9641

• UCREFRP Catalog Number: 9641
• Author: Hedrick, T. N., K. R. Bestgen and K. D. Christopherson.
• Title: Entrainment of Semi-Buoyant Beads and Razorback Sucker, Xyrauchen texanus, Larvae into Flood Plain Wetlands of the Middle Green River, Utah.
• USFW Year: 2009.
• USFW - Doc Type: C-6/RZ-ENTR,
• Copyright Material: NO

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expensive than reagent grade TC, commercially available TC was used for fish marking that

year. A 6.2 gram amount ofTC was dissolved in 800 milliliter (ml) of deionized water and was

sufficient to achieve a marking solution of350 mg/L, when added to the 19 liter (L) of water in

the marking container. The solution was buffered with tris (Trizma hydrochloride, Sigma

Chemical T-3253), a few grains at a time, to a pH of about 7.0. After acclimation, the TC

solution was added to the marking container and gently mixed. Fish were immersed in the

marking solution for four to five hr, a time sufficient to mark otoliths at those concentrations

(Muth and Meismer 1995). A small amount of air or oxygen was bubbled through the marking

solution; over-aeration produces excess foam. The solution was flushed to a waste drain (not

recirculated because antibiotic TC may affect biofilters in the hatchery) and fish were put back

into holding tanks. A few (about 10) larvae were preserved in 100% ethanol just post-marking

and then again two to three days later to ensure that fish were adequately marked. Examination

of otoliths of fish immersed in the TC solution showed that 100% of fish were marked and marks

were bright yellow and clear (Muth and Bestgen 1991). In 2005, we double-marked one batch of

larvae so that fish from different release batches could be differentiated after capture in the wild.

This was accomplished by conducting the standard marking at eight days post-hatch, followed by

another mark application at 11 days post-hatch. The three-day interval was sufficient to allow

for the marks to be spatially well-separated (not overlapping) on the otolith. Number of larvae

released was estimated volumetric ally in the hatchery; larvae were placed in plastic bags with a

large headspace of oxygen, and transported to release sites the morning of releases.

In 2005, based on our recommendation, hatchery personnel attempted to mark a batch of

razorback sucker larvae with alizarin complexone (AC), a compound successfully used in other

marking studies that produces a fluorescent red mark (Muth and Meismer 1995). We attempted

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