Effects of Artificial Propagation and the Weather on Recruitment in the Lake Ontario Whitefish Fishery

1963 ◽  
Vol 20 (3) ◽  
pp. 597-646 ◽  
Author(s):  
W. J. Christie
Keyword(s):  
Lake Trout ◽  
Lake Ontario ◽  
Climatic Conditions ◽  
Commercial Catch ◽  
Air Temperatures ◽  
Spawning Stock ◽  
Catch Statistics ◽  
The Times ◽  
One Year ◽  
Over Exploitation

No significant relationship could be found between variations in the level of fry planting and ensuing variations in the level of catch in the long-term statistics of the Lake Ontario whitefish gill-net fishery. An alternate-year planting experiment in which fry were planted in the even-numbered years 1944 through 1954, similarly failed to show a detectable level of contribution of the hatchery fish to the fishery. The supported year-classes averaged larger than those not given hatchery support but this was judged coincidental because of a phasing with an alternate-year periodicity which characterized the catch statistics over the whole series examined, and was present in the six years prior to the start of the alternate-year plantings. Estimates of spawning stock were calculated and it was not found that the progeny-per-parent ratios were significantly affected by the fry plantings.A possible explanation for the periodicity was suggested by a significant correlation between air temperatures at the times of spawning and hatching, and the strengths of the produced year-classes. Cold Novembers followed by warm Aprils appeared to provide conditions associated with the production of larger year-classes, with the opposite combinations relating to the weaker broods.The disappearance of lake trout and ciscoes from the commercial catch resulted in increased fishing pressure directed towards the capture of the whitefish. Increases in the efficiency and intensity of the fishing were observed during the period of the study and these were likely responsible for the reduction of the average age of the fish in the catch by almost one year, and the resultant restriction of the annual catch to one year-class in recent years. Probably because most of the fish are currently caught before first spawning, a decline in spawning stock was almost continuous during the study period. The year-to-year fluctuations in the level of the catch increased both because of the reduced average age, and because of a greater variation in year-class strength. The year-classes produced in favourable years tended to increase, down to quite low levels of stock. This gave a configuration similar to Ricker's Type C reproduction curve, and which differed chiefly in that the limiting diagonal representing minimum reproduction fell below the replacement diagonal. It was suggested that the whitefish may require more than one spawning, to achieve stock replacement. The present instability of the catch, and the potentially serious effect of any sustained break in the rhythm of the climatic conditions suggest a condition of over-exploitation in this case.

Lake Ontario: Effects of Exploitation, Introductions, and Eutrophication on the Salmonid Community

1972 ◽  
Vol 29 (6) ◽  
pp. 913-929 ◽  
Author(s):  
W. J. Christie
Keyword(s):  
Yellow Perch ◽  
Lake Trout ◽  
White Perch ◽  
Lake Ontario ◽  
Osmerus Mordax ◽  
Alosa Pseudoharengus ◽  
Commercial Catch ◽  
Sequence Of Events ◽  
Catch Statistics ◽  
Average Size

Commercial catch statistics were analyzed to follow the sequence of events in the deterioration of the major fish stocks of Lake Ontario. Atlantic salmon (Salmo salas), lake trout (Salvelinus namaycush), burbot (Lota lota), deepwater ciscoes (Coregonus sp.), and whitefish (Coregonus clupeaformis) have all disappeared or declined seriously in abundance. Only the colonists alewife (Alosa pseudoharengus), smelt (Osmerus mordax) and white perch (Morone americana) are currently abundant. Abundance of deepwater ciscoes is thought to have been controlled originally by the piscivores lake trout and burbot. Three deepwater cisco species are inferred to have been progressively eliminated by overfishing, leaving only the smallest and least valuable present when the fishery collapsed. The effects of the sea lamprey (Petromyzon marinus) on the Lake Ontario fishes are held to have increased with the reduction of the number of dams in the watershed, and as fishing reduced numerical abundance and average size of the prey fishes. The early colonists alewife and carp (Cyprinus carpio) were thought to have stabilized early. It was suggested smelt were suppressed for many years by trout and burbot predation, and after the release of this constraint, the smelt in turn caused the collapse of the deepwater ciscoes and other species through predation. The white perch invasion of the Bay of Quinte was thought particularly swift and successful because of the absence of predators. Yellow perch (Perca flavescens) abundance may have increased because of eutrophication effects in the nearshore areas. Recent deterioration of water quality appears so extreme as to ensure that the last premium species which used the inshore areas cannot return. Overfishing is thought to have been the major destabilizing influence. The role of the open lake predators in the vectoring of energy and materials through the system is discussed.

