2.9

NC steelhead are larger, on average, than steelhead from other watersheds in California. in general, coastal steelhead in smaller, slower coastal rivers are deeper-bodied, longer, and more robust than steelhead from larger inland rivers.

Reliable estimates of NC winter steelhead numbers are lacking because high, turbid flows during migration and spawning periods make safe, reliable sampling impractical. Historically, it is likely that about 200,000 adults returned to spawn in NC steelhead watersheds annually. Optimistically, annual adult returns today are likely less than 20,000 fish.

NC winter steelhead generally enter estuaries and rivers between September and March, with spawning peaking between December and early April. These steelhead are sexually mature when they arrive at spawning areas, usually after spending two years in freshwater and one year growing at sea. in relatively small coastal watersheds in Mendocino County, many steelhead enjoy a high likelihood of repeat spawning potential due to their relatively short migrations. Most NC steelhead that live to spawn many times are females, and they may account for a significant proportion of returning adults in a given year, depending on the stream. Females can lay between 200 and 12,000 eggs, depending on their size and condition, before migrating back to the ocean by May. Newly emerged steelhead school together and seek shallow waters with gentle currents to grow, while older juveniles maintain territories in faster water and in pool habitats. Juveniles smolt in early spring and migrate to estuaries or the ocean between March and June. Some juvenile steelhead rely on estuaries for rich feeding and growth opportunities, increasing their chances of survival at sea.

The NC steelhead populations show some genetic influence from KMP steelhead. Within the Eel River watershed, there are significant genetic differences between resident Rainbow trout upstream of natural barriers in headwater tributaries and steelhead downstream.