The Salmonids

The Basics

The total stream length accessible to anadromous fishes in the Scotts Creek watershed is 14.1 miles (Snider and others 1995). The in-stream habitat conditions are favorable for salmonid spawning and rearing although the Scotts Creek watershed presents some specific natural challenges particularly for coho (see Assessment Executive Summary). Both coho (Oncorhynchus kisutch) and steelhead (Oncorhynchus mykiss) spawn in the Scotts Creek system. Fisheries biologist Dr. Jerry Smith of San Jose State University has stated that based upon his 15 years of experience counting juvenile steelhead in Scotts Creek “the steelhead population appears to be stable and of appropriate size for this creek system.”

Spawning runs typically involve about 400 steelhead with a potential varience of up to about 200 fish from year to year. Coho runs are of a similar size but potentially of greater numbers in the one strong year-class remaining. Of the three year-classes of coho one is strong, one is weak, and one nearly extinct. The above numbers are very preliminary because no accurate means of counting was available prior to the 2003-2004 season. Measured numbers do match previous estimates.

Scotts Creek is at the southernmost edge of the current range of coho salmon. San Vicente Creek, several miles to the south of Scotts Creek, has recently been discovered to have coho as well. This small population is likely to be the result of a straying event where Scotts Creek fish were unable to enter their natal creek due to late onset of the rains (the creek mouth was still blocked by a sand berm in February). In an unusual event, San Vicente Creek opened earlier, and part of the coho run diverted into that system. Straying of coho and steelhead from one basin to another is a relatively common phenomenon in this region. Genetic work by Dr. Carlos Garza (National Marine Fisheries) confirms that a high rate of straying between Scotts Creek and Waddell Creek occurs on a regular basis.

The Monterey Bay Salmon and Trout Project

In 1976, the Monterey Bay Salmon and Trout Project (http://www.mbstp.org) was created as a community non-profit corporation, a joint venture of the Department of Fish and Game, university researchers, and concerned citizens, to provide a remedy to declining salmonid populations in the Monterey Bay region. Fish culture was decided upon to maintain local genetic material until problems could be identified, defined and resolved. In May of 1982, an agreement was consummated with Big Creek Lumber Company to maintain the Kingfisher Flat area on Big Creek, in the Scotts Creek watershed, for use as a cold-water fish hatching and rearing facility. MBSTP constructed the new hatchery and rearing facility on the remnants of CDFG’s previously-run facility.

Dave Streig (M.S. Marine Biology, 1978) was working for International Shellfish in 1982 when the MBSTP Kingfisher Flat facility manager position was created. He was hired for the position and has remained the sole full-time employee of the MBSTP. Streig’s knowledge of biology and his savvy instinct have resulted in responsible supplementation of fish populations with arguably minimal (if any) simplification of the gene pool. A complicated breeding matrix is used to ensure that the highest level of genetic diversity possible results. Great care and strong measures are taken to ensure that the hatchery-produced fish are disease free.

Bacterial kidney disease (BKD) is ubiquitous in the wild population. BKD has been traced to a production hatchery in Oregon where a management problem gave rise to the disease. Many highly experienced land managers and fisheries biologists attribute the continuing existence of coho salmon south of San Francisco to the MBSTP and to Streig’s efforts in particular.

The MBSTP has been able to re-start extinct year-classes of coho from local gene-stock several times. In wild populations coho return to spawn after two years at sea. Sometimes a precocious male, called a “Jack” will return to spawn after only one year at sea. In this way genes can move from one year-class to another. Precocious females that return a year early are unknown in the wild population. Females from MBSTP’s captive spawning and rearing process are usually exceptionally large smolt when they are released. This size advantage helps accelerate their development to the point that they return a year early as “Jills”. The offspring of these Jills can be the start of a previously-extinct year class.

The Science

The close proximity of the National Marine Fisheries Service (NMFS) facility at Terrace Point in Santa Cruz and riparian area access permission provided to NMFS by Big Creek Lumber and Cal Poly's Swanton Pacific Ranch has made the watershed much more available to the NMFS salmon ecology team. Headed by Dr. Bruce MacFarlane the participating members of the team include staff fishery biologists Sean Hayes, Ellen Freund, Erick Sturm, Morgan Bond, Chad Hanson, Arnold Ammann, and Sue Sogard. This group is finding that the Scotts Creek system is particularly well suited to the study of steelhead and coho. Universal acceptance and encouragement by the Scotts Creek Watershed Council and land-owners has helped to keep the research moving ahead smoothly.

