Yhteenveto: Organoklooriyhdisteiden kertyminen Itämeren kaloihin Diss. Commercially important Bal... more Yhteenveto: Organoklooriyhdisteiden kertyminen Itämeren kaloihin Diss. Commercially important Baltic Sea fish species such as herring (Clupea harengus L.) suffer from high concentrations of toxic and highly bioaccumulative organochlorines (OCs). This thesis investigates accumulation of these compounds in the Baltic Sea from invertebrates through herring, sprat (Sprattus sprattus (L.)) and three-spined stickleback (Gasterosteus aculeatus L.) into salmon (Salmo salar L.) and onwards to humans. Strategies to reduce present OC concentrations in fish and therefore human intake are also tested. The thesis presents some methodological insights into application of stable isotope analysis, used in accumulation studies. Age and growth seems to explain most of the individual variation in herring OC concentrations. An accumulation model constructed for herring together with empirical data suggested that growth plays a significant role in explaining the differences in OC concentration between sea areas. Changes in herring growth during past decades are the most probable explanation for observations that herring organochlorine concentrations have levelled out. Stable isotopes combined with an accumulation model developed for salmon revealed that individual and spatial variability in salmon OC concentrations arose from the differences in the salmon diet, trophic position, as well as prey OC concentrations and lipid content. Based on the theory of density-dependence in herring growth, the accumulation model combined with age-structured simulations and a probabilistic human intake model showed that concentration in the Baltic herring could be decreased substantially by increased fishing. This would also decrease human dietary intake of OCs. However, significant reduction in concentrations would require high exploitation rates and there is a risk that this would lead to over fishing of herring. Therefore, risk management of organochlorines by regulating fishing seems to be a less effective way to decrease the human dietary intake of organochlorines than directly regulating the consumption of the most contaminated herring.
Resumo-A classificação não supervisionada tem um papel muito importante na análise de imagens mul... more Resumo-A classificação não supervisionada tem um papel muito importante na análise de imagens multiespectrais, dada a sua capacidade para auxiliar a extração de conhecimento a priori de imagens. Algoritmos como k-médias e fuzzy c-médias tem sido muito utilizados nessa tarefa. A Inteligência Computacional tem-se mostrado como um importante campo para auxiliar na construção de classificadores otimizados, tanto quantoà qualidade do agrupamento de classes, quantoà avaliação da qualidade da quantização vetorial. Diversos trabalhos têm mostrado que a Filosofia, em especial o Método Dialético, tem servido como importante inspiração para a construção de novos métodos computacionais. Este trabalho apresenta uma avaliação de quatro métodos baseados na Dialética: o Classificador Dialético Objetivo e o Método Dialético de Otimização adaptadoà construção de uma versão do k-médias otimizada segundoíndices de qualidade de agrupamento, cada um desses em uma versão canônica e em outra versão obtida pela aplicação do Princípio da Máxima Entropia. Esses métodos foram comparados aos métodos k-médias, fuzzy c-médias e mapa auto-organizado de Kohonen. Os resultados mostraram que os métodos baseados na Dialética são robustos ao ruído e podem atingir resultados de quantização tão bons quanto aqueles obtidos com o mapa de Kohonen, considerado um quantizadorótimo. Palavras-chave-Segmentação de imagens, k-médias, dialética, otimização, princípio da máxima entropia, computação evolucionária.
Managing the dioxin problem in the Baltic region with focus on sources to air and edible fish : B... more Managing the dioxin problem in the Baltic region with focus on sources to air and edible fish : Balticpops - a 2-year Swedish EPA research program
This is an electronic reprint of the original article. This reprint may differ from the original ... more This is an electronic reprint of the original article. This reprint may differ from the original in pagination and typographic detail.
