Pleistocene Watershed Exchanges and the Fish Fauna of the Peel River Basin, Yukon Territory

1977 ◽  
Vol 34 (3) ◽  
pp. 388-395 ◽  
Author(s):  
R. A. Bodaly ◽  
C. C. Lindsey

The Peel River basin is a unique Canadian glacial refugium containing many relict fish populations. Peel River is presently tributary to the Mackenzie River system, but at least twice during Pleistocene glaciations it was diverted into headwaters of the Yukon River system, offering the possibility of two-way transfer of aquatic organisms between the Mackenzie and Yukon. Present fish distributions in the Peel basin are summarized. Biochemical and morphological evidence suggests that races of at least six species now inhabiting the area (Coregonus clupeaformis, Prosopium coulteri, Thymallus arcticus, Salvelinus namaycush, Esox lucius, Cottus cognatus) originated from types which either came from the Yukon River system or developed in situ in unglaciated parts of the Peel.

1977 ◽  
Vol 34 (5) ◽  
pp. 617-625 ◽  
Author(s):  
W. G. Franzin ◽  
J. W. Clayton

Frequencies of alleles of the genes governing electrophoretic phenotypes of lake whitefish (Coregonus clupeaformis) muscle glycerol-3-phosphate dehydrogenase (G-3-PDH) and lactate dehydrogenase (LDH) enzymes, the genetics of which were determined previously, proved useful tools for characterizing populations. Malate dehydrogenase (MDH) and hemoglobin electrophoretic phenotypes, the genetics of which have not been determined, proved useful only for discerning differences among large groups of populations. Using all these characters we determined postglacial routes of gene flow among western Canadian lake whitefish populations and related the biochemical data to the glacial refugia in which lake whitefish are believed to have survived the Wisconsin glaciation. Apparently most lake whitefish populations west of the Ontario–Manitoba boundary and east of the Rocky Mountains were derived from a Mississippi refugium stock with some input from the Bering refugium. At an early stage in the mixing of the two stocks, headwaters of the Peace, Athabasca, and Mackenzie rivers and the Fraser River system were invaded. Subsequently, these areas were cut off from mainstem rivers of the plains, and a G-3-PDH allele not found in early emigrants from the Mississippi refugium appeared and spread throughout the major river systems of central Canada. No evidence was found that any Mississippi stock lake whitefish were able to invade the upper Liard River and Yukon River system including the area of the Bering refugium. Bering stock lake whitefish probably emigrated from that refugium by way of headwater transfer from the Yukon River to the Liard River and possibly, by way of the Porcupine and Peel rivers, from the Yukon River to the lower Mackenzie River. Routes of postglacial dispersal suggested by geological information, rather than selection, appear to provide adequate explanations for the distributions of the biochemical characters in present day lake whitefish populations. This explanation of the biochemical data is also in accord with the distribution of modal gillraker counts in lake whitefish populations and also with the distribution of other freshwater fishes in western Canada. Key words: fish, lake whitefish, Coregonus clupeaformis, salmonidae, zoogeography, dehydrogenase, postglacial, biochemical genetics


2014 ◽  
Vol 11 (3) ◽  
pp. 3731-3776 ◽  
Author(s):  
C. Zell ◽  
J.-H. Kim ◽  
M. Balsinha ◽  
D. Dorhout ◽  
C. Fernandes ◽  
...  

Abstract. Branched glycerol dialkyl glycerol tetraethers (brGDGTs), which are transported from soil to marine sediment by rivers, have been used to reconstruct the mean annual air temperature (MAAT) and soil pH of the drainage basin using the methylation index of branched tetraethers (MBT, recently refined as MBT') and cyclization index of branched tetraethers (CBT) from coastal marine sediment records. In this study we are tracing the brGDGTs from source to sink in the Tagus River basin, the longest river system on the Iberian Peninsula, by determining their concentration and distribution in soils, river suspended particulate matter (SPM), riverbank sediments, marine SPM, and marine surface sediments. The concentrations of brGDGTs in river SPM were substantially higher and their distributions were different compared to those of the drainage basin soils. This indicates that brGDGTs are mainly produced in the river itself. In the marine environment, the brGDGT concentrations rapidly decreased with increasing distance from the Tagus estuary. At the same time, the brGDGT distributions in marine sediments also changed, indicating that marine in-situ production also takes place. These results show that there are various problems that complicate the use of the MBT'/CBT for paleoreconstructions using coastal marine sediments in the vicinity of a river. However, if the majority of brGDGTs are produced in the river, it might be possible to reconstruct the environmental (temperature and pH) conditions of the river water using appropriate aquatic calibrations, provided that marine core locations are chosen in such a way that the brGDGTs in their sediments are predominantly derived from riverine in-situ production.


