Den Avyle^7 ). Large Atlantic sturgeon arelikely to
be femalesbecause ofmarkedsexualdimorphism
(Figure 4).
stream of aspawning site toaccommodatedispersal
of embryos andlarvae.Malespawninginterval
Femalespawning interval
Mature, maleAtlantic sturgeonenter theHudson
Adult femaleAtlanticsturgeondiffersharplyfrom River starting in April and at leastsomeremain in
adult males insize,growth, migratorybehavior, and the HudsonRiver aslate as November (Dovel &
age structure(Figure 3). Spawning female sturgeon Berggren1983).Spawning males are 12 ormore
are age 15 or older,weighmorethan 34 kg, and are years old andfrom 150 to 210 cm T L (VanEenen-
greater than 200 cm T L(VanEenennaam et al. naam et al.1996.Table 1 ). Van DenAvyle^7 reported
1996, Table 1). Dovel & Berggren (1953) reported a that themaximum size lormales is 213 cm TLwhich
slightlyolder age atfirstspawning (18 years) but the issimilar to thesizesrecorded in the HudsonRiver
sameminimumsize. Age andgrowthdata(Van Ee- spawningstock(Figure 4). Nospawningmalesover
nennaam et al. 1996)clearlyindicate steady growth 20 years oldhavebeen recorded in the Hudson Riv-
in females(Figure 4) and data fromDovel &Berg- er. Male Atlanticsturgeon may notspawn annually,
gren(1983) areconsistentwiththispattern. and the periodbetweenspawnings hasbeen esti-
Adultfemalesenter theHudsonRiver Estuary mated torangefrom 1 to 5years(T.T.J.Smith1985).
for spawningbeginning in mid-May.Theymigrate Fromlimited sturgeon telemetry byDovel &
directly to the spawning groundswhich aredeep, Berggren (1983),malesappear to move upstream
channel or off-channel habitats (Dovel & Berggren onincomingtides andthenremainstationary for
1983). Thefemale sturgeon return to marinewaters several hours. Duringtheirupstreammigration,
quickly afterspawning(C.L. Smith 1985). The malesturgeonmeanderback andforthacross the
spawningperiodrangesfrom MaythroughJuly or channel, butstay in watergreater than 7.6 m deep.
possibly August i n the Hudson River estuary VanEenennaam et al. (1996)observedthat adult
(Dovel &Berggren1983, VanEenennaam et al. malesturgeonappear atspawning sites inassoci-
1996).Femalesturgeon do notappear tofeed on the ationwithfemales, indicatingthatthey search for
spawning run infreshwater (T. I. J. Smith1985). femaleswhilemovingabout in theriver.
Dovel &Berggren(1983)reportthatspawning
occursnear thesalt wedge (km 55) early in the sea-
son (lateMay),movingupstream to km 136during
June andearlyJuly.However, VanEenennaam et
al. (1996)collectedspawningAtlanticsturgeononly
at two historicallyimportantfishingsitesknown to
be spawningareas(Figure 3):nearHydePark (km
130) andCatskill (km 182). VanEenennaam et al.
(1996)arguethatspawning is unlikely tooccurnear
brackishwaterbecause sturgeoneggs,embryos and
larvae are intolerant ofsaline conditions,and some
significantlength of riverhabitat is neededdown-Egg,embryo andlarvaintervalEggs ofAtlanticsturgeon areadhesive and the em-
bryosremain on thebottom indeepchannel hab-
itats.Atlanticsturgeon embryos havebeenrecord-
ed in the HudsonRiverfrom km 60through 148
(Dovel &Berggren1983); a rangeincludingsome
brackishwaters.Sturgeon embryos andlarvae have
limited salttolerance, sotheir habitatmust bewell
upstream of thesaltfront(VanEenennaam et al.
1996: asillustrated inFigure 3). Nofurtherinforma-
tion isavailable onthisinterval of the Atlantic stur-
geonlifecycle.
Atlanticsturgeonembryos areabout 7 mm TL at
hatching, and i nhatcheries, theyreached19.9 mm
TL in 20 days(Smith et al. 1980). Thetransition(^7) Van Den Avyle,M.J.1984.Species profiles:lifehistories and
environmentalrequirements ofcoastalfishes andinvertebrates
(SouthAtlantic) – Atlantic sturgeon.U.S.Fish andWildlifeSer-
viceFWS/OBS-82/11.25.Washington.D.C. 17 pp.