9578

• UCREFRP Catalog Number: 9578
• Author: Hamilton, S. J. and e. al.
• Title: The Evaluation of Contaminant Impacts on Razorback Sucker Held in Flooded Bottomland Sites Near Grand Junction, Colorado - 1997.
• USFW Year: 2001.
• USFW - Doc Type: CAP6-WW,
• Copyright Material: NO

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present study. There were no differences among larvae from the four sources in viability,
survival, hatch, or mortality of deformed embryos or larvae. For larvae from adults held at
Adobe Creek, there were more deformed embryos in eggs held in site water than held in
reference water.
During the larval fish study, selenium was elevated in water and food organisms from
Adobe Creek and North Pond, and in food organisms from Horsethief east wetland. Although
there were differences among the three sites in concentrations of inorganic elements in water and
biota, selenium was the only element elevated to concentrations of concern. The lowest survival
of larvae from all sources occurred in site food treatments compared to reference food treatments
(Summary Table 1). Survival of larvae from Adobe Creek and North Pond adults was lower in
site water treatments compared to reference water. Survival of larvae from brood stock was
higher than Horsethief larvae even though they' were exposed to the same water and dietary
treatments, which suggests brood stock had a higher level of fitness for dealing with contaminant
stresses. Selenium residues in larvae were correlated with selenium concentrations in water and
food organisms, and elevated to concentrations reported by others to cause adverse effects in
larval fish.
Informal observations of razorback sucker larvae held at 24-Road suggest that delayed
mortality occurred in larvae from North Pond adults. Deformities were present in larvae from all
four sources, although the type of deformities and abnormal swimming behavior of larvae from
North Pond adults were different from those of larvae from the other three sources. Deformities
in larvae from North Pond adults were similar to those reported in the literature for selenium-
induced tetratogenic deformities observed in other fish species.
Possible effects from inbreeding were a concern in the egg and larval fish studies.
During the egg study, there were no differences in percent viability, percent hatch, or mortality
among the three sites, and the range of values of these measures was similar to those for
razorback sucker reported by others. During the informal razorback sucker larvae study, the
different deformities in larvae among the three sites suggested an effect from parental exposure
rather than an inbreeding effect.
A hazard assessment using selenium concentrations measured in water, sediment,
invertebrates, and fish, and a published hazard assessment protocol for selenium, suggested a
moderate hazard at Horsethief and high hazards at Adobe Creek and North Pond. Selenium
concentrations of ~4.6 lJ.g/g in food organisms adversely affected the survival of razorback
sucker larvae from Horsethief adults, which suggested a high hazard was appropriate for the
Horsethief east wetland. Based on selenium concentrations measured in water, sediment,
invertebrates, and fish given in published NIWQP reports of studies in the Green River and
upper Colorado River basins, and biological effects measured in the present study (and the
second reproduction study), selenium contamination is adversely affecting razorback sucker