SIMoN
  Sanctuary Integrated Monitoring Network
Monitoring Project

Characterization of Salinas Watershed Stream Habitat & Fish Species Composition

Principal Investigator(s)

  • Fred Watson
    California State University, Monterey Bay
Start Date: May 01, 2001
End Date: November 01, 2002

The primary objective of this project was to examine fish species distribution and to quantitatively evaluate physical habitat quality throughout the Salinas Watershed. This objective was accomplished by completing the following tasks: 1) literature review and summary of life cycle characteristics and ecology of Salinas Watershed fish species; 2) review of previous work to determine past and present abundance and distribution of fish; and 3) investigation of habitat quality accomplished by a 3-phased assessment: a) reconnaissance survey, b) detailed habitat assessment, and c) population assessment.

Summary to Date

The objective of this study was to examine the fish species distribution and evaluate habitat quality in the Salinas Watershed. In the summer and fall of both 2001 and 2002, field reconnaissance and habitat/population assessments were performed in several streams of the Salinas Watershed. Both 2001 and 2002 were considered dry water years with minimal summer/fall flow, which presented an opportunity to assess the aquatic organisms in their most limiting environmental condition.

Stream habitat in the mountainous headwater reaches is in good to excellent condition. Most of these reaches have little human development and many are protected within National Forest, parks and wilderness lands. Rainbow trout and speckled dace were observed in abundance in these upstream reaches. Foothill stream reaches had warmer water temperatures, less riparian vegetation cover and an increase in the presence of warm water fish species. Sacramento pikeminnow, Sacramento sucker and Monterey roach were the most abundant species along with some rainbow trout and speckled dace. Monterey roach were very abundant in the southern and more intermittent streams where only pools and shallow riffles existed (i.e. Paso Robles and Atascadero Creeks).

In the lowland reaches, perennial water was scarce in the western tributaries and absent in those to the east. Water was present in the Salinas River due to water releases from the bottom of Nacimiento Reservoir. The only eastern tributary with accessible perennial water was Sandy Creek near the Pinnacles National Monument. Sandy Creek had perennial water in one relatively short reach near the Pinnacles. The water was shallow and cool with an abundant riparian canopy. Speckled dace and threespine stickleback were abundant in the upstream reach, which had more pool habitats for them to inhabit.

Sediment accumulations were low at all sites, however foothill stream reaches had slightly higher accumulations. Riffle habitats had the lowest average accumulation whereas pool habitats were often the highest. Sandy Creek and the Salinas River were probably always sandy bottom streams with no immediate hard layer beneath. In general, most habitat alterations have occurred in the lowland stream reaches. Dams and reservoirs, channel modifications and pollution occur along the valley floor. Non-native fish species in the Salinas Watershed are primarily concentrated in the three reservoirs, but some escape during water releases.

Monitoring Trends

  • Stream habitat in the mountainous headwater reaches is in good to excellent condition. Most of these reaches have little human development and many are protected within National Forest, parks and wilderness lands. Rainbow trout and speckled dace were observed in abundance in these upstream reaches.
  • Foothill stream reaches had warmer water temperatures, less riparian vegetation cover and an increase in the presence of warm water fish species. Sacramento pikeminnow, Sacramento sucker and Monterey roach were the most abundant species along with some rainbow trout and speckled dace. Monterey roach were very abundant in the southern and more intermittent streams where only pools and shallow riffles existed (i.e. Paso Robles and Atascadero Creeks).
  • In the lowland reaches, perennial water was scarce in the western tributaries and absent in those to the east. Speckled dace and threespine stickleback were abundant in the upstream reach, which had more pool habitats for them to inhabit.
  • In general, most habitat alterations have occurred in the lowland stream reaches. Dams and reservoirs, channel modifications and pollution occur along the valley floor. Non-native fish species in the Salinas Watershed are primarily concentrated in the three reservoirs, but some escape during water releases.

Discussion

The aquatic fauna of the Salinas Watershed needs to be studied in greater detail. Sacramento perch, tule perch and tidewater goby could all possibly be reintroduced into the Salinas Watershed if their habitat requirements are improved, maintained and monitored.

Study Parameters

  • Sedimentation
  • Erosion
  • Habitat association
  • Dissolved oxygen
  • Stream Temperature
  • Growth
  • Distribution
  • Non-indigenous species
  • Diversity
  • Disturbance
  • Predation
  • Carrying capacity
  • Migration/movement patterns
  • Abundance
  • Conductivity
  • Macro-invertebrates

Figures and Images

Map of streams surveyed during study.

Salinas River, looking downstream, near San Ardo. (Photo by Joel Casagrande, 10/31/02)

Young of year rainbow trout in the Nacimiento river. (Photo: Joel Casagrande 9/13/02)