Crance^3 , Mosindy1937,Payne 1937,Curtis1990,
Taub^4 , Lane1991, Pitmad,Beamesderfer1993,
Dryer &Sandoval^6 , USFWS &GSMFC^7 ).has beenwidelycorrelatedwithspring andsummer
discharge(Stevens &Miller1970.Khoroshko1972,
Votinov &Kasyanov 1979,Kohlhorst et al.1991,
Veshchev1991).Flowingwaterprovidesoxygen,
disperseseggs, and excludes eggpredators.Season-
al floods scoursubstratesfree ofsand andsilt which
mightsuffocateeggs.Seasonalfloods andcorre-
sponding changes intemperature,velocity, and tur-
bidity may alsoprovide spawning cues(Kempinger
1988,Kohlhorst et al.1991,LaHaye et al.1992).
Unfortunately, many of these adaptations to
large river systems are nowdetrimental tosturgeon.
Availability offood andcriticalspawningareas are
limitedwhereconstruction of damsblocksmove-
ments amongscattered areas and createshomoge-
nous reservoirs which reduce habitat diversity.
Dam and reservoiroperation for hydropower gen-
eration, floodcontrol, irrigation, andnavigation re-
duceseasonal andannualvariability inflow which
provide suitable spawning andrearingconditions
for sturgeon andmany oftheirprey.Altered sys-
temsfavor development of a new array ofprey.
predators, and competitors.Benthic feeding and
delayedmaturationincrease vulnerability to bioac-
cumulation oftoxicpollutants (Ruelle &Keenlyne
1993).Longevity and delayed maturation make
populationsextremely susceptible to overexploita-
tion.Largesize and highfecundity increase the val-
ue of individualfish and provideincentives for ex-
cessive or illegalharvest.
Because of theuniquefeatures oftheir large river
habitats and adaptivelife history characteristics,
sturgeon require amuchbroaderdefinition of hab-
itat than istypicallyapplied tofishes whenalterna-
tives forhabitat improvement areconsidered.Fish
habitats are oftendefined ill termsofSite-Specific
conditionslikedepth,velocity,substrate, andcover.
tem-wide conditions including largeareas of di-
verse habitat;naturalvariation inflow, velocity,
temperature, andturbidity;highwaterquality; a
broad preybase; and free-flowing sectionswhich
provide suitable spawning sites(Carlson et al.1985,Alternatives for protection and restorationTo helpidentify andassess thepotentialfeasibility
of alternatives for protecting and restoring stur-
geons andtheir habitat, werecentlyconducted a
mail survey of 268sturgeon andpaddlefishbiolo-
gists andmanagersfromthroughoutNorth Amer-
ica. One pagequestionnairesincluding areturn ad-
dress and postageweresent to eachpersonidenti-
fied in a‘Summary of sturgeon andpaddlefish re-
searchers and managers’ developed by the United
StatesFish andWildlife Service.Whilesurvey re-
sults fromthissample cannot be construed as an un-
biased indication ofwhichmeasures are appropri-
ate, results should beuseful in identifying therange
of alternatives available.
Survey questions included ‘pleaselist measures
you believe to bepotentiallybeneficial to the con-
servation,productivity, or diversity ofsturgeon or
paddlefish populations with which you are familiar’
and ‘which of theabovealternativeshave been im-
plemented andproven beneficial to thetargeted
sturgeon orpaddlefishspecies?’ Inaddition,each
person was asked to (1)identifytheir experience
withsturgeon or paddlefish (basicresearch, applied
research,stockassessment/monitoring.habitat pro-
tection, fisheryregulation, or aquaculture); (2)(^3) Crance,J.H.1986.Habitatsuitability index models and in-
streamflow suitabilitycurves: shortnose sturgeon.U.S.Fish and
Wildlife Service BiologicalReport 82(10.129).
(^4) Taub,S.H. 1990 Fisherymanagementplan forAtlantic stur-
geon (Acipenser oxyrhynchus oxyrhynchus) Atlantic States Ma-
rine FisheriesCommisionFisheriesManagement Report 17.
73pp.
(^5) Pitman,V.M. 1992.Texaspaddlefish recovery plan.TexasParks
and Wildlife Department, Austin. 30 pp.
(^6) Dryer, M.P. & A.J. Sandoval. 1993. Recovery plan for the pallid
sturgeon (Scaphirhynchus albus). U.S. Fish and Wildlife Service,
Denver. 55 pp.
(^7) USFWS &GSMFC(UnitedStatesFish andWildlife Service &
Gulf States Marine Fisheries Commission). 1995. Gulf sturgeon
recovery plan. Atlanta. 170 pp.
Sturgeon habitatmust bedefined in terms of sys-