SEARCH · USGS Science
Results for “Life”
Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Life history strategies and habitat needs of the black brant
The black brant is a sea goose that depends on coastal habitats from high arctic nesting sites in Canada, Alaska, and Russia to wintering areas in the Pacific coastal states, the Baja California peninsula, and mainland Mexico estuaries. Population estimates are based on aerial surveys in Mexico, California, Oregon, and Washington during mid-winter. Despite much annual variability in estimates, a plot of the counts from 1964 to 1992 reveals a significant downward trend in the winter populations (Fig. 1). Three of four major colonies on the Yukon-Kuskokwim (Y-K) delta declined an average of 60% during the first half of the 1980’s. This is significant because about 79% of the world population of the black brant nest in these colonies (Table). Because few other breeding colonies have been consistently monitored, we have little understanding of their dynamics.
Ecological, morphological, genetic and life history characteristics of two sockeye salmon populations, Tustumena Lake, Alaska
Populations can differ in both phenotypic and molecular genetic traits. Phenotypic differences likely result from differential selection pressures in the environment, whereas differences in neutral molecular markers result from genetic drift associated with some degree of reproductive isolation. Two sockeye salmon, Oncorhynchus nerka, populations were compared using both phenotypic and genotypic characters, and causal factors were examined. Salmon spawning in a short (<3 km), shallow (<21 cm), clear, homogenous spring-fed study site spawned later, were younger, smaller, and produced fewer and smaller eggs than salmon spawning in a longer (∼80 km), deeper, stained, diverse, precipitation-dominated stream. Run timing differences were associated with differences in stream thermal regimes. Age and size at maturity differences are likely due to differences in age-specific mortality rates. Fish in the shallow spring-fed system suffered higher adult predation rates and exhibited greater egg to fry survival compared to fish in the precipitation-fed system. Salmon in both streams exhibited non-random nest site selection for deeper habitats and smaller substrates (≥2 to <64 mm mean diameter) relative to available habitat; fish from the precipitation system avoided low velocity habitats containing fine (<2 mm) substrates. Genetic comparisons of six microsatellite loci indicated that run time was a more effective reproductive isolating mechanism than geographical distance. Differences between and within the tributary spawning populations are discussed in terms of selection, genetic drift, and the homogenizing effects of gene flow. This study indicates important adaptive differences may exist between proximate spawning groups of salmon which should be considered when characterizing populations for conservation or management purposes.
Life and death of the Resurrection Plate
No abstract available.
Snake River Fall Chinook Salmon life history investigations
Predation by nonnative fishes is one factor that has been implicated in the decline of juvenile salmonids in the Pacific Northwest. Impoundment of much of the Snake and Columbia rivers has altered food webs and created habitat favorable for species such as Smallmouth Bass Micropterus dolomieu . Smallmouth Bass are common throughout the Columbia River basin and have become the most abundant predator in lower Snake River reservoirs (Zimmerman and Parker 1995). This is a concern for Snake River Fall Chinook Salmon Oncorhynchus tshawytscha (hereafter, subyearlings) that may be particularly vulnerable due to their relatively small size and because their main-stem rearing habitats often overlap or are in close proximity to habitats used by Smallmouth Bass (Curet 1993; Tabor et al. 1993). Concern