Geology topics
G.G. Scoppettone
Publications and source records attributed to G.G. Scoppettone.
Implications of habitat restoration for managing an exotic crayfish at Ash Meadows National Wildlife Refuge
No abstract available
Information on status, demographics, and life history of five populations of tui chub in the Cow Head Lake Slough Basin
Abstract not available
Cui-ui, an overlooked prey for Pyramid Lake's nesting colony of American White Pelican
No abstract available
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.
Population viability analysis of Independence Lake Lahontan cutthroat trout
No abstract available
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.
Blue tilapia, Orechromis aureus, predation on native fishes of the Muddy River, Nevada
No abstract available
Using GIS and GPS to map seasonal distribution and relative density of Independence Valley speckled dace and Independence Valley tui chub
No abstract available
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.
Growth and survivorship of Moapa dace (Osteichthyes: Cyprinidae: Moapa coriacea) in an isolated stream reach on Moapa National Wildlife Refuge
No abstract available
Growth and longevity of the cui-ui and longevity of other catostomids and cyprinids in western North America
Annulus formation on opercula of the cui-ui Chasmistes cujus in Pyramid Lake, Nevada, was validated over an 8-year interval. Many fish were old, as old as 41 years of age, As many as three annuli were hidden (covered by supporting bone) in older fish. Growth was rapid during the first 10 years, slow from 10 to 20 years, and extremely slow or nil after 20 years. Age and growth were strongly correlated for about the first 10 years of life, but less so when fish became sexually mature. Examination of opercula of 15 additional species of large catostomids and cyprinids of western North America revealed that they were older than had previously been thought.