Fatty acids in muscle tissue and eggs of female Atlantic salmon Salmo salar spawners were analyse... more Fatty acids in muscle tissue and eggs of female Atlantic salmon Salmo salar spawners were analysed to evaluate the dietary quality of their final feeding areas in the Baltic Sea. The final likely feeding area was identified by comparing stable carbon and nitrogen isotope composition of the outermost growth region (final annulus) of scales of returned S. salar with that of reference S. salar caught from different feeding areas. Some overlap of stable-isotope reference values among the three areas, in addition to prespawning fasting, decreased the ability of muscle tri-acylglycerols to discriminate the final likely feeding area and the area's dietary quality. Among three long-chained polyunsaturated fatty acids, docosahexaenoic acid (DHA; 22:6n-3), eicosapentaenoic acid (EPA; 20:5n-3) and arachidonic acid (ARA; 20:4n-6), the proportions of ARA in total lipids of spawning S. salar muscle and eggs showed a significant negative correlation with increasing probability of S. salar havi...
Knowledge and Management of Aquatic Ecosystems, 2012
littorales. Ces résultats présentent des preuves que l'écrevisse signal invasive crée un nouveau ... more littorales. Ces résultats présentent des preuves que l'écrevisse signal invasive crée un nouveau lien dans le transfert d'énergie à partir des zones littorales vers la zone profonde et donc augmente la connectivité entre ces habitats spatialement distincts. Nos résultats mettent en évidence la nécessité de mieux comprendre le rôle de l'écrevisse dans la dynamique de l'énergie d'un lac et la connectivité des habitats.
Adaptive radiation is considered an important mechanism for the development of new species, but v... more Adaptive radiation is considered an important mechanism for the development of new species, but very little is known about the role of thermal adaptation during this process. Such adaptation should be especially important in poikilothermic animals that are often subjected to pronounced seasonal temperature variation that directly affects metabolic function. We conducted a preliminary study of individual lifetime thermal habitat use and respiration rates of four whitefish (Coregonus lavaretus (L.)) morphs (two pelagic, one littoral and one profundal) using stable carbon and oxygen isotope values of otolith carbonate. These morphs, two of which utilized pelagic habitats, one littoral and one profundal recently diverged via adaptive radiation to exploit different major niches in a deep and thermally stratified subarctic lake. We found evidence that the morphs used different thermal niches. The profundal morph had the most distinct thermal niche and consistently occupied the coldest thermal habitat of the lake, whereas differences were less pronounced among the shallow water pelagic and littoral morphs. Our results indicated ontogenetic shifts in thermal niches: juveniles of all whitefish morphs inhabited warmer ambient temperatures than adults. According to sampling of the otolith nucleus, hatching temperatures were higher for benthic compared to pelagic morphs. Estimated respiration rate was the lowest for benthivorous profundal morph, contrasting with the higher values estimated for the other morphs that inhabited shallower and warmer water. These preliminary results suggest that physiological adaptation to different thermal habitats shown by the sympatric morphs may play a significant role in maintaining or strengthening niche segregation and divergence in life-history traits, potentially contributing to reproductive isolation and incipient speciation.
Factors affecting the biomagnification of organohalogens in Baltic salmon from sprat, herring and... more Factors affecting the biomagnification of organohalogens in Baltic salmon from sprat, herring and three-spined stickleback were assessed in three feeding areas. Second sea-year salmon contained (in fresh weight of whole fish) 79-250 ng g −1 polychlorinated biphenyls (ΣPCB), 0.9-2.7 pg g − 1 dibenzo-p-dioxins (ΣPCDD), 8-19 pg g − 1 dibenzofurans (ΣPCDF), 96-246 pg g − 1 coplanar PCBs, 2.4-3.6 ng g − 1 polybrominated diphenylethers (ΣPBDE), and 39-136 ng g − 1 Σ indicator PCB6. The EU limits for WHO toxic equivalent concentrations in fish feed were already exceeded in one-year-old sprat and herring and were exceeded many-fold in older age groups. The differences in the biomagnification rates of organohalogens in salmon appeared to be related to the feeding area, principal prey species, and the fat content and growth rate of the prey species.
