Neither Rain, Nor Drought, Nor Fire, Nor Inbreeding Depression Shall Keep Us from Recovering Coho Salmon (Oncorhynchus kisutch) in California

The southernmost population of Coho salmon (Oncorhynchus kisutch) in North America are found in the Santa Cruz Mountains where they are critically endangered. By the late 1990’s, stocks were depleted to one strong year class in one watershed- Scott Creek, and on the verge of extirpation.  With hopes pinned to this one river, NMFS scientists formed partnerships with other agencies and NGO’s, creating a captive broodstock program in 2001.  There were uphill challenges for 10yrs.  Coho husbandry was tough but rebuilding of vacant year classes began by 2006. Then poor ocean conditions decimated returns for 3 years, exacerbated by redd-scouring floods.  Genetic diversity declined through 2009, and then fire burned 40% of Scott Creek almost destroying the hatchery where one entire year-class resided.  A series of years followed with just a few ‘lonesome Larry’s’.  In 2010, critical husbandry changes were made to diet, tank design and egg incubation. With just 1-2 family groups remaining in 2 year-classes, we introduced new gametes from outside stocks.  Results were a 10-70x increase in production over the next 3 years.  This year, with record drought conditions, hundreds of coho salmon returned to the Santa Cruz Mountains, exceeding all returns since 2005.