Feeding behaviour, brain serotonergic activity levels, and energy reserves of Arctic char (Salvelinus alpinus) within a dominance hierarchy

1998 ◽  
Vol 76 (2) ◽  
pp. 212-220 ◽  
Author(s):  
Anders Alanärä ◽  
Svante Winberg ◽  
Eva Brännäs ◽  
Anders Kiessling ◽  
Erik Höglund ◽  
...  
Keyword(s):  
Brain Stem ◽  
Growth Rates ◽  
Salvelinus Alpinus ◽  
Feeding Activity ◽  
Arctic Char ◽  
Activity Level ◽  
Activity Levels ◽  
Energy Reserves ◽  
Serotonergic Activity ◽  
The Brain

The relationships between feeding activity, brain serotonergic activity level, and energy reserves in eight groups of Arctic char (Salvelinus alpinus) were evaluated using self-feeders in combination with passive integrated transponder (PIT) tags. Serotonin concentrations were measured in the brain stem, telencephalon, and hypothalamus. Energy reserves were measured, as fat levels, in muscle and mesenteric tissue. The self-feeding activity level was found to correlate positively (P < 0.05) with the growth rate and negatively (P < 0.05) with the serotonergic activity levels in the brain stem and telencephalon. No significant relationship was found, however, between the number of trigger activations and the muscle or mesenteric tissue lipid level. One or, in some cases, two fish in each group clearly dominated the activation of the trigger, and showed the highest growth rates and lowest stress levels, measured as brain serotonergic activity. Subordinate fish (one to three individuals) hardly ever activated the trigger, but showed relatively high growth rates and brain serotonergic activity levels that did not differ significantly from those of dominant fish. The remaining individuals showed very little feeding activity and low growth rates. In addition, brain serotonergic activity levels were significantly higher than in fish in the former two categories, indicating that the subordinate fish suffered from stress and had a low social rank.

Feeding behaviour, brain serotonergic activity levels, and energy reserves of Arctic char (Salvelinus alpinus) within a dominance hierarchy

1998 ◽  
Vol 76 (2) ◽  
pp. 212-220 ◽  
Author(s):  
Anders Alanärä ◽  
Svante Winberg ◽  
Eva Brännäs ◽  
Anders Kiessling ◽  
Erik Höglund ◽  
...  
Keyword(s):  
Feeding Behaviour ◽  
Dominance Hierarchy ◽  
Salvelinus Alpinus ◽  
Arctic Char ◽  
Activity Levels ◽  
Energy Reserves ◽  
Serotonergic Activity

The Effect of Stress and Starvation on Bratn Serotonin Utilization in Arctic Charr (Salvelinus Alpinus)

1992 ◽  
Vol 165 (1) ◽  
pp. 229-239 ◽  
Author(s):  
SVANTE WINBERG ◽  
GÖRAN E. NILSSON ◽  
K. HÅKAN OLSÉN
Keyword(s):  
Brain Stem ◽  
Salvelinus Alpinus ◽  
Arctic Charr ◽  
Serotonergic Activity ◽  
Brain Levels ◽  
Hydroxyindoleacetic Acid ◽  
Experimental Protocols ◽  
Effects Of Stress ◽  
The Brain ◽  
Starvation Experiment

The effects of stress and starvation on brain levels of serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were studied in Arctic charr (Salvelinus alpinus). Three experimental protocols were used to elucidate (1) the effect of stress in fish given food, (2) the effect of starvation, and (3) the effect of stress in fish deprived of food. In the stress experiments, fish were stressed three times a day over a four-week period, and in the starvation experiment the fish were starved for a four-week period. Stressed fish, whether given food or not, showed significantly higher concentrations of 5-HIAA, the main 5-HT metabolite, in both the telencephalon and the brain stem. The 5-HIAA/5-HT ratio (an index of serotonergic activity) was also significantly increased in the brain of stressed fish. In the telencephalon of starved fish, the 5-HT concentration was significantly decreased. However, starvation had no effect on 5-HIAA concentrations or 5-HIAA/5-HT ratios in either the telencephalon or the brain stem. These results suggest that stress increases brain serotonergic activity in Arctic charr, while starvation has no effect on the utilization of this transmitter system. It is suggested that stress could be a mediator of the increased 5-HTAA levels and 5-HIAA/5-HT ratios recently observed in low-ranking Arctic charr in a dominance hierarch.