Evidence of successful river spawning by lake trout (Salvelinus namaycush) in the Lower Niagara River, Lake Ontario

2021 ◽  
Author(s):  
Alexander Gatch ◽  
Dimitry Gorsky ◽  
Zy Biesinger ◽  
Eric Bruestle ◽  
Kelley Lee ◽  
...  
Keyword(s):  
Lake Trout ◽  
Lake Ontario ◽  
Salvelinus Namaycush ◽  
Niagara River

Effect of climatic conditions on the annual activity and hibernation cycle of Richardson's ground squirrels and Columbian ground squirrels

1977 ◽  
Vol 55 (4) ◽  
pp. 693-703 ◽  
Author(s):  
Gail R. Michener
Keyword(s):  
Rocky Mountains ◽  
Climatic Conditions ◽  
Ground Squirrels ◽  
Active Season ◽  
Southern Alberta ◽  
Annual Activity ◽  
The Times ◽  
Columbian Ground Squirrels ◽  
Spring Emergence ◽  
Species Ecology

In 1975 and 1976 the times of spring emergence, breeding, and entry into hibernation were compared for Spermophilus richardsonii and S. columbianus in an area of sympatry in the foothills of the southern Alberta Rocky Mountains. Both species emerged earlier in 1976, which had a warmer than normal spring, than in 1975, which had a cooler than normal spring. In both years S. richardsonii emerged earlier than S. columbianus and remained active longer. Juvenile S. richardsonii entered hibernation when 17–20 weeks old whereas juvenile S. columbianus were 10–11 weeks old. Yearling S. richardsonii bred, whereas yearling S. columbianus did not. Breeding success affected the time of entry into hibernation but not the time of emergence from hibernation in the next spring. A possible relationship between the periodic arousals during hibernation and the emergence pattern of squirrels in spring is discussed. The significance of flexibility of spring emergence, length of the active season, and age at breeding to survival and species ecology is considered.

Parasitic Phase of the Sea Lamprey (Petromyzon marinus) in Lake Ontario

1980 ◽  
Vol 37 (11) ◽  
pp. 2021-2038 ◽  
Author(s):  
W. J. Christie ◽  
D. P. Kolenosky
Keyword(s):  
Lake Trout ◽  
Prey Size ◽  
Lake Ontario ◽  
Sea Lamprey ◽  
Error Component ◽  
Species Preference ◽  
Fish Weight ◽  
History Of ◽  
Parasitic Phase ◽  
Parasitic Generation

Sea lamprey produced in other areas of Lake Ontario appeared to be responsible for significant levels of predation on target species of the eastern outlet basin. The life history of the lamprey is simple with only one parasitic generation present in the lake during the feeding period. Wound frequencies on gillnetted whitefish were influenced by season, fish size, gillnet set duration, and a large random error component which suggested a contagious distribution. Scar frequencies were influenced by fish age and indicated improved survival of whitefish when fish weight exceeded lamprey weight by 43 times. Lamprey impact on the whitefish stocks would probably have been more important at lower fishing intensities. The lamprey may have been prey limited, and size and species preference were probably such that lake trout and burbot were not buffered against sea lamprey by white suckers or whitefish. The analysis favored the view that lamprey were innocuous in 19th century Lake Ontario by reason of prey size and density, but climatic and other environmental effects could also have been important.Key words: sea lamprey, lake whitefish, Lake Ontario

scholarly journals Projections of surface air temperature required to sustain permafrost and importance of adaptation to climate change in the Daisetsu Mountains, Japan

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tokuta Yokohata ◽  
Go Iwahana ◽  
Toshio Sone ◽  
Kazuyuki Saito ◽  
Noriko N. Ishizaki ◽  
...  
Keyword(s):  
Climate Model ◽  
Surface Air Temperature ◽  
Climatic Conditions ◽  
Alpine Ecosystems ◽  
Adaptation To Climate Change ◽  
Freezing And Thawing ◽  
Air Temperatures ◽  
Statistical Relationships ◽  
The Stability ◽  
Slope Displacement

AbstractPermafrost is known to occur in high mountainous areas such as the Daisetsu Mountains in Japan, which are located at the southernmost limit of the permafrost distribution in the world. In this study, areas with climatic conditions suitable for sustaining permafrost in the Daisetsu Mountains are projected using bias-corrected and downscaled climate model outputs and statistical relationships between surface air temperatures and permafrost areas. Using freezing and thawing indices, the size of the area in the Daisetsu Mountains where climatic conditions were suitable for permafrost were estimated to be approximately 150 km2 in 2010. Under the RCP8.5 scenario, this area is projected to decrease to about 30 km2 by 2050 and it is projected to disappear by around 2070. Under the RCP2.6 scenario, the area is projected to decrease to approximately 20 km2 by 2100. The degradation of mountain permafrost could potentially affect the stability of trekking trails due to slope displacement, and it may also have deleterious effects on current alpine ecosystems. It is therefore important to accurately monitor changes in the mountain ecosystem environment and to implement measures to adapt to an environment that is projected to change significantly in the future.

