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

PROCEEDINGS OF THE DESERT FISHES COUNCIL 1992 - VOLUME XXIV
monitoring is piecemeal or non-existent. Even if a state or federal agency is periodically monitoring a species (e.g.
Cyprinodon diabolis), the results are not usually published annually.
It must be recognized that this suggestion poses a major task, that based upon Williams, et al. (1989), could include
up to 170 taxa of fish in the United States and Mexico. If a single DFC member was designated as coordinator for each
species, it would include nearly every dues-paying member of DFC, a monumental undertaking for a relatively small
conservation organization. By combining species by basins and localities, the job could be made slightly simpler, but
would still be complex. The benefits of a continuous data base of periodic monitoring for trend analysis is obvious.
Perhaps special concern species would not need to be monitored annually, but could be placed on an every other year
schedule. Funding to cover travel and publication costs for the project may be available from state, federal or private
agencies and organizations.
RESUMEN
Propongo la creacion de el primer comite permanente del Consejo de los Peces del Desierto (DFC), un comite para
monitorear anualmente peces selectos en el Suroeste y publiear los hallazgos en una seccidn nueva de Conteos de especies
en las memorias anuales. En el pasado, los coordinadores de Cuencas del DFC ban reportado sobre unas pocas o todas
las especies encontradas en una. cuenca, pero el proceso de colecta de datos y monitoreo fueron informales. En ocasiones,
]a informacion viene de boca de un consultor o como parte de un esfuerzo de monitoreo estatal o federal, siendo
presentada oralmente a la reunion anual y no resumida por escrito. Frecuentemente, las especies no fueron monitoreadas
del todo por varios anos.
Puede ser fuertemente argumentado que el monitoreo de especies amenazadas, en peligro o de atencion especial
no es trabajo de una organizacion privada como DFC, pero deberfa serlo de agencias estatales o federales. Algunas
agencias estatales o federates de hecho estan monitoreando estos peces raros, usualmente en sus propios terrenos o
porciones. Sin embargo la distribucidn de muchas especies no esta unida por lineas estatales o regionales (ej. El Rio
Colorado, Peces del Rio Virgin) y el monitored es solo puntual o no existente. Alin si una agencia estatal o federal esta
monitoreando periodicamente una. especie (e.g. Cyprinodon diabolis), el resultado usualmente no es publicado
anualmente.
Debe de ser recordado que esta sugerencia posee un trabajo mayor, que basado en Williams, et al. (1989), podria
incluir a mas de 170 taxas de peces en los Estados Unidos y Mexico. Si un solo miembro del DFC fuera designado como
coordinador para cada especie, podria incluir casi a todos los miembros activos del DFC, una accidn monumental para
una organizacion de conservacion relativamente pequena.
Combinando especies con cuencas y localidades, el trabajo podria ser realizado facilmente, pero podria todavfa set
complejo, los beneficios de una base de datos continua de monitoreo periodico para andlisis de tendencias es obvio.
Quizds especies de atencion especial no requeriran ser monitoreadas anualmente, pero podrian ser colocados en un
calendario anual. El apoyo financiero para cubrir los viajes y los costos de publicacion para el proyecto podrian obtenerse
de agencias y organizaciones estatales, federales o privadas.
DuMAM, J. B.* (IBD - Department of Zoology, Arizona State University, Tempe, AZ)
Evolutionary genetics of natural and refugia populations of desert pupfish Cyprinodon
macularius / Genetica evolutiva de poblaciones naturales y de refugio del pez cachorrito del
desierto Cyprinodon macularius
KEYWORDS: Cyprinodon; Colorado River delta; Salton Sea; genetics; artificial refugia; habitat fragmentation
ABSTRACT
Patterns of allozymic variation are described from four natural and nine artificial refugia populations of the
Endangered desert pupfish secured from the Colorado River delta, Sonora, Mexico and Salton Sea, California, U.S.A.
Genetic variation among delta refugia is largely a result of differences in refugia derived from separate, but
geographically proximate collections on the Colorado River delta. Patterns of genetic variation in two of three pupfish
refugia established from the Salton Sea are not representative of their source populations. Observed divergence among
refugia is most likely a consequence of genetic drift and founder effects. An analysis of associations between four
population variables (time since founding, relative habitat size, number of founders and hierarchical position) and
observed heterozygosity in the six lower Colorado delta refugia detected only one significant association. The one
significant association suggests that variation in some ref igia has been lost as a result of serial bottlenecks. The results
of this study do not agree with previous studies that detected only minimal levels of allozymic variation among refugia
and natural populations of desert pupfish. Differences in electrophoretic technique are undoubtedly responsible for at least
part of this discrepancy.
Patterns of genetic variation in natural populations are explained in light of historical processes. It appears likely
that habitat fragmentation resulting from river modifications has led to genetic divergence among formerly contiguous
natural populations on the lower Colorado delta. In contrast, four natural populations from the recently flooded Salton
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