Date

2006

Document Type

Capstone Project

Degree Name

Bachelor of Science (B.S.)

Department

Science & Environmental Policy

Abstract

The Carmel River Lagoon (CRL), along the Central California coast, is thought to provide a nursery ground for juvenile Steelhead trout (Oncorhynchus mykiss), a federally listed species under the Endangered Species Act. Every year during the summer months the Carmel River feeding this lagoon dries up due to the high demand for water by local residents. It is thought that suitable steelhead nursery grounds become limited in the absence of this fresh water inflow and by the increased salinity from winter swells into the lagoon. The purpose of this report was to monitor the water quality for suitable Steelhead trout habitat during the time period of minimal fresh water inflow in the CRL. This monitoring consisted of weekly data collection starting from July 9th 2005 and continuing to January 4th 2006. Throughout data collection salinity concentrations increased at the surface ranging from 2.0 to 7.0 ppt with a strong gradient at depths of 1-1.5 meters, where salinity rapidly increased with depth (3 to 4 meters) to levels up to 30 ppt. Data also revealed that dissolved oxygen (DO) conditions were suitable in surface waters throughout the entire time in which data was being collected (July 2005-January 2006), with a decrease in DO consistent with the halocline in relation to depth. The lower water columns (2.5-4.0m) consistently resulted in DO < 3 mg/L, suggesting that the dissolved oxygen concentrations are critical for juvenile steelhead habitat, due to anoxic layering. During this study high surface temperatures indicated stressful to steelhead, and were found in the early months of data collection, ranging from 15-23 oC (July-October 2005). Winter surface temperatures decreased to less than or equal to 16 oC (November 2005-January 2006) proved to be more suitable habitat for steelhead. At sites deeper than 2m, summer morning temperatures were greatest (up to 24 oC) at about 2m in depth, where as winter temperatures in deep water were less than 17.5 oC. Temperature increased with depths consistent to the halocline, with bottom temperatures >17.5 oC in the early months and < 17.5 oC in the later months of data collection.

Comments

Capstone Project (B.S.) Division of Science and Environmental Policy

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