48 research outputs found
Survey report from the CODFUN 2016114 Barents Sea survey 5.-11. oktober 2016
The survey is part of the project âThe cod â capelin interaction in the Barents Sea: spatial dynamics in predator prey overlap and functional response (CODFUN)â funded by the Norwegian Research Council (NRC project number 243676/E40).
The CODFUN project was motivated by the need to update and improve the current formulation of the functional response of cod used in the capelin assessment model. The functional response is the relationship between the feeding rate of individual predators and density of prey. Functional response, together with density of predators and prey is used to calculate natural mortality. In all natural environments, there is spatial heterogeneity in densities of prey and predators and their overlap. This heterogeneity becomes a very important determinant of natural mortality due to predation. The aim of the CODFUN project is to quantify and explain spatial heterogeneity in the capelin-cod interaction at different spatial scales in the Barents Sea.
The aim of the survey was to study spatial variation at the scale of individual cod and capelin schools. We aimed at quantifying attack rates of cod on capelin using acoustics, and to estimate proportion of successful attacks using stomach samples from trawl catches and handline. Furthermore, we aimed to relate variation in attack rates to variation in capelin densities and light conditionspublishedVersio
Teaching in higher education: organic methodologies
In this paper, we use process philosophy to address the increased feeling of alienation and resignation among students and teachers in Norwegian academia. By trusting the generative forces of childhood, as Deleuze and Guattari suggest, we explore changemaking potentialities in what we label âorganic
methodologiesâ in higher education. Our question is as follows: What educational potentialities might evolve if we educationalised âBabetteâs Feastâ as a collective explorative act of feminist resistance in
the academic system? As a starting point, we briefly present the short story Babetteâs Feast, written by the Danish author Karen Blixen. We experimentally educationalise the imaginary of Babetteâs feast and transform it into a contemporary feminist feast, facilitated through our masterâs program Toddler Science (0â3 years). After a brief presentation of some elements in the feminist feast, we point to processual tendencies within the feast, using Manningâs logics of major/minor gestures and Massumiâs concept of the trans-individual.publishedVersio
Predatorâprey overlap in three dimensions: cod benefit from capelin coming near the seafloor
Spatial overlap between predator and prey is a prerequisite for predation, but the degree of overlap is not necessarily proportional to prey consumption. This is because many of the behavioural processes that precede ingestion are non-linear and depend on local prey densities. In aquatic environments, predators and prey distribute not only across a surface, but also vertically in the water column, adding another dimension to the interaction. Integrating and simplifying behavioural processes across space and time can lead to systematic biases in our inference about interaction strength. To recognise situations when this may occur, we must first understand processes underlying variation in prey consumption by individuals. Here we analysed the diet of a major predator in the Barents Sea, the Atlantic cod Gadus morhua, aiming to understand drivers of variation in cod's feeding on its main prey capelin Mallotus villosus. Cod and capelin only partly share habitats, as cod mainly reside near the seafloor and capelin inhabit the free water masses. We used data on stomach contents from ~2000 cod individuals and their surrounding environment collected over 12 years, testing hypotheses on biological and physical drivers of variation in cod's consumption of capelin, using generalized additive models. Specifically, effects of capelin abundance, capelin depth distribution, bottom depth and cod abundance on capelin consumption were evaluated at a resolution scale of 2 km. We found no indication of food competition as cod abundance had no effect on capelin consumption. Capelin abundance had small effects on consumption, while capelin depth distribution was important. Cod fed more intensively on capelin when capelin came close to the seafloor, especially at shallow banks and bank edges. Spatial overlap as an indicator for interaction strength needs to be evaluated in three dimensions instead of the conventional two when species are partly separated in the water column.publishedVersio
