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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 847 records · Page 47Linked to original sources
USGS1984

Chronobiologic approach to aquaculture

Diel and seasonal changes in the environment directly or indirectly control many biological functions. Chronobiology, the study of biological functions in relation to time of day, time of year, lunar phases, and other consistent cues, could have important applications in aquaculture. Physiological conditions that vary seasonally include feeding time, tolerance of fish to stress, the state of gonad development, lipid and water content of muscle tissue, and the dress‐out weight of food fish. The quality of cultured fish may vary with the time of day when fish are fed, seined, graded, treated with therapeutic chemicals, injected with hormones, or physically disturbed. Efficiency of production and quality of aquacultural products might be improved if the activities of fish husbandry were timed to coincide with the biological rhythms of fish.

Transactions of the American Fisheries Society↗
USGS2011

Evidence for size-selective mortality after the first summer of ocean growth by pink salmon

Pink salmon Onchorhynchus gorbuscha with identifiable thermal otolith marks from Prince William Sound hatchery release groups during 2001 were used to test the hypothesis that faster-growing fish during their first summer in the ocean had higher survival rates than slower-growing fish. Marked juvenile pink salmon were sampled monthly in Prince William Sound and the Gulf of Alaska, and adults that survived to maturity were recovered at hatchery release sites the following year. Surviving fish exhibited significantly wider circuli spacing on the region of the scale formed during early marine residence than did juveniles collected at sea during their first ocean summer, indicating that marine survival after the first growing season was related to increases in early marine growth. At the same circuli, a significantly larger average scale radius for returning adults than for juveniles from the same hatchery would suggest that larger, faster-growing juveniles had a higher survival rate and that significant size-selective mortality occurred after the juveniles were sampled. Growth patterns inferred from intercirculi spacing on scales varied among hatchery release groups, suggesting that density-dependent processes differed among release groups and occurred across Prince William Sound and the coastal Gulf of Alaska. These observations support other studies that have found that larger, faster-growing fish are more likely to survive until maturity. ?? Copyright by the American Fisheries Society 2005.

Transactions of the American Fisheries Society↗
USGS1996

Balancing the three R's (regulation, research, and restoration) on the Kenai River, Alaska

The Kenai River is Alaska’s most popular salmon sport fishery. By attracting fishermen, the river contributes about $40 million annually to the local economy. Much of the fishing effort is in pursuit of the river’s chinook salmon, which are among the largest in the world. Many people benefit from the river through its numerous recreational opportunities or by making a living providing fishery support services. To preserve the fishery and the opportunities the river provides, we must find the proper balance of regulation, research, and restoration in the watershed.

Alaska↗
USGS2002

Simulation of hydrodynamics, temperature, and dissolved oxygen in Beaver Lake, Arkansas, 1994-1995

The tailwaters of Beaver Lake and other White River reservoirs support a cold-water trout fishery of significant economic yield in northwestern Arkansas. The Arkansas Game and Fish Commission has requested an increase in existing minimum flows through the Beaver Lake dam to increase the amount of fishable waters downstream. Information is needed to assess the impact of additional minimum flows on temperature and dissolved-oxygen qualities of reservoir water above the dam and the release water. A two-dimensional, laterally averaged hydrodynamic, thermal and dissolved-oxygen model was developed and calibrated for Beaver Lake, Arkansas. The model simulates surface-water elevation, currents, heat transport and dissolved-oxygen dynamics. The model was developed to assess the impacts of proposed increases in minimum flows from 1.76 cubic meters per second (the existing minimum flow) to 3.85 cubic meters per second (the additional minimum flow). Simulations included assessing (1) the impact of additional minimum flows on tailwater temperature and dissolved-oxygen quality and (2) increasing initial water-surface elevation 0.5 meter and assessing the impact of additional minimum flow on tailwater temperatures and dissolved-oxygen concentrations. The additional minimum flow simulation (without increasing initial pool elevation) appeared to increase the water temperature (<0.9 degrees Celsius) and decrease dissolved oxygen concentration (<2.2 milligrams per liter) in the outflow discharge. Conversely, the additional minimum flow plus initial increase in pool elevation (0.5 meter) simulation appeared to decrease outflow water temperature (0.5 degrees Celsius) and increase dissolved oxygen concentration (<1.2 milligrams per liter) through time. However, results from both minimum flow scenarios for both water temperature and dissolved oxygen concentration were within the boundaries or similar to the error between measured and simulated water column profile values.

