scholarly journals The capelin invasion: evidence for a trophic shift in Arctic char populations from the Cumberland Sound region

2021 ◽  
Author(s):  
Kendra Lyn Ulrich ◽  
Ross F. Tallman
Keyword(s):  
Salvelinus Alpinus ◽  
Isotope Analysis ◽  
Growth Curves ◽  
Trophic Niche ◽  
Arctic Char ◽  
Population Characteristics ◽  
Individual Growth ◽  
Δ13c And Δ15n ◽  
Cumberland Sound ◽  
Over Time

Climate change is having myriad effects on Arctic marine ecosystems and food webs. Anadromous Arctic Char, Salvelinus alpinus, feed intensively at sea during summer. In Cumberland Sound, NU, there has been a recent increased availability of a forage fish, Capelin. To investigate changes over time in Arctic Char foraging, we assessed Arctic Char trophic niche from 2002 to 2011 using stomach content analysis and stable isotope analysis (δ13C and δ15N) of muscle tissue from two river/lake systems, Isuituq and Kipisa. We also compared population characteristics by calculating Fulton’s condition factor (K) and by fitting von Bertalanffy growth curves with length-at-age data. Results revealed Capelin newly present in the diets of Arctic Char in 2011, describing a shift from a primarily invertebrate-based to a fish-based diet. No trend in δ15N (del 15N) over time suggests the trophic level of Arctic Char has not changed; however, the δ15C (del 15C) for both systems converged in 2011 on a value suggestive of feeding on Capelin. Growth curves and length-at-age analyses suggest that foraging on Capelin may have increased individual growth. Changes in the growth and condition of Arctic Char in this region could have significant economic and cultural implications.

Is boldness towards predators related to growth rate in naïve captive-reared Arctic char (Salvelinus alpinus)?

2007 ◽  
Vol 64 (4) ◽  
pp. 665-671 ◽  
Author(s):  
Mika VM Laakkonen ◽  
Heikki Hirvonen
Keyword(s):  
Growth Rate ◽  
Captive Breeding ◽  
Salvelinus Alpinus ◽  
Antipredator Behavior ◽  
Underlying Mechanism ◽  
Arctic Char ◽  
Individual Growth ◽  
Detailed Knowledge ◽  
Individual Growth Rate ◽  
Slow Growing

Previous studies have shown that the antipredator responsiveness of fish degenerates through generations in captive breeding. However, detailed knowledge of the underlying mechanism is still largely lacking. We tested the hypothesis that hatchery fish supposedly selected for faster growth in the hatchery environment are bolder towards predators than their slower-growing conspecifics. This was examined by comparing the antipredator behavior of predator- naïve fast- and slow-growing individuals of a captive-bred Arctic char (Salvelinus alpinus) population to chemical cues from natural predators burbot (Lota lota) and pikeperch (Sander lucioperca). As behavioral responses depended on char body size, we compared boldness towards predators of size-matched fast- and slow-growing char. We found no differences in four behavioral antipredator traits between size-matched groups of fast- and slow-growing char. According to these results, boldness to predator cues is not related to individual growth rate in captive-bred Arctic char.

Accumulation of Persistent Pollutants in Normal and Dwarfed Arctic Char (Salvelinus alpinus sp. complex)

1993 ◽  
Vol 50 (12) ◽  
pp. 2574-2580 ◽  
Author(s):  
Johan Hammar ◽  
Per Larsson ◽  
Maris Klavins
Keyword(s):  
Growth Rate ◽  
Salvelinus Alpinus ◽  
Arctic Char ◽  
Individual Growth ◽  
The Arctic ◽  
Growth Strategies ◽  
Sympatric Populations ◽  
Fast Growing ◽  
Persistent Pollutants ◽  
Slow Growing

