay.
Last year the DSF removed the 50-year-old dam that kept fish out of the stream and didn’t allow nutrients to spill into Smelt Cove, according to a Downeast Salmon Federation news release.
“We found a few tomcod downstream of the dam and a few smelt eggs on the face of the dam last year,” DSF fish biologist Brett Ciccotelli said in the release. “This year, tomcod are swimming way past where the dam used to be and are spawning in the stream again. We hope to find smelt here in the spring, too.”
According to a U.S. Department of the Interior species profile from 1987, “Atlantic tomcod are widespread along coastal regions of the northeastern coast of the U.S. They are abundant in estuarine habitats such as river mouths and salt marshes. These same habitats are subject to a wide variety of human sources of disturbance.”
Among those human-caused disturbances that affect the small fish: dams.
At the beginning of 2018, the DSF purchased the property surrounding Smelt Brook, with aid from the Maine Natural Resource Conservation Program and other groups and individuals. Later, students from Sumner High School in East Sullivan surveyed the pond, using fly rods and barbless hooks, searching for brook trout.
DSF habitat restoration project manager Shri Verrill supervised dam removal, fish passage and restoration of the salt marsh in September.
Behind the dam was 50 years worth of sediment that had been impounded.
“There was about two feet of muck at the bottom of the pond. After we dewatered it, I got myself pretty well stuck in the muck while rescuing some remnant fish and amphibians,” Verrill said.
An excavator, along with bulldozers and dump trucks, took out the dam, allowing Smelt Brook to flow freely into Smelt Cove. According to the release, rain and high tides helped the stream cut through the sediment and uncover gravel bars as far as 150 feet upstream from the dam site.
Tomcod spawn in December and January, under the ice of the stream, and the DSF said that earlier this winter they swam through the old dam site for the first time in 50 years, and found those head-of-tide gravel areas and laid their eggs.