Water-Resources Investigations Report↗
USGS1985

Fishery survey and related limnological conditions of Williams Lake, Hubbard County, Minnesota

Bluegill ( Lepomis macrochirus ), pumpkinseed sunfish ( Lepomis gibbosus ), largemouth bass ( Micropterus salmoides ), yellow perch ( Perca flavescens ) rock bass ( Amploplites rupestris ), black crappie ( Pomozis nigromaculatus ), and northern pike ( Esox lucius ) were found in Williams Lake, Hubbard County, Minnesota, during a fishery survey of the lake in late August 1982. The most abundant fish were the bluegills. These fish live in the large littoral zone of the lake; this zone underlies 55% of the surface area of the lake. The most ubiquitous benthic invertebrate in the littoral zone ( amphipods ) and the most abundant benthic invertebrate ( chironomid larvae ) were major food sources for the bluegill. Other organisms found in the stomach contents of fish collected in this survey were zooplankton, gastropods, Diptera larvae, odonates, terrestrial insects, and other fish. Daphnia were the only zooplankters of a diverse plankton community that were found in stomach contents. The abundance of fish other than bluegill was typical for a system in which northern pike is the major predator.

Minnesota↗
USGS1963

Age, growth, and maturity of round whitefish of the Apostle Islands and Isle Royale Regions, Lake Superior

The round whitefish has been of some commercial importance in the upper Great Lakes but production in Lake Superior has generally been small; the United States average was 26,600 pounds for 1929-59. This study is based on 1,173 fish collected in the Apostle Islands in 1958-60 and 103 collected at Isle Royale in 1958 and 1960. The average age of 6.0 years at Isle Royale was concluded to be significantly higher than the mean of 4.2 years in the Apostle Islands. The body-scale relation is a straight line with an intercept of 1.1 inches on the length axis. Weight of Apostle Islands round whitefish captured in several months increased as the 3.22 power of the length. Growth in length was relatively slow; nearly or fully 7 years were required to reach an acceptable commercial length of 14 inches in both the Apostle Islands and at Isle Royale. The calculated weights at the end of the seventh year were 12.6 ounces in the Apostle Islands and 13.8 ounces at Isle Royale. Minimum length at maturity of male round whitefish (7.0-7.4 inches) was less than that of females (8.5-8.9 inches). At age-group II, 11.1 percent of male round whitefish, but only 1.5 percent of the females were mature. All males were mature as age-group V and all females as age-group VI. Males dominated the younger age groups but females were more numerous in the older ones. Estimates of the number of eggs in 37 round whitefish ovaries yielded an average of 5,330 eggs for fish 10.5-17.4 inches long.

Fishery Bulletin↗
USGS1967

Residues in fish, wildlife, and estuaries. Indicator species near top of food chain chosen for assessment of pesticide base levels in fish and wildlife--clams, oysters, and sediment in estuarine environment

Federal efforts to determine pesticide levels in fish and wildlife are being carried out by the Bureau of Sport Fisheries and Wildlife, U. S. Department of the Interior. Monitoring estuarine pesticide levels in clams, oysters, and sediments is a joint endeavor of the Bureau of Commercial Fisheries, U. S. Department of the Interior, and the Water Supply and Sea Resources Program of the National Center for Urban and Industrial Health, Public Health Service, U. S. Department of Health, Education, and Welfare.

Pesticides Monitoring Journal↗
USGS1959

Mycobacterial infections in adult salmon and steelhead trout returning to the Columbia River Basin and other areas in 1957

The degree of incidence of acid -fast bacillus infections in adult salmonid fishes was determined. The disease was shown to be widely distributed in the area examined. It is believed the primary source of infection is derived from the hatchery practice of feeding infected salmon products to juvenile fish. One group of marked adults that had been hatchery reared for 370 days showed a 62 percent incidence of infection. A statistical analysis indicated that length of fish is independent of infection

California, Oregon, Washington↗
USGS2017

Comparison of oyster populations, shoreline protection service, and site characteristics at seven created fringing reefs in Louisiana: Key parameters and responses to consider

