SPAWN Monitoring Fish in Lagunitas Creek

Watershed Monitoring & Fish Surveys

Fish Surveys

Join SPAWN as we survey the Coho smolt population in Lagunitas and San Geronimo creeks!

Coho salmon and steelhead trout (Oncorhynchus mykiss) are found in the Lagunitas Creek Watershed, Marin County. Coho are listed as “endangered” in this region (Central California Coast Evolutionary Significant Unit) at both the State and Federal level. Steelhead are listed as “threatened.” SPAWN helps monitor and track these fish populations.

Each spring we lead surveys on the San Geronimo, Arroyo and Larsen Creeks of the young salmon that are starting their migration to the sea. These young salmon are known as smolts. In the winter we lead spawning surveys of the adult fish on 10 tributaries to San Geronimo Creek.

Check out this short time-lapse video of one of our daily fish checks on Lagunitas Creek!

Watershed Monitoring

Lagunitas watershed is currently officially listed as `impaired’ by the Regional Water Quality Control Board for sediment, pathogens, and nutrients. SPAWN surveys creeks and tests water quality in the area through a partnership with the Regional Water Quality Control Board.

SPAWN volunteers collect water samples from creeks in the watershed, which are home to federally ‘threatened’ coho salmon, steelhead trout and countless other species.

Volunteers will be trained in water quality sampling techniques, creek safety and data collection.

Fish Rescue

From April to October each year, SPAWN surveys our local streams and pays close attention to salmon populations, and water levels.  

If a creek or pool is in danger of going dry, SPAWN crews will begin relocation efforts. Crews delay relocation as long as possible in an effort to maximize  the fishes time in their chosen stream habitat. Relocation usually begins in June but can start as early as April depending on creek flows and rainfall.

Over 15,000 juvenile coho and steelhead have been saved from drying pools by SPAWN since this effort began in 1999.

Fish are dip-netted out of pools and placed in an insulated cooler equipped with a battery operated aerator. Approximately every 15-45 minutes, captured fish are transported to a perennial flow section downstream on their natal tributary or to San Geronimo Creek at or downstream of the confluence where they would have passed had they not become stranded. The exact release location is dictated by the availability of nearby pool habitat and issues of access on private property. To assure that pools where fish are relocated to are not overstocked, field crews relocate fish to several pools along stretches and make sure to release fish into pools where connectivity allows both upstream and downstream migration.

Upon capture of fish, individuals are identified and lengths measured and stream conditions recorded. In some cases, measurements are done on a random sample of fish, especially if hundreds were caught at a site. In some cases, to minimize stress, particularly when air temperature reach 32º C or higher, fish will be identified but not measured prior to relocation.

Get involved in fish rescues, watershed monitoring and fish surveys! Learn valuable technical skills while working outdoors. Contact Preston Brown at preston@tirn.net or call 415-663-8590.