scholarly journals Relationship between habitat distribution, growth rate, and plasticity in congeneric larval dragonflies

2005 ◽  
Vol 83 (8) ◽  
pp. 1128-1133 ◽  
Author(s):  
S J McCauley
Keyword(s):  
Growth Rate ◽  
Predation Risk ◽  
Growth Rates ◽  
Lepomis Macrochirus ◽  
Negative Relationship ◽  
Activity Level ◽  
Activity Levels ◽  
Habitat Distribution ◽  
Invertebrate Predators ◽  
The Relationship

The relationship between habitat distribution, growth rate, and plasticity was examined in the larvae of three species of dragonfly in the genus Libellula L., 1758. Growth rates were compared under three conditions: in the absence of predation risk, in the presence of sunfish (Lepomis macrochirus Rafinesque, 1819; Pisciformes: Centrachidae), and in the presence of invertebrate predators. I assessed how the habitat distributions of the three species of dragonfly, specifically how commonly they occur with fish, were related to growth rates and to the level of growth plasticity under different levels of perceived predation risk. There was a negative relationship between growth rate and the frequency with which species coexist with sunfish. Growth-rate plasticity was limited and does not appear to be important in determining the ability of species to coexist with alternative top predator types. Only one species exhibited growth-rate plasticity, decreasing growth in response to the predator with which it most commonly coexists but not to the species which poses the greatest predation risk. A comparison of growth rates and activity levels in the presence and absence of these predators suggests that growth and activity level parallel each other in these species.

Food intake and spontaneous swimming activity in Arctic char (Salvelinus alpinus): role of brain serotonergic activity and social interactions

1998 ◽  
Vol 76 (7) ◽  
pp. 1366-1370 ◽  
Author(s):  
Øyvind Øverli ◽  
Svante Winberg ◽  
Børge Damsård ◽  
Malcolm Jobling
Keyword(s):  
Food Intake ◽  
Social Interactions ◽  
Salvelinus Alpinus ◽  
Arctic Char ◽  
Swimming Activity ◽  
Serotonergic Activity

Life History of Two Isolated Populations of Arctic Char (Salvelinus alpinus) in Spring-Fed Tributaries of the Canning River, Alaska

1973 ◽  
Vol 30 (8) ◽  
pp. 1215-1220 ◽  
Author(s):  
P. McCart ◽  
P. Craig
Keyword(s):  
Growth Rates ◽  
Bering Sea ◽  
Salvelinus Alpinus ◽  
Arctic Char ◽  
Isolated Populations ◽  
Meristic Characters ◽  
History Of ◽  
Western Arctic ◽  
Mature Fish ◽  
Two Populations

Two isolated populations of Arctic char (Salvelinus alpinus) in spring-fed tributaries of the Canning River, Alaska, had meristic characters that corresponded to those of the Western Arctic–Bering Sea form of Arctic char. The two populations demonstrated slight differences in growth rates, age at maturity, longevity, and food habits. The fish were characterized by small size (maximum 235 mm), low growth rates, low fecundities (maximum 199 eggs), and annual spawning after maturity. Mature fish were darkly pigmented and parr marks were retained throughout life. The spawning season appeared to be sometime in November, when the eggs of mature females averaged 3.8 mm in diameter.

