Search results for "Fish"
showing 10 items of 3164 documents
Diet composition and seasonal feeding patterns of a freshwater ringed seal (Pusa hispida saimensis)
2015
The Saimaa ringed seal (Pusa hispida saimensis) is one of the few freshwater seal populations worldwide. The major conservation issue of this critically endangered population is bycatch mortality. We used digestive tract content and stable isotopes (d13C and d15N) to estimate the diet and seasonal feeding patterns for gaining better understanding of the seals feeding habits and potential conservation implications. The diet was similar across age groups. Altogether 15 fish species were identified and the most important were smelt (Osmerus eperlanus), ruff (Gymnocephalus cernuus), perch (Perca fluviatilis), vendace (Coregonus albula) and cyprinids. The high d15N values suggested that the seal…
Classroom effect on primary school students’ self-concept in literacy and mathematics
2019
AbstractAccording to the big-fish-little-pond effect (BFLP) model, high individual academic performance in a particular subject is related to high self-concept in that subject, whereas high average classroom performance has a negative effect on self-concept. In the present study, data from Finnish primary school students in grade 3 (504 students), grade 4 (487 students), and grade 6 (365 students) are used to examine whether the assumptions of the BFLP effect model hold already in primary school. Furthermore, we examined gender differences in BFLP effect. The results showed that as expected students’ high performance in literacy and in mathematics was related to high self-concept in the sam…
Ecology, fisheries and management of wild brown trout populations in boreal inland waters
2010
Eutrophication of aquatic ecosystems is an increasing problem, especially threatening small and shallow freshwater lakes. While the extreme inputs of nutrients (phosphorus and nitrogen) can nowadays be reduced and controlled rather efficiently, additional measures to reverse eutrophication may be needed. These often involve biomanipulation, typically mass removal of cyprinid fish. However, the success of biomanipulations has many times been limited or short lived. The reasons for this are not well known, perhaps because the more subtle impacts of biomanipulation on the ecosystem-wide processes of lakes have not been thoroughly studied. Natural abundance stable isotopes may provide a cost-ef…
UV-B exposure causes DNA damage and changes in protein expression in northern pike (Esox lucius) posthatched embryos.
2012
The ongoing anthropogenically caused ozone depletion and climate change has increased the amount of biologically harmful UV-B radiation, which is detrimental to fish in embryonal stages. The effects of UV-B radiation on the levels and locations of DNA damage manifested as cyclobutane pyrimidine dimers (CPDs), heat shock protein 70 (HSP70) and p53 protein in newly hatched embryos of pike were examined. Pike larvae were exposed in the laboratory to current and enhanced doses of UV-B radiation. UV-B exposure caused the formation of CPDs in a fluence rate-dependent manner, and the CPDs were found deeper in the tissues with increasing fluence rates. UV-B radiation induced HSP70 in epidermis, and…
Spore-forming parasites infecting muscles of freshwater fishes : ecology and epidemiology
2017
Fish parasites may potentially harm fisheries and aquaculture. Infected fish are unusable, even though they would not pose a direct risk to human health. The aim of this thesis was to investigate the ecology and epidemiology of three previously unknown or poorly known spore-forming parasites infecting muscles of economically important fish species. The first novel microsporidian species, here described as Microsporidium luciopercae, was found from pike-perch (Sander lucioperca) and European perch (Perca fluviatilis) and formed opaque-looking patches in the muscles. The second novel microsporidian species, Myosporidium spraguei, was found from pike-perch and burbot (Lota lota) and occurred w…
Attitude and Divergence in Business Students: An Examination of Personality Differences in Business and Non-Business Students
2008
Many studies have reported that economics and business students have been more apt to act in selfinterested ways when compared to their counterparts in other academic fields. It is our contention that past studies have not shed light on the underlying psychological differences which might be leading to this difference in behavior. We put forth evidence that certain business majors are correlated with a marked increase in levels of narcissism and decreased levels of empathy, as measured by psychological personality tests.Many studies have reported that economics and business students have been more apt to act in selfinterested ways when compared to their counterparts in other academic fields…
Exploring phage-bacterium interactions : new ways to combat a fish pathogen
2014
Appraisal of Combined Applications of Trichoderma virens and a Biopolymer-Based Biostimulant on Lettuce Agronomical, Physiological, and Qualitative P…
2020
The current research elucidated the agronomical, physiological, qualitative characteristics and mineral composition of lettuce (Lactuca sativa L. var. longifolia) after treatments with a beneficial fungus Trichoderma virens (TG41) alone or in combination with a vegetal biopolymer-based biostimulant (VBP
Varying plant protein sources in the diet of sea bass Dicentrarchus labrax differently affects lipid metabolism and deposition
2010
The liver activity of lipogenic enzymes, the lipid content in various tissues, and plasma lipid levels of major, were measured in sea bass (D. labrax) fed over 96 days either a, fish meal-based control diet or preparations where 70% of fish meal protein was replaced by wheat gluten singly or in combination with pea or soybean meals. Relative to the controls, sea bass fed the wheat gluten-based diet resulted in stimulated lipogenesis in liver and increased lipid deposition in muscle. The opposite occurred when a substantial amount of soybean meal was included in the diet. Mesenteric fat depots were apparently insensitive to major changes in dietary protein source in fish showing similar inta…
Effects of pyrolysis temperature on the hydrologically relevant porosity of willow biochar
2018
Biochar pore space consists of porosity of multiple length scales. In direct water holding applications like water storage for plant water uptake, the main interest is in micrometre-range porosity since these pores are able to store water that is easily available for plants. Gas adsorption measurements which are commonly used to characterize the physical pore structure of biochars are not able to quantify this pore-size range. While pyrogenetic porosity (i.e. pores formed during pyrolysis process) tends to increase with elevated process temperature, it is uncertain whether this change affects the pore space capable to store plant available water. In this study, we characterized biochar poro…