Coastal erosion threatens many low-lying areas around the globe. Rising sea levels from climate change are expected to increase coastal erosion and exacerbate flooding and storm surges. This is particularly true in low-lying coastal Louisiana, which developed as the Mississippi River changed course (delta switching) over the past 7000 years. Periods of land loss and gain resulted in an intricate coastal environment composed of shallow water areas with wetlands, swamps, barrier islands, and ridges (Day et al. 2007). This complex habitat sustains high economic and biological productivity, supporting the largest commercial fishery in the lower 48 states, providing habitat for important species of fish and wildlife, mitigating storm surge, and delivering protection for oil and gas production facilities, including five of the nation’s largest ports. Because of past and ongoing geological and physical processes, such as subsidence, sea level rise, tropical cyclonic activity, and direct human activities (Barras 2009; Chmura et al. 1992; Georgiou et al. 2005), coastal Louisiana is estimated to have lost an area almost the size of Delaware (4877 km2) between 1932 and 2010, with recent analyses indicating losses averaging 42.9 km2/year (Couvillion et al. 2011).

Book chapter↗
USGS2021

Angler-caught salmonid diets illustrate Lake Ontario Alewife population and predator-prey dynamics

Lake Ontario fisheries decision makers use information about the status and trajectory of prey fish populations, such as alewife, for salmonid sport fish management. In 2020, the April bottom trawl survey, typically used to assess alewife, was canceled the day after it began due to Coronavirus health concerns. This prompted NYSDEC and USGS science teams to initiate a diet study using angler-collected samples to provide information on the alewife population in 2020. Over 800 salmonid diets were collected from across Lake Ontario southern shore from May through September. Past diet studies illustrated alewife size distribution in piscivore diets overlapped April trawl survey-based distributions (proportion overlap = 0.51- 0.81, n = 5). In 2020 few age-1 sized alewife (40 - 140 mm) were observed in salmonid diets, suggesting that 2019 alewife reproduction was below average. Given that alewife reproductive success from 2017 and 2018 were also below average, the 2021 Lake Ontario adult alewife population will likely be at a record low for the 43-year time series. For all years and piscivore species, adult-sized Alewife ( total length > 140 mm) were the predominate size consumed by piscivores greater than 400 mm (~ 16 inches). Sizes of alewife in the diet were positively related to piscivore size. Diet composition, by dry weight, indicated alewife remain the dominant prey supporting salmonids and diets were generally similar to trawl-based estimates of prey fish community composition. The most notable deviation from this pattern included round goby, which comprised substantial portions of brown trout and lake trout diets in 2013 and 2020. These results inform decision making related to Lake Ontario salmonid stocking and predator prey dynamics and highlight the utility of angler-caught piscivore diets for indicating alewife population status.

Lake Ontario↗
USGS1987

Habitat Suitability Index Models: Juvenile English sole

English sole (Parophrys vetulus) is one of the major commercial groundfish species caught along the Pacific coast. Landings in the United States and Canada averaged 4,947 t/yr between 1975 and 1984, placing it third in importance among flatfish caught by Pacific coast trawlers (Pacific Marine Fisheries Commission 1985). Juvenile English sole are also among the most abundant fishes in many bays and estuaries along the Pacific (Westrheim 1955; Sopher 1974; Ambrose 1976; Rogers 1985). The English sole is not an important recreational species.

FWS/OBS↗
USGS1983

Species Profiles: Life histories and environmental requirements (Gulf of Mexico): Brown shrimp

Species profiles are literature summaries on the taxonomy, morphology, range, life history, and environmental requirements of coastal aquatic species. They are designed to assist in environmental impact assessment. The brown shrimp, Penaeus aztecus, is the major species in the Gulf of Mexico shrimp fishery, the most valuable $302 million in 1980) commercial fishery in the United States. It is heavily preyed on by many fishes. Spawning occurs offshore from about September to May and most postlarvae move into estuaries from February through April. Within the estuary they occupy shallow water near marshes with soft substrate. Juveniles emigrate from estuaries to offshore areas from May through August. They grow as fast as 3.3 mm per day in estuaries. Adults concentrate around the 55-m contour offshore. Postlarval and juvenile shrimp are normal1y taken in water temperatures above 10?C and rapid growth occurs above 18?C. Few shrimp are collected below 5 ppt salinity. Brown shrimp are benthic feeders and prefer soft substrates. High populatiorls are associated with coastal marshes.

FWS/OBS↗