Geology topics

Research about Lake Ontario

Source-linked reports with geographic coverage including Lake Ontario.

138 records · Page 8Linked to original sources

USGS2002

The relationship between the abundance of smallmouth bass and double-crested cormorants in the eastern basin of Lake Ontario

Available population and diet data on double-crested cormorant ( Phalacrocorax auritus ) and smallmouth bass ( Micropterus dolomieui ) numbers, demographics, and exploitation rates were synthesized to examine the relationship between cormorant and smallmouth bass abundance in the U.S. waters of the eastern basin of Lake Ontario. It was found that after the number of cormorants nesting on Little Galloo Island in New York exceeded 3,500 pairs in 1989, survival of young smallmouth bass, not yet of legal size for the sport harvest (< 305 mm), began to decline. Despite production of strong year classes in 1987 and 1988, abundance of smallmouth bass measured from gill net surveys declined to its lowest level by 1995 and remained there through 1998. Stable or increasing catch and harvest rates in other local fisheries along the U.S. shore suggested that declines in smallmouth bass abundance in the eastern basin were not related to water quality. Stable or increasing growth rates for smallmouth bass age 2 and older since the 1980s further indicated that food resource limitation was also not the cause for declines in abundance. Comparisons of estimates of size and age-specific predation on smallmouth bass by cormorants with projected smallmouth bass population size indicated that much of the increased mortality on young smallmouth bass, could be explained by cormorant predation.

Lake Ontario↗

USGS1996

Fecundity of hatchery lake trout in Lake Ontario

Fecundity (egg number) was determined from 26 stocked (617-800 mm, total length) lake trout (Salvelinus namaycush) collected in western Lake Ontario during September 1992. Previous to this study, fecundity was evaluated only once in Lake Ontario using native stocks in 1927. The following relationships between fecundity and total length (TL) and weight (W) were obtained. Fecundity = -12,492 + 25.87 TL(mm) and Fecundity = -1,010 + 1,307 W(kg). Relative fecundity (number of eggs per kg of body weight) was unrelated to body weight and averaged 1,592 eggs kg -1 . Fecundity of contemporary lake trout based on length was significantly lower than that of historic native stocks, but was similar to contemporary stocked lake trout in Lake Superior.

Lake Ontario↗

USGS1996

Predation by sea lamprey (Petromyzon marinus) on lake trout (Salvelinus namaycush) in southern Lake Ontario, 1982-1992

Dead lake trout ( Salvelinus namaycush ) killed by sea lamprey (P etromyzon marinus ) were collected from the bottom of Lake Ontario using bottom trawls. The number of dead lake trout per hectare could be predicted from the number of type A-1 sea lamprey marks observed on live fish in September gillnet surveys ( r 2 = 0.60, P < 0.01) but not from the sum of marks of types A-1, A-2, and A-3 combined. Sea lamprey selectively attacked and killed the largest lake trout. The lengths and ages of live fish with A-1 marks increased as the population of longer, older lake trout in the lake increased, and the length distributions of fish killed by sea lamprey were not different ( P > 0.05) from those of live fish with A-1 marks in 5 of 6 years where comparisons could be made. Compared with Lake Superior strain lake trout, Seneca Lake strain fish were only 0.41 times as likely to be attacked by sea lamprey and were less likely to die from an attack (both differences P < 0.05). Conservative estimates of the numbers of lake trout killed by sea lamprey in southern Lake Ontario from October to mid-November ranged from 17,000 in 1988 to 121,000 in 1984.

