Search results for "trout"

Retene, pyrene and phenanthrene cause distinct molecular-level changes in the cardiac tissue of rainbow trout (Oncorhynchus mykiss) larvae, part 1 – …

2020

Polycyclic aromatic hydrocarbons (PAHs) are contaminants of concern that impact every sphere of the environment. Despite several decades of research, their mechanisms of toxicity are still poorly understood. This study explores the mechanisms of cardiotoxicity of the three widespread model PAHs retene, pyrene and phenanthrene in the rainbow trout (Oncorhynchus mykiss) early life stages. Newly hatched larvae were exposed to each individual compound at sublethal doses causing no significant increase in the prevalence of deformities. Changes in the cardiac transcriptome were assessed after 1, 3, 7 and 14 days of exposure using custom Salmo salar microarrays. The highest number of differentiall…

Parasite-induced aggression and impaired contest ability in a fish host

2010

Abstract Background Success of trophically transmitted parasites depends to a great extent on their ability to manipulate their intermediate hosts in a way that makes them easier prey for target hosts. Parasite-induced behavioural changes are the most spectacular and diverse examples of manipulation. Most of the studies have been focused on individual behaviour of hosts including fish. We suggest that agonistic interactions and territoriality in fish hosts may affect their vulnerability to predators and thus the transmission efficiency of trophically transmitted parasites. The parasite Diplostomum spathaceum (Trematoda) and juvenile rainbow trout, Oncorhynchus mykiss, were used to study whe…

Cardiovascular, ventilatory and haematological responses of brown trout (Salmo trutta L.), to the combined effects of acidity and aluminium in humic …

1995

Two year old brown trout (Salmo trutta L.) were exposed for 7 days to pH 4.7 alone and with aluminium at concentrations of 0.28 and 0.45 mg l−1, respectively, in the water of River Rutajoki, Central Finland. The labile aluminium accounted for less than 30% of the total added amount in the humic water. During the exposures the fish were monitored by a non-contact bioelectronic monitoring system which records heart and ventilation rates of the fish. Terminal blood samples were obtained to evaluate the degree of stress. No mortality occurred during any of the exposures. Acid stress alone and with aluminium caused an immediate acute response in heart and ventilation rates, which remained higher…

Acute toxicity of some chlorinated phenols, catechols and cresols to trout.

1981

Shoaling behaviour of fish under parasitism and predation risk

2008

Shoaling is a common antipredatory adaptation in several fish species. However, parasite infections may alter shoaling behaviour of fish by impairing fish sensory/motor systems and by reducing the net benefit of shoaling. In an experimental study, we investigated whether Diplostomum spathaceum (Trematoda) eye flukes alter shoaling behaviour of rainbow trout, Oncorhynchus mykiss, and if this has an interaction with predation risk. The parasite reduces the vision of fish by inducing cataract formation, which in previous studies has been shown to alter fish escape responses and crypsis. We found that the shoals of infected fish contained fewer individuals and they divided into separate groups …

Bioelectronic monitoring of parasite-induced stress in brown trout and roach

1996

A non-contact bioelectronic monitoring system was used to record changes in heart rate, ventilation rate and swimming activity in brown trout Salmo trutta and roach Rutilus rutilus, following exposure to two species of cercariae of digenean trematodes: Diplostomum pseudospathaceum which is a common parasite in the lens of fishes and xiphidiocercariae of Plagiorchis elegans, a parasite of anatid birds, both of which have the snail Lymnaea stagnalis as their first intermediate host. Swimming activity increased significantly in roach exposed to Diplostomum cercariae at densities as low as 3.8l−1 and remained elevated for 24–36 h post exposure. Brown trout showed no response when exposed to low…

Prevention of fungal infestation of rainbow trout (Oncorhynchus mykiss) eggs using UV irradiation of the hatching water

2013

Abstract Fungal infestation by water mold Saprolegnia spp. causes great losses in aquaculture and fish egg hatching. To find a safe and effective alternative for the fungal prevention, we studied continuous disinfection of the inlet water by UV irradiation and ozonation combined with low concentration hydrogen peroxide (H 2 O 2 ) treatments in a rainbow trout ( Oncorhynchus mykiss ) egg hatching system. High dose of UV irradiation (400 mWs/cm 2 ) of the inlet water decreased the mortality of rainbow trout eggs from the 77.3% to 14.3% in a 28 day trial. UV irradiation did not modify water quality parameters, while combination of UV irradiation and H 2 O 2 caused up to fivefold increase in th…

Intercohort competition causes spatial segregation in brown trout in artificial streams

1999

When together in a flume, 13-cm LS (age-1) trout appeared to increase their activity and behaved more aggressively, whereas 10-cm LS (age-0) trout tended to move less and were rarely aggressive in the presence of the larger size class. Both size classes were less mobile and preferred lower water velocities in winter than in summer, and increased their use of instream cover in winter. When both size classes were present, only small trout decreased their use of low water velocities and cover. The results indicate that intercohort competition may cause spatial segregation among size groups of brown trout, especially in winter when trout attempt to minimize their maintenance costs.

Otter Lutra lutra predation on farmed and free‐living salmonids in boreal freshwater habitats

2002

In this paper we aim to define whether fish farms or stocked trout streams substantially contribute to the diet of otters Lutra lutra living in freshwater habitats of Mid-Finland. Diet was assessed using spraint analysis. We especially focused on areas with fish farms and stocked trout Salmo trutta streams (salmonid-rich habitat) and used ‘normal’ (salmonid-poor) habitats as control. Frequency of salmonid remains in spraints was significantly higher in salmonid-rich habitats than elsewhere in all seasons, the difference increasing from summer to winter. In salmonid-rich habitats, however, salmonid consumption was not strongly seasonal. Data from spraint collection indicated a shift in activ…

Effects of soybean meal based diet on growth performance, gut histopathology and intestinal microbiota of juvenile rainbow trout (Oncorhynchus mykiss)

2006

Abstract Effects of soybean meal (SBM) based diet on growth performance, histology of the intestinal epithelium and on the gut microbiota of juvenile rainbow trout (Oncorhynchus mykiss) were investigated on two trials lasting for 8 weeks (Trial I) and 18 weeks (Trial II). The microbiological characterization was done both with conventional plating techniques, biochemical profiling and length heterogeneity analysis of PCR amplified 16S rDNA (LH-PCR). Typical histological changes were found after 18 weeks of SBM feeding (Trial II). Mean height of simple foldings were significantly higher within the group fed with fish meal (FM) based diet. These changes were not, however, reflected in the app…