Limestone and salmon eggs

The eggs came from salmon of Pleasant River origin raised to adult size at Craig Brook National Fish Hatchery in East Orland. Craig Brook staff are currently spawning hundreds of salmon that are a key piece of the salmon restoration program in Maine. The 2,500 eggs the DSF received were a portion of the eggs from five females and five males that were spawned to produce fry for stocking next spring. Within an hour of fertilization the eggs were put into containers and transported to Columbia Falls where they will be reared for the next two years in the Pleasant River Fish Hatchery.
These eggs are being reared as part of an ongoing collaborative research project looking at the effects of acid rain, and low pH on the growth and survival of juvenile Atlantic salmon in the Pleasant River. The DSF has partnered with USGS, University of Maine Orono and Machias, and Maine DEP to carry out this project. The project involves exposing half of the fish to straight river water, with all of its fluctuations in pH and chemistry, and the other half of the fish to water that has been buffered with calcium carbonate (limestone) to maintain the pH between six and seven (a healthy range for salmon). If the salmon raised in straight river water show impaired growth and survival, as compared to buffered fish, it may indicate that current river chemistry is impairing salmon restoration. The project will also look at effects of the blueberry pesticide Velpar and low pH on salmon prey capture ability. If this project demonstrates strong negative impacts from low pH and its resulting changes in chemistry, it may justify the use of calcium carbonate to buffer large portions of the river to aid in the restoration of the river and its salmon population.
For more information contact the DSF at , 483-4336 or e-mail

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