New York, Ontario↗

USGS1994

Deep structure beneath Lake Ontario: Crustal-scale Grenville subdivisions

Lake Ontario marine seismic data reveal major Grenville crustal subdivisions beneath central and southern Lake Ontario separated by interpreted shear zones that extend to the lower crust. A shear zone bounded transition between the Elzevir and Frontenac terranes exposed north of Lake Ontario is linked to a seismically defined shear zone beneath central Lake Ontario by prominent aeromagnetic and gravity anomalies, easterly dipping wide-angle reflections, and fractures in Paleozoic strata. We suggest the central Lake Ontario zone represents crustal-scale deformation along an Elzevir–Frontenac boundary zone that extends from outcrop to the south shore of Lake Ontario.Seismic images from Lake Ontario and the exposed western Central Metasedimentary Belt are dominated by crustal-scale shear zones and reflection geometries featuring arcuate reflections truncated at their bases by apparent east-dipping linear reflections. The images show that zones analogous to the interpreted Grenville Front Tectonic Zone are also present within the Central Metasedimentary Belt and support models of northwest-directed crustal shortening for Grenvillian deep crustal deformation beneath most of southeastern Ontario.A Precambrian basement high, the Iroquoian high, is defined by a thinning of generally horizontal Paleozoic strata over a crestal area above the basement shear zone beneath central Lake Ontario. The Iroquoian high helps explain the peninsular extension into Lake Ontario forming Prince Edward County, the occurrence of Precambrian inlier outcrops in Prince Edward County, and Paleozoic fractures forming the Clarendon–Linden structure in New York.

Lake Ontario↗

USGS1993

Genetic comparison of naturally spawned and artificially propagated Lake Ontario lake trout fry: Evaluation of a stocking strategy for species rehabilitation

Two strategies have been used in the effort to restore lake trout Salvelinus namaycush to Lake Ontario. First, lake trout strains from multiple wild and hatchery sources have been stocked to maximize genetic variability in the lake, Second, a unique hatchery “strain” of fish to be stocked was created each year with gametes collected from adult, hatchery‐origin fish that had survived to maturity after being stocked into Lake Ontario. Several hatchery strains may be represented among the adults captured and used to propagate this unique strain, termed the “Ontario strain.” The “Ontario strain” may have a genetically based potential for enhanced survival over other strains stocked in Lake Ontario because it is composed of the progeny of fish that have survived from the yearling to the adult life stage, Unlike naturally spawned fish, however, the “Ontario strain” has been shielded from natural selection during the critical period of mortality from spawning through the first year of life, The purpose of this study was to determine whether the “Ontario strain” was genetically representative of the wild fry produced in the lake, We examined the strain composition of three year‐classes of wild‐caught fry and six year‐classes of the “Ontario strain” using allozyme data with mixed‐stock analysis. The hatchery and wild fry were genetically dissimilar. In addition, the composition of the “Ontario strain” changed from predominantly Seneca strain in 1983–1984 to predominantly Superior and Killala strains from 1983 to 1989. Mixed‐stock estimates indicated that in contrast to the hatchery‐reared fry, strain composition of wildcaught fry did not vary greatly from year to year. Progeny of Seneca × Seneca crosses were the predominant fry in the three year‐classes of wild fry. The genetic dissimilarity between the “Ontario strain” fry and wild‐caught fry could be caused by differential mortality among the wild fry between spawning and fry emergence or by differential vulnerability of strains to the gill‐net sampling used to capture adults for gamete collection. Based on these results, the development of a new hatchery brood stock from wild‐caught fry is recommended as an alternative to the collection and propagation of gametes from mature hatchery‐origin lake trout. In addition, the composition of the hatchery strains stocked should be altered to emphasize those strains that reproduce successfully. Both options should be considered in order to speed the rehabilitation process.

Lake Ontario↗

USGS1992

Effect of stocking season and technique on survival of lake trout in Lake Ontario

To identify the stocking season and technique that resulted in maximum contribution of hatchery‐reared lake trout Salvelinus namaycush to the population in Lake Ontario, paired lots of yearlings were stocked near shore in March, near shore in May, and offshore by helicopter in May. All mortality associated with stocking season and technique apparently had occurred by age 2. Therefore, survival comparisons were based on combined recoveries of age‐2 and older fish. We found statistically significant differences in survival ratios for 19 of 30 comparisons among individual paired lots, but results were not consistent. For example, among 17 comparisons of lake trout stocked near shore in May and offshore in May, survival was significantly better for fish stocked near shore in four cases and for fish stocked offshore in six cases. With fish stocked near shore in May used as the control group, mean survival ratios (near shore March : near shore May : offshore May) were 0.86:1.00:1.12. However, the 95% confidence interval indicated that the survival ratios were not significantly different from 1:1:1. Variables other than stocking date and technique apparently had a major influence on survival of lake trout following stocking in Lake Ontario. Predation by large salmonids may have been the dominant mechanism affecting survival.