Sexual difference in PCB concentrations of lake trout (Salvelinus namaycush) from Lake Ontario

2010 ◽  
Vol 408 (7) ◽  
pp. 1725-1730 ◽  
Author(s):  
Charles P. Madenjian ◽  
Michael J. Keir ◽  
D. Michael Whittle ◽  
George E. Noguchi
Keyword(s):  
Sexual Difference ◽  
Lake Trout ◽  
Lake Ontario ◽  
Salvelinus Namaycush

Frost hardiness and winter photosynthesis of Thujapiicata and Pseudotsugamenzlesll seedlings grown at three rates of nitrogen and phosphorus supply

1995 ◽  
Vol 25 (1) ◽  
pp. 18-28 ◽  
Author(s):  
B.J. Hawkins ◽  
M. Davradou ◽  
D. Pier ◽  
R. Shortt
Keyword(s):  
Net Photosynthesis ◽  
Douglas Fir ◽  
Frost Hardiness ◽  
Nutrient Concentrations ◽  
Nitrogen And Phosphorus ◽  
Red Cedar ◽  
Air Temperatures ◽  
Foliar Nutrient ◽  
One Year ◽  
P Supply

One-year-old seedlings of western red cedar (Thujapiicata Donn ex D.Don) and Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) were grown for one season in five nutrient treatments with nitrogen (N) supplied in solution at rates of 20, 100, or 250 mg•L−1 and phosphorus (P) supplied at rates of 4, 20, or 60 mg•L−1. Growth, onset of dormancy, frost hardiness on six dates, and foliar nutrient concentrations in autumn and spring were measured. Midwinter rates of net photosynthesis and transpiration were measured at air temperatures of 4, 7, and 11 °C in seedlings from all nutrient treatments. Recovery of net photosynthesis and transpiration in whole seedlings from the three N treatments was assessed at intervals for 28 days after the seedlings were frozen to −5, −15, and −25°C. Foliar N content differed significantly among nutrient treatments and was positively correlated with supply. Mitotic activity ceased earliest in plants with low N supply. Douglas-fir seedlings in the low-N treatment also ceased height growth earliest. These differences in growth had no significant correlation with frost hardiness. No consistent differences in frost hardiness among nutrient treatments were observed. Higher rates of N and P supply resulted in higher rates of winter net photosynthesis. Net photosynthesis was reduced dramatically by night frost, with greater damage occurring at lower temperatures. Net photosynthesis recovery occurred most quickly in seedlings with the midrate of N and P supply.

The Incidence of Climatic Conditions Favourable to Coffee Berry Disease in Kenya

1971 ◽  
Vol 7 (4) ◽  
pp. 303-314 ◽  
Author(s):  
J. M. Waller
Keyword(s):  
Air Temperature ◽  
Spore Germination ◽  
Growing Season ◽  
Climatic Conditions ◽  
Tree Canopy ◽  
Disease Development ◽  
Spore Dispersal ◽  
Coffee Berry ◽  
Coffee Berry Disease ◽  
Air Temperatures

SUMMARYClimatic conditions affecting the development of CBD are assessed by measuring wetness within the tree canopy and air temperature. Saturation of the tree canopy, necessary for spore dispersal, occurs most frequently at the tops of trees and the duration of wetness permitting spore germination is most prolonged at night. Night air temperatures are closest to berry temperatures and are important in assessing infection periods. Disease development in 1968 and 1969 was related to the number of infection periods during the growing season. Polythene tree covers which kept trees sufficiently dry to stop disease development were used in determining infection at different times of the year.

Dechlorane plus monoadducts in a lake ontario (Canada) food web and biotransformation by lake trout (Salvelinus namaycush)liver microsomes

2013 ◽  
Vol 32 (6) ◽  
pp. 1376-1381 ◽  
Author(s):  
Gregg T. Tomy ◽  
Ed Sverko ◽  
Vince Palace ◽  
Bruno Rosenberg ◽  
Robert McCrindle ◽  
...  
Keyword(s):  
Food Web ◽  
Lake Trout ◽  
Liver Microsomes ◽  
Lake Ontario ◽  
Salvelinus Namaycush ◽  
Dechlorane Plus
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