8008

• UCREFRP Catalog Number: 8008
• Author: Haines, G. B., S. H. Severson and T. Modde.
• Title: Evaluation of Batch Marking Techniques for Culturing the Endangered Razorback Sucker and Colorado Squawfish.
• USFW Year: 1997.
• USFW - Doc Type: \
• Copyright Material: NO

Table 1. - Dates of marking fish, numbers of fish marked, and dates of checking fish for
recognizable marks. rbs = razorback sucker, csf = Colorado squawfish.
Date Number 1 st Date 2nd Date
Trial Species marked marked checked checked
1 rbs 6 Jun 95 80 8, 13 Nov 95 23 Oct 96
1 csf 6 Jun 95 343 27 Nov 95 24 Sep 96
2 rbs 7 Jun 95 80 8, 13 Nov 95 23 Oct 96
2 csf 8 Jun 95 335 27 Nov 95 24 Sep 96
3 rbs 8 Jun 95 80 8, 13 Nov 95 23 Oct 96
3 csf 13 Jun 95 335 27 Nov 95 24 Sep 96

Results and Discussion

The results of the experiment are summarized for razorback sucker in Tables 2 and 3 and

Colorado squawfish in Tables 4 and 5. The V -shaped freeze brand was recognizable on greater than

99% of treated fish after 15 months for both the razorback sucker and Colorado squawfish. The

freeze brand blackened tissues and deformed scales. On previous occasions we used an O-shaped

brand and found it just as recognizable as the V, but a horizontal bar-shaped brand was not

recognizable. The edges of the bar became distorted as the fish grew and blended with the fish's

natural markings. Freeze brand retention rates were similar to those reported by others. LaJeone and

Bergerhouse (1991) reported 95% of branded walleye retained recognizable marks after 5 months

in a rearing pond. Fay and Pardue (1985) reported 92% retention of aT-shaped brand on rainbow

trout Oncorhynchus myldss after 22 weeks. They also noted that 60% of the brands had deteriorated

to poor quality.

Recognition of the elastomer had mixed results, depending on the species, color, and

location. Recognition was easier for Colorado squawfish than razorback sucker (grand means of

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