Monterey Bay Salmon & Trout Project

My name is Ian Mallett; I am a senior at San Lorenzo Valley High School.  For several years, I have been working with assistance from Terry Umstead to analyze the data collected at the rubber dam. 

My statistical-analysis work shows that fish are seen upstream soon after rains occur, and the number of fish can be predicted roughly by the amount of rainfall.  In addition, I have constructed a simulation-analysis that gives a rough prediction of fish migrations at every phase of their life-cycle.  For my analyses, I have won first place at the Santa Cruz County Science Fair two consecutive years.  Attached is a research poster on the topic I presented at the Monterey Bay sanctuary Symposium, which explains my project in more depth. 

During my analysis, a large portion of the data collected at the rubber dam was entered into a spreadsheet. It can be viewed here:

The Poster for the project is here.

As the 2009-2010 steelhead season progressed on the San Lorenzo River, anecdotal reports came in from fishermen indicating that most of the fish being caught were of hatchery origin, and that there were very few wild fish in the river. Subsequently, when a fish trap was put in place on the fish ladder at the Felton Dam, we found a ratio of better than 10 hatchery fish [from wild parents] to each in-stream produced wild fish. In other words, this year there were more than ten times as many adult spawners in the San Lorenzo River than there would have been without hatchery fish.

Although not a proven fact, it appears that very low summer flows over the past several years have severely limited the in-stream rearing habitat for wild juveniles, thereby contributing to the low number of returning wild adults. It is significant, then, that this year’s returning hatchery adults will provide much more in-stream spawning than that from the wild adults alone. There will be a greatly increased number of juveniles [from our hatchery spawners] available to occupy the increased rearing habitat in the good water flows we’ll have in the San Lorenzo River this year. The presence of these hatchery steelhead in the San Lorenzo River means that spawning numbers will not be the limiting factor for in-stream production. This will greatly speed up the population recovery from the low water years. Our hatchery spawners will have raised juvenile populations to significantly higher levels this first good water year, than if only wild fish were spawning.

On Tuesday March 30, a crew of volunteers planted approximately 5,250 San Lorenzo River [SLR] steelhead smolts in Paradise Park. These fish made up that portion of the year 2009 SLR production fish that were reared in the hatchery for a full year. The rest had been released earlier in the winter due to concerns over potential floods and mudslides at the hatchery from watershed damage caused by the Lockheed Fire in August.

Here the crew prepares to load smolts from Pool #4 into the F-450 planting truck.

The winter of 2008-2009 was another rough season for the Monterey Bay Salmon & Trout Project. Many of our programs are operating at a reduced level and some not at all. Unlike many organizations, our problems do not stem from a lack of funding or participation by our volunteers. Our hatchery is dealing first hand with the collapse of the ocean’s food chain in 2005 and 2006. It hit all of California and Oregon, with the worst effects ranging from the Klamath River, south to the Monterey Bay. We saw the complete loss of our 2005 Coho Salmon brood stock of 30,000 fish released. This was one of our largest releases of Coho Salmon. We know that these fish made it to the ocean; therefore the only explanation is the collapse of the food chain in our area when they went out to sea in March 2005. A similar event occurred in the ocean in 2006. Then, again this winter, with no rain until February 2009, we saw only two Coho Salmon return to Scott Creek and a greatly reduced run of Steelhead. We are working hand in hand with Fish & Game and the National Marine Fisheries Service to operate a captive brood stock program, in an attempt to save the remaining genetics of this run of Coho Salmon. We are hoping for a miracle and a lot of rain next winter.