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Jonsson, Bror
Publications (10 of 34) Show all publications
Watz, J., Bergman, E., Calles, O., Enefalk, Å., Gustafsson, S., Hagelin, A., . . . Bror, J. (2015). Ice cover alters the behavior and stress level of brown trout Salmo trutta. Behavioral Ecology, 26(3), 820-827
Open this publication in new window or tab >>Ice cover alters the behavior and stress level of brown trout Salmo trutta
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2015 (English)In: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 26, no 3, p. 820-827Article in journal (Refereed) Published
Abstract [en]

Surface ice in rivers and lakes buffers the thermal environment and provides overhead cover, protecting aquatic animals from terrestrial predators. We tested if surface ice influenced the behavior (swimming activity, aggressive encounters, and number of food items eaten) and stress level (coloration of eyes and body) of stream-living brown trout Salmo trutta at temperatures of 3–4 °C in indoor experimental flumes. We hypothesized that an individual’s resting metabolic rate (RMR, as measured by resting ventilation rate) would affect winter behavior. Therefore, groups of 4 trout, consisting of individuals with high, low, or mixed (2 individuals each) RMR, were exposed to experimental conditions with or without ice cover. Ice cover reduced stress responses, as evaluated by body coloration. Also, trout in low RMR groups had a paler body color than those in both mixed and high RMR groups. Trout increased their swimming activity under ice cover, with the highest activity found in high RMR groups. Ice cover increased the number of aggressive encounters but did not influence the number of drifting food items taken by each group. In mixed RMR groups, however, single individuals were better able to monopolize food than in the other groups. As the presence of surface ice increases the activity level and reduces stress in stream-living trout, ice cover should influence their energy budgets and production. The results should be viewed in light of ongoing global warming that reduces the duration of ice cover, especially at high latitudes and altitudes.

Place, publisher, year, edition, pages
Oxford: Oxford University Press, 2015
Keywords
aggression, climate change, energy budget, metabolic rate, winter
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-35931 (URN)10.1093/beheco/arv019 (DOI)000356585100024 ()
Available from: 2015-04-29 Created: 2015-04-29 Last updated: 2017-12-06Bibliographically approved
Otero, J., L'Abee-Lund, J. H., Castro-Santos, T., Leonardsson, K., Storvik, G. O., Jonsson, B., . . . Vollestad, L. A. (2014). Basin-scale phenology and effects of climate variability on global timing of initial seaward migration of Atlantic salmon (Salmo salar). Global Change Biology, 20(1), 61-75
Open this publication in new window or tab >>Basin-scale phenology and effects of climate variability on global timing of initial seaward migration of Atlantic salmon (Salmo salar)
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2014 (English)In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 20, no 1, p. 61-75Article in journal (Refereed) Published
Abstract [en]

Migrations between different habitats are key events in the lives of many organisms. Such movements involve annually recurring travel over long distances usually triggered by seasonal changes in the environment. Often, the migration is associated with travel to or from reproduction areas to regions of growth. Young anadromous Atlantic salmon (Salmo salar) emigrate from freshwater nursery areas during spring and early summer to feed and grow in the North Atlantic Ocean. The transition from the freshwater ('parr') stage to the migratory stage where they descend streams and enter salt water ('smolt') is characterized by morphological, physiological and behavioural changes where the timing of this parr-smolt transition is cued by photoperiod and water temperature. Environmental conditions in the freshwater habitat control the downstream migration and contribute to within- and among-river variation in migratory timing. Moreover, the timing of the freshwater emigration has likely evolved to meet environmental conditions in the ocean as these affect growth and survival of the post-smolts. Using generalized additive mixed-effects modelling, we analysed spatio-temporal variations in the dates of downstream smolt migration in 67 rivers throughout the North Atlantic during the last five decades and found that migrations were earlier in populations in the east than the west. After accounting for this spatial effect, the initiation of the downstream migration among rivers was positively associated with freshwater temperatures, up to about 10 °C and levelling off at higher values, and with sea-surface temperatures. Earlier migration occurred when river discharge levels were low but increasing. On average, the initiation of the smolt seaward migration has occurred 2.5 days earlier per decade throughout the basin of the North Atlantic. This shift in phenology matches changes in air, river, and ocean temperatures, suggesting that Atlantic salmon emigration is responding to the current global climate changes.

