Oak Bluffs students practice hatch and release
If fishermen find themselves landing some nice brown trout in Upper Lagoon Pond, they may have Oak Bluffs School sixth-graders to thank for it. On March 3, the students released 132 brown trout fry into the freshwater pond, after hatching them from eggs and nurturing them in a classroom fish tank since last November.
Fifty-eight students in three sixth-grade classes participated in a "Trout in the Classroom" project under the direction of teaching assistant Leah Tofte-Dorr in Lenny Schoenfeld's classroom. Teachers Holly Thomas and Jane Thomas also lent their support and help on field trips.
Miranda Pettit, Connor Chisholm, and Thamaris Marta (from left) watch like proud parents as the tiny trout swim off to independence. Photos by Ralph Stewart
Ms. Tofte-Dorr, who is finishing her teaching degree requirements for Bridgewater State College, got the idea for the fish project from a friend who teaches in New York. After she requested funding for the project last October, the Oak Bluffs School and the Parent-Teacher Organization responded quickly with $1,000 towards buying a 50-gallon fish tank, equipment and supplies so that she could get the project started in November.
The Massachusetts Division of Fisheries and Wildlife (DFW) donated the trout eggs from the State's Sandwich fish hatchery to the school, along with fish food. The project began with exactly 283 eggs, as counted and recorded by Ms. Tofte-Dorr and her students.
Each student kept a worksheet packet in which they carefully recorded data and made drawings of the fish from the egg stage through hatching and developing into fry. The project incorporated several learning skills, including art, observational science, and record-keeping.
Smaller in diameter than an eraser on a pencil, the eggs were suspended at first in a net in the tank to keep them from being sucked into the water filter. Ms. Tofte-Dorr covered the tank with cardboard initially to simulate the dark environment of the bottom of a pond.
The trout fry wait for release as students transfer them to the pond with nets and bowls.
Since trout prefer cold water, Ms. Tofte-Dorr said, a chilling unit kept the water in the fish tank at 50 degrees, which also helped the fry acclimate to the temperature they would experience in the pond.
Student Hannah Moore shared her drawings, starting with the yellowish-white egg, through which the fish eyes could be seen. At one stage, Hannah explained, the fish hatched from their eggs but remained attached to the yolk sac, which fed them until they developed fins and started swimming.
Hannah said what surprised her the most about the project was how slowly the fish grew. She thought they would be about 6 to 10 inches long by the time they were released, but they were only about one and a half to two inches.
Their slow growth rate was linked to the fish tank's water temperature, Ms. Tofte-Dorr explained. If she had raised the water temperature, the fish would have grown more quickly. However, faster growth stresses the fish, requires more food, and leads to overcrowding, she said.
In addition to classroom work, about 18 students volunteered to come in before school or during homeroom or recess to check the water pH and ammonia levels in the fish tank, change the water, and feed the fish, for which they received credit towards community service.
Three of the caretakers - Zoli Clarke, Asher Cottrell, and Jack O'Malley - shared some of their observations. Despite the ideal conditions in the tank, there was a high mortality rate. Asher said the stage where they experienced the most losses was right after the eggs hatched. Zoli agreed, estimating they lost about half of their stock by that point.
Asked what the project taught him, Zoli said he learned a lot about ecosystems. Jack said he thought it was interesting to watch how the fish reacted to their environment as they grew. Asher agreed, adding that even in a tank, the fish exhibited natural instincts, such as the smaller ones hanging back to avoid the more aggressive ones. He predicted the ones that stayed at the top of the tank and were more interested in eating were more likely to be caught by fishermen.
The project did not end with the release of the fish. Students will be sampling the pond, drawing maps, and making observations of the release site as part of their current science unit on ecology. Not only does the fish project tie lessons in ecology together, Ms. Tofte-Dorr said, but it also helps students feel a sense of ownership in protecting the pond by knowing they contributed to the life that is in it.
The DFW issued a permit to Ms. Tofte-Dorr allowing the release of the trout fry into Upper Lagoon Pond on March 3, a prelude to the agency's release of adult brook, brown, and rainbow trout from the Sandwich fish hatchery into several Island ponds on March 21.