Knowledge of ingredients assimilation and biomass contribution to recipient fish is important in ... more Knowledge of ingredients assimilation and biomass contribution to recipient fish is important in feed formulation. The stable isotopes of 13 C and 15 N were used to investigate the assimilation and biomass contribution of bambaranut, Voandzeia subterranea, meal (BNM), corn, Zea mays, meal (CM) and fish meal (FM), in FM substituted diets of first feeding African catfish, Clarias gariepinus, during a 30-d experiment. The catfish larvae were stocked at 40 fish/15 L three replicate glass aquaria. Larvae were fed with experimental diets varying FM, BNM, and CM. Proportions of FM : BNM : CM in the experimental diets were: feed 1 (F1) 60:20:20; feed 2 (F2) 40:40:20; feed 3 (F3) 20:60:20; and feed 4 (F4) 20:20:60. Feeds and larval stable isotopes of δ 13 C and δ 15 N were analyzed. Larval specific growth rates (SGRs) were high, enhancing incorporation of dietary δ 13 C and δ 15 N. The SGR was highest for catfish fed F1 and F2 but significantly lower for those on F3 and F4. Results of δ 13 C and δ 15 N analyses showed that the biomass contribution from FM was similar to BNM, which were better than CM at equal inclusion levels. The nitrogen contribution per ingredient to larval somatic crude protein was increasing with increases in ingredient inclusion and assimilation. Stable isotope analysis is useful for analyzing assimilation and utilization of nutrients.
... The date of hatching was recorded and the Elliott–Hurley model was then used to predict the t... more ... The date of hatching was recorded and the Elliott–Hurley model was then used to predict the time of emergence based on water temperature. ... The model of Elliott & Hurley (1998a) was used to predict the timing of emergence from gravel at each study site. ...
Canadian Journal of Fisheries and Aquatic Sciences, 2008
Atlantic salmon ( Salmo salar ) collected from three locations around the northern Baltic Sea in ... more Atlantic salmon ( Salmo salar ) collected from three locations around the northern Baltic Sea in 2003–2004 showed large spatial and individual variation in their organochlorines (OCs) (polychlorinated dibenzo-p-dioxins and furans and polychlorinated biphenyls). This variation could be explained only partly by their size or sea age. The variability arose from the differences in salmon diet, trophic position, and prey OC concentrations and lipid content. A salmon bioenergetics accumulation model was used to evaluate the contribution of salmon growth and their diet to the observed individual variation in OC content. Our model revealed that the contribution of three main prey species in the OC accumulation of salmon varied markedly between the study areas. Amount of lipids in salmon explained a large proportion of their OC concentration. However, trophic position of salmon calculated from the δ15N values explained almost 80% of the variation in lipid-normalized OC concentrations. In the...
Page 1. ORIGINAL PAPER Do introduced crayfish affect benthic fish in stony littoral habitats of l... more Page 1. ORIGINAL PAPER Do introduced crayfish affect benthic fish in stony littoral habitats of large boreal lakes? Timo J. Ruokonen • Juha Karjalainen • Mikko Kiljunen • Markku Pursiainen • Heikki Hämäläinen Received: 19 ...
Climate change is projected to increase mean temperature of northern lakes by the end of the twen... more Climate change is projected to increase mean temperature of northern lakes by the end of the twenty-first century. To simulate this scenario, during 2004–2007 we imposed artificial mixing in Halsjärvi, a small, polyhumic, boreal lake in southern Finland, to increase the depth of the thermocline by ~1.5 m. The aims of the experiment were to evaluate potential effects of climate change
Summary 1. Stable isotope analyses coupled with mixing models are being used increasingly to eval... more Summary 1. Stable isotope analyses coupled with mixing models are being used increasingly to evaluate ecological management issues and questions. Such applications of stable isotope analyses often require simultaneous carbon and nitrogen analyses from the same sample. Correction of the carbon isotope values to take account of the varying content of 13C-depleted lipids is then frequently achieved by a lipid-normalization procedure using a model describing the relationship between change in ��13C following lipid removal and ...
