Smolt Outmigration from Tributaries in the San Geronimo Valley
For the period of monitoring by both SPAWN and MMWD from 2006-2009 the San Geronimo sub-watershed provided suitable rearing habitat to support an average of 40% of the Lagunitas Watershed's estimated coho smolt population, validating the importance of continued conservation and monitoring efforts in this area. Since the San Geronimo sub-watershed is roughly 10% of the total area of the entire Lagunitas watershed, it is very apparent the coho love the San Geronimo Valley!
Each spring (Mar-Jun), SPAWN Biologists and volunteers head out to San Geronimo Creek and its tributaries every morning (7 days a week) and monitor the movement of coho smolts as they mature and head toward Tomales Bay and then the Pacific Ocean. When a juvenile coho has survived through the winter in the freshwater stream where it was born, it begins a transformation to prepare itself for life in the salty ocean. When the fry reaches about 100mm, its par marks faded, and silver scales appear, it is known as a smolt.
SPAWN, in partnership with CA DFG, the Marin RCD and Stillwater Sciences, undertook the 1st outmigration smolt study on San Geronimo Creek during the Spring of 2006.
In 2007, SPAWN expanded its study to monitor coho movement in Arroyo and Larsen Creek, two important spawner tributaries.
In 2008, SPAWN continued its monitoring of outmigrating salmonid with even more volunteer support.
The 2009 season was difficult due to a lack of funding, but SPAWN persisted and completed its fourth year of outmigration monitoring in 3 tributaries, with lots of volunteer support!
Complete reports detailing these activities are available to download below.
The 2010 season began March 16th! Due to the lack of fish and funding for the monitoring, SPAWN is not monitoring Arroyo and Larsen Creeks this year. However, we have teamed up with MMWD, DFG, and NPS this year to share monitoring duties at the SPAWN's and MMWD's monitoring stations. We also have a great many dedicated volunteers who enjoy getting their feet wet in the creeks! Updates on fish numbers to come!
If you like to write technical papers and analyze fish data, please contact us to assist in the preparation of our next report!