Diurnal and nocturnal feeding activity in Arctic char (Salvelinus alpinus) and rainbow trout (Oncorhynchus mykiss)

1997 ◽  
Vol 54 (12) ◽  
pp. 2894-2900 ◽  
Author(s):  
Anders Alanärä ◽  
Eva Brännäs
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Salvelinus Alpinus ◽  
Feeding Activity ◽  
Activity Patterns ◽  
Arctic Char ◽  
Diel Activity ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Nocturnal Feeding ◽  
Nocturnal Fish

When food is limited and competition for it is high, individual fish may adopt different diel activity patterns. We followed individual feeding activity in groups of 10 Arctic char (Salvelinus alpinus) and rainbow trout (Oncorhynchus mykiss) using a combined self-feeding and PIT-tag system. Food was supplied at low and high rewards to five replicate groups of Arctic char and rainbow trout. Four categories were identified in both species: high-triggering diurnal (diurnal fish with the highest self-feeding activity), low-triggering diurnal, nocturnal, and nontriggering fish. On average, the photophase proportion of the total daily activity was approx 90% in diurnal and approx 20% in nocturnal individuals. Rainbow trout offered high rewards did not show any diel preferences. Diurnal Arctic char and rainbow trout with the highest self-feeding activity were initially larger and had the highest growth rates, indicating a high social position. Nocturnal fish were initially smaller and their proportion of trigger actuations much lower than the high-triggering diurnal fish. These still grew successfully whereas nontriggering fish grew significantly less. Thus, some individuals with a low social status may apply an alternative strategy to attain adequate growth by feeding at night when dominant individuals are less aggressive. This may be referred to as concurrent dualism (diurnalism and nocturnalism).

Diel patterns of activity and substrate preference in young Arctic char from the Koroc River, northern Quebec

1988 ◽  
Vol 66 (11) ◽  
pp. 2500-2502 ◽  
Author(s):  
N. J. Adams ◽  
D. R. Barton ◽  
R. A. Cunjak ◽  
G. Power ◽  
S. C. Riley
Keyword(s):  
Salvelinus Alpinus ◽  
Feeding Activity ◽  
Arctic Char ◽  
Substrate Preference ◽  
Invertebrate Drift ◽  
Diel Periodicity ◽  
Diurnal Activity ◽  
Diel Patterns ◽  
Nocturnal Feeding

Young Arctic char (Salvelinus alpinus) were observed in a stream tank located on the bank of the Koroc river, northern Quebec. Early in the summer, char were most active from dusk to dawn, and at midday, mainly over gravel or sand. Some nocturnal feeding activity was evident. As the summer progressed, this diel periodicity in activity became less pronounced; char exhibited increasing diurnal activity, most of it over rubble substrata. Char preferred rubble for resting throughout the summer. Invertebrate drift decreased from July through August so that, although fish were active more of the time, the rate of feeding during periods of activity declined.

Food intake and spontaneous swimming activity in Arctic char (Salvelinus alpinus): role of brain serotonergic activity and social interactions

1998 ◽  
Vol 76 (7) ◽  
pp. 1366-1370 ◽  
Author(s):  
Øyvind Øverli ◽  
Svante Winberg ◽  
Børge Damsård ◽  
Malcolm Jobling
Keyword(s):  
Food Intake ◽  
Social Interactions ◽  
Salvelinus Alpinus ◽  
Arctic Char ◽  
Swimming Activity ◽  
Serotonergic Activity ◽  
Behavioural Patterns ◽  
Dominant Fish ◽  
Hydroxyindoleacetic Acid ◽  
Social Subordination

We investigated the relationship between social interactions, brain serotonergic activity, and two behavioural patterns in juvenile Arctic char (Salvelinus alpinus): feeding and spontaneous swimming activity. Dominant and subordinate individuals were observed during rearing in pairs, followed by rearing in isolation. Throughout the experiment, levels of both food intake and swimming activity remained high in dominant fish. When they were in pairs, food intake was completely inhibited in subordinate fish; thus, dominant fish were able to monopolise food. At the same time, brain serotonergic activity, as indexed by the ratio of 5-hydroxyindoleacetic acid (5-HIAA) to serotonin (5-hydroxytryptamine, 5-HT) was elevated in the hypothalamus and brain stem of subordinate fish compared with dominants. During subsequent rearing in isolation, food intake, but not spontaneous locomotor activity, gradually increased in previously subordinate fish, while serotonergic activity fell to near that of dominants. Thus, appetite inhibition in subordinate fish can be reversed by rearing in isolation, an effect that may be related to the reversal of a stress-induced activation of brain serotonergic neurones accompanying social subordination. Reduced swimming activity is either a long-lasting response to social subordination or reflects permanently different behavioural strategies of subordinate and dominant individuals.

