Douglas Parkinson and I performed a fishery reconnaissance of lower Pescadero Creek, Tar Creek, Tick Creek, Sargent Creek, and Carnaderos Creek on Mission Del Rio Ranch, March 4-5, 1992.

The lower reaches of Uvas Creek (also known as Carnaderos Creek) was walked to the confluence with the Pajaro River to evaluate the confluence of the two streams as holding habitat for returning adult steelhead.  The lower end of Tar Creek was also examined.  Tick Creek and Tar Creek were inspected at various locations by windshield survey.

The lower reaches of Pescadero Creek and Tar Creek, tributaries to the Pajaro River on the Sargent Ranch near Gilroy were surveyed as potential habitat for Steelhead rainbow trout.  These creeks were electro fished in a range of habitats.  A Smith-Root Type 15-A backpack electro fisher with a single anode probe and a rat-tail cathode were used.  A single netter assisted the backpack operator.

Pescadero Creek was electro fished on March 4, 1992 in the afternoon from about 1400 hours to about 1630 hours.

Sample Site 1 (See Pescadero map)

Pool, run and riffle habitats in a 250 ft section were electro fished.  Sampling effort was specifically directed at stream habitats with good depth and cover elements that would be likely refuges for juvenile steelhead.

Riffle sculpins and a lone male three spines stickleback in breeding colors were the only species captured in this site. The presence of riffle sculpins indicates excellent water quality and adequate water temperatures for steelhead.

The riparian vegetation cover is excellent with both good canopy closure from the mature riparian forest and overhead cover from the lower shrub level.

The bank side root masses from the mature trees also provide an excellent in stream cover and assist in creating the necessary scour for greater stream depths in pools.  One plunge pool appeared to be greater than 6 ft deep with excellent under back cover.

There were limited spawn able gravels present and there appeared to have been some recent attempts are redd digging by adults.  However, the recent storm event from the previous ten days may have scoured the gravels to give the appearance of a recently prepared redd.

The overall quality as steelhead rearing habitat in the short section of stream that was surveyed was good to excellent with spawning habitat only fair.

Sample Site 2

Riffle, pool and run habitats were electro fished in about 200 ft of stream.  A single juvenile steelhead/rainbow trout, silvery and about 180 mm FL was captured at this site along with two Sacramento suckers, some riffle sculpins and several California roaches.  It is not known if the juvenile trout was a smolt migrating downstream or a resident trout, however, its silvery color suggests that it is a steelhead.  The presence of the other species indicates that this stream can support resident fish.

The riparian vegetative canopy here was not as dense as the first site.

One recently constructed salmonid redd was identified at this site.  The clean bright gravels were arranged in a mound that was a typical of the surrounding stream channel contours.

Some evidence of sediment accumulation in the form of the silty fines was noted in the channel.  We were not able to determine if the sediment was generated by natural causes or by some of land use.

Tar Creek (also known as La Brea Creek)

The Tar Creek sample area began downstream of the natural tar seeps at the oil wells and included three sample sites (figure 2).  The stream was qualitatively electro fished on March 5, 1992.  In spite of rain showers that occurred throughout the day the stream remained clear enough to capture stunned fish.  No steelhead rainbow trout were captured in the sample sites, nor were there any evidence of steelhead redds.

The physical stream habitat appeared to be good to excellent for steelhead rainbow trout from above US Highway 101 to sample site one.  The riparian forest canopy closure is excellent for providing shade, sufficient depth and cover exists in the pools.  There are pools sufficiently deep to provide cover for adult steelhead.

Even though no steelhead rainbow trout were captured nor evidence of redds observed, steelhead probably still use this system.  Mr. George Scovel, the former owner and still current resident, related that steelhead used Tar Creek in the past.  He mentioned that fish would not be seen during previous drought periods, but would appear during wetter rainfall years.

Sample Site 1

About 1450 ft of stream was spot electro fished at this site.  Likely appearing fish habitat was selectively sampled, especially habitats with good cover.  Only three green sunfish were captured.

 No evidence of spawning steelheads were observed at this site, even though there was some suitable spawning locations observed.

Sample Site 2

Approximately 600 ft of stream habitat was selectively and qualitatively electro fished.  Three spines stickleback were the only species captured.  Globules of oil were accumulating on the surface in backwater areas and on debris in contact with the water surface.  No evidence of spawning was observed.

Sample Site 3

Approximately 200 ft of stream was shocked at the vicinity of US Highway 101.  Three spines sticklebacks were the only species collected.

Tick Creek

Tick Creek was surveyed below US Highway 101.  In spite of the rain showers, the creek was flowing at only ½ cfs.  The stream was channelized, shallow and nearly totally covered with aquatic vegetation.  The channel represented very poor potential as steelhead habitat.  The reach of Tick Creek about US Highway 101 flowed through pastureland without any significant riparian vegetation along the channel.

Sargent Creek

Sargent Creek was not surveyed due to of lack of access on account of the rain.  However, no residents interviewed know of any occurrence of steelhead.  The drainage area appears to be too small to support a consistently perennial stream.

Pajaro/Uvas Confluence

A large pool on the Pajaro River upstream of the confluence of the Pajaro River and Uvas Creek (also known as Carnaderos Creek) was examined to determine if it had been isolated by a recent channel realignment of Uvas Creek.  The large pool was reported to have been a significant holding and staging area for adult steelhead to wait for sufficient flows in the tributaries before ascending them to spawn.  Riparian vegetation along the alleged old Uvas Creek channel leading to the pool on the Pajaro River suggests that his existed in the recent past.  However, the mature riparian vegetation suggests that this has not occurred for some time.  The current large pool on the Pajaro River upstream of Uvas Creek appears to be a former beaver dam.  Considering that most of the flow coming down Uvas Creek and the lack of good water quality in the Pajaro River, adult steelhead probably remains in the Uvas Pajaro confluence rather than using this old pool.

Planting of Steelhead Smolts

The California Department of Fish and Fame planted 200 steelhead juveniles in Tar Creek and 600 in Pescadero Creek at the request of Mr. Herman Garcia.  These fishes are from San Lorenzo River stock and were 10”-12” at the time of release.  Because of their size, it is expected that they will remain in these creeks a very short time before moving downstream.

It is not known whether these fish will imprint to these waters given their size.  However, their size should improve their survivorship.  Assuming a 5% return (because of their size and improved survivorship) Tar Creek should receive 2 adults and Pescardero Creek 6 adults.  This is the expected range of the response to the plant.  Central California coast steelhead tends to stray i.e., they will ascend streams that are not their natal streams.  Given these factors, the biological effects of the plant are undetermined.

Protecting Base Flows

The base flows of Pescadero and Tar Creeks must be protected.  They are small for those used by steelhead, but the presence of perennial flow enhances their values as rearing areas for steelhead.  The presence of other species such as riffle sculpins and Sacramento suckers indicate excellent water quality needed by steelhead and sufficient water to support even resident species.  At the time of the surveys, Pescadero Creek was flowing at about 3 cfs and Tar Creek was flowing around 2 cfs.  Mr. Herman Garcia stated that these flows were what they were flowing during August 1991, impressive flows during the fifth year of a drought.

Development of land necessarily includes increase in impervious surfaces such as roads, driveways, roofs and the like.  These deny surface area for precipitation to soak into the ground to be released later as flow in streams. Instead, runoff occurs earlier and this flow is lost to the stream, lowering based flows.  Eventually perennial stream become intermittent streams decreasing their value to steelhead and becoming useless to resident species.  Accordingly, we strongly recommend mitigation for any impervious surfaces stemming from the project.

Original printout: Aquatic Systems Research Paper