Med stadig økning i produksjon av oppdrettslaks og et relativt lavt antall tilgjengelig vannkilder til smoltproduksjon, ser man økt bygging av RAS-anlegg. Ved rensing av produksjonsvannet er første vannbehandlingstrinn mekanisk filtrering etterfulgt av biofiltrering, rensesystemets flaskehals. Biofilteret renser vannet for nitrogenholdige molekyler (TAN), som er giftig for laks, og er sensitivt for ...

The commercial farming of juvenile lumpfish requires monitoring of gonadal development to achieve synchronized production. Conventional methods such as gonadosomatic index (GSI), sex hormone analyses, gonadal histology, endoscopy, and gene expression analyses are costly, invasive, and often involve sacrificing the fish. We assessed the efficiency of ultrasound as a non-invasive method for monitoring ...

We analysed with multigene (18S and COI) metabarcoding the effects of the proliferation of invasive seaweeds on rocky littoral communities in two Spanish Marine Protected Areas. The invasive algae studied were <i>Caulerpa cylindracea</i>, <i>Lophocladia lallemandii</i> and <i>Asparagopsis armata</i>. They are canopy-forming, landscape-dominant seaweeds, and we were interested in their effects on the ...

Conical pots with a plastic entrance cone on the top are a type of fishing gear used to harvest snow crabs (Chionoecetes opilio) in Arctic regions. In this study, we assessed the effect of pot entrance diameter on the catch efficiency of snow crabs. We used catch data collected during sea trials of pots with different entrance cone diameters, and we conducted laboratory experiments where morphological ...

Key messages <ul> <li>Climate change affects communities and livelihoods in fisheries and aquaculture, and efforts to adapt to and mitigate climate change must therefore be humancentred.</li> <li>Climate adaptation strategies must emphasize the need for poverty eradication and food security, in accordance with the Paris Agreement, the United Nations 2030 Agenda for Sustainable Development and ...

Utviklingen i den norske oppdrettsnæringen har vært forrykende, men de siste årene stagnert. Dette skyldes blant annet problemer med parasitten Lepeophtheirus salmonis, lakselus. En rekke forebyggende og bekjempende metoder er tatt i bruk av næringen og i denne studien undersøkes det forebyggende luseskjørtet. Skjørtet fungerer som en presenning og strekkes rundt de øverste delene av merdene, i denne ...

Micro- and nanoplastic particles, produced from the breakdown of larger plastic debris, represent a whole new field of hazardous pollution with the potential to cause great damage on a range of marine species. This escalating concern of plastic pollution in marine environments and its consequential impacts on marine species, has emphasized the urgency for an in-depth understanding of the uptake and ...

In addition to indirect support to fisheries, marine habitats also provide non-use benefits often overlooked in most bioeconomic models. We expand a dynamic bioeconomic fisheries model where presence of natural habitats reduces fishing cost via aggregation effects and provides non-use benefits. The theoretical model is illustrated with an application to cold-water corals in Norway where two fishing ...

Pollution from lost, abandoned, or discarded fishing gear is recognized as a global nature conservation concern. Longlining with hooks is a commonly applied fishing method in fisheries around the world. The longline gear consists of a mainline with a number of baited hooks that are attached to it by thinner twine (snoods) which are often made of plastic material such as polyamide (nylon) or ...

Sea trials to test size selectivity equipment in trawls are often limited in time because they are costly, and the results can be influenced by multiple factors that are often overlooked. In the Barents Sea gadoid trawl fishery, the use of a size sorting grid in front of the codend is compulsory. The flexigrid, a netting section containing two flexible grids, is the most widely used grid section in ...