Abundance Trends

The Oregon Department of Fish and Wildlife estimates that in years of favorable ocean conditions during the late 1800s and early 1900s, as many as one to two million coho returned to spawn in Oregon’s coastal rivers and streams (Stout et al. 2012). These runs declined steadily through the mid and late 1900s, dropping to all-time lows in the 1970s and again in the 1990s. Today, many Oregon Coast coho populations have improved, but runs continue to fluctuate with variable ocean conditions.

National Marine Fisheries Service
Caption: Comparison of historical (1892–1956) and recent (1958–2015) estimates of Oregon Coast ESU spawner abundance and pre-harvest recruits.  Horizontal lines are the geometric mean recruits for 1892–1940 and 1960–2009. Dark line is one interpretation of the long-term trend. (NMFS 2016. Analysis based on data from Cleaver 1951, Mullen 1981a, and Mullen 1981b; recent data from Wainwright et al. 2008 and ODFW 2016.)