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Geology topics

P.H. Rissler

Publications and source records attributed to P.H. Rissler.

16 recordsLinked to original sources
USGS2011

Effects of population increase on cui-ui growth and maturation

Cui-ui Chasmistes cujus is endemic to Pyramid Lake, Nevada. The cui-ui population declined during much of the 20th century as a result of water diversion and the formation of a shallow and virtually impassable delta at the mouth of the Truckee River, its spawning habitat. The population increased more than 10-fold to more than 1 million adults after access to the river was restored, creating a period of relatively higher density. This change presented the opportunity to test intraspecific density effects on cui-ui age and length at maturity and on growth. We also compared the year-class structure of the adult population before and after improved access. At low density, cui-ui mean age at maturation was 9.2 years for males and 9.6 for females; at high density, it was significantly higher: 11.8 years for males and 12.0 for females. There was no significant change in mean fork length at maturity related to population increase. Growth patterns differed between high and low density, the low-density fish growing faster than high-density fish before their respective mean age of maturity; past their mean age at maturity, high-density fish grew significantly faster than low-density fish. Fish in both density periods reached similar lengths by about 19-20 years of age. Year-class structure for both density periods consisted of strong year-classes, which predominated the adult population for several years.

Transactions of the American Fisheries Society↗
USGS2005

Habitat restoration as a means of controlling non-native fish in a Mojave desert Oasis

Non-native fish generally cause native fish decline, and once non-natives are established, control or elimination is usually problematic. Because non-native fish colonization has been greatest in anthropogenically altered habitats, restoring habitat similar to predisturbance conditions may offer a viable means of non-native fish control. In this investigation we identified habitats favoring native over non-native fish in a Mojave Desert oasis (Ash Meadows) and used this information to restore one of its major warm water spring systems (Kings Pool Spring). Prior to restoration, native fishes predominated in warm water (25-32??C) stream and spring-pool habitat, whereas non-natives predominated in cool water (???23??C) spring-pool and marsh/slack water habitat. Native Amargosa pupfish (Cyprinodon nevadensis) and Ash Meadows speckled dace (Rhinichthys osculus nevadensis) inhabited significantly faster mean water column velocities (MWCV) and greater total depth (TD) than non-native Sailfin molly (Poecilia latipinna) and Mosquitofish (Gambusia affinis) in warm water stream habitat, and Ash Meadows speckled dace inhabited significantly faster water than non-natives in cool water stream habitat. Modification of the outflow of Kings Pool Spring from marsh to warm water stream, with MWCV, TD, and temperature favoring native fish, changed the fish composition from predominantly non-native Sailfin molly and Mosquitofish to predominantly Ash Meadows pupfish. This result supports the hypothesis that restoring spring systems to a semblance of predisturbance conditions would promote recolonization of native fishes and deter non-native fish invasion and proliferation. ?? 2005 Society for Ecological Restoration International.

Nevada↗
USGS2002

Status of the preston white river springfish (Crenichthys baileyi albivallis)

We determined the distribution and estimated population number of Preston White River springfish (Crenichthys baileyi albivallis) in summer 1998 and winter 1999. The total population was <5000 fish persisting in only 4 of 6 spring systems from which it had been previously captured. To improve its status, we recommend conservation measures.

Western North American Naturalist↗
USGS2000

Reproductive longevity and fecundity associated with nonannual spawning in cui-ui

The cui-ui Chasmistes cujus, a long-lived (40 years or more) and highly fecund catostomid, is often prevented from spawning in drought years. We studied the effect of cui-ui age on egg viability and the effect of nonannual spawning on fecundity in relation to length, age, and growth rate. Egg hatching and survival of swim-up larvae were examined for the offspring of first-time spawners, intermediate-aged females, and old females. Fecundity was tested for three growth categories (fast, intermediate, and slow) in years that were sufficiently wet to allow fish to spawn in the Truckee River and after dry years when fish did not spawn because of river inaccessibility. Females in the fast-growth category were first-time spawners, those in the middle-growth category were young to middle aged, and those in the slow-growth category were middle aged to old. Females up to 44 years of age still had viable eggs and a reproductive life of at least 29 years. Fecundity was greater after no-spawn years (dry year) compared with a spawn year (wet year), especially for fish in the slow-growth category. This study provides insight into the reproductive adaptation of a long-lived western North American catostomid and suggests possible reasons for the wide variation in fecundity in other long-lived catostomids. Our data will be used to improve the accuracy of an existing cui-ui population viability model. The revised model will have greater sensitivity to cui-ui survival relative to their spawning frequency and, thus, contribute to better management of conditions needed for the long-term survival of endangered cui-ui.

Nevada↗
USGS1998

The status of Moapa coriacea and Gila seminuda and status information on other fishes of the Muddy River, Clark County, Nevada

Moapa coriacea is endemic to the headwaters (Warm Springs area) of the Muddy River, Clark County, Nevada. The Warm Springs area was snorkeled and Moapa coriacea and Gila seminuda enumerated in August 1994 after a fire, and in May 1997 after a diversion dam had been removed from the downstream end. Gila seminuda had been reported in greatest abundance downstream from the Warm Springs area and we estimated the population there through mark and recapture from January to March 1995. There was a dramatic reduction in native fishes in the Warm Springs area between 1994 and 1997, coinciding with the invasion of Oreochromis aurea. Downstream from the Warm Springs area Gila seminuda was the most frequently netted species while O. aurea was relatively scarce. The fish population (native and non-native) decreased in a downstream direction; the causative factor(s) have not been identified.

Nevada↗