9719

• UCREFRP Catalog Number: 9719
• Author: Bestgen, K.R.
• Title: Results of alizarin complexone marking to test survival of early life stages of razorback sucker Xyrauchen texanus and fathead minnow Pimephales promelas in two water types from Ouray National Fish Hatchery.
• USFW Year: 2005.
• USFW - Doc Type: Larval Fish Laboratory, Colorado Stae University
• Copyright Material: NO

Tests were conducted to determine if alizarin complexone (ALC), was toxic to small
razorback suckers Xyrauchen texanus when used in combination with two different Ouray
National Fish Hatchery well water sources. Alizarin complexone is a calcium stain that can be
used for marking eazly stages of fish because it is incorporated into bony tissue as fish grow.
Otoliths examined under ultra-violet light fluoresce when subjected to appropriate concentrations
of ALC for appropriate durations of time. Tests were conducted because of mortality offish in
May 2005 when marking of razorback sucker larvae was attempted. Appazently all fish died
within 20 minutes of starting the mazking period (M. Montague, pers. Comm., Ouray National
Fish Hatchery). It was hypothesized that high levels of manganese in mazking water may have
interacted with the potassium in the solution used to dissolve the ALC to create potassium
permanganate, a known fish toxicant. Previous tests with razorback suckers (Muth and Meismer
1995, Southwestern Naturalist) showed no toxicity when marked with ALC in combination with
well water from the Aquatic Reseazch Laboratory (ARL) at Colorado State University.
We first tested water from an easily accessible well from Ouray on 7 July 2005.
Apparently that was not the water used to mazk fish in. We then tested water on 15 August 2005
that was from a more difficult to access Ouray well source that had higher concentrations of
metals, including manganese, which was the water that was used to mark the fish in. We diluted
solutions of ALC, first dissolved in 1-N solutions of KOH and buffered to neaz neutral (pH =
7.6) with either 50% ARL or Ouray water mixed with distilled water (50%) to achieve a mazking
solution of 50 mg/L. We filled 1-L beakers with mazking solutions and aerated them, and added
randomly allocated batches of 10 fish to each of the beakers. Tests for each of the ARL, Ouray,
and reference water types were replicated three times. We allowed fish to remain immersed in
the 50 mg/L mazking solutions for 4 h, which were ALC concentrations and marking durations in
the ranges successfully tested by Muth and Meismer (1995). After the 4-hr marking period, fish
were strained from the marking solution with a net and placed into ARL water. Fish mortalities
were noted at that time (postmarking), and for 24 and 48 hr post-testing periods. Survival values
reported were for the 48 hr duration observations. Reference water tests with each fish species
were also conducted using equal portions of ARL, Ouray, and distilled water. Reference fish
were handled similazly to fish marked in ALC except were not immersed in the marking solution.
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