1976 ◽  
Vol 33 (11) ◽  
pp. 2489-2499 ◽  
Author(s):  
J. R. Arthur ◽  
L. Margolis ◽  
H. P. Arai

Forty-six species of parasites (14 Protozoa, 7 Monogenea, 7 Digenea, 8 Cestoda, 2 Acanthocephala, 4 Nematoda, 3 Copepoda, and 1 Hirudinoidea) were recovered from 383 specimens of 8 species of fishes collected from Aishihik and Stevens lakes, Yukon Territory, during the summer of 1973. Four species, Chloromyxum dubium Auerbach, 1908, C. esocinum Dogiel, 1934, Sphaerospora cristata Shulman, 1962 (all Protozoa), and Crepidostomum metoecus Braun, 1900 (Digenea) are reported for the first time from North America.Aspects of the systematics and distribution of several species are discussed and the following new synonymies recognized: Tetraonchus rauschi Mizelle and Webb, 1953 with T. borealis (Olsson, 1893) (Monogenea);Cystidicola stigmatura (Leidy, 1886) with C. farionis Fischer, 1798; and Raphidascaris canadensis Smedley, 1933 with R. acus (Bloch, 1779) (both Nematoda).Substantial differences in the parasite fauna of Aishihik and Stevens lakes are noted; the possible consequences of the introduction of species of potential economic and pathogenic importance e.g. Henneguya zschokkei (Gurley, 1893), Hexamita salmonis (Moore, 1923) (both Protozoa), Discocotyle sagittata (Leuckart, 1842) (Monogenea), Neoechinorhynchus rutili (O. F. Müller, 1780) (Acanthocephala), and Triaenophorus nodulosus (Pallas, 1781) (Cestoda) into new areas as a result of the proposed diversion of Stevens Lake (Yukon River system) into Aishihik Lake (Alsek River system) are discussed.


1992 ◽  
Vol 49 (4) ◽  
pp. 760-768 ◽  
Author(s):  
C. J. Foote ◽  
J. W. Clayton ◽  
C. C. Lindsey ◽  
R. A. Bodaly

Lake whitefish (Coregonus clupeaformis) could have survived through (at least) the Illinoisan and Wisconsinan Pleistocene glacial maxima in an area in the vicinity of the present Nahanni National Park in the Northwest Territories of Canada according to the geological evidence. This possibility was addressed by an analysis of the genetic makeup of 43 lake whitefish populations in the Northwest Territories, the Yukon Territory, British Columbia, and Alberta. Populations in the lower Liard, Tetcela, Fraser, and upper Peace River systems as well as the headwaters of the Athabasca River were distinguished from both the Bering glacial refuge race populations inhabiting the Yukon and upper Liard River basins in the Yukon Territory and the Mississippi–Missouri glacial refuge race populations inhabiting most of the Northwest Territories, Alberta, and areas further to the east by a specific combination of electrophoretic mobility alleles. This evidence supports the hypothesis of the survival and subsequent dispersal of lake whitefish from a Nahanni glacial refugium. Possible dispersal routes and the limited extent of introgression among races are discussed.


2014 ◽  
Vol 11 (19) ◽  
pp. 5637-5655 ◽  
Author(s):  
C. Zell ◽  
J.-H. Kim ◽  
M. Balsinha ◽  
D. Dorhout ◽  
C. Fernandes ◽  
...  

Abstract. Branched glycerol dialkyl glycerol tetraethers (brGDGTs), which are thought to be transported from soil to marine sediment by rivers, have been used to reconstruct the mean annual air temperature (MAAT) and soil pH of the drainage basin using the methylation index of branched tetraethers (MBT, recently refined as MBT') and cyclization index of branched tetraethers (CBT) from coastal marine sediment records. In this study, we trace the brGDGTs from source to sink in the Tagus River basin, the longest river system on the Iberian Peninsula, by determining their concentration and distribution in soils, river suspended particulate matter (SPM), riverbank sediments, marine SPM, and marine surface sediments. The concentrations of brGDGTs in river SPM were substantially higher and their distributions were different compared to those of the drainage basin soils. This indicates that brGDGTs are mainly produced in the river itself. In the marine environment, the brGDGT concentrations rapidly decreased with increasing distance from the Tagus estuary. At the same time, the brGDGT distributions in marine sediments also changed, indicating that marine in situ production also takes place. These results show that there are various problems that complicate the use of the MBT'/CBT for paleoreconstructions using coastal marine sediments in the vicinity of a river. However, if the majority of brGDGTs are produced in the river, it might be possible to reconstruct the environmental (temperature and pH) conditions of the river water using appropriate aquatic calibrations, provided that marine core locations are chosen in such a way that the brGDGTs in their sediments are predominantly derived from riverine in situ production.


