8094

• UCREFRP Catalog Number: 8094
• Author: Dryer, M. P. and A. J. Sandvol.
• Title: Recovery Plan for the Pallid Sturgeon ‎(
• USFW Year: 1993.
• Copyright Material: NO

shovelnose sturgeon. All larval Scaphirhynchus spp. that ,have been collected
have been classified as shovelnose sturgeon because of the rarity of pallid.
sturgeon.) Spawning reportedly occurs between June and August (Forbes and
Richardson 1905). Females collected in June. and .July in Lake Sharpe., a
reservoir on the Missouri: River in South Dakota, contained mature ova and
presumably were ready to spawn.. However, there has been, no evidence of
successful reproduction during 10 years of sampling. for young-of-the-year ,fish
in Lake Sharpe (Kallemeyn 1983).
Kallemeyn (1983) reported that pallid sturgeon males reach sexual maturity at
53.3-58,4 cm (21 to 23 in), but size and age of females at sexual- maturity are
unknown... Conte et a1. (1988) indicated that females of most sturgeon in North
America do not mature until 7 years of age and typically require several years
for eggs to mature between spawnings.
The age of sexual maturity and intervals between.. spawning were estimated #or
nine pallid sturgeon by recording what were interpreted to be spawning-events
from pectoral fin ray cross sections (L. Jenkins,. U.S.-Fish & Wildlife
Service, pers.- comm. 1991). Sexual maturity for males was estimated to be
7 to 9 years, with 2- to 3-year intervals between spawning years. Females
were estimated to reach sexual maturity in 15 to 20 years, with 3- to 10-year
interval s. between spawning years.. Time-of sexual: maturity and the intervals
between spawning years is likely to be influenced by available forage,
environmental-conditions; and other factors.
Keenlyne et al. (1992) estimated fecundity for a female pallid sturgeon taken
from the upper Missouri River. The authors found the mass of mature eggs
weighed 1,952 g, which represented 11.4 percent of total body weight. -Total
fecundity was estimated- at 170;000 eggs for this female.
While there may be differences in the spawning requirements between-the- pallid
sturgeon and shovelnose sturgeon, the shovelnose sturgeon still provides the
closest model for determining spawning requirements. Because there is little
information available on pallid sturgeon spawning, spawning requirements are
extrapolated from what is known regarding shovelnose sturgeon spawning,
shovelnose sturgeon-spawn over substrates of rock, rubble, or gravel in the
main channel of the Missouri/Mississippi Rivers and major tributaries, or on
wing dams in the-main stem of larger rivers (Christiansen.-.1975; Elser et al.
1977; Moos 1978; Helms 1974). shovelnose sturgeon spawning occurs in the
unchannelized Missouri River near Vermillion, South Dakota, when water
temperatures-reach 18°C to 19°C.(64°F to 66°F), which can be from late May
through June. Spawning was suspected to occur in the relatively swift water
in or near the main channel (Moos 1978). shovelnose sturgeon spawning occurs
in the Tongue River, Montana, a Yellowstone River tributary, from early June
until mid-July at water temperatures of 16.9°C to 21.5°C (61°F to 70°F) (Elser
et al. 1977). Initiation of shovelnose sturgeon spawning migrations have-been
associated-with increased flows. in June (Berg 198.1).
Food and Feeding Habits: Carlson et al. (1985) determined composition of-food
categories, by volume and frequency of~:occurrence, in the diet of shovelnose
sturgeon (n=234), pallid sturgeon (n=9), and presumed hybrids {n=9). Aquatic
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