Quantifying importance of marine prey in the diets of two partially anadromous fishes

2011 ◽  
Vol 68 (11) ◽  
pp. 2020-2028 ◽  
Author(s):  
Heidi K. Swanson ◽  
Karen A. Kidd ◽  
James D. Reist
Keyword(s):  
Lake Trout ◽  
Salvelinus Alpinus ◽  
Salvelinus Namaycush ◽  
Arctic Char ◽  
Food Sources ◽  
Future Research ◽  
Anthropogenic Stressors ◽  
Trout Population ◽  
Marine Food ◽  
Pelagic Prey

The importance of marine prey sources for partially anadromous fishes has received little study and is complicated by considerable plasticity in life history. We determined proportional contributions of marine, freshwater benthic, and freshwater pelagic prey to anadromous and resident Arctic char (Salvelinus alpinus) and lake trout (Salvelinus namaycush) from several partially anadromous populations in the Canadian Arctic. Bayesian mixing models (MixSIR) applied to δ34S and δ13C ratios in lake-specific models indicated that marine prey accounted for 90%–91% of anadromous Arctic char diet and 60%–66% of anadromous lake trout diet. When these estimates were combined with proportion of anadromous individuals in partially anadromous populations, marine food sources accounted for 31%–44% of Arctic char population productivity and 16%–26% of lake trout population productivity. Although future research is needed to refine and quantify variability around these estimates, our results will allow better predictions of the effects of anthropogenic stressors on partially anadromous fishes.

Anadromy in Arctic populations of lake trout (Salvelinus namaycush): otolith microchemistry, stable isotopes, and comparisons with Arctic char (Salvelinus alpinus)

2010 ◽  
Vol 67 (5) ◽  
pp. 842-853 ◽  
Author(s):  
Heidi K. Swanson ◽  
Karen A. Kidd ◽  
John A. Babaluk ◽  
Rick J. Wastle ◽  
Panseok P. Yang ◽  
...  
Keyword(s):  
Lake Trout ◽  
Salvelinus Alpinus ◽  
Salt Water ◽  
Salvelinus Namaycush ◽  
Otolith Microchemistry ◽  
Scientific Data ◽  
Arctic Char ◽  
Arctic Lakes ◽  
Size Dependent ◽  
The Family

In the family Salmonidae, lake trout ( Salvelinus namaycush ) are considered the least tolerant of salt water. There are, however, sporadic reports of lake trout in coastal, brackish habitats in the Canadian Arctic. Otolith microchemistry analyses conducted on lake trout and Arctic char ( Salvelinus alpinus ) from four Arctic lakes in the West Kitikmeot region of Nunavut, Canada, revealed that 37 of 135 (27%) lake trout made annual marine migrations. Anadromous lake trout were in significantly better condition (K = 1.17) and had significantly higher C:N ratios (3.71) than resident lake trout (K = 1.05 and C:N = 3.34). Anadromous lake trout also had significantly higher δ15N (mean = 16.4‰), δ13C (mean = –22.3‰), and δ34S (mean = 13.43‰) isotope ratios than resident lake trout (means = 12.84‰, –26.21‰, and 1.93‰ for δ15N, δ13C, and δ34S, respectively); results were similar for Arctic char and agree with results from previous studies. Mean age of first migration for lake trout was 13 years, which was significantly older than that for Arctic char (5 years). This could be a reflection of size-dependent salinity tolerance in lake trout, but further research is required. These are the first detailed scientific data documenting anadromy in lake trout.

Natural Hybridization between Arctic Char (Salvelinus alpinus) and Lake Trout (S. namaycush) in the Canadian Arctic

1993 ◽  
Vol 50 (12) ◽  
pp. 2652-2658 ◽  
Author(s):  
Chris C. Wilson ◽  
Paul D.N. Hebert
Keyword(s):  
Lake Trout ◽  
Salvelinus Alpinus ◽  
Canadian Arctic ◽  
Restriction Endonuclease Analysis ◽  
Salvelinus Namaycush ◽  
Arctic Char ◽  
Natural Hybridization ◽  
Low Levels ◽  
Allozyme Loci ◽  
Endonuclease Analysis

Natural interspecific hybrids between lake trout (Salvelinus namaycush) and Arctic char (S. alpinus) ranged in frequency from 1.8 to 6.8% in four of eleven lakes containing both species on the northern Melville Peninsula, N.W.T., and were also detected at several other sites across the Canadian Arctic. Hybrids were heterozygous for each of seven diagnostic allozyme loci between S. alpinus and S. namaycush, and were morphologically intermediate between the parental species. Restriction endonuclease analysis of mitochondrial DNA revealed that all but one of the hybrids had S. namaycush as their maternal parent. Resampling of two lakes where hybrids were detected revealed low levels of bidirectional nuclear introgression between the two species and limited transfer of S. namaycush mtDNA into S. alpinus.

