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Iq ~~ ~1~'~~ cad ~~~~hhneK ~~~,~ <br />Conservation Genetics in the <br />Management of Desert Fishes <br />GARY K MEFFE' <br />University of Georgia's Savannah River Ecology Laboratory X03 _ 7 ~ ~ ,. ~ 4 ~ ~ <br />Drawer E <br />Ailten, SC 29801, U.S.A. <br />ROBERT C. VRIJENHOEK <br />Center for Applied Genetics <br />Cook College <br />Rutgers University <br />New Brunswick, NJ 08903, U.S.A. <br />AbsttacK: The status and security ojfrstres in North Ameri- <br />can deserts bane steadily declined in Ibis century due to <br />man's activities in this naturally fragile region 117e address <br />genetic aspects of the population shucture of desert fishes as <br />applicable to conservation and recovery programs by devel- <br />oping two zoogeographic models of rsotation and gene flow <br />In the Death Valley model; populations are isotatet~ with no <br />chance of natural gene flow among item Genetic diversity <br />within populations tends to be low, but genetic divergence <br />among populations within a species is high. In the Stream <br />Hierarchy model; a complicated hierarchical genetic struc- <br />ture exists and is a function of geographic praximity and <br />connectivity of habitats Within-habitat genetic diversity <br />tends to be higher, and among-habitat differentiation lower, <br />than in the Death Valley model These lwo systems must be <br />recognized as distinct and managed differently. TVe also sug- <br />gest three areas of experimentation needed to better under- <br />stand and manage genetic stocks of desert fishes relation- <br />ships between beterorygosity and jitnes~ experimental <br />mixing of similar stocks to examine effects of increased het- <br />erozygosity, and analysis of tbe relati:~e roles of genetic ad• <br />aptation anti phenotypic plasticity in local differentiation <br />Resumer: E! ettatus y la seguridad de los peces en los desi- <br />ertos Norteamericanos ha empeorado a un ritmo sostenrdo <br />durante este siglo debido a las actividades del hombre en <br />esta regi6n de naturaleza fragiL Discutimos aspectos gene- <br />tical de ta estructura pobtacional de peces del desierto con <br />respecto a su aplicabi[idad a programas de conservation y <br />recuperaci6n medtante el desarrollo de dos modelos zoo- <br />geograficos de aislamiento y flujo genetico. En el modelo de <br />Death Valley, las poblaciones estan aisladas, sin ni>{guna <br />oportunidad Para el flujo de material genetieo entre eltas La <br />diverstdad genetics dentro de estas poblaciones fiends a ser <br />bajq Pero ta dfvergencia genetics entre pobtaciones de una <br />especie dada es alto En el modelo de stream hierarchy, exists <br />una complicada estructura genetics jerarqurzada y esta esta <br />dada en funcion de la praximutad geogrkfica y ta conectiv- <br />idad de habitats La diversidad genetics al interior de un <br />habitat fiends a ser mbs alts y ta diferencuicion entre ha- <br />bitats mcis Baja que tas del modelo de Death Valley. Debe <br />reconocerse que estos dos sutemas son dtstintos y deben ser <br />manejados dijerentements Tambien sugertmos tres areas de <br />experimentaci6n requeridaspara comprendery manejarme- <br />jor los stocks geneticos de peces del desierto: relaciones enire <br />heterocigoticidad y adecuacion, mezcla experimental de <br />stocks simitares pars examinar los efectos al aumento de <br />beterocigotttida~ y el anklisis de los roles retativos de ta <br />adaptacYOn genetics y ta ptasttcidad fenotipica con respecto <br />en ta diferertciacion local <br />Correspondence sbou/d be addreuer! Jo G x MefJe <br />157 <br />Conservation Biology <br />Volume 2, No. 2, June 1~8 <br />