Subsidence, crustal structure, and thermal evolution of Georges Bank basin
B. Ann Swift, D. S. Sawyer, J. A. Grow, Kim D. Klitgord
1987, American Association of Petroleum Geologists Bulletin (71) 702-718
A geophysical study of Georges Bank basin defines a deep crustal structure that is interpreted in terms of the basin's tectonic and thermal history. Gravity models along three basin cross sections delineate two zones of crustal thinning at the basement hinge zone and oceanic crustal margins. These two zones bound...
Seismic stratigraphy and facies of continental slope and rise seaward of Baltimore Canyon Trough
John S. Schlee, K. Hinz
1987, American Association of Petroleum Geologists Bulletin (71) 1046-1067
As part of a survey of the United States continental rise seaward of the northern Baltimore Canyon Trough, four major depositional sequences were mapped on a grid of 2,350 km of multichannel seismic reflection profiles. The sequences, which range in age from Jurassic (?) to Quaternary, record a gradual sedimentary...
Unusual larval habitats and life history of chironomid (Diptera) genera
Patrick L. Hudson
1987, Entomologica Scandinavica Supplements (29) 369-373
Ninety-three genera, representing all subfamilies of Chironomidae, are organized into 9 categories of unusual habitats or life history including hygropetric, riparian (bank, floodplain, upland), hyporheic, symbiotic, and intertidal; others live in water held in plants or mine into unusual substrates. In riparian zones precise location of optimum habitat is difficult...
Recent changes in Lake Michigan's fish community and their probable causes, with emphasis on the role of the alewife (Alosa pseudoharengus)
Gary W. Eck, LaRue Wells
1987, Canadian Journal of Fisheries and Aquatic Sciences (44) 53-60
Deepwater ciscoes (Coregonus spp.) or "chubs" of Lake Michigan far surpassed those of Lake Huron in yield, population density, and resilience following severe depletion in the 1960s and 1970s, when the bloater (C. hoyi) composed more than 90% of the stocks. The population decline of bloaters in recent decades was mainly attributed...
Dispersal of three strains of hatchery-reared lake trout in Lake Ontario
Joseph H. Elrod
1987, Journal of Great Lakes Research (13) 157-167
Rates of dispersal and resultant geographical distributions were determined for three strains of hatchery-reared lake trout (Salvelinus namaycush) stocked at six sites in U.S. waters of Lake Ontario. The strains were Lake Superior (SUP); Clearwater Lake, Manitoba (CWL); and Seneca Lake,...
Seasonal bathythermal distribution of juvenile lake trout in Lake Ontario
Joseph H. Elrod, Clifford P. Schneider
1987, Journal of Great Lakes Research (13) 121-134
Bathythermal distributions of hatchery-reared lake trout (Salvelinus namaycush) of three genetic strains (Lake Superior; Clearwater Lake, Manitoba; and Seneca Lake, New York) were described from catches with bottom trawls in Lake Ontario during April-May, June, July-August, and October, 1978–1984. This work was part of a program to evaluate post-stocking performance...
Dynamics of the recovery of the western Lake Erie walleye (Stizostedion vitreum vitreum) stock
Richard W. Hatch, Stephen J. Nepszy, Kenneth M. Muth, Carl T. Baker
1987, Canadian Journal of Fisheries and Aquatic Sciences (44) 15-22
After its 1957 collapse under intensive fishing and environmental stresses, the walleye (Stizostedion vitreum vitreum) stock of western Lake Erie remained low throughout the 1960s. A moratorium on both sport and commercial fishing, resulting from the 1970 discovery of mercury concentrations in walleye flesh, provided an opportunity for the development...
Meeting future information needs for Great Lakes fisheries management
W.J. Christie, John J. Collins, Gary W. Eck, Chris I. Goddard, John M. Hoenig, Mark Holey, Lawrence D. Jacobson, Wayne MacCallum, Stephen J. Nepszy, Robert O’Gorman, James Selgeby
1987, Canadian Journal of Fisheries and Aquatic Sciences (44) 439-447
Description of information needs for management of Great Lakes fisheries is complicated by recent changes in biology and management of the Great Lakes, development of new analytical methodologies, and a transition in management from a traditional unispecies approach to a multispecies/community approach. A number of general problems with the collection...
Prey fish dynamics and salmonine predator growth in Lake Ontario, 1978-84
Robert O’Gorman, Roger A. Bergstedt, Thomas H. Eckert
1987, Canadian Journal of Fisheries and Aquatic Sciences (44) 390-403
The size of hatchery-reared brown trout (Salmo trutta) and coho salmon (Oncorhynchus kisutch), 1 yr after release in Lake Ontario, declined when the stocking of salmonines was increased between 1978 and 1984. The principal prey species, alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax), failed to show the expected, predator-induced downturn...
Mechanics of gravitational spreading of steep-sided ridges («sackung»)
W. Z. Savage, D. J. Varnes
1987, Bulletin of the International Association of Engineering Geology (35) 31-36
Large-scale gravitational spreading of steep-sided ridges characterized by linear fissures, trenches, and uphill-facing scarps high on the sides and tops of ridges are known worldwide. Such spreading, termed sackung, is commonly attributed to pervasive plastic deformation of a rock mass, and is here analyzed as such. Beginning with a previously...
Earthquakes, September-October 1987
W. J. Person
1987, Earthquakes & Volcanoes (USGS) (19) 180-183
Predicting Great Lakes fish yields: tools and constraints
C.A. Lewis, D.H. Schupp, W.W. Taylor, J.J. Collins, Richard W. Hatch
1987, Canadian Journal of Fisheries and Aquatic Sciences (44) 411-416
Prediction of yield is a critical component of fisheries management. The development of sound yield prediction methodology and the application of the results of yield prediction are central to the evolution of strategies to achieve stated goals for Great Lakes fisheries and to the measurement of progress toward those goals....