Genetic Differences in Retention of Swimbladder Gas Between Two Populations of Lake Trout (Salvelinus namaycush)

1974 ◽  
Vol 31 (8) ◽  
pp. 1351-1354 ◽  
Author(s):  
P. Ihssen ◽  
J. S. Tait
Keyword(s):  
Brook Trout ◽  
Depth Distribution ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Genetic Differences ◽  
Trout Population ◽  
Two Populations

Lake trout (Salvelinus namaycush) derived from two populations differed in retention of swimbladder gas. The two reciprocal interpopulation crosses were intermediate to the parent populations. The two F1 hybrids obtained by crossing fish from each lake trout population with brook trout (S. fontinalis) were also found different in retention. Gas retention was correlated with depth distribution of the parent populations, high retention being associated with deeper distribution.

Lake Trout (Salvelinus namaycush) Growth Potential Predicted from Cisco (Coregonus artedii) Population Structure and Conductivity

1989 ◽  
Vol 46 (9) ◽  
pp. 1531-1538 ◽  
Author(s):  
Edward A. Trippel ◽  
F. William H. Beamish
Keyword(s):  
Lake Trout ◽  
Fork Length ◽  
Growth Efficiency ◽  
Salvelinus Namaycush ◽  
Growth Potential ◽  
Food Sources ◽  
Stepwise Multiple Regression ◽  
Order Of Magnitude ◽  
Mean Size ◽  
Coregonus Artedii

Trophic dynamics between lake trout (Salvelinus namaycush) and cisco (Coregonus artedii) were examined in a set of 10 northwestern Ontario lakes that ranged in conductivity by nearly an order of magnitude. Diets revealed the possibility of interspecific competition for invertebrate prey prior to initiation of piscivory by lake trout at approximately 200 mm fork length (FL). Von Bertalanffy growth equations (based on otolith ages) were used to estimate time to attain this length (1.4–3.0 yr). Contrary to anticipated results, lake trout reached this size more rapidly in lakes with high cisco abundance. Presumably, this relationship was caused by improved food conditions for young trout in some of the more productive waterbodies. However, after removing the collinearity between lake conductivity and nonpiscivorous growth by regression analysis, there was no relationship between the time for lake trout to reach 200 mm and cisco abundance. Piscivorous growth varied (L∞ = 508 to 740 mm) extensively among the 10 populations and was likely a function of growth efficiency from different food sources. Using stepwise multiple regression, 81% of the L∞ variation among lakes was explained by cisco abundance and mean size. Linear regression between L∞ and mean size of trout (but not trout abundance) on conductivity generated significant positive relationships.

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.

Mitochondrial DNA and Conservation of an Aboriginal Arctic Char (Salvelinus alpinus oquassa) from Floods Pond, Maine

1994 ◽  
Vol 51 (1) ◽  
pp. 62-67 ◽  
Author(s):  
Irv Kornfield ◽  
Frederick W. Kircheis
Keyword(s):  
Mitochondrial Dna ◽  
New England ◽  
Lake Trout ◽  
Salvelinus Alpinus ◽  
Restriction Endonuclease Analysis ◽  
Arctic Char ◽  
Eastern Canada ◽  
Fish Samples ◽  
Endemic Population ◽  
Distinct Lineage

Periods of low water in Floods Pond, Maine, USA, during spawning seasons for an endemic population of landlocked Arctic char, Salvelinus alpinus oquassa, have contributed to several year-class failures. To determine the genetic uniqueness of these fish, samples of Arctic char from five isolated lakes in New England and eastern Canada were examined by restriction endonuclease analysis of mitochondrial DNA (mtDNA) and compared with samples of lake trout (Salvelinus namaycush) and Arctic char from Scandinavia. Results suggest that (1) Arctic char of eastern North America should all be considered members of Salvelinus alpinus oquassa, (2) char from Floods Pond possess a unique mtDNA banding pattern for one restriction enzyme not observed in fish from any other sampled locality (this difference delineates a distinct lineage of Arctic char whose preservation is warranted on genetic grounds), and (3) unique banding patterns did not characterize any other studied char population, including geographic variants (these populations may be viewed as genetically homogeneous, and none warrant individual protection based upon our genetic characterizations). We contend that genetically identified lineages in the early stages of divergence warrant preservation.

Limnological and Biological Observations in the Region of the Ungava or Chubb Crater, Province of Quebec

1955 ◽  
Vol 12 (4) ◽  
pp. 487-498 ◽  
Author(s):  
N. V. Martin
Keyword(s):  
Deep Water ◽  
Vascular Plants ◽  
Crater Lake ◽  
Lake Trout ◽  
Salvelinus Alpinus ◽  
Fork Length ◽  
Salvelinus Namaycush ◽  
Surface Oxygen ◽  
Secchi Disc ◽  
Total Solids

Ungava Crater Lake, at 73° 41′ W.L. and 61° 17′ N.L., lies in a meteoritic crater of the northern Quebec tundra. The lake is nearly circular, 1.7 miles in diameter, with steep walls and a maximum known depth of 825 feet. Secchi disc transparency was 35 metres. Summer surface temperatures were 3–4 °C., of the deep water a little less. Surface oxygen was abundant, pH was 6.5–6.6. Total solids in the water were less than 20 parts per million, and hardness was only 1.7 p.p.m. Three kinds of mammals and 14 of birds were found in the crater region. Arctic char, Salvelinus alpinus, were the only fish taken in the crater lake. Specimens up to 21.8 inches fork length and 18 years old were taken; they fed on insects and other char. Char in other nearby waters grew somewhat faster but ate the same foods; mature females as small as 4.0 inches were seen. Lake trout, Salvelinus namaycush, in a lake near the crater reached 33.5 inches and 15.8 pounds. Growth was very slow, the greatest age determined being 21 years, at 13 pounds. Twenty-nine species of vascular plants were collected close to the crater.

