Search results for " life stage"
showing 6 items of 6 documents
Diet and trophic niche of the invasive signal crayfish in the first invaded Italian stream ecosystem.
2021
The occurrence of the signal crayfsh Pacifastacus leniusculus in the Valla Stream was the frst established population of this invasive species recorded in an Italian stream ecosystem. We evaluated the seasonality of diet and trophic niche of invasive signal crayfsh in order to estimate the ecological role and efects on native communities of the stream ecosystem. We studied the diferences in food source use between sexes, life stages and seasons using carbon and nitrogen stable isotope analyses. To supplement stable isotope analyses, we evaluated food source usage using traditional stomach content analysis. We tested the hypothesis that juveniles have a diferent diet, showing diferent trophi…
Role of protozooplankton in the diet of North Sea autumn spawning herring (Clupea harengus) larvae
2022
AbstractThe role of small prey (< 200 µm) in larval marine fish nutrition is largely understudied. Here, we explore the contribution of protozooplankton (PZP 20–200 µm) to larval fish diets, compared to metazoan microzooplankton (MZP 55–200 µm). More specifically, we tested whether the contribution of PZP increased during the low productivity season and decreased as larvae grow. We used North Sea autumn spawning herring (Clupea harengus) as a case study, as it is a key species with high commercial and ecological importance. In autumn and winter, the potential PZP and MZP prey was dominated by cells < 50 µm (mainly Gymnodiniales, Pronoctiluca pelagica,Tripos spp. and Strombidium spp.),…
Trophic Requirements of the Sea Urchin Paracentrotus lividus Varies at Different Life Stages: Comprehension of Species Ecology and Implications for E…
2022
Investigations on trophic requirements of different life cycle stages of Paracentrotus lividus are crucial for the comprehension of species ecology and for its artificial rearing. The future success of echinoculture depends heavily on the development of suitable and cost-effective diets that are specifically designed to maximize somatic growth during the early life stages and gonadal production in the later stages. In this context, a considerable number of studies have recommended animal sources as supplements in sea urchin diets. However, with the exception of Fernandez and Boudouresque (2000), no studies have investigated the dietary requirements over the different life stages of the sea …
Use of Early Juvenile Zebrafish Danio Rerio for In-Vivo Assessment of Endocrine Modulation by Xenoestrogens
2013
Reliable and cost-effective early-life stage (ELS) bioassays incorporating practical experimentation without compromising scientific relevance are crucial in chemical risk assessment. This study investigated the use of 20 days- post-fertilization life stage ( 20dpfZF ) of zebrafish Danio rerio to screen environmental chemicals known to be estrogenic in adult fish. Firstly, studies with key genes in steroidogenesis were conducted; the brain isoform of aromatase gene ( cyp19a1b ) being the most prominently expressed biomarker. Regulation of mRNA levels of molecular biomarkers, vitellogenin 1 gene ( vtg1) and cyp19a1b were selected to assess the endocrine modulation by xenoestrogens, 17α-ethin…
Effects of bioheapleaching technology utilizing metal mine emissions on fish in boreal freshwaters
2018
Emissions from metal mining activities are known to deteriorate the quality of aquatic habitats and impair the condition and reproductive potential of fish. Metal extraction by biomining methods has been considered to cause fewer emissions, but for example in Finland, the impacts of a bioheapleaching technology utilizing metal mine on the local freshwaters have been substantial. In this thesis, the impacts of the bioheapleaching mine emissions on three native fish species, brown trout (Salmo trutta) European perch (Perca fluviatilis) and whitefish (Coregonus lavaretus pallasi), were investigated. Manganese and sulphate concentrations have been elevated in the mining impacted waters, and in …
Otolith chemical composition suggests local populations of Antarctic silverfish Pleuragramma antarctica (Boulenger, 1902) around Antarctica are expos…
2021
The Antarctic silverfish Pleuragramma antarctica is a key species in the Southern Ocean ecosystem, and it is potentially threatened by the climate change affecting Antarctic ecosystems. Assessing the possible exposure to similar or different environmental conditions at early life stages and gathering information about connectivity or segregation between local populations of P. antarctica can be key for planning sound management strategies for this species. By using Laser Ablation Inductively Coupled Plasma Mass Spectrometry, we characterized the otolith chemical composition of 163 adult Antarctic silverfish collected from three areas located thousands of kilometers apart from each other: Ca…