Report of the Joint Russian-Norwegian Working Group on Arctic Fisheries (JRN-AFWG) 2022
On 30 th March 2022 all Russian participation in ICES was temporally suspended. Although the announcement of the suspension stressed the role of ICES as a âmultilateral science organizationâ, this suspension applied not only to research activities, but also to the ICES work providing fisheries advice for the sustainable management of fish stocks and ecosystems. As a result of the suspension, the ICES AFWG provided advice only for saithe, coastal cod north, coastal cod south, and golden redfish ( Sebastes norvegicus ). Northeast Arctic (NEA) cod, haddock and beaked redfish ( Sebastes mentella ) assessments have been conducted outside of ICES in a newly constituted Joint Russian-Norwegian Working Group on Arctic Fisheries (JRN-AFWG). Although this work has been conducted independently of ICES, the methodologies agreed at ICES benchmarks and agreed HCRs (Harvest Control Rules) have been followed in providing this advice.publishedVersio
Advice on fishing opportunities for beaked redfish in 2023 and 2024 in ICES subareas 1 and 2
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Advice on fishing opportunities for Northeast Arctic cod in 2023 in ICES subareas 1 and 2
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Advice on fishing opportunities for Northeast Arctic haddock in 2023 in ICES subareas 1 and 2
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Advice on fishing opportunities for Northeast arctic haddock in 2024 in ICES subareas 1 and 2
Stock Name: Northeast Arctic haddock (ICES areas 1 and 2)
The Joint Russian-Norwegian Arctic Fisheries Working Group (JRN-AFWG) advises that when the Joint NorwegianâRussian Fisheries Commission management plan is applied, catches in 2024 should be no more than 127 550 tonnes.publishedVersio
Gytefeltskartlegging NordĂžstarktisk hyse: Toktnummer 2022609
Gytekartleggingstokt for nordÞstarktisk hyse ble gjennomfÞrt 8. -19. april 2022 med FF Kristine Bonnevie. Toktet startet i BodÞ og ble avsluttet i TromsÞ. Toktet dekket det antatte gyteomrÄdet langs Eggakanten mellom Malangsgrunnen og BjÞrnÞyrenna. Kontinuerlige akustiske registringer ble gjort langs 3194 nautiske mil kurslinjer. Det ble tatt 38 stasjoner med egghÄv og CTD, og 29 bunntrÄl. Gytende hyse ble funnet i de fleste trÄlhalene. De innsamlete eggene er sendt til genetisk analyse for Ä kunne skille torsk- og hyseegg.publishedVersio
Report of the Joint Russian-Norwegian Working Group on Arctic Fisheries (JRN-AFWG) 2023
On 30 th March 2022 all Russian participation in ICES was temporally suspended. Although the announcement of the suspension stressed the role of ICES as a âmultilateral science organizationâ, this suspension applied not only to research activities, but also to the ICES work providing fisheries advice for the sustainable management of fish stocks and ecosystems. As a result of the suspension, the ICES AFWG provided advice only for saithe, coastal cod north, coastal cod south, and golden redfish ( Sebastes norvegicus ). Northeast Arctic (NEA) cod, haddock and Greenland halibut assessments have been conducted outside of ICES in a newly constituted Joint Russian-Norwegian Working Group on Arctic Fisheries (JRN-AFWG). Although this work has been conducted independently of ICES, the methodologies agreed at ICES benchmarks and agreed HCRs (Harvest Control Rules) have been followed in providing this advice.
The Greenland halibut model has been revised at an ICES benchmark in 2023. The JRN-AFWG has agreed to use the new ICES model, with the addition of revising the Russian survey tuning index (as was recommended at the benchmark). Although the overall biomass level in the model has been revised, the trends and advice are similar to the old model. The Greenland halibut advice is for one year to bring the timing back in line with the slope survey, after this a two-year advice cycle will resume. The main worry with that stock is a history of TACs and catches well above advice. Given that the model is now indicating that the stock will drop below B pa by the end of 2023, continuing to set quota above advice poses a risk of serious harm to the stock.publishedVersio