8242

• UCREFRP Catalog Number: 8242
• Author: Haines, G. B., S. H. Severson and T. Modde
• Title: Evaluation of Razorback Sucker and Colorado Squawfish Batch Marking Techniques
• USFW Year: 1998
• USFW - Doc Type: The Progressive Fish-Culturist
• Copyright Material: YES

274

HAINES ET AL.

TABLE 2.-Percent recogmtlOn of marks 5 and 15
months after marking young Colorado squawfish with
elastomer implants at the base of the anal fin and on the
jaw and freeze branding (side). Percentages are means of
three trials. Percentage for mean excludes control fish.
Location Correctly
and color Number identified Number
or type observed (%:':: SD) of deaths
5 months
Anal fin
Control 201 99 :':: I 3
Green 195 81 :':: 16 3
Blue 203 67 :':: 24 0
Red 198 98 :':: 2 I
Orange 196 97:':: I 3
Mean 86
Jaw
Control 204 100:':: 0 2
Green 195 82 :':: 5 3
Blue 197 87:':: II 4
Red 201 94 :':: 2 0
Orange 196 96 +: 4 1
Mean 90
Side
Control 503 99 :':: 0 2
Freeze 490 99:':: 2 2
15 months
Anal fin
Control 39 100:':: 0 81
Green 49 74 :':: 32 76
Blue 36 49 :':: 29 82
Red 49 95 :':: 8 75
Orange 32 77:'::22 84
Mean 74
Jaw
Control 37 100:':: 0 82
Green 40 62:':: 14 80
Blue 44 45 :':: 5 79
Red 43 88 :':: 9 79
Orange 41 96 :':: 3 79
Mean 73
Side
Control 100 99 :':: 2 81
Freeze 105 99:':: 2 79

formed scales. It was recognizable on greater than
99% of treated fish after 15 months for both spe-
cies. Retention rates were similar to those reported
by others. LaJeone and Bergerhouse (1991) re-
ported 95% of branded walleyes retained recog-
nizable marks after 5 months in a rearing pond.
Fay and Pardue (1985) reported 92% retention of
a T-shaped brand on rainbow trout Oncorhynchus
mykiss after 22 weeks. They also noted that 60%
of the brands had deteriorated to poor quality.
Recognition of the elastomer implants had
mixed results, depending on the species, color, and
location. Recognition was easier for Colorado
squawfish than for razorback suckers (grand means
of88% versus 60% after 5 months, and 74% versus
60% after 15 months). This was the result of the

lighter pigmentation of the Colorado squawfish.
Haines and Modde (1996) marked Colorado
squawfish (35-45 mm TL) on the dorsal surface
with red elastomer. They reported 98% retention
after 21 d and 85% after 142 d.
Red and orange marks were more easily rec-
ognized than blue and green. For Colorado squaw-
fish, significant differences were found among col-
ors after 5 months (P = 0.02) and 15 months (P
= 0.003); orange was better recognized than blue
(P = 0.03) after 5 months, and orange (P = 0.002)
and red (P = 0.001) were better recognized than
blue after 15 months. For razorback suckers, the
differences among colors were not as great (P =
0.16 after 5 months; P = 0.07 after 16 months),
but the same pattern persisted. Most often misiden-
tification was the result of not seeing any mark
rather than confusing one mark for another. Oc-
casionally, however, blue was confused with green
and red with orange. When viewing the elastomer,
the ultraviolet lamp projected a bluish color and
may have accounted for the low detection rate of
the blue elastomer.
No single elastomer implant location was best
for either the razorback sucker or Colorado squaw-
fish. For Colorado squawfish, the jaw and the base
of the anal fin appeared equally suitable after 5 (P
= 0.33) and 15 (P = 0.82) months. For the ra-
zorback sucker, the anal fin site was best after 5
months (P = 0.004) but not after 15 months (P =
0.91). Tissue elaboration accounted for some loss
of elastomer visibility at the anal fin site. The ra-
zorback suckers grew from 21.5 g to 247.0 g over
16 months, and the Colorado squawfish grew from
23.5 g to 141.0 g over 15 months. Five months
after marking, we dissected seven Colorado
squawfish that had received elastomer implants,
and in several instances, exposed more elastomer
than could be seen when the fish were viewed un-
der ultaviolet lamp. At the lower-jaw site we were
unable to expose any more elastomer than we ob-
served using the ultraviolet lamp. In a number of
instances, elastomer implants at the base of the
anal fin migrated to tissues between anal fin rays
after 5 months. These marks were easily visible
15 months after marking.
Dewey and Zigler (1996) found elastomer re-
tention for adult blue gills was more than 99% after
6 months for fish marked on the dorsal surface of
the skull, at the insertion of the dorsal fin, below
the dorsal fin, and on the caudal peduncle. Juvenile
bluegills lost elastomer marks applied to the dorsal
surface of the skull but retained all other marks.
Bonneau et al. (1995) reported elastomer retention

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