Classwork combined with fieldwork to find best place to release salmon fry
By DAVID SMITH/ecoRI News contributor
RICHMOND, R.I. — The group of about 20 Chariho Middle School seventh-graders moved through the brush unaware of the finds they would soon discover in the clear, cool water of Meadow Brook.
Minutes before their arrival, their science teacher, Daniel Potts, gathered them in a field maintained by the Rhode Island Department of Environment (DEM) about a half-mile south of the Pine Hill Road brook. Dip nets, waders and water-testing equipment were spread out on the grass. He explained how to use a dip net by pulling against the current, and to take small steps if they donned the waders and to not go in water over their knees.
Only one student raised his hand when Potts asked how many had ever worn waders.
It was 43 degrees and overcast on this recent day and a few of the students pulled heavy clothing out of a box that Potts had brought along to ward off the chill.
In all, there were three groups totaling about 120 students at various points along the brook, which stretches about a mile and a half along Pine Hill Road and flows south to Meadow Brook Pond.
Earlier, the students walked out of their classrooms, crossed rural Switch Road, and hiked across a turf field before heading into the woods and their appointed spots along the brook.
The trip’s goal was to take what they learned in the classroom and see it firsthand in the woods and stream. The students are raising about 300 salmon fry in a classroom tank. The fry were given to them by the DEM.
Potts said the students observe the fry daily and take notes. The observations and data the students collect, along with this fieldwork, are designed to help them write a paper on which location in the brook would be the most beneficial for the baby salmon to survive. The project involves science, math and English.
Fieldwork included collecting data on the level of oxygen in the water, its pH level, phosphate and nitrate levels, and the number and types of macroinvertebates available for the salmon to eat. Potts told the students that he hoped they would collect at least 100 macroinvertebrates, but at the end of the effort the students had collected 65.
Potts said that it was likely that whomever wrote the most convincing paper about where to release the fry, would be allowed to take part in the release. That part of the project is expected at the end of the month.
Although Meadow Brook flows into Meadow Brook Pond on Route 91, there is a dam that prevents the fish from following the stream to where it connects with the Pawcatuck River. Fishermen seek the prize fish in the pond. The state creel limits for salmon is two and they must be at least 15 inches in length.
It didn’t take long for the students to dip their nets into the brook. As the bugs came up in the nets, not everyone wanted to wrest them free of mud and twigs and put them in a container of water.
John Hexton said he was looking forward to the field experience after studying the different classes of macroinvertebrates. “Coming out here allows us to see it,” he said.
Potts said that on another occasion he was with a group of students that found seven species of fish in the brook.
Colin Campo said that it was interesting seeing “the kinds of things that live in this ecosystem.” “It’s pretty fun, even though I got wet,” he said. “I really like science.”
Kate Powers and Gina Foley were running a test to see how much dissolved oxygen was in the water. Their reading was 9.44 parts per million (ppm), which according to Potts, was a good reading and certainly able to sustain fish.
The girls also recorded a pH level of 6.4, which was slightly acidic, and expected, but denoted a healthy brook.
“It’s cold,” Powers said.
“It’s better than sitting in a classroom,” Foley replied.
Potts also checked on the level of nitrates being collected by Daniel Lloyd and Ryan Martira. Their nitrate reading of 0.88 ppm was a little out of the expected range and would be worth another check. The students were using the equipment for the first time. Potts said that in the 16 years of gathering data, the average nitrate reading was about 0.2 ppm.
The boys also recorded a phosphate level of 3.5 ppm.
“The worst problem in the brook is sediment washing into it,” Potts said.
A good indicator of the brook’s health is the number of macroinvertebrates and their size. “Hellgrammites live in the stream for years,” Potts said. “If there had been a bad year they would have died and we wouldn’t find big ones.”
The hellgrammites the students recently found were large. On this day, the students also found stone flies, may flies, caddis nymph, dragonfly nymphs and one Johnny darter.
The collected creatures were taken back to the field to be counted. Each student marked a data collection paper recording all the bugs and fish that were collected, as well as information about the quality of the water and various characteristics of the brook. The information will help them write their paper on where to release the salmon fry.
After, all of the bugs and fish were brought back to the brook and released.