Trophic cascades in streams: effects of nutrient enrichment on autotrophic and consumer benthic communities under two different fish predation regimes

2000 ◽  
Vol 57 (7) ◽  
pp. 1380-1394 ◽  
Author(s):  
Barry JF Biggs ◽  
Steven N Francoeur ◽  
Alexander D Huryn ◽  
Roger Young ◽  
Christopher J Arbuckle ◽  
...  
Keyword(s):  
Nutrient Enrichment ◽  
Salmo Trutta ◽  
Benthic Communities ◽  
Trophic Cascades ◽  
Fish Predation ◽  
Grazing Pressure ◽  
Artificial Substrates ◽  
Bottom Up ◽  
Brown Trout Salmo Trutta ◽  
Periphyton Biomass

We tested the hypothesis that differences in top-level predators could mediate the importance of top-down versus bottom-up forces in stream food chains using three streams dominated by Galaxias (fish native to New Zealand) and three dominated by brown trout (Salmo trutta) (an introduced species). These two fish species have quite different predation strategies and energetic requirements. Periphyton in the Galaxias streams formed relatively low biomass (indicative of high invertebrate grazing), whereas periphyton in two of the three trout streams formed relatively high biomass (indicative of lower grazing pressure). Periphyton biomass response to inorganic nutrient enrichment varied by fish type. Invertebrate densities on artificial substrates were higher in the Galaxias streams, with the exception of chironomids. Nutrient enrichment of periphyton led to increases in total invertebrate densities, but these increases were greater in the Galaxias streams where invertebrate predation was thought to be lower. Our results suggest that the specific feeding behavior traits of the consumers should be considered when investigating trophic cascades or predicting effects of bottom-up nutrient enrichment on autotrophy.

scholarly journals Persistent organic pollutants in river food webs: influence of trophic position and degree of heterotrophy

2005 ◽  
Vol 62 (9) ◽  
pp. 2021-2032 ◽  
Author(s):  
Olof Berglund ◽  
Per Nyström ◽  
Per Larsson
Keyword(s):  
Food Webs ◽  
Salmo Trutta ◽  
Trophic Position ◽  
Dry Weight ◽  
Grazing Pressure ◽  
Weight Basis ◽  
Trophic Levels ◽  
Brown Trout Salmo Trutta ◽  
Lipid Weight ◽  
The Mean

We investigated how the degree of autotrophy/heterotrophy and organism trophic position influenced the bioaccumulation of polychlorinated biphenyls (PCBs) in 10 benthic river food webs consisting of terrestrial detritus, periphyton, invertebrates, and age-0 brown trout (Salmo trutta) in southern Sweden. Concentrations of PCBs increased with trophic position, estimated from δ15N and δ13C, on a dry weight basis (ng·g–1 dry weight) but not on a lipid weight basis (ng·g–1 lipid). PCB biomagnification factors between the first and second trophic levels (invertebrates/ periphyton and invertebrates/detritus) ranged between 0.3 and 2.3 and between the second and third levels (trout/invertebrates) between 0.3 and 2.0 on a lipid weight basis. The mean proportion of carbon ultimately derived from terrestrial sources, α, was 0.82 ± 0.19 for invertebrates and 0.67 ± 0.28 for trout. Contrary to our hypothesis, PCB concentrations in trout were positively related to α (r2 = 0.58–0.77, p < 0.05). As α and the periphyton density (g C·m–2) in the rivers was positively related (r2 = 0.88, p < 0.01), we propose that this relationship was due to an increased retention and exposure of PCBs to trout in rivers with low grazing pressure and high periphyton density.

scholarly journals Environmental conditions limit the distribution of Lepidurus arcticus (Branchiopoda, Notostraca) in lakes on the Hardangervidda mountain plateau, Southern Norway

2019 ◽  
Vol 39 ◽  
pp. 77-110 ◽  
Author(s):  
Tore Qvenild ◽  
Trygve Hesthagen
Keyword(s):  
Water Quality ◽  
Salmo Trutta ◽  
Growing Season ◽  
Fish Predation ◽  
Mean Value ◽  
The Arctic ◽  
Striking Difference ◽  
Brown Trout Salmo Trutta ◽  
Tadpole Shrimp ◽  
Southern Norway

