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These data were compiled to evaluate the reproductive ecology of Agassiz's desert tortoises (Gopherus agassizzi) in the Sonoran Desert of California using two populations within Joshua Tree National Park, including five reproductive seasons that spanned 20 years (1997-1999, 2015-2016). Compared to their conspecifics inhabiting the Mojave Desert, the reproductive ecology of G. agassizii in the Sonoran Desert is understudied. Climatic variation between the two deserts can affect reproductive ecology, including fecundity and clutch phenology. Mature female tortoises (straight-line carapace length ≥ 20 cm) outfitted with radiotransmitters were located and X-radiographed approximately every 10-14 days during the reproductive...
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Macrhybopsis reproduction and propagule traits were studied in the laboratory using two temperature regimes and three hormone treatments and which methods produced the most spawns. Only sicklefin chub (M. meeki) spawned successfully although sturgeon chub (M. gelida) released unfertilized eggs. All temperature and hormone treatments produced M. meeki spawns, but two treatments had similar success rates at 44 and 43%, consisting of a constant daily temperature with no hormone added, or daily temperature fluctuations with hormone added to the water. Spawns consisted of multiple successful demersal circular swimming spawning embraces interspersed with circular swims without embraces. The most spawns observed for one...
Using a variety of sampling techniques and observations we describe aspects of the reproductive ecology and early life-history of Bear Lake sculpin, Cottus extensus, a species endemic to Bear Lake, Utah-Idaho. Adult sculpin spawned in shallow water (0.5-6.0 m depths) in cavities beneath large cobbles and boulders. During 1993, egg mass densities were highest (> 4.0 m(2)) at 1.0-2.0 m depths. Electivity indices verified substrate selection and also indicated an avoidance of sand- and gravel-embedded materials. During years of low water elevation, suitable spawning substrates were restricted to one Or two limited areas of the lake and comprised < 0.004% of the total benthic area. Disturbance from turbulence, as would...
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Broodstock, individual Faxonius quadruncus, were collected for culturing eggs until hatch. Hatchling crayfish were to be used in toxicity testing to assess hazards of metals mixtures to young Faxonius quadruncus
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Mule deer (Odocoileus hemionus) fawn:doe (f:d) ratios in December have declined by 0.015 fawns/doe/year from 1972 through 1995 in Colorado, USA. To determine whether lower pregnancy or fetal production was the cause of low December f:d ratios, we estimated mule deer pregnancy rates in the Poudre River drainage during January 1998 and pregnancy and fetal rates on the Uncompahgre Plateau during February 1999. Twenty-seven (93.1%) of 29 yearling and adult does in the Poudre River drainage were detected pregnant with pregnancy-specific protein-B (PSPB). This proportion did not differ (P > 0.2) from the proportion of yearling and adult does that were pregnant when collected by various methods in previous studies in Colorado....
The single greatest obstacle to the restoration of large, healthy, populations of bighorn sheep (Ovis canadensis) in the western United States is epizootic outbreaks of bronchopneumonia that may kill 20?100% of the animals in populations. Although the species is capable of rapid initial growth rates following restoration into new habitat (? = 1.23?1.30 have been observed), these rates of increase are typical only a few years following the release of a population, and then most populations either decline to extirpation or remnant status (<30 animals) or remain at <100 individuals. We studied the fecundity and survivorship of three increasing, and three declining and suspected diseased, populations of bighorn sheep...
The single greatest obstacle to the restoration of large, healthy, populations of bighorn sheep (Ovis canadensis) in the western United States is epizootic outbreaks of bronchopneumonia that may kill 20–100% of the animals in populations. Although the species is capable of rapid initial growth rates following restoration into new habitat (λ = 1.23–1.30 have been observed), these rates of increase are typical only a few years following the release of a population, and then most populations either decline to extirpation or remnant status (<30 animals) or remain at <100 individuals. We studied the fecundity and survivorship of three increasing, and three declining and suspected diseased, populations of bighorn...


    map background search result map search result map Long-Term Trends in Mule Deer Pregnancy and Fetal Rates in Colorado Reproductive strategy, spawning induction, spawning temperatures and early life history of captive sicklefin chub Macrhybopsis meeki-Data Female Faxonius (formerly Orconectes) quadruncus broodstock for toxicity testing Reproductive ecology data for female Agassiz's desert tortoises (Gopherus agassizii) in Joshua Tree National Park, USA Reproductive ecology data for female Agassiz's desert tortoises (Gopherus agassizii) in Joshua Tree National Park, USA Female Faxonius (formerly Orconectes) quadruncus broodstock for toxicity testing Long-Term Trends in Mule Deer Pregnancy and Fetal Rates in Colorado