Sean Hayes has been focusing on behavioral issues relating primarily to steelhead. He has also been collecting data on coho and habitat quality. His work has shown that the captive spawning, rearing, and release techniques employed by the MBSTP do not have ecological effects on the success of fish that spawn in the creek. Specifically, the juvenile hatchery fish that are released do not compete with fish hatched in the creek. This is because the hatchery fish are well into smoltification when they are released. During this hormonal change, which occurs in preparation for the transition to salt water, the “smolts” do not feed. The hatchery fish usually move into the ocean within a week or two of being released to the creek. It appears that the hatchery fish all go to sea as a group, whereas some of the creek’s “wild” fish remain in the creek for a second year before going to sea. Some stay in the creek and never go to sea. This is a natural normal behavior for steelhead (freshwater steelhead are rainbow trout). The hatchery smolts are larger (from consistent high quality nutrition) and adapted to schooling behavior (presumably from living in a large group in the hatchery raceways). MBSTP hatchery fish and “wild” fish do interbreed in the creek. Work evaluating the genetic effects of this interbreeding is still underway. The habitat quality parameters observed by Dr. Hayes indicate that the creek provides good quality habitat for salmonids.

Dr. Carlos Garza is a geneticist who leads the molecular ecology group at the NMFS lab in Santa Cruz. Their work has shown that coho spawned and reared at MBSTP are genetically very similar to the "wild" fish in Scott Creek. They are also genetically very similar to those found in nearby Waddell and San Vicente Creeks. Coho salmon from Gazos Creek are a little less similar. The next most similar (in genetic distance) salmon populations are those in Lagunitas Creek (which empties into the southern tip of Tomales Bay, Marin County) and streams on the Mendocino County coast, including the Noyo, Big and Big Salmon Rivers. In 2002, Garza began doing fast-turn-around DNA fingerprinting to help determine the breeding matrix for the MBSTP. Garza's gene typing enables the captive spawning program to maintain higher diversity and avoid inbreeding by not mating siblings and other close relatives together.

Jerry Smith (Ph. D.) of San Jose State University has conducted juvenile steelhead and coho counts in late summer every year starting in 1988. The survey is by electro-fishing and distribution and abundance data is collected from Gazos, Waddell, and Scotts Creeks. Dr. Smith has also surveyed and evaluated habitat parameters in these creeks. Dr. Smith has consistently observed favorable water quality parameters for salmonids. Large woody debris (LWD) surveys were conducted by Dr. Smith on Gazos, Waddell, and Scotts Creeks. Also observed and recorded by Dr. Smith was that the recruitment of LWD is sporadic and that the material is reworked into different configurations and locations during high flows nearly every season. The higher the flow the more the LWD moves. This changes the locations of pools, riffles, and spawning gravels. Dr. Smith has also made consistent observation of the large quantity of sediment that moves through these creek systems. Particularly on Scotts Creek where a predominance of lightweight mudstone occurs. Observations by Dr. Smith show clearly that late season high flow events (caused by high rainfall intensity) have a strong negative effect on salmonid reproductive success. Particularly for coho. This is because redds (salmon egg nests) get scoured out, transported, and dispersed downstream along with the gravel. This results in the destruction of the eggs. Coho spawning is completed by mid February but steelhead spawning continues into April. Later spawning steelhead eggs are less likely to be washed out by high flows. The heaviest rains typically come in December, January, and February.

The California Department of Fish and Game (DFG) http://www.dfg.ca.gov ) has conducted a variety of surveys and studies on the Scotts Creek system over the years. These studies have demonstrated that the system is in a naturally functioning condition that provides good quality habitat for salmonids. There was one notable exception (see Water Use). The DFG has, through its administration of SB 271 funding, supported and provided guidance to the SCWC through the first six years of its existence.

Issues

The Coho

Local populations of Coho salmon are listed as "endangered" under the endangered species act (ESA) (both state and federal). The ESA's provide legal tools intended to aid in slowing the loss of the beautiful diversity of life to extinction. As with nearly all legal tools, it does not always work well. Sometimes these laws conflict with their goals.

Many salmon and steelhead populations have been listed as “Threatened” or “Endangered” under state and federal law. The decline of the salmon and how best to reverse the trend is an extremely complex issue. Some information on the history of this tragedy can be found in the books Salmon Without Rivers by Lichatowich (2001, Island Press) and A Common Fate, by Cone (1995, Henry Holt and Co., N.Y.).