1963 ◽  
Vol 20 (3) ◽  
pp. 749-767 ◽  
Author(s):  
C. C. Lindsey

Squanga Lake in the Canadian headwaters of the Yukon River contains two species of humpback whitefish, characterized by modal first arch gill raker counts of 23 and 28 but with overlap in the range of counts. The species can be separated more sharply by raker counts of the second arch, also with modes of 23 and 28. Seven other morphometric characters not correlated with gill raker count each have significantly different means, but some overlap, between the species.In June the species with high raker count mainly occupies the pelagic zone, while the low count species occupies the bottom layers at all depths. The high count species feeds mainly on plankton, the low count species on bottom organisms. The high count species spawns in inlet and outlet streams in November and December. Gonad development in June suggests that the low count form spawns later, in localities unknown. Samples from early winter spawning runs contained exclusively high count individuals. A few fish, probably hybrids, had raker count corresponding to one species and most other morphological characters corresponding to the other. Tentative names for the species are Coregonus clupeaformis (high gill raker count) and Coregonus pidschian.


2013 ◽  
Vol 10 (7) ◽  
pp. 9615-9644 ◽  
Author(s):  
C. I. Michailovsky ◽  
P. Bauer-Gottwein

Abstract. River basin management can greatly benefit from short-term river discharge predictions. In order to improve model produced discharge forecasts, data assimilation allows for the integration of current observations of the hydrological system to produce optimal forecasts and reduce prediction uncertainty. Data assimilation is widely used in operational applications to update hydrological models with in situ discharge or level measurements. In areas where timely access to in situ data is not possible, remote sensing data products can be used in assimilation schemes. While river discharge itself cannot be measured from space, radar altimetry can track surface water level variations at crossing locations between the satellite ground track and the river system called virtual stations (VS). Use of radar altimetry in operational settings is complicated by the low temporal resolution of the data (between 10 and 35 days revisit time at a VS depending on the satellite) as well as the fact that the location of the measurements is not necessarily at the point of interest. Combining radar altimetry from multiple VS with hydrological models could overcome these limitations. In this study, a rainfall runoff model of the Zambezi River Basin is built using remote sensing datasets and used to drive a routing scheme coupled to a simple floodplain model. The Extended Kalman filter is used to update the states in the routing model with data from 9 Envisat VS. Model fit was improved through assimilation with Nash-Sutcliffe model efficiencies increasing from 0.21 to 0.63 and from 0.82 to 0.87 at the outlets of two distinct watersheds. However, model reliability was poor in one watershed with only 54% and 55% of observations falling in the 90% confidence bounds, for the deterministic and assimilation runs respectively, pointing to problems with the simple approach used to represent model error.


Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 265
Author(s):  
Akarath Soukhaphon ◽  
Ian G. Baird ◽  
Zeb S. Hogan

The Mekong River, well known for its aquatic biodiversity, is important to the social, physical, and economic health of millions living in China, Myanmar, Laos, Thailand, Cambodia, and Vietnam. This paper explores the social and environmental impacts of several Mekong basin hydropower dams and groupings of dams and the geographies of their impacts. Specifically, we examined the 3S (Sesan, Sekong Srepok) river system in northeastern Cambodia, the Central Highlands of Vietnam, and southern Laos; the Khone Falls area in southern Laos; the lower Mun River Basin in northeastern Thailand; and the upper Mekong River in Yunnan Province, China, northeastern Myanmar, northern Laos, and northern Thailand. Evidence shows that these dams and groupings of dams are affecting fish migrations, river hydrology, and sediment transfers. Such changes are negatively impacting riparian communities up to 1000 km away. Because many communities depend on the river and its resources for their food and livelihood, changes to the river have impacted, and will continue to negatively impact, food and economic security. While social and environmental impact assessments have been carried out for these projects, greater consideration of the scale and cumulative impacts of dams is necessary.


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