Stable isotope analyses coupled with mixing models are being used increasingly to evaluate ecolog... more Stable isotope analyses coupled with mixing models are being used increasingly to evaluate ecological management issues and questions. Such applications of stable isotope analyses often require simultaneous carbon and nitrogen analyses from the same sample. Correction of the carbon isotope values to take account of the varying content of 13C-depleted lipids is then frequently achieved by a lipid-normalization procedure using
Yhteenveto: Organoklooriyhdisteiden kertyminen Itämeren kaloihin Diss. Commercially important Bal... more Yhteenveto: Organoklooriyhdisteiden kertyminen Itämeren kaloihin Diss. Commercially important Baltic Sea fish species such as herring (Clupea harengus L.) suffer from high concentrations of toxic and highly bioaccumulative organochlorines (OCs). This thesis investigates accumulation of these compounds in the Baltic Sea from invertebrates through herring, sprat (Sprattus sprattus (L.)) and three-spined stickleback (Gasterosteus aculeatus L.) into salmon (Salmo salar L.) and onwards to humans. Strategies to reduce present OC concentrations in fish and therefore human intake are also tested. The thesis presents some methodological insights into application of stable isotope analysis, used in accumulation studies. Age and growth seems to explain most of the individual variation in herring OC concentrations. An accumulation model constructed for herring together with empirical data suggested that growth plays a significant role in explaining the differences in OC concentration between sea areas. Changes in herring growth during past decades are the most probable explanation for observations that herring organochlorine concentrations have levelled out. Stable isotopes combined with an accumulation model developed for salmon revealed that individual and spatial variability in salmon OC concentrations arose from the differences in the salmon diet, trophic position, as well as prey OC concentrations and lipid content. Based on the theory of density-dependence in herring growth, the accumulation model combined with age-structured simulations and a probabilistic human intake model showed that concentration in the Baltic herring could be decreased substantially by increased fishing. This would also decrease human dietary intake of OCs. However, significant reduction in concentrations would require high exploitation rates and there is a risk that this would lead to over fishing of herring. Therefore, risk management of organochlorines by regulating fishing seems to be a less effective way to decrease the human dietary intake of organochlorines than directly regulating the consumption of the most contaminated herring.
Resumo-A classificação não supervisionada tem um papel muito importante na análise de imagens mul... more Resumo-A classificação não supervisionada tem um papel muito importante na análise de imagens multiespectrais, dada a sua capacidade para auxiliar a extração de conhecimento a priori de imagens. Algoritmos como k-médias e fuzzy c-médias tem sido muito utilizados nessa tarefa. A Inteligência Computacional tem-se mostrado como um importante campo para auxiliar na construção de classificadores otimizados, tanto quantoà qualidade do agrupamento de classes, quantoà avaliação da qualidade da quantização vetorial. Diversos trabalhos têm mostrado que a Filosofia, em especial o Método Dialético, tem servido como importante inspiração para a construção de novos métodos computacionais. Este trabalho apresenta uma avaliação de quatro métodos baseados na Dialética: o Classificador Dialético Objetivo e o Método Dialético de Otimização adaptadoà construção de uma versão do k-médias otimizada segundoíndices de qualidade de agrupamento, cada um desses em uma versão canônica e em outra versão obtida pela aplicação do Princípio da Máxima Entropia. Esses métodos foram comparados aos métodos k-médias, fuzzy c-médias e mapa auto-organizado de Kohonen. Os resultados mostraram que os métodos baseados na Dialética são robustos ao ruído e podem atingir resultados de quantização tão bons quanto aqueles obtidos com o mapa de Kohonen, considerado um quantizadorótimo. Palavras-chave-Segmentação de imagens, k-médias, dialética, otimização, princípio da máxima entropia, computação evolucionária.
Managing the dioxin problem in the Baltic region with focus on sources to air and edible fish : B... more Managing the dioxin problem in the Baltic region with focus on sources to air and edible fish : Balticpops - a 2-year Swedish EPA research program
This is an electronic reprint of the original article. This reprint may differ from the original ... more This is an electronic reprint of the original article. This reprint may differ from the original in pagination and typographic detail.
