Search results for "Fish"
showing 10 items of 3164 documents
Kalavarojen kestävä käyttö : suunnittelu ja toteutus
2018
Kalastuksen ohjaus
2018
Tutkimus ja seuranta
2018
Kalavarojen käyttö ja hoito pysyvät kestävällä pohjalla, kun päätökset perustetaan mahdollisimman luotettavaan ja ajantasaiseen tietoon. Tietoa tarvitaan toiminnan kaikissa vaiheissa, mutta erityisesti silloin, kun asetetaan tavoitetilaa ja osatavoitteita sekä myöhemmin, kun on aika arvioida toimenpiteiden tuloksellisuutta. Tässä luvussa esitellään alueelliseen käyttöön soveltuvia tiedonhankintamenetelmiä sekä annetaan ohjeita aineistojen keruuseen ja tulosten tulkintaan. nonPeerReviewed
Multiple-batch spawning: a risk-spreading strategy disarmed by highly intensive size-selective fishing rate
2022
Can the advantage of risk-managing life-history strategies become a disadvantage under human-induced evolution? Organisms have adapted to the variability and uncertainty of environmental conditions with a vast diversity of life-history strategies. One such evolved strategy is multiple-batch spawning, a spawning strategy common to long-lived fishes that ‘hedge their bets' by distributing the risk to their offspring on a temporal and spatial scale. The fitness benefits of this spawning strategy increase with female body size, the very trait that size-selective fishing targets. By applying an empirically and theoretically motivated eco-evolutionary mechanistic model that was parameterized for …
Size-selective harvesting fosters adaptations in mating behavior and reproductive allocation, affecting sexual selection in fish
2019
The role of sexual selection in the context of harvest‐induced evolution is poorly understood. However, elevated and trait‐selective harvesting of wild populations may change sexually selected traits, which in turn can affect mate choice and reproduction. We experimentally evaluated the potential for fisheries‐induced evolution of mating behaviour and reproductive allocation in fish. We used an experimental system of zebrafish (Danio rerio) lines exposed to large, small or random (i.e. control) size‐selective mortality. The large‐harvested line represented a treatment simulating the typical case in fisheries where the largest individuals are preferentially harvested. We used a full factoria…
Molecular Cytogenetic Characterization of the Sicilian Endemic Pond Turtle Emys trinacris and the Yellow-Bellied Slider Trachemys scripta scripta (Te…
2020
Turtles, a speciose group consisting of more than 300 species, demonstrate karyotypes with diploid chromosome numbers ranging from 2n = 26 to 2n = 68. However, cytogenetic analyses have been conducted only to 1/3rd of the turtle species, often limited to conventional staining methods. In order to expand our knowledge of the karyotype evolution in turtles, we examined the topology of the (TTAGGG)n telomeric repeats and the rDNA loci by fluorescence in situ hybridization (FISH) on the karyotypes of two emydids: the Sicilian pond turtle, Emys trinacris, and the yellow-bellied slider, Trachemys scripta scripta (family Emydidae). Furthermore, AT-rich and GC-rich chromosome regions were detected …
Sustainability of interlocked fishing district -management concept for commercial fishing in Finnish lake fishery
2012
Production and extraction of astaxanthin from Phaffia rhodozyma and its biological effect on alcohol-induced renal hypoxia in Carassius auratus
2015
The effect of astaxanthin (3,3â²-dihydroxy-s-carotene-4,4â²-dione) on alcohol-induced morphological changes in Carassius auratus, as an experimental model, was determined. The yeast Phaffia rhodozyma was used as a source of astaxanthin. The animals were divided into three groups for 30 days: one group was treated with ethanol at a dose of 1.5% mixed in water, the second one with EtOH 1.5% and food enriched with astaxanthin from P. rhodozyma, and the third was a control group. After a sufficient experimental period, the samples were processed using light microscopy and evaluated by histomorphological and histochemical staining, and the data were supported by immunohistochemical analysis, u…
Plasma polyunsaturated fatty acids are directly associated with cognition in overweight children but not in normal weight children
2016
Aim Polyunsaturated fatty acids are essential nutrients for the normal development of the brain. We investigated the associations between plasma polyunsaturated fatty acids and cognition in normal weight and overweight children. Methods The study recruited 386 normal weight children and 58 overweight children aged six to eight years and blood samples were drawn after a 12-hour fast. We assessed plasma polyunsaturated fatty acids using gas chromatography, cognition using Raven's Coloured Progressive Matrices, and overweight and obesity using the age-specific and sex-specific cut-offs from the International Obesity Task Force. The data were analysed by linear regression analyses adjusted for …
Implications of fisheries‐induced evolution for population recovery: Refocusing the science and refining its communication
2019
The argument that sufficiently high fishing mortality (selective or not) can effect genetic change in fished populations has gained considerable traction since the late 1970s. The intervening decades have provided compelling experimental and model‐based evidence that fisheries‐induced evolution (FIE) can cause genetic changes in life history, behaviour and body shape, given sufficiently high trait heritability, selection intensity and time. Fisheries‐induced evolution research has also identified or inferred negative implications to population recovery and sustainable yield, prompting calls for evolutionarily enlightened management to reduce the probability of FIE and mitigate its risks. Su…