Keywords
Atlantic salmon, North Atlantic, freshwater conditions, phenology, sea surface temperature, smolt emigration
National Category
Biological Sciences
Identifiers
urn:nbn:se:kau:diva-34201 (URN)10.1111/gcb.12363 (DOI)000327998600007 ()
Available from: 2014-10-09 Created: 2014-10-09 Last updated: 2017-12-05Bibliographically approved
Jonsson, B. & Jonsson, N. (2014). Early environment influences later performance in fishes. Journal of Fish Biology, 85(2), 155-188
Open this publication in new window or tab >>Early environment influences later performance in fishes
2014 (English)In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 85, no 2, p. 155-188Article in journal (Refereed) Published
Abstract [en]

Conditions fish encounter during embryogenesis and early life history can leave lasting effects not only on morphology, but also on growth rate, life-history and behavioural traits. The ecology of offspring can be affected by conditions experienced by their parents and mother in particular. This review summarizes such early impacts and their ecological influences for a variety of teleost species, but with special reference to salmonids. Growth and adult body size, sex ratio, egg size, lifespan and tendency to migrate can all be affected by early influences. Mechanisms behind such phenotypically plastic impacts are not well known, but epigenetic change appears to be one central mechanism. The thermal regime during development and incubation is particularly important, but also early food consumption and intraspecific density can all be responsible for later life-history variation. For behavioural traits, early experiences with effects on brain, sensory development and cognition appear essential. This may also influence boldness and other social behaviours such as mate choice. At the end of the review, several issues and questions for future studies are given.

Keywords
epigenetic effects, growth, life-history traits, maternal effects, sex ratio, social behaviour
National Category
Biological Sciences
Identifiers
urn:nbn:se:kau:diva-34198 (URN)10.1111/jfb.12432 (DOI)000340393800001 ()
Available from: 2014-10-09 Created: 2014-10-09 Last updated: 2017-12-05Bibliographically approved
Jonsson, B. & Jonsson, N. (2014). Naturally and hatchery produced European trout Salmo trutta: do their marine survival and dispersal differ?. Journal of Coastal Conservation, 18, 79-87
Open this publication in new window or tab >>Naturally and hatchery produced European trout Salmo trutta: do their marine survival and dispersal differ?
2014 (English)In: Journal of Coastal Conservation, ISSN 1400-0350, E-ISSN 1874-7841, Vol. 18, p. 79-87Article in journal (Refereed) Published
Abstract [en]

We tested whether marine survival and migration pattern differed between naturally and hatchery produced European trout Salmo trutta of different origins. The hatchery fish were released 150 m above the river estuary of the southwestern, Norwegian River Imsa, the home of the local population. Recaptures were used as proxy for survival. Wild and local hatchery fish survived better than transplanted hatchery stocks. Trout that were 1 year at release survived less well than 2-year olds, and small individuals less well than larger ones. Relative to their body size at release, populations that originated most distant from the River Imsa, the Baltic River Emån and the Norwegian mountain Lake Tunhovd, exhibited the poorest sea survival. At sea, trout chiefly moved less than 240 km from the river of release, but there were significant differences in dispersal among populations. Hatchery-produced River Emån and Lake Tunhovd trout moved farther from the River Imsa than the south Norwegian sea trout populations, and the marine distributions of the former were similar to that of the natural River Imsa trout. Large fish moved farther from the river than smaller ones. Straying to other rivers was low among wild and local hatchery-produced fish, and significantly lower than among most transplanted populations, and River Emån trout in particular. Thus, the River Imsa trout appeared better adapted to survival under the local conditions than non-local trout with consequences for optimal population management.

Keywords
Carlin tagging, North Sea, Migration Distance, population variation, River Imsa, Straying
National Category
Biological Sciences
Identifiers
urn:nbn:se:kau:diva-34200 (URN)10.1007/s11852-012-0224-1 (DOI)000335390400002 ()
Available from: 2014-10-09 Created: 2014-10-09 Last updated: 2017-12-05Bibliographically approved
Jonsson, N. & Jonsson, B. (2014). Time and size at seaward migration influence the sea survival of Salmo salar. Journal of Fish Biology, 84(5), 1457-1473
Open this publication in new window or tab >>Time and size at seaward migration influence the sea survival of Salmo salar
2014 (English)In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 84, no 5, p. 1457-1473Article in journal (Refereed) Published
Abstract [en]

Whether time of seaward migration of young Atlantic salmon Salmo salar influences their subsequent survival and growth was investigated in the River Imsa, south-western Norway. Salmo salar were tagged when moving downstream through a trap near the outlet between 1976 and 2010 and recaptured on their adult return. Most descended as smolts in April and May, but some descended during the other months of the year. Annual variation in timing of the smolt migration was significantly correlated with variation in water temperature during spring. Mean total body length of the descending S. salar varied with month of seaward migration. The sea survival of S. salar emigrating from the River Imsa between January and May was 2·8 times higher than for those descending between June and December. The sea survival of the various cohorts decreased with increasing river temperature in April to May, prior to the smolt migration, and decreasing day number when the smolts moved to sea. The size of smolts descending the river between April and May did not affect the survival at sea as much as it affected the survival of migrants descending in any other month of the year. The majority of the downstream migrating S. salar were 2 years old, but proportionally, more 1 year olds moved downstream in the autumn than in the rest of the year. Mean duration between downstream migration of the young and the return migration of the grilse was shortest (12·7 months) for those descending in July and August and longest for those descending in October (21 months). Mean monthly specific growth rate was highest for those migrating downstream between May and July and lowest for those emigrating in September. Based on the present results, it was hypothesized that S. salar emigrating between April and August migrated directly out into the ocean, while those that emigrated between October and March stayed in the estuary until the subsequent spring.

