Calling all community scientists!
This just in from the California Department of Fish and Wildlife:
The California Department of Fish and Wildlife (CDFW) has created a new method for reporting Rainbow Trout/steelhead observations and for reporting situations where trout populations might require intervention, such as excessive drying or isolation. This comes in the form of two online surveys, the “Trout and About!” observation survey and the “Help a Trout Out!” rescue survey.
The “Trout and About!” observation survey can be used by members of the public to document their trout sightings, interesting behavior witnessed, or even colonization of new streams. This can help CDFW develop a heat map of trout observations across the landscape and a citizen science dataset to better understand how the public interacts with Rainbow Trout/steelhead. While we are most excited about steelhead, we also welcome observations of other anadromous species1 and resident trout.
The “Help a Trout Out!” rescue survey can be used to report situations where Rainbow Trout/steelhead might require intervention and/or relocation due to deteriorating habitat conditions. The information included in the survey can help CDFW assess the urgency of the rescue during the busy summer and fall seasons and respond in a timely manner.
About rainbow trout and steelhead
Rainbow trout and steelhead are members of the same species, Oncorhynchus mykiss. This amazingly versatile fish species is native to coastal rivers and streams on the California Coast, including in San Luis Obispo County. Individuals that live their entire lives in freshwater are known as rainbow trout, or “resident” fish. Individuals that spend their adult lives in the ocean and then return to freshwater to spawn are known as steelhead, or “anadromous” fish. Steelhead typically return to the same stream where they were born in order to spawn, and unlike salmon, they can spawn multiple times throughout their lives.
The genetically distinct population segment that is native to our region is known as the South-Central California Coast (SCCC) Steelhead. The steelhead native to our region are listed as threatened under the Endangered Species Act.
The Salinas River is considered critical habitat for steelhead. Its tributaries, especially those on the western side of the Salinas Valley, have good spawning habitat for steelhead and rainbow trout. Steelhead aren’t generally known to spawn in the Salinas River itself because it is too sandy, and sandy soil doesn’t provide enough airflow for steelhead eggs to get the oxygen they need. However, the Salinas River serves as a migratory corridor for steelhead to reach gravel-rich spawning grounds in the tributaries.
How to tell the difference between rainbow trout and steelhead
Rainbow trout/steelhead typically display spots and a pinkish stripe on the sides of their body. To distinguish between rainbow trout (resident fish) and steelhead (anadromous fish), look for differences in size and coloration. In our area, rainbow trout are typically under 16 inches in length, while steelhead tend to be much larger—often between 24 and 36 inches long. Additionally, steelhead may have a more silvery coloration than resident fish due to their time spent in a marine environment.
Where do rainbow trout/steelhead like to spawn?
Rainbow trout/steelhead spawn in cool, clean freshwater streams in areas with fast-flowing water and a gravel bottom. The female builds a nest (called a redd) by vigorously shaking her tail, using the power of the water’s movement to create a depression in the stream floor that contains the perfect size gravels for her eggs. By ‘sorting’ the gravels in this way, she ensures that the developing eggs will be sheltered while also receiving adequate oxygen.
The above video shows a pair of rainbow trout spawning. The male was observed repeatedly chasing off several other males during the spawning process. The fish in this video are resident rainbow trout, which is evident due to their size (well under 16 inches).
Did you know? Although in the above video the male fish was larger than the female, this is not always the case. Because they are the same species (O. mykiss), rainbow trout and steelhead can reproduce with one another. Huge ocean-run female steelhead can spawn with smaller resident males. Additionally, the offspring of resident fish can decide at any time to become anadromous and go to the ocean!
Rainbow trout/steelhead are such fascinating and incredible fish, and they are facing big challenges to their survival as a species. As community scientists, we can all help with conservation and restoration efforts by submitting observation surveys and rescue surveys to CDFW when we are lucky enough to see these fish in our rivers and creeks.
Learn more and spread the word
See what steelhead look like at different life stages in this video from Coastal Watershed Council:
Here is a flyer that you can share to spread the word about these new surveys:
- “Other anadromous species” — That means you can also submit a survey for Pacific lamprey sightings! ↩︎