Fatty acids in muscle tissue and eggs of female Atlantic salmon Salmo salar spawners were analyse... more Fatty acids in muscle tissue and eggs of female Atlantic salmon Salmo salar spawners were analysed to evaluate the dietary quality of their final feeding areas in the Baltic Sea. The final likely feeding area was identified by comparing stable carbon and nitrogen isotope composition of the outermost growth region (final annulus) of scales of returned S. salar with that of reference S. salar caught from different feeding areas. Some overlap of stable-isotope reference values among the three areas, in addition to prespawning fasting, decreased the ability of muscle tri-acylglycerols to discriminate the final likely feeding area and the area's dietary quality. Among three long-chained polyunsaturated fatty acids, docosahexaenoic acid (DHA; 22:6n-3), eicosapentaenoic acid (EPA; 20:5n-3) and arachidonic acid (ARA; 20:4n-6), the proportions of ARA in total lipids of spawning S. salar muscle and eggs showed a significant negative correlation with increasing probability of S. salar havi...
Knowledge and Management of Aquatic Ecosystems, 2012
littorales. Ces résultats présentent des preuves que l'écrevisse signal invasive crée un nouveau ... more littorales. Ces résultats présentent des preuves que l'écrevisse signal invasive crée un nouveau lien dans le transfert d'énergie à partir des zones littorales vers la zone profonde et donc augmente la connectivité entre ces habitats spatialement distincts. Nos résultats mettent en évidence la nécessité de mieux comprendre le rôle de l'écrevisse dans la dynamique de l'énergie d'un lac et la connectivité des habitats.
Adaptive radiation is considered an important mechanism for the development of new species, but v... more Adaptive radiation is considered an important mechanism for the development of new species, but very little is known about the role of thermal adaptation during this process. Such adaptation should be especially important in poikilothermic animals that are often subjected to pronounced seasonal temperature variation that directly affects metabolic function. We conducted a preliminary study of individual lifetime thermal habitat use and respiration rates of four whitefish (Coregonus lavaretus (L.)) morphs (two pelagic, one littoral and one profundal) using stable carbon and oxygen isotope values of otolith carbonate. These morphs, two of which utilized pelagic habitats, one littoral and one profundal recently diverged via adaptive radiation to exploit different major niches in a deep and thermally stratified subarctic lake. We found evidence that the morphs used different thermal niches. The profundal morph had the most distinct thermal niche and consistently occupied the coldest thermal habitat of the lake, whereas differences were less pronounced among the shallow water pelagic and littoral morphs. Our results indicated ontogenetic shifts in thermal niches: juveniles of all whitefish morphs inhabited warmer ambient temperatures than adults. According to sampling of the otolith nucleus, hatching temperatures were higher for benthic compared to pelagic morphs. Estimated respiration rate was the lowest for benthivorous profundal morph, contrasting with the higher values estimated for the other morphs that inhabited shallower and warmer water. These preliminary results suggest that physiological adaptation to different thermal habitats shown by the sympatric morphs may play a significant role in maintaining or strengthening niche segregation and divergence in life-history traits, potentially contributing to reproductive isolation and incipient speciation.
Factors affecting the biomagnification of organohalogens in Baltic salmon from sprat, herring and... more Factors affecting the biomagnification of organohalogens in Baltic salmon from sprat, herring and three-spined stickleback were assessed in three feeding areas. Second sea-year salmon contained (in fresh weight of whole fish) 79-250 ng g −1 polychlorinated biphenyls (ΣPCB), 0.9-2.7 pg g − 1 dibenzo-p-dioxins (ΣPCDD), 8-19 pg g − 1 dibenzofurans (ΣPCDF), 96-246 pg g − 1 coplanar PCBs, 2.4-3.6 ng g − 1 polybrominated diphenylethers (ΣPBDE), and 39-136 ng g − 1 Σ indicator PCB6. The EU limits for WHO toxic equivalent concentrations in fish feed were already exceeded in one-year-old sprat and herring and were exceeded many-fold in older age groups. The differences in the biomagnification rates of organohalogens in salmon appeared to be related to the feeding area, principal prey species, and the fat content and growth rate of the prey species.
