Search results for "food.dish"
showing 10 items of 32 documents
The use of fish bile metabolite analyses as exposure biomarkers to pulp and paper mill effluents
1998
The exposure of caged one-year-old whitefish (Coregonus lavaretus) to wood extractives and chlorophenolics from pulp and paper mill effluents in Lake Saimaa (SE Finland) was investigated. Whitefish were exposed at 17 locations affected by effluents from pulp and paper mills and at 5 reference areas. Resin and fatty acids and chlorophenolics in bile were analysed by GC and GC-MS. Cholesterol concentration in bile was also measured. Results show that despite of process changes to ECF and waste water treatment improvements employed by the pulp and paper industry in the study area, it is still possible to detect elevated concentrations of these substances in the bile of fish exposed in the vici…
HELMINTH ASSEMBLAGES OF WHITEFISH (COREGONUS LAVARETUS) IN INTERCONNECTED LAKES: SIMILARITY AS A FUNCTION OF SPECIES SPECIFIC PARASITES AND GEOGRAPHI…
2004
This article examined the composition of parasite assemblages of whitefish (Coregonus lavaretus) in 8 interconnected lakes in northeastern Finland and evaluated the role of coregonid specific parasites and the geographical distance between populations in determining the similarity of the assemblages. Parasite assemblages were compared using the Jaccard qualitative similarity index and a quantitative similarity index and by incorporating the allogenic-autogenic species concept and the effects of 2 corresponding measures of geographical distance between the lakes. The majority of the parasite species found (10 of 14) were specific to salmonids. Similarity of assemblages of autogenic parasites…
Indice de réflexion latérale du saumon Atlantique (Salmo salar), de la truite de mer (Salmo trutta), du corégone (Coregonus lavaretus) et du brochet …
2000
L'indice de reflexion acoustique laterale (TS) de 19 saumons Atlantique (Salmo salar), 16 truites de mer (Salmo trutta), 10 coregones (Coregonus lavaretus) et 7 brochets (Esox lucius) a ete mesure en utilisant un sondeur de 200 kHz, afin d'etudier la relation entre l'indice TS et la taille, le poids et la surface du poisson. Les effets de l'angle d'incidence sur l'indice TS ont aussi ete etudies. Des modeles lineaires entre TS et le logarithme de l'indice de taille du poisson ont ete ajustes et ont montre que la meilleure prevision provient de l'indice de longueur. Classiquement, l'erreur standard de l'estimation etait de 1,2 a 2,9 dB. Les resultats des mesures de TS sur des poissons de lon…
Predation by signal crayfishPacifastacus leniusculuson fish eggs and its consequences for coregonid recruitment
2015
The character and magnitude of predation by the invasive, ectothermic Pacifastacus leniusculus, a crayfish widely introduced to Europe and Japan from North America, on the eggs of coregonid fishes, vendace Coregonus albula and whitefish Coregonus lavaretus were examined by experimentation, modelling and field data. The present results showed that P. leniusculus has the potential to be very efficient predator of fish eggs under winter conditions, but the predation by P. leniusculus did not significantly decrease production of coregonid larvae during the years with a high P. leniusculus population in the study lake. Hence, the mortality caused by the novel invertebrate predator appeared to co…
Reproductive success of Coregonus species in areas loaded by effluents from paper mills
1992
The annual reproductive success of Coregonus albula and C. lavaretus in some polluted and clean areas of the central parts of L. Paijanne was estimated in 1981–90 on the basis of occurrence of larvae in shore seine and seine net samples after the ice melted. In polluted areas (0-5 km from Kaipola paper mill) larvae of coregonids were found only occasionally. In semipolluted areas (5–15 km from the paper mill) the densities of larvae were usually less than 0.1 ind m-2. In ‘clean’ areas the mean densities of larvae ranged from 0.45 to 5.34 inds m-2. A relatively high reproductive success of vendace was observed in 1984–85, moderate success in 1982–83 and low success in 1986–90. The larvae of …
Eye fluke infection and lens size reduction in fish: a quantitative analysis.
2008
Parasites have a variety of harmful effects on their hosts, some of which may be overlapping or complementary and thus easily overlooked but which are still important for the overall severity of infection. We investigated the effect of Diplostomum sp. eye fluke infection on the size of the eye lens in a range of wild and farmed fish species and those exposed to controlled parasite infection. We found that asymmetry in intensity of infection between the right and left lens of an individual fish affected lens size such that the lens with the higher intensity of infection was smaller. Interestingly, however, this was observed only in 3 of the 10 species studied (whitefish, smelt and sea trout)…
Growth and survival of European whitefish larvae under enhanced UV-B irradiance
2004
Two laboratory rearing experiments with newly hatched European whitefish Coregonus lavaretus larvae were performed to study the effects of UV-B (280–315 nm) radiation on their survival and growth. The results indicate that under normal circumstances in Finnish lakes, enhanced UV irradiance will not be a threat to the survival of newly hatched European whitefish larvae.
Population size estimation of larval coregonids in large lakes: Stratified sampling design with a simple prediction model for vertical distribution
2009
Abstract The lake-specific vertical distribution of larval coregonids was assessed annually in Finnish lakes by bongo net sampling. The effect of inter-annual and inter-lake variation in vertical distributions on population estimates of larval coregonids were analysed in 1999–2008. The vertical distribution of newly hatched vendace ( Coregonus albula (L.)) and European whitefish ( Coregonus lavaretus L. s.l.) larvae was analysed and high inter-annual and lake-specific variation in the larval vertical distribution was found. Generally, in both littoral and pelagic areas, larvae were aggregated near the water surface, mostly in the top 30 cm layer. We compared observed and predicted density e…
The natural history of Echinorhynchus bothniensis Zdzitowiecki and Valtonen, 1987 (Acanthocephala) in a high Arctic lake.
2015
The acanthocephalan Echinorhynchus bothniensis Zdzitowiecki and Valtonen, 1987 differs from most other species in the genus Echinorhynchus Zoega in Muller, 1776 by infecting mysids (order Mysida) instead of amphipods (order Amphipoda) as intermediate hosts. Here we report on the occurrence of E. bothniensis in mysids (Mysis segerstralei Audzijonytė et Vainola) and in its fish definitive hosts in a high Arctic lake. Out of 15 907 sampled mysids, 4.8% were infected with a mean intensity of 1.05 worms (range 1-5), although there was notable variation between samples taken in different years and sites. Larger mysids appear more likely to be infected. Of five fish species sampled, charr,Salvelin…
EFFECT OF TRIAENOPHORUS CRASSUS (CESTODA) INFECTION ON BEHAVIOR AND SUSCEPTIBILITY TO PREDATION OF THE FIRST INTERMEDIATE HOST CYCLOPS STRENUUS (COPE…
2000
Some parasites have been shown to manipulate host behavior so that parasite transmission to the next host is enhanced. Infection with Triaenophorus crassus Forel (Cestoda) caused alterations in the activity and microhabitat selection of the first intermediate host Cyclops strenuus Fischer (Copepoda) in the laboratory. Infected copepods made more starts to swim but spent less time swimming than uninfected copepods. These changes were independent of the intensity of infection. In a water column illuminated from above, infected copepods approached the surface, whereas uninfected ones remained close to the bottom. In the dark both infected and uninfected copepods stayed near the bottom. Finally…