over juvenile salmon predation spawned a number of large-scale studies to quantify its effect in the late 1980s, 1990s, and early 2000s (Poe et al. 1991; Rieman et al. 1991; Vigg et al. 1991; Fritts and Pearsons 2004; Naughton et al. 2004). Smallmouth Bass predation represented 9% of total salmon consumption by predatory fishes in John Day Reservoir, Columbia River, from 1983 through 1986 (Rieman et al. 1991). In transitional habitat between the Hanford Reach of the Columbia River and McNary Reservoir, juvenile salmon (presumably subyearlings) were found in 65% of Smallmouth Bass (>200 mm) stomachs and comprised 59% of the diet by weight (Tabor et al. 1993). Within Lower Granite Reservoir on the Snake River, Naughton et al. (2004) showed that monthly consumption (based on weight) ranged from 5% in the upper reaches of the reservoir to 11% in the forebay. However, studies in the Snake River were conducted soon after Endangered Species Act (ESA) listing of Snake River Fall Chinook Salmon (NMFS 1992). During this time, Fall Chinook Salmon abundance was at an historic low, which may explain why consumption rates were relatively low compared to those from studies conducted in the Columbia and Yakima rivers where abundance was higher (e.g., Tabor et al. 1993; Fritts and Pearsons 2004). We speculate that predation on subyearlings by Smallmouth Bass in the Snake River may have increased in recent years for several reasons. Since their ESA listing, recovery measures implemented for Snake River Fall Chinook salmon have resulted in a large increase in the juvenile population (Connor et al. 2013). Considering that subyearlings probably now make up a larger portion of the forage fish population, it is plausible they should make up a large portion of Smallmouth Bass diets. Second, migrating subyearlings delay downstream movement in the transition zones of the Clearwater River and Snake River for varying lengths of time (Tiffan et al. 2010), which increases their exposure and vulnerability to predators. Spatial overlap in locations of Smallmouth Bass and subyearlings that died during migration provides support for this (Tiffan et al. 2010). Finally, the later outmigration of subyearlings from the Clearwater River results in their presence in Lower Granite Reservoir during the warmest summer months when predation rates of Smallmouth Bass should be highest. In 2016, we focused our efforts on Smallmouth Bass predation in Lower Granite Reservoir downstream of the transition zones and the confluence area where we worked during 2012–2015. Similar to past years, our first objective was to quantify Smallmouth Bass consumption rates of subyearlings, determine relative bass abundance, and describe bass diets. In addition, Tiffan et al. (2016a) posited that predation risk to subyearlings may be higher in shoreline habitats that are more suitable for Smallmouth Bass and lower in shoreline habitats that are more suitable for subyearlings. To test this hypothesis, our second objective examines the relationship between Smallmouth Bass predation of subyearlings and habitat suitability.
Evolution and life-history organization of Yellowstone cutthroat trout
No abstract available.
Physiological ecology of amphibians and reptiles: Natural history and life history attributes framing chemical exposure in the field
No abstract available.
Biosecurity and regulatory considerations for transfer of cryopreserved sperm and early life stages of aquatic species
No abstract available.
Observations on the Life History of Ogcodes rufoabdominalis in Northern Utah (Diptera: Acroceridae)
Detailed observations were made on the emergence and feeding habits of the acrocerid parasite Ogcodes rufoabdominalis from lycosid spiders. One hundred and twenty field-collected hosts yielded six parasites in May. Eggs, first and third instars, and pupae are described for the first time, as well as mating and oviposition.
