7821

• UCREFRP Catalog Number: 7821
• Author: Hamilton, S. J., et al.
• Title: Evaluation Of Toxicity To Larval Razorback Sucker Of Selenium-Laden Food Organisms From Ouray NWR On The Green River, Utah.
• USFW Year: 1996.
• USFW - Doc Type: \
• Copyright Material: NO

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the fact, it now seems clear that the S 1 site was contaminated sufficiently with selenium in
the food chain to result in elevated residues in larvae above those typically found in
uncontaminated reference sites.

One unusual laboratory study reported that larval bluegill (Lepomis macrochirus) in the
control treatment contained selenium concentrations of 3.3 j.1g/g, but were fed a commercial diet
containing only 0.8 j.1g/g (Coyle et al. 1993). However, they also reported that the brine shrimp
nauplii they fed larvae from 5 days posthatch to 30 days posthatch contained selenium
concentrations of 2.7 j.1g/g. In their study, selenium concentrations in adult reproductive tissue
of control fish were 1.5-2 j.1g/g and in eggs was about 1.5 j.1g/g. Thus, larvae must have
accumulated selenium for the brine shrimp to reach a residue of 3.3 j.1g/g because the commercial
diet only contained 0.8j.1g/g. Coyle et al. (1993) reported that up to 5 days posthatch, larval
survival was >90%, but after 3 days of feeding brine shrimp. survival of control larvae decreased
dramatically and was less than 25%. These results match the reduced survival pattern in the
present study. ~vforeover, the selenium concentration in brine shrimp reported by Coyle et al.
(I993) was very similar to the selenium concentrations in zooplankton from S 1 in the present
study (2.3-3.5 ;.<g/g). However, Coyle et al. (1993) concluded that the high mortality of larvae in
their study was due to starvation resulting from unsuccessful transition between endogenous and
exogenous feeding. Nevertheless, the 3.3 j.1g/g selenium residue in control is substantially higher
than the typical range of selenium concentrations in control or reference fish (0.4-2.0 j.1g/g; Table
13).

Nauplii of brine shrimp have been used at the Yankton ERS in culturing larvae of
Colorado squawfish. razorback sucker, and bonytail for the past several years and survival has
been >90%. Other investigators have reported high survival of larval fish fed brine shrimp
nauplii when culturing yellow perch (Perca flavescens) (Hinshaw 1985) and bluegill (Smith
1976). Brine shrimp eggs purchased from Aquarium Products, Glen Burnie, MD, and used in
fish culture at Yankton ERS contained selenium concentrations of 1.83 j.1g/g wet weight
(analyzed at Yankton ERS in 1992). Selenium concentrations in nauplii were 3.0 j.1g/g dry
weight (assuming 88.4% moisture measured in brine shrimp nauplii as part of the analysis in
1996) in 1992.2.4 j.1g/g (assuming 88.4% moisture) in 1993. and 2.7 j.1g/g in 1996. These
concentrations of selenium in brine shrimp nauplii are similar to those of Coyle et al. (1993),
who reported 2.7 j.1g/g in nauplii from eggs purchased from Aquarium Products (personal
communication. Eugene Greer, NBS. Columbia, MO, 1996). In the present investigation. no
brine shrimp were used to culture larvae in studies 1,3, and 4, but were used to culture larvae in
study 2 for 4 days prior to the initiation of the study with 1 a-day old larvae. Consequently, it is
possible that some of the selenium in the larval razorback suckers in study 2 was accumulated
from brine shrimp nauplii.

Brine shrimp were the only food given to larval razorback suckers during the
supplemental feeding studies conducted for 20 days. Survival of larvae in the supplemental
feeding study was 90% or greater, thus indicating that food organisms containing selenium
concentrations of2.7 j.1g/g may not cause adverse effects in larval razorback suckers -- in the
absence of other physical, biological, or chemical stressors. Because high survival of larval fish

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