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Document Type:
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Journal Article
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Center:
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NWFSC
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Document ID:
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6333
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Author:
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C. A. Rice
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Year:
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2005
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Title:
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Effects of shoreline modification on a northern Puget Sound beach: microclimate and embryo mortality in summer spawning surf smelt (Hypomesus pretiosus)
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Journal:
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Estuaries and Coasts
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Volume:
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29
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Issue:
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1
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Pages:
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63-71
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Date:
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03/13/2005
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Keywords:
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shoreline modification, beach microclimate
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Abstract:
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Human alteration of Puget Sound shorelines is extensive yet its ecological consequences are largely
undocumented. This study evaluates differences between natural and heavily modified beaches in terms of microclimate and
one aspect of biological condition. Electronic data loggers were placed at a tidal height of approximately 3.7 m (12 ft) above
mean lower low water during July 1620, 2001, to monitor light intensity, substrate and air temperatures, and humidity.
Substrate samples were collected at the end of the monitoring period to evaluate condition and density of eggs from surf
smelt (Hypomesus pretiosus), a forage fish species that spawns on gravel-sand beaches in the upper intertidal zone. The
modified beach had significantly higher daily mean light intensity, air temperature, and substrate temperature, and
significantly lower daily mean relative humidity. Particularly striking were the differences in substrate temperature, which, on
the natural beach, ranged from 12.1uC to 18.2uC (mean 5 14.1uC) and on the modified beach ranged from 14.4uC to 29.4uC
(mean 5 18.8uC). In addition to these different means and more extreme values, microclimate conditions on the modified
beach were more variable, indicative of a less buffered environment. The proportion of smelt eggs containing live embryos
on the altered beach was approximately half that of the natural beach.
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Divisions:
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EC
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