Snake River fall chinook salmon life history investigations, 2018 annual report
The following report is divided into three sections each of which describes work conducted by different project cooperators. Chapter One describes smallmouth bass (Micropterus dolomieu) predation on subyearling fall Chinook salmon (Oncorhynchus tshawytscha) in Lower Granite Reservoir in 2018. Smallmouth bass abundance increased seasonally in shoreline habitats and was highest in the lower reach of the reservoir (1,239 fish/km of shoreline). Abundance ranged from 40,743 to 81,595 in 2018. We examined the relationship between smallmouth bass predation and subyearling habitat suitability. Bass abundance was highest in “natural” habitat (i.e., habitat with natural substrate that was not deemed suitable for subyearlings) and fish were generally larger in habitat classified as “suitable” (i.e., habitat deemed suitable rearing) for subyearling Chinook salmon. Subyearlings were present in all habitat types sampled but their abundance was 2–3 times lower in the lower reach of the reservoir. Sand rollers (Percopsis transmontana)—a common prey of smallmouth bass—were present in greatest numbers in “suitable” habitat in the upper reach and “natural” habitat in the middle reservoir reach, but few were observed in the lower reservoir. The total loss of subyearlings to smallmouth bass predation in 2018 (120,023) was slightly less than one-half that of 2016 (266,988) and more than twice that of 2017 (47,830). Total sand roller loss in 2018 (149,106) was slightly more than one-half the losses estimated in 2016 and 2017. Chapter Two describes the feasibility of using stable isotopes of carbon and nitrogen to distinguish hatchery and natural origin subyearling fall Chinook salmon that were consumed by smallmouth bass. A discriminant function was fit from isotopic signatures and fork length from known-origin hatchery and natural subyearlings. The function had an overall correct classification rate of 97.2%. Of subyearlings consumed by smallmouth bass the function correctly classified 94.3% of hatchery fish but only 64.3% of natural fish based on fish origins that were validated with parentage-based tagging (PBT) analysis. Most of the fish consumed by smallmouth bass were of hatchery origin and most of those were of the spring/summer run early in the year and of the fall run later in the year. Based on analysis of known-origin hatchery fish collected at Lower Granite Dam through time following release, using stable isotopes as a discriminatory tool is probably only effective for about two weeks following release, but may have greater utility in unimpounded systems where fish emigrate seaward more quickly. The third section of this report is a Master’s Thesis that covers work conducted under contracts 46273 REL 14 and 79562. The first chapter of the thesis examined growth of subyearling fall Chinook salmon rearing in three sections of the Snake and Clearwater rivers and Lower Granite Reservoir. Growth and food consumption were highest in the reservoir section than in riverine sections, though growth was not significantly higher in the reservoir for the full duration of the study. Julian date was the strongest predictor of growth and consumption, and both growth and consumption decreased over the course of the study, even when accounting for allometric growth effects. Findings suggest that fish rearing in the reservoir section during their early growth period may have an ephemeral energetic advantage relative to fish rearing in natal river sections. The second chapter of the thesis examined the spatial variation in natal river rearing and downstream movement in Snake River fall Chinook salmon. Based on otolith analyses, natal origin was related to differential habitat use with fish from the Clearwater River accruing 48% of their freshwater growth in their natal river compared to 40% for Snake River fish. These differences were associated with different mean size at natal river exit and at ocean entry.
Book review of The bear doesn’t know-Life and wonder in bear country by Paul Schullery
No abstract available.
Effects of hard water precipitates on early life stage brook trout
Brook trout (Salvelinus fontinalis) have been extirpated from many karst-geology streams in West Virginia; however, the causes are not fully understood. Specifically, the impact of calcareous precipitate (marl), which is common in hard-water environments, has not been evaluated as an impediment to juvenile survival. Accordingly, two lab-based studies were conducted to determine if brook trout egg and alevin survival is inhibited by marl. In the first study, three aeration treatments were applied to a limestone spring source (13–14 C; ~300 mg L-1 hardness), resulting in different pH levels and an increasing degree of marl precipitate. Treatments included: raw/untreated (RU; no marl), once-aerated (OA; limited marl), and continuously aerated (CA; significant marl) water. Brook trout eggs obtained from a local hatchery were fertilized and stocked among gravel-filled trays receiving each water type. Mortality occurred faster in CA water where marl coated egg surfaces; however, cumulative survival was negligible for all water types. After 53 days, no surviving alevins remained in RU or CA, and 1% survival was observed in OA water; however, extra eggs maintained in a marl-producing system at 8 C without gravel demonstrated > 50% survival. A second study was carried out to investigate this discrepancy. Survival was evaluated at three temperatures with and without gravel while producing a thin coating of marl. Increased prevalence of alevin deformities and significantly lower survival were observed at 13.7 C versus 8.1 and 11.2 C, but gravel inclusion did not affect these variables. Potentially harmful effects of marl were observed; however, juvenile brook trout survival was higher during Study 2. This research suggests that brook trout reintroduction efforts in karst-geology streams should be focused on microhabitats with limited marl production and adequate water temperatures for juvenile survival.