Morro Bay and its watershed are fortunate to be a home to a unique species, Oncorhynchus mykiss. Some of these fish spend their entire lives in freshwater creeks and are called rainbow trout. Others—though they are genetically identical—hatch in freshwater creeks, migrate to the ocean to grow to adulthood, and then return to our creeks to reproduce. These fish are called steelhead trout, and they are the anadromous (or saltwater-going) form of the same species. Both varieties of the fish can be referred to generally as trout.
As adults, steelhead and rainbow trout live in different habitats and are different in appearance, despite being genetically identical. The color and patterns on rainbow trout varies slightly depending on habitat, but they can have blue, green or yellow hues with a silvery belly, a pink stripe along their sides and dark spots on their backs. Steelhead are typically larger than rainbow trout and are more silver or brassy in color. For more information on these species, visit the National Wildlife Federation and the NOAA Fisheries websites.
While steelhead were once abundant in our area, they are now federally-listed as a threatened species. These fish require good habitat, clean waters, and creeks free of structures that block their path upstream to spawn and downstream to reach the ocean. Another threat comes in the form of invasive species. Sacramento pikeminnow are known predators of trout and compete with them for food and habitat. The Estuary Program works to maintain water quality and quantity, remove migration barriers, and manage threats to trout, such as this invasive fish.
Sacramento pikeminnow are not native to the Morro Bay watershed, but they are native to parts of California. Pikeminnow prefer streams that have complex habitat such as deep pools and undercut banks that provide shelter. Though considered a slow growing fish, pikeminnow grow rapidly for the first five years of life. They can live for more than 16 years and spawn annually. To learn more about pikeminnow, visit the UC Davis California Fish Website.