A Niche Definition for Lake Trout (Salvelinus namaycush) and Its Use to Identify Populations at Risk

1994 ◽  
Vol 51 (11) ◽  
pp. 2513-2519 ◽  
Author(s):  
Phil A. Ryan ◽  
Terry R. Marshall
Keyword(s):  
Oxygen Content ◽  
Lake Trout ◽  
Cold Water ◽  
Natural Populations ◽  
Oxygen Demand ◽  
Oxygen Depletion ◽  
Salvelinus Namaycush ◽  
Phosphorus Concentration ◽  
Suitable Habitat ◽  
Populations At Risk

Lake trout (Salvelinus namaycush) populations require cold water with high dissolved oxygen content for survival. We developed models that predict the availability of such habitat, using lake mean depth, which describes both the thermal regime and the initial oxygen reserves, and using a measure of primary productivity, which defines the subsequent oxygen demand of the sediments and water column. Measures of primary production include either phosphorus concentration, chlorophyll a concentration, or Secchi disk transparency. The models are presented as a series of seasonal oxygen depletion isopleths that predict the extent to which the oxygen content of thermally suitable habitat is lost during the period of thermal stratification. The presence or absence of native lake trout in lakes of northwestern Ontario superimposed on these graphs indicated that natural populations seldom occur in lakes in which the seasonal oxygen depletion exceeds 40%. This isopleth is a niche boundary in its representation of adverse temperature and oxygen conditions for lake trout. The delineation of this boundary permits the identification of lakes where lake trout populations could be seriously affected by cultural eutrophication, overfishing, or climate warming.

scholarly journals Impact of Global Warming on Dissolved Oxygen and BOD Assimilative Capacity of the World’s Rivers: Modeling Analysis

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2408
Author(s):  
Steven C. Chapra ◽  
Luis A. Camacho ◽  
Graham B. McBride
Keyword(s):  
Dissolved Oxygen ◽  
Natural Waters ◽  
Cold Water ◽  
Oxygen Demand ◽  
Oxygen Depletion ◽  
Assimilative Capacity ◽  
Mountainous Regions ◽  
Modeling Analysis ◽  
Lower Oxygen ◽  
The Impact

For rivers and streams, the impact of rising water temperature on biochemical oxygen demand (BOD) assimilative capacity depends on the interplay of two independent factors: the waterbody’s dissolved oxygen (DO) saturation and its self-purification rate (i.e., the balance between BOD oxidation and reaeration). Although both processes increase with rising water temperatures, oxygen depletion due to BOD oxidation increases faster than reaeration. The net result is that rising temperatures will decrease the ability of the world’s natural waters to assimilate oxygen-demanding wastes beyond the damage due to reduced saturation alone. This effect should be worse for nitrogenous BOD than for carbonaceous BOD because of the former’s higher sensitivity to rising water temperatures. Focusing on streams and rivers, the classic Streeter–Phelps model was used to determine the magnitude of the maximum or “critical” DO deficit that can be calculated analytically as a function of the mixing-point BOD concentration, DO saturation, and the self-purification rate. The results indicate that high-velocity streams will be the most sensitive to rising temperatures. This is significant because such systems typically occur in mountainous regions where they are also subject to lower oxygen saturation due to decreased oxygen partial pressure. Further, they are dominated by salmonids and other cold-water fish that require higher oxygen levels than warm-water species. Due to their high reaeration rates, such systems typically exhibit high self-purification constants and consequently have higher assimilation capacities than slower moving lowland rivers. For slow-moving rivers, the total sustainable mixing-point concentration for CBOD is primarily dictated by saturation reductions. For faster flowing streams, the sensitivity of the total sustainable load is more equally dependent on temperature-induced reductions in both saturation and self-purification.

Mercury Uptake by Lake Trout, Salvelinus namaycush, Relative to Age, Growth, and Diet in Tadenac Lake with Comparative Data from Other PreCambrian Shield Lakes

1983 ◽  
Vol 40 (2) ◽  
pp. 114-120 ◽  
Author(s):  
Hugh R. MacCrimmon ◽  
Christopher D. Wren ◽  
Barra L. Gots
Keyword(s):  
Growth Rate ◽  
Lake Trout ◽  
Cold Water ◽  
Salvelinus Namaycush ◽  
Mercury Accumulation ◽  
Osmerus Mordax ◽  
Rainbow Smelt ◽  
Precambrian Shield ◽  
Safe Level ◽  
Mercury Uptake

