data). Savannah River fish held for culture also
spawned at 17 - 18°C (Smith et al. 1985).
Spawning occurs at moderate river discharge lev-
els and high discharge can deleteriously affect
spawning. In the Connecticut and Merrimack riv-
ers, spawning occurs after peak spring flows, when
only rain events or regulated flows create high dis-
charge (Taubert 1980b, Buckley & Kynard I985b,
Kieffer & Kynard 1996). For adults that spawn di-
rectly below a hydropower dam in tailrace flows,
the facility’s operation controls the suitability of
water velocities for spawning and rearing of eggs
and embryos. High river discharge in May of 1983.
1991,1992, and 1996 during the normal spawning pe-
riod of Connecticut River adults likely inhibited fe-
males from spawning by creating unacceptably fast
water velocities at or near the bottom (Buckley &
Kynard I985b. M. Kieffer & B. Kynard unpublished
data). All information supports Buckley & Kynard
(1985b) that acceptable river conditions (flows)
must be available before endogenous factors trig-
ger ovulation and spawning.
Although channels are used for spawning in
many rivers, Connecticut River females used a wide
rangeofwater depths, so depth may be less impor-
tant that water velocity. Channel with gravel sub-
strate was likely used for spawning in the Saint John
River (Dadswell 1979), channel with gravel, rubble,
and ledge bottom in the Androscoggin River
(Squiers et al.^14 ), channel with rubble in the Merri-
mack River (Kieffer & Kynard 1996), shallow rilfle
channels in the Delaware River (O’Herron et al.
1993), channel curves with rocks, gravel/sand/logs
in the Savannah River (Hall et al. 1991, Collins &
Smith 1995),and channel with gravel, cobble, and
large rocks adjacent to bluff formations in the Alta-
maha River (Rogers & Weber^9 ). Connecticut River
females tracked for 3 years during spawning used
water depths of 1.2-10.4 m and bottom velocities of
0.4–1.8 m sec–1(mean, 0.7 m sec–1; Kieffer & Kynard
1996, P. Vinogradov, M. Kieffer & B. Kynard unpub-
lished data).
Telemetry of spawning fish throughout the spe-
cies’ range indicates that spawning occurs during a
few days to 2 - 3 weeks (Androscoggin River -
Squiers et al.^14 , Merrimack River - Kieffer & Ky-
nard 1996, Connecticut River -Buckley & Kynard
1985b, M. Kieffer & B. Kynard unpublished data,
Delaware River - O’Herron et al. 1993; and Savan-
nah River -Hall et al. 1991). The end of spawning is
easily determined because fish leave the spawning
area and move downstream, some at the rapid rate
of 32 km d–1(Buckley & Kynard 1985b, Hall et al.
1991, Kieffer & Kynard 1996). When shortnose stur-
geon move up- or downstream, they follow the
channel (M. Kieffer & B. Kynard unpublished da-
ta).Eggs, embryos, and larvaeEarly life history is complex in this lithophilous spe-
cies (Balon 1975, 1985). Females deposit brown to
black demersal eggs (approximately 3.5 mm dia-
meter) that quickly adhere to bottom material and
increase to approximiately 4 mm diameter. Em-
bryos hatch in 111 hours at 18-20° C or about 200
hours at 12° C (Buckley & Kynard 1981, Smith et al.
1995). Free embryos (eleutheroembryos) 1-8 days
old are 7-11 mm long, black in color, pliotonegative,
and seek cover during final development (Rich-
mond & Kynard 1995). Embryos have large yolk-
sacs, poorly developed sensory systems and can
only swim using swim-up and drift behavior. The
photonegative behavior of embryos suggests that
they would hide under any available cover in
spawning areas. Eleutheroembryos develop into
feeding larvae (about 15 mm TL) in 8-12 days at 15-
17° C, and, as Bemis & Grande (1992) pointed out,
this is a period of rapid change in the acquisition of
sensory, feeding, and locomotor systems. Larvae
have well-developed eyes, open electrosensory
(ampullary) organs, a mouth with teeth, and fins
that enable them to swim normally. In laboratory
tests, larvae were photopositive, nocturnally active.
and preferred white substrate and the deepest wa-
ter available (Richmond & Kynard 1995). The se-
lection of deep water by larvae was also indicated
by their capture in river channels (Taubert & Dad-
swell 1980, Bath et al. 1981).
Recent laboratory studies of Connecticut River
larvae found most ceased downstream migration
after 2 days, although some emigration continued
for 14 days (C. Cauthron & B. Kynard unpublished