scholarly journals Bottom-Up Forces Drive Increases in the Abundance of Large Daphnids in Four Small Lakes Stocked with Rainbow Trout (Oncorhynchus mykiss), Interior British Columbia, Canada

Ecosystems ◽  
2019 ◽  
Vol 23 (4) ◽  
pp. 873-890 ◽  
Author(s):  
Graham R. Mushet ◽  
Kathleen R. Laird ◽  
Peter R. Leavitt ◽  
Stephen Maricle ◽  
Andrew Klassen ◽  
...  
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Food Web ◽  
Low Oxygen ◽  
Selective Predation ◽  
Bottom Up ◽  
Fishless Lakes ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Widespread Phenomenon ◽  
Cascading Trophic Interactions

Abstract The introduction of salmonids into lakes of western North America for sport fishing is a widespread phenomenon. While numerous investigations have documented cascading trophic interactions upon the introduction of fish into naturally fishless systems, little research has been done to investigate the importance of natural fish status (fishless vs. fish bearing) in modulating historical food web response to dual forcing by bottom-up (resource regulation from nutrients) and top-down (planktivory from stocked fish) processes. We used the paleolimnological record to reconstruct food web changes in four lakes in interior British Columbia that have been stocked with rainbow trout since the early to mid-1900s. Analysis of pigments, diatoms, and Cladocera was undertaken in cores from all lakes. We predicted that if fish were important in structuring cladoceran abundance and composition, we would document a decline in the abundance of large daphnids post-stocking in our two naturally fishless lakes, and little change in the two fish-bearing lakes. Instead, we documented increased abundance of large daphnids after stocking in all lakes in the early to mid-1900s, a finding inconsistent with size-selective predation from planktivorous fish. Further, our data suggest that deep, low-oxygen refugia may be important in sustaining populations of large Daphnia, a process which was enhanced by increased nutrients and lake production according to sub-fossil diatom and pigment analyses. This study shows that fish stocking does not invariably result in a decrease in large-bodied Cladocera and that nutrients and lake type can modulate the response of invertebrate planktivores.

Stream habitat and rainbow trout (Oncorhynchus mykiss) physiological stress responses to streamside clear-cut logging in British Columbia

2005 ◽  
Vol 35 (3) ◽  
pp. 541-556 ◽  
Author(s):  
Eric Mellina ◽  
Scott G Hinch ◽  
Edward M Donaldson ◽  
Greg Pearson
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Chronic Stress ◽  
Stress Responses ◽  
Plasma Cortisol ◽  
Acute Stress ◽  
Physiological Stress ◽  
Stream Habitat ◽  
Clear Cut ◽  
Rainbow Trout Oncorhynchus Mykiss

The impacts associated with streamside clear-cut logging (e.g., increased temperatures and sedimentation, loss of habitat complexity) are potentially stressful to stream-dwelling fish. We examined stream habitat and rainbow trout physiological stress responses to clear-cut logging in north-central British Columbia using 15 streams divided into three categories: old growth (reference), recently logged (clear-cut to both banks 1–9 years prior to the study), and second growth (clear-cut 25–28 years prior to the study). We used plasma cortisol and chloride concentrations as indicators of acute stress, and interrenal nuclear diameters, impairment of the plasma cortisol response, and trout condition and length-at-age estimates as indicators of chronic stress. No statistically significant acute or chronic stress responses to streamside logging were found, despite increases in summertime stream temperatures (daily maxima and diurnal fluctuations) and a reduction in the average overall availability of pool habitat. Our observed stress responses were approximately an order of magnitude lower than what has previously been reported in the literature for a variety of different stressors, and trout interrenal nuclear diameters responses to the onset of winter were approximately five times greater than those to logging. The overall consistency of our results suggests that the impacts of streamside clear-cut logging are not acutely or chronically stressful to rainbow trout in our study area.