Keywords
post-smolts, recapture rate, sea growth, seasonal seaward migration, water temperature
National Category
Biological Sciences
Identifiers
urn:nbn:se:kau:diva-34199 (URN)10.1111/jfb.12370 (DOI)000335446600013 ()
Available from: 2014-10-09 Created: 2014-10-09 Last updated: 2017-12-05Bibliographically approved
Jonsson, B., Jonsson, N. & Finstad, A. G. (2013). Effects of temperature and food quality on age at maturity of ectotherms: an experimentaltest of Atlantic salmon. Journal of Animal Ecology, 82(1), 201-210
Open this publication in new window or tab >>Effects of temperature and food quality on age at maturity of ectotherms: an experimentaltest of Atlantic salmon
2013 (English)In: Journal of Animal Ecology, ISSN 0021-8790, E-ISSN 1365-2656, Vol. 82, no 1, p. 201-210Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Blackwell Wiley, 2013
Keywords
body size, climate change, condition factor, growth rate, lipid density, maturation
National Category
Natural Sciences
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-34185 (URN)10.1111/j.1365-2656.2012.02022.x (DOI)000313752300021 ()
Available from: 2014-10-09 Created: 2014-10-09 Last updated: 2017-12-05Bibliographically approved
Guenard, G., Boisclair, D., Ugedal, O., Forseth, T., Jonsson, B. & Fleming, I. A. (2012). An experimental study of the multiple effects of brown trout Salmo trutta on the bioenergetics of two Arctic charr Salvelinus alpinus morphs. Journal of Fish Biology, 81(4), 1248-1270
Open this publication in new window or tab >>An experimental study of the multiple effects of brown trout Salmo trutta on the bioenergetics of two Arctic charr Salvelinus alpinus morphs
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2012 (English)In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 81, no 4, p. 1248-1270Article in journal (Refereed) Published
Abstract [en]

This study investigated the importance of competition with brown trout Salmo trutta as a driver of the morphological and behavioural divergence of two morphs of Arctic charr Salvelinus alpinus. The morphs originated from two lakes differing in absence or presence of the competitor. The bioenergetics and behaviour of S. alpinus were quantified in replicate experimental enclosures (mean volume: 150 m(3)) stocked with 15 S. alpinus of one morph or the other and in the absence or presence of nine S. trutta. The presence of S. trutta decreased growth rate, affected food consumption and increased activity costs in S. alpinus, but provided little support for the hypothesis that competition with S. trutta is a major driver of the divergence of the two S. alpinus morphs. Both morphs responded similarly in terms of mean growth and consumption rates per enclosure, but the association between individual morphology and growth rate reversed between allopatric and sympatric enclosures. While the activity patterns of the two morphs were unaffected by the presence of S. trutta, their swimming speed and activity rate differed. Since the profound differences in the structure of the physical habitat of the source lakes provided a more likely explanation for the difference observed among these two morphs than interspecific competition, it is hypothesized that physical habitat may sometimes be a significant driving force of the phenotypic divergence.

Keywords
Competitive Behavior, Ecosystem, Energy Metabolism
National Category
Biological Sciences
Identifiers
urn:nbn:se:kau:diva-34205 (URN)10.1111/j.1095-8649.2012.03414.x (DOI)000308506900009 ()
Available from: 2014-10-09 Created: 2014-10-09 Last updated: 2017-12-05Bibliographically approved
Finstad, A. G. & Jonsson, B. (2012). Effect of incubation temperature on growth performance in Atlantic salmon. Marine Ecology Progress Series, 454, 75-82
Open this publication in new window or tab >>Effect of incubation temperature on growth performance in Atlantic salmon
2012 (English)In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 454, p. 75-82Article in journal (Refereed) Published
Abstract [en]