Knowledge of ingredients assimilation and biomass contribution to recipient fish is important in ... more Knowledge of ingredients assimilation and biomass contribution to recipient fish is important in feed formulation. The stable isotopes of 13 C and 15 N were used to investigate the assimilation and biomass contribution of bambaranut, Voandzeia subterranea, meal (BNM), corn, Zea mays, meal (CM) and fish meal (FM), in FM substituted diets of first feeding African catfish, Clarias gariepinus, during a 30-d experiment. The catfish larvae were stocked at 40 fish/15 L three replicate glass aquaria. Larvae were fed with experimental diets varying FM, BNM, and CM. Proportions of FM : BNM : CM in the experimental diets were: feed 1 (F1) 60:20:20; feed 2 (F2) 40:40:20; feed 3 (F3) 20:60:20; and feed 4 (F4) 20:20:60. Feeds and larval stable isotopes of δ 13 C and δ 15 N were analyzed. Larval specific growth rates (SGRs) were high, enhancing incorporation of dietary δ 13 C and δ 15 N. The SGR was highest for catfish fed F1 and F2 but significantly lower for those on F3 and F4. Results of δ 13 C and δ 15 N analyses showed that the biomass contribution from FM was similar to BNM, which were better than CM at equal inclusion levels. The nitrogen contribution per ingredient to larval somatic crude protein was increasing with increases in ingredient inclusion and assimilation. Stable isotope analysis is useful for analyzing assimilation and utilization of nutrients.
... The date of hatching was recorded and the Elliott–Hurley model was then used to predict the t... more ... The date of hatching was recorded and the Elliott–Hurley model was then used to predict the time of emergence based on water temperature. ... The model of Elliott & Hurley (1998a) was used to predict the timing of emergence from gravel at each study site. ...
Canadian Journal of Fisheries and Aquatic Sciences, 2008
Atlantic salmon ( Salmo salar ) collected from three locations around the northern Baltic Sea in ... more Atlantic salmon ( Salmo salar ) collected from three locations around the northern Baltic Sea in 2003–2004 showed large spatial and individual variation in their organochlorines (OCs) (polychlorinated dibenzo-p-dioxins and furans and polychlorinated biphenyls). This variation could be explained only partly by their size or sea age. The variability arose from the differences in salmon diet, trophic position, and prey OC concentrations and lipid content. A salmon bioenergetics accumulation model was used to evaluate the contribution of salmon growth and their diet to the observed individual variation in OC content. Our model revealed that the contribution of three main prey species in the OC accumulation of salmon varied markedly between the study areas. Amount of lipids in salmon explained a large proportion of their OC concentration. However, trophic position of salmon calculated from the δ15N values explained almost 80% of the variation in lipid-normalized OC concentrations. In the...
Page 1. ORIGINAL PAPER Do introduced crayfish affect benthic fish in stony littoral habitats of l... more Page 1. ORIGINAL PAPER Do introduced crayfish affect benthic fish in stony littoral habitats of large boreal lakes? Timo J. Ruokonen • Juha Karjalainen • Mikko Kiljunen • Markku Pursiainen • Heikki Hämäläinen Received: 19 ...
Climate change is projected to increase mean temperature of northern lakes by the end of the twen... more Climate change is projected to increase mean temperature of northern lakes by the end of the twenty-first century. To simulate this scenario, during 2004–2007 we imposed artificial mixing in Halsjärvi, a small, polyhumic, boreal lake in southern Finland, to increase the depth of the thermocline by ~1.5 m. The aims of the experiment were to evaluate potential effects of climate change
Summary 1. Stable isotope analyses coupled with mixing models are being used increasingly to eval... more Summary 1. Stable isotope analyses coupled with mixing models are being used increasingly to evaluate ecological management issues and questions. Such applications of stable isotope analyses often require simultaneous carbon and nitrogen analyses from the same sample. Correction of the carbon isotope values to take account of the varying content of 13C-depleted lipids is then frequently achieved by a lipid-normalization procedure using a model describing the relationship between change in ��13C following lipid removal and ...
Stable isotope analyses coupled with mixing models are being used increasingly to evaluate ecolog... more Stable isotope analyses coupled with mixing models are being used increasingly to evaluate ecological management issues and questions. Such applications of stable isotope analyses often require simultaneous carbon and nitrogen analyses from the same sample. Correction of the carbon isotope values to take account of the varying content of 13C-depleted lipids is then frequently achieved by a lipid-normalization procedure using
Uploads
Papers by M. Kiljunen