Effects of rainbow trout (Oncorhynchus mykiss) on amphibians in productive recreational fishing lakes of British Columbia

2007 ◽  
Vol 64 (12) ◽  
pp. 1770-1780 ◽  
Author(s):  
Joanna Lynne McGarvie Hirner ◽  
Sean P Cox
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Body Size ◽  
Oncorhynchus Mykiss ◽  
Relative Abundance ◽  
Amphibian Conservation ◽  
Recreational Fishing ◽  
Study Region ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Salamander Larvae

Stocking lakes with trout to enhance recreational fishing can negatively affect native aquatic species. Our objectives were (i) to compare presence, relative abundance, body size, and developmental stage of amphibians in lakes with and without rainbow trout (Oncorhynchus mykiss) in British Columbia’s southern interior, and (ii) to estimate the size of trout impact for application to amphibian conservation. Presence of long-toed salamander (Ambystoma macrodactylum), Columbia spotted frog (Rana luteiventris), and Pacific treefrog (Pseudacris regilla) was not significantly different between lake types. In contrast, western toad (Bufo boreas) larvae presence and relative abundance were significantly higher in lakes with trout. Relative abundance of salamander larvae was significantly lower in lakes with trout, but hypothesis testing did not provide consistent evidence of significantly lower abundances of spotted frog and treefrog larvae. However, estimated ratios of relative abundance (impact) indicated that larvae of the salamander and two frogs were ≥65% less abundant in lakes with trout. Salamander larvae were significantly smaller in lakes with trout. Although amphibians may currently coexist with trout in our study region, trout stocking policy in British Columbia should consider amphibian conservation because the presence of trout is associated with lower amphibian abundance and body size in individual lakes.

scholarly journals Have Invasive Mysids (Mysis diluviana) Altered the Capacity of Osoyoos Lake, British Columbia to Produce Sockeye Salmon (Oncorhynchus nerka)?

2018 ◽  
Vol 11 (1) ◽  
pp. 1-26 ◽  
Author(s):  
Kim D. Hyatt ◽  
Donald J. McQueen ◽  
Athena D. Ogden
Keyword(s):  
British Columbia ◽  
Food Web ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Zooplankton Biomass ◽  
Top Down ◽  
Bottom Up ◽  
Annual Variations ◽  
Mysis Diluviana ◽  
Zooplankton Prey

Background:During 2005-13, at Osoyoos Lake, British Columbia, we investigated trophic relationships among fry ofOncorhynchus nerkaWalbaum (Sockeye and kokanee), a suite of limnetic planktivores includingMysis diluviana, and their zooplankton prey.Objectives:Our goal was to quantify the impacts that a recently introduced population ofMysiswould have on density, growth and survival of resident age-0 Sockeye Salmon.Methods:Evidence ofMysisimpact was based on (a) simple correlation analysis between various biophysical performance measures and (b) production and bioenergetics models used to identify the strength of bottom-up (i.e. production-driven) and top-down (i.e.consumption-driven) processes.Results:This nine-year study indicated that the Osoyoos Lake food web was strongly influenced by external events These included: large annual variations in river discharge, an earthen dam failure and effluent input from an Okanagan River tributary, and highly variable recruitment ofO. nerkafry given out-of-basin factors (harvest, marine survival) controlling adult salmon returns. Surprisingly, large annual variations inO. nerkarecruitment (0.63 - 7.0 million fry), did not induce significant “top-down” associations in growth, survival or subsequent production among the macro-planktivores (pelagic fish andMysis) and their zooplankton prey. A single significant correlation (p ≤ 0.05) betweenO. nerkafry abundance and their von BertalanffyW∞parameter emerged from a set of 14 potential top-down associations tested. By contrast, we identified several strongly positive “bottom-up” effects in which survival ofO. nerkafry was significantly associated (p ≤ 0.01) with annual variations in total zooplankton biomass,Daphniabiomass andEpischurabiomass. Our results indicate thatMysisplayed a dual role in the Osoyoos Lake pelagic food web. As predators, they accounted for an average (June-October) of 64% of the total prey biomass consumed by fish andMysis. As prey,Mysiscontributed an average of 35% of the prey biomass consumed by fish. Consumption by fish andMysistogether accounted for daily losses of only 4.5% of non-mysid zooplankton biomass and 34% of daily zooplankton production.Conclusion:We conclude that in all years, combined prey consumption byMysisand fish was never high enough, acting alone, to reduce the availability of their potential zooplankton forage base. However, we also estimate that in the absence ofMysis,O. nerkafry could experience a 43% increase in their daily food intake and that fish andMysismight control their principal prey taxa when exogenous factors (e.g.annual discharge) induced major reductions in zooplankton biomass. Finally, althoughMysishas clearly altered the energy flow pathways from plankton to fish in the Osoyoos Lake food-web, mysids have not precluded rebuildingO. nerkaabundance to levels at or exceeding historic maxima.