Population Biology of Lake Trout (Salvelinus namaycush) of Lake Superior before 1950

1971 ◽  
Vol 28 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Gary T. Sakagawa ◽  
Richard L. Pycha
Keyword(s):  
Mortality Rate ◽  
Population Biology ◽  
Lake Trout ◽  
Lake Superior ◽  
Indirect Evidence ◽  
Total Mortality ◽  
Growth Yield ◽  
Salvelinus Namaycush ◽  
Natural Mortality ◽  
Trout Population

Scale samples collected in 1948 were used to estimate the instantaneous total mortality rate (0.70) and growth for lake trout (Salvelinus namaycush) in Lake Superior before the population had been significantly reduced by the sea lamprey (Petromyzon marinus). Indirect evidence indicates that the instantaneous natural mortality rate was probably 0.10–0.25. The Ricker model was used to calculate yield per recruitment, which varied with natural mortality and growth. Natural mortality was more critical than growth; yield per recruitment increased 183.3% with a 60% decrease in instantaneous natural mortality (from 0.25 to 0.10). For the prelamprey lake trout population the yield per recruitment was about 12–34 lb; the recruitment of about 3.6–10.1 million lake trout of age 1.5 resulted in an annual commercial production of 4 million lb.

The transmission, life span, and population biology of Cystidicola cristivomeri White, 1941 (Nematoda: Habronematoidea) in char, Salvelinus spp.

1981 ◽  
Vol 59 (3) ◽  
pp. 498-509 ◽  
Author(s):  
Geoff A. Black ◽  
Murray W. Lankester
Keyword(s):  
Population Biology ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Mature Female ◽  
Arctic Char ◽  
Mysis Relicta ◽  
Northwestern Ontario ◽  
Third Stage ◽  
Paratenic Hosts ◽  
Fish Hosts

The population biology of Cystidicola cristivomeri White, 1941 was investigated in lake trout, Salvelinus namaycush, in three lakes in northwestern Ontario and in arctic char, S. alpinus, in Gaviafaeces Lake, Northwest Territories. Young lake trout fed selectively on large Mysis relicta, which were more frequently infected with C. cristivomeri (up to 5.1%) than small mysids. Pontoporeia affinis was not a suitable intermediate host in nature and there was no evidence that fish paratenic hosts were important in transmitting this nematode to lake trout.Most C. cristivomeri appear to live at least 10 years in naturally infected lake trout and arctic char. In these fishes the size of C. cristivomeri infrapopulations is determined by several factors. The feeding preferences of fish hosts and the availability of forage in individual lakes determine the extent and duration of feeding on M. relicta. Each naturally infected mysid contains only one third-stage C. cristivomeri larva. In the swim bladder of infected fishes, the proportion of female C. cristivomeri reaching sexual maturity and the length of females is inversely related to the total number of worms present. The length of mature female worms, in turn, is positively correlated with the rate at which they produce eggs. As a result, the egg output of C. cristivomeri at the infrapopulation level is density dependent.

Improved interpretation of labelled fish otoliths: a cost-effective tool in sustainable fisheries management

2005 ◽  
Vol 56 (5) ◽  
pp. 705 ◽  
Author(s):  
T. Niva ◽  
P. Keränen ◽  
J. Raitaniemi ◽  
H. M. Berger
Keyword(s):  
Salmo Trutta ◽  
Lake Trout ◽  
Salvelinus Alpinus ◽  
Arctic Charr ◽  
Cost Effective ◽  
Salvelinus Namaycush ◽  
Sander Lucioperca ◽  
Alizarin Red ◽  
Brown Trout Salmo Trutta

A total of 222 pairs of alizarin red S (ARS)-labelled and 75 pairs of unlabelled sagittal otoliths from six hatchery-reared species, including Arctic charr (Salvelinus alpinus (L.)), lake trout (Salvelinus namaycush (Walbaum)), salmon (Salmo salar L.), brown trout (Salmo trutta L.), whitefish (Coregonus sp.) and pikeperch (Sander lucioperca (L.)), were used in blind tests to determine whether sawing a 0.4-mm thick slice from the otolith would improve the interpretation of labelled otoliths. The fish were labelled in 1995–2002. Fish age at labelling varied from two weeks to three months, immersion time from three to six hours and concentration of ARS 50–100 ppm. Blind tests were arranged so that sawed slices were contrasted with entire otoliths using stereomicroscope under UV epi-illumination. According to blind tests, the accuracy of interpretation of ARS-labelled otoliths was 97.0% from the slices and 92.3% from entire otoliths. The role of different filters in detecting false marks owing to autofluorescence is discussed. Cost-benefits of the method are discussed briefly.

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