9721

• UCREFRP Catalog Number: 9721
• Author: Brouder, M.J.
• Title: Age and growth of roundtail chub in the upper Verde River, Arizona.
• USFW Year: 2005.
• USFW - Doc Type: Transactions of the American Fisheries Society
• Copyright Material: YES

...

868

BROUDER

TABLE I.-Mean back-calculated total length (TL) of roundtail chub at the end of each growing season in the upper
Verde River, Arizona, March 1997-December 1999,

Number Annulus
Age
(year-class) of fish 2 3 4 5 6 7
1 (1996) 79 104
2 (1995) 70 103 184
3 (1994) 58 100 170 220
4 (1993) 47 102 180 245 285
5 (1992) 16 107 186 257 298 330
6 (1991) 8 93 184 248 302 345 382
7 (1990) 2 103 187 246 303 345 380 412
Mean 1L 101 181 243 297 340 381 412
Increment 101 80 62 54 43 41 32

between sexes (P > 0.05); however, analysis of
covariance (ANCOV A) indicated a significant dif-
ference (F = 674.5; df = 311; P < 0.0001) in sex-
specific length-weight relations of roundtail chub,
females being heavier per unit of length than
males. The length-weight relationship for males
and females of the upper Verde River roundtail
chub population is best described by the following
equations:

FIGURE I.-Photograph of cross section of roundtail
chub sagittal otoliths depicting annual (top) and daily
(bottom) increments, The line on the top figure denotes
the plane of measurement from the focus to each annulus
and edge. The arrows show where the annuli were mea-
sured (outer edge of the thin opaque zone).

10glOTW = 3.140 10glOTL - 5.411
(N = 151; r2 = 0.95) and
log IOTW = 3.142 log IOTL - 5.345
(N = 56; r2 = 0.96).

Growth of the upper Verde River roundtail chub
population (both sexes combined) was greatest
during the first year of life (10 I mm) and declined
steadily afterward from 80 mm at age 2 to 32 mm
at age 7 (Table 1). Growth of roundtail chub in
the upper Verde River is best described by

L, = 499.30[1 - e-O.23(t-O.l47)].

Otolith Validation

Otoliths exhibited alternating wide translucent
and narrow opaque zones (Figure 1), and marginal
increment analysis indicated that a single opaque
band was formed once a year (Figure 2). Mean
marginal increments were significantly lower (P
= 0.015) in May than in any other month, further

3.0

~ 2.5,
E
!
"; 2.0
~

..s 1.5
=
.
"E'
i 1.0
.
=
~
0.5

suggesting that 0
year.
Otoliths were
ranging from 58
Ponds Hatchery
validate annulus
of 99 otoliths (I
preparation) fre
fish, the number
100% of the tim
Daily rings were
liths of age-O ha
ages based on da
70% of the time
of the time with
specti vel y .

The age stm
roundtail chub I
distinct cohorts,
year-classes cor
in both 1998 an,
early spring of
occurred, and B
relationship bet'
of roundtail chul
classes in yean
supports this hy
The maximun
chub from the \
similar to that]
Gila and Green
Kramer 1969).
roundtail chub i
reported for ro\
Gila River bas
Fossil Creek, A
River, Utah (V
dition, growth
reported by oth
observation tha
year. Fast grow
upper Verde R
plained by the
1995 floods. II
native fishes by
native fishes (
1987; Rinne aJ
and compete fc
placement of
source utilizati
may ultimately
individual gro'

0.0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dee
Month

FIGURE 2.-Mean marginal increment distances by
month (:!:SE) for all ages of roundtail chub collected in
the Verde River, Arizona.