scholarly journals Ecotypic differentiation of native rainbow trout (Oncorhynchus mykiss) populations from British Columbia

2005 ◽  
Vol 62 (7) ◽  
pp. 1523-1539 ◽  
Author(s):  
E R Keeley ◽  
E A Parkinson ◽  
E B Taylor
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Large Scale ◽  
Spatial Scales ◽  
Morphological Differentiation ◽  
Predictive Ability ◽  
Geographic Area ◽  
Ecotypic Differentiation ◽  
Rainbow Trout Oncorhynchus Mykiss

We sampled 34 native rainbow trout (Oncorhynchus mykiss) populations over a wide geographic area of British Columbia to determine whether variation in morphology is related to differences in habitat or fish community characteristics experienced by a population. After correcting for differences in body size, the most dramatic differences occurred in external characteristics between stream- and lake-dwelling populations. Rainbow trout from streams had more robust bodies with larger caudal peduncles and heads and longer paired fins than rainbow trout from lakes. Unlike other lake populations, piscivorous rainbow trout populations had relatively large heads and mouths that were more similar in size to those of stream-dwelling populations. We found fewer differences in the size of internal organs across ecotypes, producing little predictive ability of these characteristics to differentiate populations of rainbow trout. We also sampled 27 additional rainbow trout populations with unknown fish communities to determine how well large-scale patterns predict morphological differentiation over a smaller spatial scale. Of the five ecotypes that we detected at a smaller scale, the largest differences again occurred between stream and lake populations. Our data suggest that external morphological variation among populations of rainbow trout covaries with ecological conditions at a variety of spatial scales, particularly between lakes and rivers.

Historical Status of Fish Populations in Canadian Rocky Mountain Lakes Inferred from Subfossil Chaoborus (Diptera: Chaoboridae) Mandibles

1994 ◽  
Vol 51 (6) ◽  
pp. 1376-1383 ◽  
Author(s):  
S. Lamontagne ◽  
D. W. Schindler
Keyword(s):  
Rainbow Trout ◽  
National Parks ◽  
Rocky Mountain ◽  
Historical Evidence ◽  
Fishless Lakes ◽  
Chaoborus Flavicans ◽  
Predominant Species ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Chaoborus Americanus ◽  
Couesius Plumbeus

We used subfossil Chaoborus mandibles preserved in sediments of Cabin, Caledonia, and Celestine lakes, Alberta, to determine whether fish were present in the lakes (which now contain rainbow trout (Oncorhynchus mykiss) and lake chub (Couesius plumbeus)) prior to the first fish stockings early this century. We first tested whether Chaoborus were good indicators of the presence of fish in montane lakes in a survey of 43 lakes in jasper and Banff national parks. Chaoborus americanus was the only species inhabiting fishless lakes and was also found in three lakes with low fish density (co-occurring with C. flavicans in two of the three lakes). Other lakes containing fish had either C. flavicans or no Chaoborus species. Subfossils revealed that C. americanus was the predominant species prior to this century in Cabin and Celestine lakes, suggesting that these lakes were originally fishless; C. americanus (and C. trivittatus in Cabin Lake) were eliminated early this century, contemporarily with the first recorded fish stockings. Chaoborus flavicans was the only species recovered from Caledonia Lake, suggesting that the lake had fish prior to this century; while it is not possible to identify the species originally present, historical evidence suggests that rainbow trout is native to Caledonia Lake.

Lepeophtheirus cuneifer Kabata, 1974 (Copepoda: Caligidae) from seawater-reared rainbow trout, Oncorhynchus mykiss, and Atlantic salmon, Salmo salar, in the Strait of Georgia, British Columbia, Canada

1991 ◽  
Vol 69 (5) ◽  
pp. 1414-1416 ◽  
Author(s):  
S. C. Johnson ◽  
L. J. Albright
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Atlantic Salmon ◽  
Oncorhynchus Mykiss ◽  
Salmo Salar ◽  
Strait Of Georgia ◽  
Atlantic Salmon Salmo Salar ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Important Parasite

Adults, preadults, and chalimus larvae of Lepeophtheirus cuneifer were recovered from rainbow trout, Oncorhynchus mykiss, and Atlantic salmon, Salmo salar, cultured in seawater in the southern Strait of Georgia, British Columbia. This species has not been reported previously from these hosts or in Canadian waters. It was found only in low abundance and is not an economically important parasite of farmed salmonids in British Columbia.

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