The salmon are released as inch long fry, usually in mid to late May. This date can be moved up or back depending on the particular needs of the school or facilitator. Before release can occur, an appropriate site must be selected. A riffle in a cold water stream provides the best habitat. Riffles have a moderate current and gravel bottom. Gravel is extremely important for providing the salmon with safe refuge from predators. Other factors to think about when selecting a release site:
Matching Incubator and Stream Water Temperatures: It is important that the stream and incubator water temperatures be close in order to avoid shocking the fish. A severe and sudden temperature change can kill fish. As a general rule, it is better to transfer fish from warmer to colder water, NOT the other way around. The salmon fry can tolerate a maximum sudden decrease in temperature of about 8 degrees Fahrenheit. They can tolerate a sudden increase in temperature of only about 2-3 degrees. Needless to say, it is best to track stream temperature before releasing the fish. Because of a school's location, this may not be possible in some cases. That is why an incubator temperature of about 55 degrees is recommended at this time of year. That temperature will be "in the ballpark" of the stream's actual temprature in May - or within an acceptable margin that will allow for equilibrating the water temperature at the stream's edge (this is done by slowly adding small amounts of stream water to the fry bucket).
Moving Salmon to the River: Stocking day is the culminating program activity for the Adopt-A-Salmon/Trout Family program. The day begins with students transferring their salmon/trout family from the incubator to a five gallon plastic bucket using a dip net. It is much easier to net all the fish if the gravel has been removed (carefully!) ahead of time. A bait bucket aerator (a $6 item available at most angling supply centers) will keep the water aerated. If the trip is particularly lengthy (more than an hour) use of an insulated container is recommended. Ice (made from dechlorinated water) can be added to the transport container to maintain temperatue if the trip is extremely long.
Having arrived at the stream, the facilitator or teacher generally leads a brief discussion abut salmon habitat requirements and why the particular stocking site was chosen. Next each student is given a cup of fish and directed to approach the stream bank. If a school has a particularly large number of students, the hatchery may have to supplement the number of salmon brought from the school. It is very important that each student be given some fish. Upon the direction of the teacher or facilitator, the students gently pour their fish into the stream.
Students should watch the behavior of the fish. Do the fry stay up high in the current or immediately hide behind some gravel? Do the fish turn color? What other interesting things do the students notice? What other creatures are apparent in the stream? Other fish? Crayfish? Aquatic insects? Where do they fit in the food web with respect to the salmon/trout? A simple survey of the stream's forage base using the "kick seining" method can be an interesting extended activity while at the stream.