Interspecific variations in thermal growth performance of ectotherms have received considerable recent interest fueled by the focus on ecological climate change effects. Amongpopulation variations in growth are commonly observed in field studies. However, the role of pheno typic plasticity in shaping this variation is largely unexplored in teleost fishes. Here, we tested for the effect of incubation temperature on thermal scaling of growth and maximum growth performance of the anadromous salmonid Atlantic salmon Salmo salar L. Salmon eggs were incubated and reared until the onset of exogenous feeding at either heated or natural temperatures or transferred from natural to heated temperatures at the time of hatching, creating 3 different embryonic temperature treatments (heated, natural or mixed). We subsequently tested for juvenile growth performance of these groups at 8 temperatures ranging from 6 to 24°C. Maximum growth was significantly higher in the heated than the natural and mixed incubation temperature groups, but we did not observe differences in the thermal scaling of growth performance. Neither the upper nor lower thermal limit for growth nor the optimal growth temperature differed be tween the 3 incubation temperature treatments. However, thermal conditions experienced by in cubating embryos affected later growth performance. Although similar results have been observed previously among reptiles, this is to our knowledge the first empirical support for this hypothesis among teleost fishes. Phenotypic plasticity in growth performance can likely explain many of the contrasting findings from previous research on countergradient growth effects in teleost fishes.

Keywords
Countergradient variation, Growth reaction norms, Salmo salar L., Thermal adaptation, Thermal performance
National Category
Biological Sciences
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-34206 (URN)10.3354/meps09643 (DOI)000304605500006 ()
Available from: 2014-10-09 Created: 2014-10-09 Last updated: 2017-12-05Bibliographically approved
Guenard, G., Boisclair, D., Ugedal, O., Forseth, T., Fleming, I. A. & Jonsson, B. (2012). The bioenergetics ofdensity-dependent growth in Arctic char (Salvelinus alpinus L.). Canadian Journal of Fisheries and Aquatic Sciences, 69, 1651-1662
Open this publication in new window or tab >>The bioenergetics ofdensity-dependent growth in Arctic char (Salvelinus alpinus L.)
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2012 (English)In: Canadian Journal of Fisheries and Aquatic Sciences, ISSN 0706-652X, E-ISSN 1205-7533, Vol. 69, p. 1651-1662Article in journal (Refereed) Published
National Category
Zoology Fish and Aquacultural Science
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-34321 (URN)10.1139/F2012-093 (DOI)
Available from: 2014-10-13 Created: 2014-10-13 Last updated: 2018-07-19Bibliographically approved
Jonsson, B., Finstad, A. G. & Jonsson, N. (2012). Winter temperature and food quality affect age and size at maturity in ectotherms: an experimentaltest with Atlantic salmon. Canadian Journal of Fisheries and Aquatic Sciences, 69(11), 1817-1826
Open this publication in new window or tab >>Winter temperature and food quality affect age and size at maturity in ectotherms: an experimentaltest with Atlantic salmon
2012 (English)In: Canadian Journal of Fisheries and Aquatic Sciences, ISSN 0706-652X, E-ISSN 1205-7533, Vol. 69, no 11, p. 1817-1826Article in journal (Refereed) Published
Abstract [en]

Field studies have revealed that many ectotherms mature younger and smaller in warmer environments although they grow faster. This has puzzled ecologists because the direct effect of factors that accelerate growth is expected to be larger, not smaller size. We tested this experimentally for Atlantic salmon (Salmo salar) at two winter temperatures and diets. Logistic regression revealed that the probability of maturation during the second year in sea water, relative to the probability of older maturation, increased with temperature and growth rate during the first winter. Also, large size and high condition factor 1 year prior to maturation stimulated maturation. In females, a high lipid diet increased the probability of maturation as one-sea-winter fish, and there were significant interactions between winter temperature and food quality and between body size and condition factor the first autumn in sea water. Thus, if the direct effect of temperature on growth rate is the main effect of warming, salmon are likely to attain maturity younger and smaller. Also, richer food decreased age at maturation in females. This finding has consequences for interpretations of climate change impacts on age at maturity in Atlantic salmon and may also hold for many other ectotherm species.

Salmo salar) at two winter temperatures and

diets. Logistic regression revealed that the probability of maturation during the second year in sea water, relative to the

probability of older maturation, increased with temperature and growth rate during the first winter. Also, large size and

high condition factor 1 year prior to maturation stimulated maturation. In females, a high lipid diet increased the probability of

maturation as one-sea-winter fish, and there were significant interactions between winter temperature and food quality and

between body size and condition factor the first autumn in sea water. Thus, if the direct effect of temperature on growth rate is

the main effect of warming, salmon are likely to attain maturity younger and smaller. Also, richer food decreased age at

maturation in females. This finding has consequences for interpretations of climate change impacts on age at maturity in Atlantic salmon and may also hold for many other ectotherm species.

Place, publisher, year, edition, pages
Canada. Dept. of Fisheries and Oceans; National Research Council Canada, National Research Council Canada, 2012
National Category
Zoology Fish and Aquacultural Science
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-34186 (URN)10.1139/f2012-108 (DOI)000311209800010 ()
Available from: 2014-10-09 Created: 2014-10-09 Last updated: 2018-08-07Bibliographically approved
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