Something to think about as we watch the Coho we released at the Great Salmon Send-Off make their way to the sea.

A recent study of Coho salmon in three small Olympic Peninsula rivers with estuaries show a complex life history that includes juveniles that migrate to sea early in their first year and others that stay in the stream for up to a year before they migrate into the sea where they reside for six or eighteen months.

In addition, the study found that some of the juveniles migrate among the three rivers and in and out of salt water before making their final migration to the sea.

This migration diversity is not uncommon. In fact, studies in 2011-2013 have found up to five or more juvenile coho salmon life histories in one river basin, allowing the species to spread the risk of mortality.