Lake trout, Salvelinus namaycush, released into Tadenac Lake as juveniles, show a pronounced acceleration in growth rate, following a change in diet from benthic invertebrates to rainbow smelt, Osmerus mordax, beginning at age 6 (> 30 cm). An abrupt increase in the rate of mercury accumulation in white muscle of these fish occurs at the same time. Mercury levels in lake trout ([Formula: see text] = 0.24–3.44 μg/g) and coresident smelt ([Formula: see text] = 0.06–0.48 μg/g) from Tadenac and eight neighboring lakes reveal maximum levels reaching 10.0 and 0.84 μg/g, respectively. Mercury levels in lake trout from Tadenac Lake, an undisturbed PreCambrian Shield ecosystem without detected indigenous sources, exceed the "safe" level (0.5 μg/g) at sexual maturity and at a size less than generally acceptable for human utilization. Mercury accumulation by the trout is correlated with length (r = 0.92) in each lake population examined, but substantial among-lake differences occur in fish of comparable ages. As the growth rates are similar in various waters, differences in extent of mercury accumulation is attributed to differences in mercury availability among lakes. In view of a strong correlation (r = 0.96) between mercury levels in smelt and trout calculated at standardized length, it is proposed that the smelt is an appropriate indicator species for the ranking of cold-water lakes relative to the availability of mercury for uptake by lake trout and other living aquatic organisms.Key words: mercury uptake, lake trout, rainbow smelt, growth rate, diet

Effects of forestry roads on reproductive habitat and exploitation of lake trout (Salvelinus namaycush) in three experimental lakes

2000 ◽  
Vol 57 (S2) ◽  
pp. 97-104 ◽  
Author(s):  
John M Gunn ◽  
Rod Sein
Keyword(s):  
Lake Trout ◽  
Natural Populations ◽  
Fork Length ◽  
Salvelinus Namaycush ◽  
Spawning Habitat ◽  
Trout Population ◽  
Access Road ◽  
Short Term Study ◽  
Opaque Plastic ◽  
Spawning Sites

This study was designed to test the effects of two potential impacts of forest access roads on lake trout (Salvelinus namaycush) lakes in the Boreal Shield ecozone: (i) loss of reproductive habitat through siltation and (ii) increased access and exploitation. During an 9-year study (1991-1999) in Whitepine Lake, access to seven original spawning sites and over 250 alternate spawning sites was progressively removed by covering the substrate with opaque plastic sheeting to simulate siltation. No effects on recruitment of lake trout have yet been detected. Mark-recapture estimates of juvenile (<370 mm fork length) abundance remained high, mean body size did not increase, and emergent alevins continued to be produced from the alternate spawning sites each year. Similar results occurred in a short-term study in Helen Lake. The lack of obvious effects of reproductive habitat loss was in sharp contrast with the rapid and severe effects that fishing pressure exerted on the lake trout population in Michaud Lake where access was improved by construction of a 12-km forest access road. These findings suggest that lake trout can tolerate substantial losses in spawning habitat, but natural populations, particularly in small lakes, must be protected from excessive exploitation.

scholarly journals Predator–prey dynamics mediate long-term production trends of cisco (Coregonus artedi) in a northern Wisconsin lake

2018 ◽  
Vol 75 (11) ◽  
pp. 1969-1976 ◽  
Author(s):  
Timothy P. Parks ◽  
Andrew L. Rypel
Keyword(s):  
Lake Trout ◽  
Cold Water ◽  
Predator Prey ◽  
Populations At Risk ◽  
Coregonus Artedi ◽  
Unique Strain ◽  
Strong Inverse Relationship ◽  
Over Time ◽  
Production Approach

We quantified production, biomass, and production to biomass (P/B) ratios for cisco (Coregonus artedi) in Trout Lake, Wisconsin, USA (2001–2015). Across all years, annual production, biomass, and P/B were variable ranging 0.6–30.2 kg·ha−1·year−1, 1.2–39.7 kg·ha−1, and 0.4–0.9·year−1, respectively. Cisco production exhibited obvious decline. However, neither biomass nor P/B changed significantly over time. Long-term patterns of environmental conditions remained unchanged during the study and were unrelated to cisco production. However, lake trout (Salvelinus namaycush) relative abundance showed a strong inverse relationship with cisco production and biomass. Intense lake trout stocking has occurred in this lake over time to conserve a genetically unique strain of the species. These management efforts may have had the unintended consequence of amplifying top-down predation on cisco. Since cisco P/B has gone largely unchanged, cisco production would be predicted to rebound quickly to adaptive reductions in lake trout stocking. Further increases in lake trout numbers could place both populations at risk of collapse. This study provides an example of a fisheries production approach for understanding and conserving cold-water fisheries, especially in lakes dominated by ciscoes.

Mitochondrial DNA Diversity among Broodstocks of the Lake Trout, Salvelinus namaycush

1988 ◽  
Vol 45 (12) ◽  
pp. 2114-2122 ◽  
Author(s):  
Peter M. Grewe ◽  
Paul D. N. Hebert
Keyword(s):  
Mitochondrial Dna ◽  
Great Lakes ◽  
Lake Trout ◽  
Natural Populations ◽  
Restriction Enzymes ◽  
Salvelinus Namaycush ◽  
Brood Stock ◽  
Base Pairs ◽  
Specific Distribution ◽  
Western Great Lakes

