Environmental Groups Shock Fish … for Science
August 24, 2013
PROVIDENCE — It was like a scene out of “Ghostbusters.” Greg Gerritt donned chest-high waders and rubber gloves and carried a 35-pound backpack that sported a digital display, battery pack and wires poking out at odd angles as he led his volunteer team into the Woonasquatucket River.
Gerritt and his team stepped into the waist-deep river, extending a long shaft, wired to the backpack and culminating in a Frisbee-sized metal ring, into the water. His team members flanked him, nets at the ready. Gerritt clamped down on a lever attached to the shaft, causing his backpack to begin beeping. On the far shore, inside a small rocky cove, something immediately began to thrash. The team moved closer, plunged a net into the water and scooped out a 3-foot-long black eel. It writhed uncontrollably in the net before quickly escaping back into the river.
The volunteers participating in the wildlife monitoring study of the Woonasquatucket River, below the dam at Rising Sun Mills, could barely contain their excitement. The eel was the first of many creatures pulled from the river’s shallow depths Aug. 16 during a three-hour monitoring session organized by the Woonasquatucket River Watershed Council (WRWC), the Wood-Pawcatuck Watershed Association (WPWA) and Friends of the Moshassuck. By morning’s end, volunteers had netted a variety of fish, a blue crab and Asiatic clams — the eel retained the record for biggest specimen counted.
The purpose of the urban fish monitoring program is to collect data at three urban rivers, according to Alicia Lehrer, WRWC’s executive director. She said the program compares fish in more pristine upstream locations to those in urbanized downstream locations and monitors fish populations on an annual basis to help determine if overall water and habitat quality is changing.
“People will be able to relate to river quality through the lens of the fish populations in the rivers,” Lehrer said. “That’s a lot easier to relate to than dissolved oxygen and nitrogen.”
The program is funded by a two-year, $57,000 grant awarded to the WRWC, WPWA and friends of the Moshassuck by the Environmental Protection Agency’s Small Urban Waters grant program.
According to Denise Poyer, program director of the WPWA, 2013 is a trial year for the study. Volunteers are being introduced to and gaining experience with the equipment and methods that will be used to monitor river wildlife in future years. Data collection will begin in earnest in 2014.
The program’s monitoring method relies on an electro-shocker and fishing nets. The battery in the backpack sends an electric charge into the water. The result is a field of electrified water that extends about a foot in every direction. During the Aug. 16 monitoring session the backpack was set at 200 volts.
Fish swimming within the field become stunned and float to the top, where they are easily netted. The fish are then placed in 5-gallon buckets filled with water. After a predetermined section of river is monitored, the captured fish are identified, measured and returned to the river.
The electric shock generated by the backpack is modest. Most fish recover within a minute of swimming into the electric field. Some even recover before they can be netted. Netters wear rubber gloves to avoid being shocked if they place their hands in the water while the backpack is activated.
“I’ve been shocked before,” Poyer assured the somewhat-skeptical volunteers. “It doesn’t hurt. It’s like touching a cattle fence.”
A range of people volunteered for the recent monitoring session. Chris Kane and his 9-year-old son Geo helped shock and net fish, carry buckets and measure the shocked specimens. Kane, an art teacher at Jacqueline M. Walsh School for the Performing and Visual Arts in Pawtucket, previously helped WRWC create the ceramic fish mural on the fish ladder at Riverside Park. Geo, a budding naturalist, was able to identify a variety of fish and birds on his own. He credited his father with being a good teacher.
Jessica Herron used the monitoring session as an excuse to get away from the computer. Herron is currently designing an app that will track wildlife by allowing anyone with the app to input sightings into a huge database. “It’s fun to actually do this,” she said. “I’m saying, ‘oh, so that’s what (people using my app) will be doing.’”
Emily Horton-Hall, a technical consultant at KEL Sustainability, also decided to get away from the office for the day to help shock fish. “I am always looking to learn new skills,” she said.
“An important secondary purpose of the project is to get people excited about the rivers,” Poyer said. “We want to show people that these rivers are not dead. They are not healthy yet either, but we hope that through restoration programs we can get river fish back in the rivers.”
Some river fish, including the tessellated darter and the fallfish, are already swimming in the monitored section of the Woonasquatucket River. Other fish, such as the abundant bluegills, are pond fish that have colonized calmer portions of the river as the ecosystem has fallen out of balance, according to Poyer.
Other specimens found during the monitoring session included white suckers, American eels, golden shiners and a hogchoker — a flounder-like flatfish.
Ray Hartenstine, a specialist of freshwater invertebrates, said volunteers discovered a population of endangered mussels during a recent monitoring session at the Falls River. As for the Woonasquatucket River, Hartenstine is concerned about the Asiatic clam, an invasive species that he said degrades the quality of the habitat.
Poyer said she hopes the project will result in a long-term volunteer monitoring program. “We hope to involve the community either as volunteers or simply by raising their level of awareness about their urban rivers,” she said. “Ultimately, we want them to develop an emotional attachment to the rivers and become good stewards.”