Two extreme growth fractions of introgressed sympatric populations of the Arctic char (Salvelinus alpinus) species complex from Lake Blåsjön, northern Sweden, were sampled for individual concentrations of persistent pollutants originating from atmospheric deposition. Slow growing char (dwarfs) had significantly higher levels of SPCB (sum of PCB congeners found) and p,p-DDE (dominating DDT-compound) than fast growing char (normals). Besides demonstrating a highly divergent growth pattern the introgressed populations also inhabit a great range of depths, and the seasonal food consumption rates may differ between extreme growth fractions, although the same major invertebrates (introduced Mysis relicta and Pallasea quadrispinosa) are consumed over the year. However, of the life history parameters differing in late spring, individual growth rate was the most important factor explaining the variation in the levels of the pollutants studied. The results support the hypothesis of a biomass "dilution" of pollutants in fish, illustrated by lower levels in fast growing char and higher levels in the slow-growing dwarfs. Individuals with alternative growth strategies in sympatric conspecific communities thus provide unique opportunities to study growth rate as a variable influencing levels of persistent pollutants in fish.

Cannibalism and trophic structure in a high Arctic lake: insights from stable-isotope analysis

1995 ◽  
Vol 52 (6) ◽  
pp. 1195-1201 ◽  
Author(s):  
Keith A. Hobson ◽  
Harold E. Welch
Keyword(s):  
Primary Production ◽  
Food Web ◽  
Salvelinus Alpinus ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Fork Length ◽  
Isotope Ratios ◽  
High Arctic ◽  
Arctic Char ◽  
Small Fish

Stable-nitrogen (15N/14N) isotope ratios (from 2.1‰ in moss to 14.5‰ in Arctic char, Salvelinus alpinus), showed enrichment with trophic level in the food web of Char Lake, Northwest Territories, and may be used to infer trophic position. The average 15N enrichment of 1.5‰ between moss or algae and invertebrates suggests input to the food web of isotopically lighter nitrogen than that measured for these sources of primary production. Stable-carbon (13C/12C) isotope ratios differed between moss and algae by almost 10‰ and indicate that carbon in the Char Lake food web is derived from a blend of these sources of primary production. Arctic char δ15N values for muscle tissue were positively correlated with fork length and clustered into three distinct groups: small fish (1–3 cm, mean δ15N = 5.7‰), which possibly consumed more benthic particles than previously assumed; intermediate-size fish (10–35 cm, mean δ15N = 10‰), which likely depended on larval char as well as their primary zooplankton and chironomid prey; and larger Arctic char, which showed a mean stepwise increase in δ15N of 3.7‰. This suggests that complete cannibalism in this population generally occurs abruptly and is exercised by a relatively small number of large individuals.

scholarly journals Stable Isotope Analyses of Multiple Tissues of Great Shearwaters (Ardenna Gravis) Reveals Long-Term Dietary Stability, Short-Term Changes in Diet, and Can be Used as a Tool to Monitor Food Webs

Diversity ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 163 ◽  
Author(s):  
Hong ◽  
Wiley ◽  
Powers ◽  
Michener ◽  
Kaufman ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Food Web ◽  
Food Webs ◽  
Trophic Level ◽  
Isotope Analysis ◽  
Diet Shift ◽  
Turnover Rates ◽  
Δ13c And Δ15n ◽  
Isotopic Signatures ◽  
Over Time

The great shearwater (Ardenna gravis) is a common pelagic bird with a distribution that spans almost the entire Atlantic basin, which in conjunction with its relatively high abundance, makes great shearwaters an effective bio indicator. We compared δ13C and δ15N values from the feathers, red blood cells (RBCs), and plasma of great shearwaters collected in 2014 and 2015 from the waters off Massachusetts and Cape Cod. The δ13C and δ15N values of RBCs were quite constant between sampling periods and years, suggesting a generally stable food web over that time period. However, the δ13C of plasma indicates a small seasonal change in diet between July and September for both years, with plasma δ15N values suggesting a slight increase in trophic level late in summer. Comparison of the δ15N of RBCs and plasma indicates that great shearwaters experienced a diet shift during the first few weeks of summer 2014, but not in 2015. Comparisons with other studies suggest that these shearwaters feed at a lower trophic level than great shearwaters sampled in the Bay of Fundy and that there is a decrease in δ13C with increasing latitude, which could indicate a more pelagic diet in northern waters. Stable isotope analysis of the sixth primary feathers provided evidence that these feathers are molted in the Northern Hemisphere and that the diet of great shearwaters shortly after arrival was different in 2014 and 2015. This study demonstrates that within species comparisons of tissue isotopic signatures over time and comparisons of isotopic signatures of tissues with different turnover rates, can detect changes in diet and be used as a tool to monitor for changes in marine food webs over time and space. The relevant signals remain informative even in the absence of species-specific data on tissue-diet discrimination factors, tissue turnover rates, or knowledge of dietary components and their stable isotopic signatures, suggesting dietary changes indicative of a corresponding change in the food web.