Mitochondrial DNA was purified from 151 lake trout (Salvelinus namaycush) representing nine brood stocks along with an additional 30 fish from two natural populations. Eighteen restriction endonucleases were employed to analyze 126 brood stock fish. Two of these enzymes (Hind III and Bam HI) were used to examine the fish from the natural populations (Hare Island (Lake Superior) and North Knife Lake (Manitoba)) and the remaining brood stock samples from the Manitou (12 fish) and Seneca (13 fish) strains. The mitochondrial genome of the lake trout was 16 800 ± 200 base pairs in length. A single heteroplasmic individual was discovered in the Manitou strain. It contained two genomes, the less frequent of which was 20 base pairs shorter than the other. The 18 restriction enzymes resolved 13 mitochondrial clones which fell into three major groups. These clonal groups, which can be identified by their Bam HI restriction phenotypes, have a specific distribution: a western Great Lakes group, a central Great Lakes group, and an eastern Great Lakes group. Seven mitochondrial clones were unique to a particular stock. In addition there were dramatic shifts in the relative proportions of the six remaining mitochondrial clones among the brood stocks. These results indicate that mitochondrial DNA markers have great potential for the identification and management of lake trout strains.

Investigation of the Contribution of Natural Organic Runoff to Dissolved Oxygen Depletion in the Red Deer River

1979 ◽  
Vol 14 (1) ◽  
pp. 71-88
Author(s):  
S.E. Penttinen ◽  
P.H. Bouthillier ◽  
S.E. Hrudey
Keyword(s):  
Dissolved Oxygen ◽  
Red Deer ◽  
Stream Water ◽  
Oxygen Demand ◽  
Oxygen Depletion ◽  
Experimental Program ◽  
Nitrogen Budgets ◽  
Carbon And Nitrogen ◽  
Tributary Stream ◽  
Small Tributary

Abstract Studies on the chronic low dissolved oxygen problems encountered under winter ice in the Red Deer River have generally been unable to account for dissolved oxygen depletion in terms of known manmade inputs. An experimental program was developed to assess the possible nature and approximate bounds of oxygen demand due to natural organic runoff carried to the Red Deer River by a small tributary stream, the Blindman River. The study employed an electrolytic respirometer on stream water samples subjected to prior concentration by vacuum evaporation. Evaluation of carbon and nitrogen budgets in conjunction with the measured oxygen demand indicate that biochemical oxygen demand is originating with natural organic runoff in tributaries of the Red Deer River. The results provide a basis for estimation of the possible contribution to the observed oxygen demand in the Red Deer River originating from natural organic runoff.

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

An examination of the PCB: lipid relationship among individual fish

1997 ◽  
Vol 54 (5) ◽  
pp. 1031-1038
Author(s):  
C A Stow ◽  
L J Jackson ◽  
J F Amrhein
Keyword(s):  
Salmo Trutta ◽  
Lake Michigan ◽  
Oncorhynchus Tshawytscha ◽  
Lake Trout ◽  
Coho Salmon ◽  
Salvelinus Namaycush ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Strong Linear Correlation ◽  
Brown Trout Salmo Trutta ◽  
The Relationship

We examined data from 1984 to 1994 for five species of Lake Michigan salmonids to explore the relationship between total PCB concentration and percent lipid. When we compared mean species lipid and PCB values, we found a strong linear correlation. When we compared values among individuals, we found modest positive PCB:lipid associations in brown trout (Salmo trutta), chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), and rainbow trout (Oncorhynchus mykiss) collected during spawning, but positive associations were not apparent among nonspawning individuals. Lake trout (Salvelinus namaycush) exhibited no discernible PCB:lipid relationship. Our results are not incompatible with previous observations that contaminants are differentially partitioned into lipids within a fish, but these results do suggest that lipids are not a major factor influencing contaminant uptake.

Classification of Sea Lamprey (Petromyzon marinus) Attack Marks on Great Lakes Lake Trout (Salvelinus namaycush)

1980 ◽  
Vol 37 (11) ◽  
pp. 1989-2006 ◽  
Author(s):  
Everett Louis King Jr.
Keyword(s):  
Great Lakes ◽  
Lake Trout ◽  
Petromyzon Marinus ◽  
Attachment Site ◽  
Sea Lamprey ◽  
Salvelinus Namaycush ◽  
Oral Disc ◽  
Field Assessment ◽  
Sea Lampreys

Criteria for the classification of marks inflicted by sea lamprey (Petromyzon marinus) into nine categories were developed from laboratory studies in an attempt to refine the classification system used in field assessment work. These criteria were based on characteristics of the attachment site that could be identified under field conditions by unaided visual means and by touching the attachment site. Healing of these marks was somewhat variable and was influenced by the size of lamprey, duration of attachment, severity of the wound at lamprey detachment, season and water temperature, and by other less obvious factors. Even under laboratory conditions staging of some wounds was difficult, especially at low water temperatures. If these criteria are to be used effectively and with precision in the field, close examination of individual fish may be required. If the feeding and density of specific year-classes of sea lampreys are to be accurately assessed on an annual basis, close attention to the wound size (as it reflects the size of the lamprey's oral disc) and character of wounds on fish will be required as well as consideration of the season of the year in which they are observed.Key words: sea lamprey, attack marks, lake trout, Great Lakes

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