EPA's Vessel General Permit and Small Vessel General

physiological damage to the receptors (Baatrup 1991).
These concentration thresholds for juvenile salmonid sensory and behavioral responses fall
within the range of other sublethal endpoints affected by dissolved copper, such as behavior,
growth, and primary production (Hecht et al. 2007). In addition to sensory effects, impaired
disease resistance, hyperactivity, impaired respiration, disrupted osmoregulation, pathology of
kidneys, liver, and gills, impaired function of olfactory organs and brain, altered blood
chemistry, and enzyme activity have been documented in fish, with effects thresholds as low as
0.1 ug/L (Eisler 2000). Like olfactory effects, other sublethal effects may manifest quickly and
persist after exposure ceases. For example, rapid elevations of plasma cortisol, an indicator of
stress, occurred in rainbow trout after a 1-hour exposure to approximately 0.2 μg/L of copper at a
hardness of 12 mg/L (Munoz et al. 1991). The elevated plasma cortisol levels were maintained
throughout the experiment’s duration of 21 days. Elevated plasma cortisol levels are indicative
of stress, and potentially represent a diversion of energy from normal physiological processes
that may render salmonids more vulnerable to disease.
Information for effects on other anadromous species groups is limited to data for white sturgeon.
This species group, particularly early life stages, is highly sensitive to copper, with LC20
response thresholds falling within the range of concentrations causing sensory effects in
salmonids as described by Hecht et al. (2007) (Vardy et al. 2011, Little et al. 2012). Data on
copper for marine mammals are limited to tissue concentrations (Varanasi et al. 1994, Sanpera et
al. 1996, Wagemann et al. 1996, Wood and VanVleet 1996, Sydeman and Jarman 1998, Meador
et al. 1999, Welfinger-Smith et al. 2011).
Sublethal effects from low levels of copper have also been documented in mussels and other
mollusks. Exposure to copper at concentrations