Lake Ontario↗

USGS1989

Genetic differentiation among lake trout strains stocked into Lake Ontario

The lake trout Salvelinus namaycush is the focus of an international effort by fishery management agencies to restore this once‐native species to Lake Ontario. Evaluation of reproductive success and comparisons among stocked lake trout strains require genetic markers. We used allozyme variation to make genetic comparisons among strains of lake trout stocked into Lake Ontario. Forty‐two proteins presumed to be encoded by 102 loci were resolved electrophoretically; 18 loci were polymorphic. Among 16 samples from five principal origins (Finger Lakes, Great Lakes basin, northern New York–Adirondack, Manitoba, and mixed origins–Lake Ontario), the average observed heterozygosity was 0.029, and the proportion of polymorphic loci was 0.125. Significant differences occurred among the 16 samples at all 18 possible locus comparisons. The average F st value was 0.14. Hierarchical analysis indicated that the variation among samples within an origin was greatest within the Great Lakes basin, which included the greatest number of samples and represented the largest geographic area. Most variation observed among samples, however, occurred among origins. The 1983 and 1984 hatchery year classes produced from the 1978 Seneca brood stock did not differ significantly. The 1981 Seneca brood stock more closely resembled the sample of wild lake trout from Seneca Lake than progeny from the 1978 brood stock. The closer affinity of the 1981 brood stock to wild Seneca lake trout may be due to the larger number of wild adults from Seneca Lake used to found these fish than was used to establish the 1978 brood stock. Siscowet (“fat”) and “lean” lake trout from Lake Superior were significantly different from each other; however, the level of variation between them was not greater than that among samples from other origins, and thus did not support recognition of siscowet lake trout as a distinct subspecies. The Jenny Lake strain possessed a genetic affinity to the siscowet sample from Lake Superior. Historical reports about the origin of this strain suggest that siscowet lake trout from northern Lake Michigan may have been used to found this strain. Therefore, the Jenny Lake strain may serve as a gene source for the establishment of the siscowet lake trout in Lake Ontario. The substantial differentiation among lake trout strains reported here supports the feasibility of using allozyme markers to identify the parental sources of naturally produced young.

Lake Ontario↗

USGS1988

Assessment of sea lamprey ( Petromyzon marinus ) predation by recovery of dead lake trout ( Salvelinus namaycush ) from Lake Ontario, 1982-85

During 1982-85, 89 dead lake trout ( Salvelinus namaycush ) were recovered with bottom trawls in U.S. waters of Lake Ontario: 28 incidentally during four annual fish-stock assessment surveys and 61 during fall surveys for dead fish. During the assessment surveys, no dead lake trout were recovered in April-June, one was recovered in August, and 27 were recovered in October or November, implying that most mortality from causes other than fishing occurred in the fall. The estimated numbers of dead lake trout between the 30- and 100-m depth contours in U.S. waters ranged from 16 000 (0.08 carcass/ha) in 1983 to 94 000 (0.46 carcass/ha) in 1982. Of 76 carcasses fresh enough to enable recognition of sea lamprey ( Petromyzon marinus ) wounds, 75 bore fresh wounds. Assuming that sea lamprey wounding rates on dead fish were the same as on live ones of the same length range (430-740 mm), the probability of 75 of the 76 dead lake trout bearing sea lamprey wounds was 3.5 x 10 -63 if death was independent of sea lamprey attack, thus strongly implicating sea lampreys as the primary cause of death of fish in the sample. The recovery of only one unwounded dead lake trout also suggested that natural mortality from causes other than sea lamprey attactks is negligible.