TIME COURSE OF CHANGES IN BRAIN SEROTONERGIC ACTIVITY AND BRAIN TRYPTOPHAN LEVELS IN DOMINANT AND SUBORDINATE JUVENILE ARCTIC CHARR

1993 ◽  
Vol 179 (1) ◽  
pp. 181-195
Author(s):  
S. Winberg ◽  
G. E. Nilsson
Keyword(s):  
Social Interaction ◽  
Brain Stem ◽  
Time Course ◽  
Arctic Charr ◽  
Control Level ◽  
Brain Regions ◽  
Temporary Increase ◽  
Serotonergic Activity ◽  
Dominant Fish ◽  
The Brain

Concentrations of serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) and tryptophan (TRP, the amino acid precursor of 5-HT) were measured, and 5-HIAA/5-HT ratios calculated, in the telencephalon, hypothalamus and brain stem of Arctic charr (Salvelinus alpinus) with 1–21 days experience of a dominant or subordinate position in a pair. Brain 5-HIAA levels and 5-HIAA/5-HT ratios (an index of serotonergic activity) increased rapidly in all three areas of the brain in subordinate fish and remained high for up to 21 days. The brain stem 5-HIAA concentration in dominant fish showed a temporary increase after 1 day of social interaction, but returned to the control level 2 days later. The social interactions did not affect 5-HT concentrations in any of the brain regions. An initial, but temporary, increase in brain TRP concentration was seen in both subordinate and dominant fish. After 1–3 days of social interaction, brain TRP levels declined. This decline was most pronounced in subordinate individuals which, after 7 and 21 days, had hypothalamic TRP concentrations significantly lower than those of controls. Moreover, TRP levels in the telencephalon after 21 days, and in the hypothalamus after 7 days, were significantly lower in subordinate individuals than in dominant fish. These results show that subordinate experience rapidly causes a sustained increase in brain 5-HT metabolism which does not correlate with changes in brain TRP levels. Thus, the increases in brain 5-HIAA concentration and in brain 5-HIAA/5-HT ratios probably reflect an increase in functional 5-HT release, a phenomenon that appears to have a wide distribution in the brain.

Uncoupling of Somatic and Otolith Growth Rates in Arctic Char (Salvelinus alpinus) as an Effect of Differences in Temperature Response

1988 ◽  
Vol 45 (9) ◽  
pp. 1514-1524 ◽  
Author(s):  
Henrik Mosegaard ◽  
Henrik Svedäng ◽  
Kjell Taberman
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Salvelinus Alpinus ◽  
Somatic Growth ◽  
Arctic Char ◽  
Fish Growth ◽  
Effect Of Temperature ◽  
Otolith Growth ◽  
Different Temperatures ◽  
Wet Weight

Experiments were conducted to study the effect of temperature, fish size, and somatic growth rate on mean daily otolith growth rate in Arctic char (Salvelinus alpinus) fry fed maximum rations. Long-term experiments at two different temperatures (8 and 13 °C) showed exponential relationships between otolith weight and fish wet weight, with the exponent of wet weight for the higher temperature being significantly higher than for the lower temperature. Increasing exponents at each sampling date indicated a difference in growth rates of the char and its otoliths. Short-term experiments showed that specific growth rate of the fry at six different temperatures was that of an optimum curve whereas the otolith growth rate continued to increase with increasing temperatures. A clear uncoupling between otolith growth rate and fish growth rate was demonstrated whereas temperature and fish wet weight modeled otolith growth rate reasonably well. It was found that otolith growth rate expressed as daily increase in weight gave a model with better fit and higher generality than growth rate along various radii. Several examples of uncoupling between fish growth rate and otolith growth rate in the literature were reexamined, and an explanation of otolith growth rate in terms of a metabolic expression was suggested.

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