The MBSTP hatchery and coho captive brood-stock program are an essential component to the NOAA Coho Recovery Plan. The Southern coho (Central Coast Coho that spawn in creeks and rivers south of San Francisco) still have a chance of recovery because of the MBSTP/NOAA Coho Captive Brood-stock Program. The fish that are produced by hatchery spawning the captive brood may be the last source of the Southern coho genetic family. In extreme drought conditions the spawning run fish cannot enter the creeks and rivers because the mouths are blocked by sandbars. The first substantial rains of the wet season typically cause the creeks and rivers to swell and wash away the blocking sandbars. In drought years this can happen too late in the season to let the coho spawning run in. Also, when it is extremely dry, there is not enough water in the creeks for the fish to swim upstream to the gravel beds where they need to spawn. The hatchery produced and reared fish are the native gene-stock. They can carry the population through bad drought years when wild spawning in creeks and rivers fails.