It is not entirely clear that the coho are “native” to streams south of San Francisco. Existing historical evidence has been called into question on the basis of a number of inconsistencies and questionable reports. It has been determined that much hatchery fish planting has taken place over many years, with fish from numerous sources. Some archeological evidence indicates that coho bones are not found in local Native American “kitchen middens,” the presumption being that if the fish were available, the people would have eaten them- as they did eat steelhead (whose bones are found in local middens). For some compelling information indicating that coho are not native to streams south of San Francisco connect to http://www.ccfassociation.org.

The ESA was intended to apply to natural native populations. President George W. Bush, early in the summer of 2004, further complicated an already complex and confusing situation by declaring that all hatchery-produced fish should be counted in the determination of a salmon population’s status with respect to the ESA (this was in direct contradiction to the advice of a panel of scientists commissioned to advise President Bush on the subject).

The native or non-native status of the local coho needs to be resolved as best as is possible. Protection and support of introduced species that are outside their natural range can have undesirable consequences in unbalancing local ecosystems and cause socio-political backlash that reflects poorly on the ESA.

The coho of Scotts Creek are being well supported. The MBSTP supports the population by a supplementation process that is condoned by the scientists most knowledgeable about that process in NMFS and DFG. The financial support for MBSTP comes from the private sector (primarily small donors from the local area). Agency financial support is very limited as a result of serious questions that have been raised about the role of hatcheries in general, which has led to a failure to support the unique mission, technique, and role of the MBSTP hatchery.

It appears that the most probable future for coho in our watershed will not be determined by the ESA, but by the degree of local political will to assist the fish population in the face of several potential outcomes: 1) coho become more-robustly self-supporting (this would likely require a climate change on the central coast of California); 2) it becomes clear that the coho are not native here, are damaging to the local ecology and should be intentionally extirpated; 3) the decision is made to see if they can make it on their own without supplementation or concerted year-class replacement efforts (recent history indicates that ceasing supplementation would very likely result in extirpation); or finally 4) continue hatchery support in maintenance of a “wild” population that is best adapted to local conditions.

The Water

There are no longer any heavy demands on surface waters in the watershed. One particularly egregious agricultural overuse problem that occurred in the early 90s was stopped by DFG. Currently all agricultural water use (with one exception) is from deep wells. A draw-down test demonstrated that maximal pumping of these wells does not affect creek flow volume. A small area of pasture is irrigated with creek water. The pasture is maintained for cattle (replacement heifers) by pumping water from the lowermost reach of a tributary to Scotts Creek. Pump rates are limited to between 35 and 50 gallons per minute (0.11 CFS maximum). The diversion is operated for short periods of time with sensitivity to the creek habitat. If visible drawdown of the creek occurs, the diversion rate is slowed. During low flows the irrigation frequency is reduced. The reach from which the water is drawn is a short, steep, fast-moving riffle with little cover for rearing salmonids. Temporary minor reductions in flow volume may not have an appreciable effect on aquatic life in this location.

The Lockheed Martin facility in the upper watershed has a registered right to draw up to 10,000 gallons a day from its storage reservoir on Mill Creek. All other surface water use is for rural domestic purposes. A small number of homes operate diversions (exercising their riparian right). These diversions are usually supplementary to an alternate source such as a spring or well and suction hoses are all properly screened to protect aquatic life. Well water is generally not favored because high iron sulfide content makes it unpleasant and in some cases unpalatable. Special treatment of this well water helps but does not totally alleviate the problem. Nevertheless, most homes in the watershed do use well water. It is important to note that properly functioning septic systems return the majority (90%) of domestically used water to the natural ground water system in a sanitary way. It does not appear that domestic diversions (either individually or cumulatively) appreciably affect creek flow volumes or water quality.

An attempt should be made to achieve a better understanding of the specific relationship between creek flow volumes and the level of the water table. The study should be designed to answer the questions of when, where, and to what degree are creeks in the system likely to become influent versus effluent (losing water to the zone of saturation as opposed to gaining water from the zone of saturation). Information on influency should be correlated to rainfall history, flow volume history, and geology of the alluvial aquifer as best as is possible. A proper study of this type would need to be fairly long-term in order to get a clear understanding of the relationships.