Lake Superior revisited 1984
Wayne R. MacCallum, James H. Selgeby
1987, Canadian Journal of Fisheries and Aquatic Sciences (44) 23-36
The Lake Superior fish community has changed substantially since the early 1960s, when control of the sea lamprey (Petromyzon marinus) became effective. Self-reproducing stocks of lake trout (Salvelinus namaycush) have been reestablished in many inshore areas, although they have not yet reached pre-sea lamprey abundance; offshore lake trout are probably...
Acid rain stimulation of Lake Michigan phytoplankton growth
Bruce A. Manny, G.L. Fahnenstiel, W.S. Gardner
1987, Journal of Great Lakes Research (13) 218-223
Three laboratory experiments demonstrated that additions of rainwater to epilimnetic lake water collected in southeastern Lake Michigan stimulated chlorophyll a production more than did additions of reagent-grade water during incubations of 12 to 20 d. Chlorophyll a production did not begin until 3–5 d after the rain and lake water were mixed. The stimulation...
Horizontal ichthyoplankton tow-net system with unobstructed net opening
Robert T. Nester
1987, North American Journal of Fisheries Management (7) 148-150
The larval fish sampler described here consists of a modified bridle, frame, and net system with an obstruction-free net opening and is small enough for use on boats 10 m or less in length. The tow net features a square net frame attached to a 0.5-m-diameter cylinder-on-cone plankton net...
Effects of freezing in and out of water on length and weight of Lake Michigan bloaters
Richard E. Sayers
1987, North American Journal of Fisheries Management (7) 299-301
The purpose of this study was to determine if freezing significantly alters the length or weight of bloaters Coregonus hoyi. Bloaters were collected from southern Lake Michigan and were frozen for periods of 2-200 d. Freezing in water caused a significant decrease in length and a significant increase in weight....
15N/14N variations in Cretaceous Atlantic sedimentary sequences: Implication for past changes in marine nitrogen biogeochemistry
G.H. Rau, M.A. Arthur, W.E. Dean
1987, Earth and Planetary Science Letters (82) 269-279
At two locations in the Atlantic Ocean (DSDP Sites 367 and 530) early to middle Cretaceous organic-carbon-rich beds (“black shales”) were found to have significantly lower δ15N values (lower15N/14N ratios) than adjacent organic-carbon-poor beds (white limestones or green claystones). While these lithologies are of marine origin, the black strata in...
Aquifer response to recharge and pumping San Bernardino ground-water basin, California
W. F. Hardt, J. R. Freckleton
1987, Water-Resources Investigations Report 86-4140
No abstract available....
Feed conversion indices: Controversy or convention?
N. C. Parker
1987, Progressive Fish-Culturist (49) 161-166
Various methods of calculating and reporting the efficiency of food use in fish husbandry are examined. The effects of moisture content of feed and fish flesh, supplemental feeds augmented with natural feed items, differences in energy content due to feed formulations, and the usefulness of the various feed efficiency indices...
Diatoms and tonsteins as paleoenvironmental and paleodepositional indicators in a Miocene coal bed, Costa Rica.
J. D. Sanchez, J.P. Bradbury, B.F. Bohor, D. A. Coates
1987, Palaios (2) 158-164
The Venado Formation is composed of more than 300 m of mudstone, siltstone, sandstone, limestone, volcaniclastics, and coal beds. The coal beds are of unknown lateral extent and mainly occur in the middle part of the formation. Diatoms are a useful microscopic tool for identifying the depositional environments. They indicate...
The role of stand history in assessing forest impacts
V.H. Dale, T.W. Doyle
1987, Environmental Management (11) 351-357
Air pollution, harvesting practices, and natural disturbances can affect the growth of trees and forest development. To make predictions about anthropogenic impacts on forests, we need to understand how these factors affect tree growth. In this study the effect of disturbance history on tree growth and stand structure was examined...
Susceptibility of brook trout (Salvelinus fontinalis) to experimental infections with different serotypes of Yersinia ruckeri
R. C. Cipriano, T. Ruppenthal, W. B. Schill, S. W. Pyle, E.B. Schotts Jr.
1987, Microbios Letters (35) 27-31
Comparing geotechnical to geologic estimates for past overburden in the Pierre-Hayes, South Dakota area: an argument for in-situ pressuremeter determination ( USA).
D. S. Collins, T. C. Nichols Jr.
1987, Mountain Geologist (24) 51-54
A knowledge of past overburden thickness is useful for designing underground structures such as waste repositories. This study attempts to determine if a correlation can be made between a geologic estimate and two types of geotechnical calculations of past overburden thickness. In the Pierre-Hayes area, Late Cretaceous Pierre Shales is...
Crescentic dunes on the inner continental shelf off northern California
D.A. Cacchione, M.E. Field, D.E. Drake, G. B. Tate
1987, Geology (15) 1134-1137
Large crescentic dunes that resemble barchans have been discovered within elongate scour depressions on the northern California inner continental shelf by using side-scan sonar. These dunes appear to be migrating obliquely to the regional shelf gradient; a preferred offshore direction of transport is...
UTILIZATION OF GEOGRAPHIC INFORMATION SYSTEMS TECHNOLOGY IN THE ASSESSMENT OF REGIONAL GROUND-WATER QUALITY.
Douglas Nebert, Dean Anderson
1987, Conference Paper
The U. S. Geological Survey (USGS) in cooperation with the U. S. Environmental Protection Agency Office of Pesticide Programs and several State agencies in Oregon has prepared a digital spatial database at 1:500,000 scale to be used as a basis for evaluating the potential for ground-water contamination by pesticides and...