scholarly journals Multi-indicator evidence for habitat use and trophic strategy segregation of two sympatric forms of Arctic char from the Cumberland Sound region of Nunavut, Canada

2021 ◽  
Author(s):  
Kendra Lyn Ulrich ◽  
Ross F. Tallman
Keyword(s):  
Fatty Acid ◽  
Stable Isotope ◽  
Trophic Niche ◽  
Arctic Char ◽  
Trophic Levels ◽  
Fatty Acid Profiles ◽  
Δ13c And Δ15n ◽  
Sympatric Forms ◽  
Trophic Strategy ◽  
Trophic Niches

We analyzed Arctic Char stable isotope ratios and fatty acid composition from two geographically proximal Nunavut lakes, Qasigiyat and Iqalugaarjuit, to determine if anadromous and resident Arctic char occupied different trophic niches. Resident Arctic char had lower δ13C and δ34S, indicative of a freshwater feeding, compared to anadromous individuals. Significantly lower δ15N of residents suggests the ecotypes feed at different trophic levels. Significantly wider δ13C and δ15N ranges in residents implied a broader trophic niche or a wider range in baseline prey isotope values. Results also provide further evidence for resident use of the estuarine environment in Qasigiyat. Immature Arctic char occupy a different trophic niche than both resident and anadromous fish within Iqalugaarjuit, but this relationship is less clear in Qasigiyat. Distinct stable isotope and fatty acid profiles indicate that resident and anadromous Arctic char have distinct trophic niches, marine for anadromous, freshwater for resident. Immature Arctic char seem to occupy a distinct niche from both anadromous and resident fish, which likely relates to use of both freshwater and estuarine environments, depending on developmental stage. We show the first evidence of the fatty acid differences and niche segregation between sympatric anadromous and resident ecotypes in Arctic Char.

Stability of physiological and behavioural determinants of performance in Arctic char (Salvelinus alpinus)

2001 ◽  
Vol 58 (5) ◽  
pp. 961-968 ◽  
Author(s):  
C J Cutts ◽  
C E Adams ◽  
A Campbell
Keyword(s):  
Metabolic Rate ◽  
Competitive Ability ◽  
Salvelinus Alpinus ◽  
Standard Metabolic Rate ◽  
Arctic Char ◽  
Energetic Cost ◽  
Behavioural Determinants ◽  
Relative Differences ◽  
Over Time ◽  
Behavioural Dominance

The physiological and behavioural mechanisms that confer behavioural dominance are poorly understood. Although recent studies have shown a link between metabolism and dominance, these studies relied on single measurements of both, and assumed that inter-individual variation of physiology and behaviour were repeatable over time. This paper demonstrates that standard metabolic rate is a repeatable trait in Arctic char (Salvelinus alpinus L.) and that relative differences between individuals are consistent across a range of environmental conditions. Furthermore, there were positive associations between metabolic rate, aggression, and competitive ability that were also repeatable over time. However, there was no relationship between competitive ability (measured as feeding attempts) and subsequent growth. This may be due to an energetic cost of dominance: high rates of food capture were only attainable through high rates of effort. This, in addition to elevated aggression, was thought to exert an energetic cost that could not be fully offset by the increased food intake.

First confirmation of salmonid alphavirus infection in Arctic char Salvelinus alpinus and in Austria

2018 ◽  
Vol 130 (1) ◽  
pp. 71-76
Author(s):  
E Lewisch ◽  
T Frank ◽  
H Soliman ◽  
O Schachner ◽  
A Friedl ◽  
...  
Keyword(s):  
Salvelinus Alpinus ◽  
Arctic Char ◽  
Alphavirus Infection
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