51813_Sturgeon biodioversity an.PDF

do not mature until age 7 (Helms 1973). In areas of
poor food supply. males and females become sex-
ually mature at a smaller size (Moos 1978). Females
do not spawn every year with the frequency of
spawning influenced by food supply and ability to
store adequate fat to produce mature gametes
(Christenson 1975. Moos 1978). Gonads of mature
males represent 2-6% of body weight and 10-22%
of females (Zweiacker 1967, Helms 1973. Christen-
son 1975, Moos 1978).
Several authors have identified what are believed
to be reproduction problems with this species. June
(1977) reported finding shovehose sturgeon with
mature eggs into July in Missouri River reservoirs
with up to 52% of the females showing massive fol-
licular atresia and concluded that this demonstrat-
ed unfavorable spawning conditions for the stur-
geon as a result of river impoundment. He also re-
ported high levels (2.1 % incidence rate) of herma-
phroditism in shovelnose sturgeon; a phemonenon

also noted on other Missouri River studies by Carl-

son et al. (1985), with a 3% incidence rate, and Moos

(1978), with a 1.6% incidence rate. Carlson et al.

(1985) also discovered hybridization withS. albus.

Several authors have noted a lack of natural repro-

duction in areas of the Missouri River and have at-

tributed it to man-made alterations to shovelnose

sturgeon habitat (Bailey & Cross 1954, June 1977.

Moos 1978).

Current harvest

The shovelnose sturgeon is presently classified as a

sport fish in 12 states and a commercial species in 7

(Table 1). It is considered extirpated in 3 states, is

fully protected in 4, and is considered rare, threat-

ened, or of special concern in 8 states. Some states

have dual classifications and some classify it differ-

ently in various waters.

Table 1. Classification, status. and type of fishery allowed in states within the range of the shovelnose sturgeon.

State Classification Status Type of fishery

Since 1940 Since 1990 Sport Commercial

Alabama Extirpated Decline Extinct No No

Arkansas Commercial Decline U nknown Yes Yes

Illinois Sport/commerci al Unknown U n k n ow n Yes Yes

lndiana None U nknown Unknown Yes Yes

Iowa Sport/commercial Unknown Stable Yes Yes

Kansas Sport Decline Unknown Yes No

Kentucky Sport U nk n o wn Unknown Yes Yes

Louisiana Special concern Unknown Unknown No No

Minnesota Sporticoncern Unknown Stable Yes No

Missouri Sport/commercial Decline Unknown Yes Yes

Nebraska Sport Decline Stable Yes No

New Mexico Extirpated Extinct Extinct No No

North Dakota Protected Decline Stable No No

Ohio Endangered Decline Unknown No No

Oklahoma Special concern Decline Unknown N o N o

Pennsylvania Extirpated Unknown Unknown No No

Tennessee Extirpated Unknown Unknown No No

Texas Endangered Decline Unknown No No

Wisconsin Sport/commercial Decline Unknown Yes Yes

Wyoming Sport/concern Decline Stable Yes N o

Mississippi Rare Unknown Unknown No No

Montana Sport Unknown Stable Yes No

SouthDakota Protected Unknown Unknown No No

WestVirginia Extirpated Decline Extinct No No