The Arctic tadpole shrimp Lepidurus arcticus has a circumpolar distribution where the Hardangervidda mountain plateau in Norway marks its southernmost limit. Within this area, we searched for L. arcticus in 238 lakes in 27 catchments. On Hardangervidda, the distribution pattern of L. arcticus is highly skewed. In the 16 catchments located in the central and eastern parts, L. arcticus was recorded in 70% of all the lakes studied (n=191). The remaining 11 catchments located in western areas, are almost free of lakes with L. arcticus (n=47). The most striking difference between these two areas is the significantly higher level of snow deposition in the western areas. This delays the ice break-up, which results in lower water temperatures and a shorter growing season. The water of lakes in western areas (N=36) is also more dilute than those in the central and eastern areas (N=201), with mean calcium concentrations of 0.81±0.48 and 1.62±1.12 mg L-1, respectively. In the lakes in the central and eastern areas hosting L. arcticus (N=95), the mean value was slightly higher (1.67±1.14 mg L-1). The combination of low water temperature, a short growing season and dilute water low in calcium may explain the near total absence of L. arcticus in the western part of Hardangervidda. All lakes contain brown trout Salmo trutta, and as L. arcticus is heavily sought for as food, the analyses of fish stomachs are the most reliable method of detecting the species. However, this prey-predator relationship may severely reduce the population of L. arcticus, and their presence may also be a function of the proximity of species refugia. This is evident in the context of fish predation, but also of water quality. Hence, in the central and eastern parts of the plateau, where L. arcticus is common, their occurrence increased significantly with lake size, being found in 54% of the lakes <1.0 km2, as opposed to 97% in the bigger lakes. Furthermore, L. arcticus is most frequently found in lakes at altitudes between 1100 and 1299 m a.s.l. We conclude that environmental constraints limit the distribution of L. arcticus on Hardangervidda. The projected increase in temperature towards the end of this century may exterminate L. arcticus from the lower parts of Hardangervidda, especially in the most shallow lakes. Many of the lakes have water quality with pH <6.0 and calcium concentration <1.0 mg L-1. In such lakes L. arcticus is living on the edge of its survival, and the projected increase in precipitation may dilute the waters even further, pushing L. arcticus nearer to its extinction threshold.

Resistance of erythrocytes from Brown trout (Salmo trutta m. trutta L.) affected by ulcerative dermal necrosis syndrome

2011 ◽  
Vol 14 (3) ◽  
pp. 443-448 ◽  
Author(s):  
N. Kurhalyuk ◽  
H. Tkachenko ◽  
K. Pałczyńska
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Thiobarbituric Acid ◽  
Control Group ◽  
Thiobarbituric Acid Reactive Substance ◽  
Tbars Level ◽  
Reactive Substance ◽  
Brown Trout Salmo Trutta

Resistance of erythrocytes from Brown trout (Salmo trutta m. trutta L.) affected by ulcerative dermal necrosis syndrome In the present work we evaluated the effect of ulcerative dermal necrosis (UDN) syndrome on resistance of erythrocytes to haemolytic agents and lipid peroxidation level in the blood from brown trout (Salmo trutta m. trutta L.). Results showed that lipid peroxidation increased in erythrocytes, as evidenced by high thiobarbituric acid reactive substance (TBARS) levels. Compared to control group, the resistance of erythrocytes to haemolytic agents was significantly lower in UDN-positive fish. Besides, UDN increased the percent of hemolysated erythrocytes subjected to the hydrochloric acid, urea and hydrogen peroxide. Results showed that UDN led to an oxidative stress in erythrocytes able to induce enhanced lipid peroxidation level, as suggested by TBARS level and decrease of erythrocytes resistance to haemolytic agents.

Evaluation of brown trout (Salmo trutta fario) fillets’ shelf life: Fed with a humic supplemented diet

2021 ◽  
Vol 29 ◽  
pp. 100675
Author(s):  
Muhammed Atamanalp ◽  
Arzu Ucar ◽  
Esat Mahmut Kocaman ◽  
Gonca Alak
Keyword(s):  
Shelf Life ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Brown Trout Salmo Trutta ◽  
Salmo Trutta Fario
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