7774

• UCREFRP Catalog Number: 7774
• Author: Desert Fishes Council, H., Dean A., ed.)‎.
• Title: Proceedings of the Desert Fishes Council Volume XXIV, 1992 Annual Symposium, 18 to 21 November, Mesa, Arizona.
• USFW Year: 1992.
• USFW - Doc Type: November 18-21.
• Copyright Material: NO

ABSTRACTS OF PRESENTATIONS IN ORDER PRESENTED
En este estudio investigamos la variabilidad (43 loci) en C. formosa de 5 cuencas y C. bocagrande en Ojo Solo.
Usando Cyprinella lepida y Cyprinella lutrensis como grupos externos de comparaci6n, hip6tesis filogeneticas (distancia
de Wagner, PAUP, FREQPARS) fueron usadas para evaluar modas similares de especiaci6n y tasas de divergencia que
operan dentro de este grupo de especies.
LANG, B. K.*; PLATANIA, S. P. (UNM Ichthyofaunal Studies Program, DepaRment of Biology, University of New Mexico, Albuquerque, NM)
Current distribution and status of the Rio Grande silvery minnow, Hybognathus amarus /
Distribucian actual y situaci6n del charalito plateado del Rio Grande, Hybognathus amarus
KEYWORDS: Hybognathus amarus; Rio Grande; New Mexico
ABSTRACT
The Rio Grande silvery minnow, Hybognathus amarus, has experienced a 95 % reduction in its historic range and
currently is known only from the Middle Rio Grande in New Mexico. Demands by water users, fluctuations in regional
precipitation patterns, and the decline in native fish populations stimulated the need for systematic survey to determine
the conservation status of the middle Rio Grande ichthyofauna with specific focus on H. amarus. The first phase of a
five-year cooperative study was initiated in 1992 and designed to document the present distribution and status of H.
amarus. The study area consisted of three distinct zones, demarcated by drainage diversion structures, along a 186 km
reach of the middle Rio Grande from Cochiti Reservoir downstream to Elephant Butte Reservoir. Hybognathus amarus
was taken in 46 of 81 (57%) mainstem Rio Grande collections and one irrigation canal return site. Over 82% (38 of 46)
of these occurrences were in the southern two regions (downstream of Isleta Diversion Dam) of the study area. While
eight sites upstream of Isleta Diversion Dam yielded H. amarus, none were taken in the 25 km reach between Angostura
Diversion Dam and Cochiti Reservoir.
RESUMEN
El charalito plateado del Rio Grande, Hybognathus amarus, ha experimentado una reducci6n del 95 % de su area
hist6rica de distribuci6n y actualmente se conoce solo de ]a regi6n central del Rio Grande en Nuevo M6xico. La demanda
de agua por usuarios, ]as fluctuaciones en los patrons regionales de precipitaci6n, el decline de las poblaciones nativas
estimularon la necesidad de estudios sistematicos para determinar el estado de conservaci6n de la ictiofauna de la regi6n
central del Rio Grande enfocado especificamente sobre H. amarus. La primera fase de un estudio cooperativo de cinco
anos fue iniciado en 1992 y fue disehado para documentar la distribuci6n actual y situaci6n de H. amarus. Este estudio
consisti6 de tres zonas distintas, demarcadas por ]a estructura de diversion de la cuenca, a to largo de un segmento de
186 km de la regi6n central del R. Grande desde la presa Cochiti rfo abajo hasta la Presa Elephant Butte. Hybognathus
amarus fue capturado en 46 de 81 (57%) colectas en el cauce principal del R. Grande y en un sitio dentro de un canal
de irrigacion. Mas del 82% (38 de 46) estas ocurrencia fueron en las dos regiones sur (rfo abajo de la Presa de
derivaci6n Isleta) del area de estudio. Mientras que en ocho sitios rfo arriba de la Presa de Derivaci6n Isleta se encontr6
H. amarus, ninguno fue capturado en el segmento de 25 km entre ]as Presas de Derivaci6n Angostura y Cochiti.
NAKAGAWA, P. A.; SOLTz, D. L.*; SANDERS, B. M. (PAN and BSM - Molecular Ecology Institute and Department of Biology,
CSULB, Long Beach, CA; DLS - Department of Biology, CSULB, Long Beach, CA)
The Role of Stress Proteins in the Physiological Adaptation of the Amargosa Pupfish,
Cyprinodon nevadensis / El papel de las proteinas "stress" en la adaptaci6n fisiol6gica del
cachorrito Amargosa Cyprinodon nevadensis
KEYWORDS: chaperonin; Cyprinodon; hsp70; heat-shock proteins; stress-70; stress proteins; thermotolerance
ABSTRACT
The cellular stress response or heat-shock response, is involved in protecting organisms from damage as a result
of exposure to a wide variety of environmental stressors. The response entails the rapid synthesis of a suite of proteins
referred to as stress proteins. These proteins are ubiquitous and highly conserved. Their synthesis is closely correlated
with acquired tolerance in which a conditioning heat shock confers the ability to survive a subsequent, more severe heat
shock that otherwise would be lethal to the organism. Two of these proteins, stress-70 and chaperonin, are molecular
chaperones which under normal conditions help maintain protein homeostasis. They also repair and protect other cellular
proteins from temperature induced damage.
Surprisingly, little is known about the role of stress proteins in organismic adaptation under natural environmental
conditions. If stress proteins are involved in this adaptation then we reasoned that an extensive stress protein response
would occur in species which have successfully colonized more unpredictable and extreme environments. Further,
studying differences in the stress response, perhaps differences in induction of stress protein synthesis or the appearance
of unique proteins, between subspecies with differential tolerances to environmental factors might allow the identification
of successful adaptive strategies.
To this end we have conducted an intraspecific study of the stress response in two subspecies of Amargosa pupfisb
Cyprinodon nevadensis which occupy different habitats. One subspecies, Cyprinodon nevadensis amargosae, lives in a
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