Lake Ontario↗

USGS1986

Dynamics of alewives in Lake Ontario following a mass mortality

The U.S. Fish and Wildlife Service and the New York Department of Environmental Conservation assessed the population of alewives Alosa pseudoharengus in U.S. waters of Lake Ontario during 1976–1982 with bottom trawls. Alewives were abundant in 1976 but a die-off greatly reduced their numbers during the winter of 1976–1977. The population quickly recovered, however, adult abundance increasing nearly sevenfold during 1978–1981. In spring 1981 the bottom population in southern Lake Ontario was estimated to be 5.25 × 10 9 fish weighing 128,500 t. Estimated average alewife biomass per hectare during 1978–1982 far exceeded the estimates for either Lake Michigan during 1967–1982 or western Lake Huron during 1973–1982. Recruitment of age-II fish to the population was affected by abundance of adults in two ways: (1) the number of yearlings produced was directly related to adult abundance at low population levels but inversely related at high population levels; and (2) survival of yearlings to age II was inversely related to adult abundance. Growth in 1977 was exceptional, leaving a wide, unmistakable band on scales of the previously slow-growing adults. This wide growth zone served as a marker to identify survivors of the 1976–1977 die-off and to show that each year after 1978 a successively larger proportion of survivors was failing to grow in length or to form an annulus (54% in 1979, 96% in 1980, and 100% in 1981). There was no marker on scales of alewives recruited after the die-off, but the apparent age composition of our catches strongly suggested that most of them also failed to grow in 1981.

Transactions of the American Fisheries Society↗

USGS1979

Lake Ontario geological and geophysical data sources

A bibliography of various geological and geophysical data sources was compiled as part of an overall effort to evaluate the status of research on the Great Lakes. We hope that such a summary will be a catalyst for additional work and be an aid in planning future work. Our presentation has two forms: maps showing the locations of the different data types and a bibliography which lists the references from the maps and additional relevant papers. The charts shown in this map summarize the data source for Lake Ontario.

Lake Ontario↗

USGS1975

Dynamics of turbidity plumes in Lake Ontario

Large-turbidity features along the 275-kilometre long south shore of Lake Ontario were analyzed using LANDSAT-1 images. The ESIAC system developed by the Stanford Research Institute, was used to obtain enlargements and false-color renditions of turbidity plumes. After projection on a video screen, individual turbidity features were analyzed, mapped, and photographed. The Niagara River plume, as much as 500 square kilometres in area, is by far, the largest turbidity feature in the lake. Based on image tonal comparisons, turbidity in the Welland Canal is usually higher than that in any other watercourse discharging into the lake throughout the shipping season. Somewhat less turbid water enters the lake from the Port Dalhousie diversion channel and the Genesee River. Relatively clear water resulting from the deposition of suspended matter in numerous upstream lakes is discharged by the Niagara and Oswego rivers. Plume analysis corroborates the presence of a prevailing eastward flowing longshore current along the entire south shore. This current is most persistent at the Oswego River outlet but is quite variable in the Rochester embayment, where rapid shifts in water movement were occasionally detected in LANDSAT images. The position of the spring thermal bar, a zone, of maximum density water corresponding to the 4°C isotherm, was approximately located in images obtained during April 1973. Although eastward moving currents were detected on the inshore side of the thermal bar, westward moving counter currents seem to be dominant along its offshore side. Plumes generated by beach erosion were readily detected in the images. Such areas are identified by light to very light, long, narrow plumes paralleling the coastline. Extensive areas of the south shore are subject to erosion, but the most severely affected beaches are situated between Fifty Mile Pt., Ontario and Thirty Mile Pt., N.Y., along the Rochester embayment, and between Sodus Bay and Nine Mile Pt. Color illustrations of figure accession numbers EDC-010077 to EDC-010106 are available for purchase from the EROS Data Center, Sioux Falls, South Dakota 57198.

Lake Ontario↗

USGS1973

Remote sensing of turbidity plumes in Lake Ontario

High-altitude photography provides an effective method of monitoring the spatial extent of turbidity plumes in Lake Ontario. Large plumes generated by the Niagara, Genesee, and Oswego Rivers are identifiable on photographs obtained from about 60,000 feet above the lake on July 6, 1970, October 19, 1970, and May 29, 1971. The Niagara plume, covering as much as 43 sq mi of the lake's surface, is the largest turbidity feature. The configuration of the plumes is a function of river discharge, level of turbidity, and wind speed and direction.

Journal of Research of the U.S. Geological Survey↗