Published 26.10.2016

Paper of the Month: Twinning salmonids – a new source to knowledge about conjoined twins?

Conjoined twins are frequently observed in fish hatcheries. However, they normally die during the first feeding period and rarely achieve adulthood. In this study we investigated different types of conjoined salmonid twins at the yolk sac stage, and dissected a fully developed conjoined twin specimen obtained at Institute of Marine Research, Matre Research Station. This may contribute in filling in knowledge – gaps on this subject also in higher species.

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Published 28.06.2016

Paper of the Month - Reproductive strategy of a migratory fish stock: implications of spatial variations in natural mortality

The reproductive strategy in a migratory marine fish may be influenced by spatial variations in mortality in early life-stages. In a new study a team of scientists, including Hjort Centre researchers Geir Ottersen and Frode Vikebø, examine how spawning time and location affect offspring survival and growth of Barents Sea cod. A drift model for early life-stages of the cod is combined with empirical estimates of spatial variation in mortality at two different life-stages. The study is now available online in Canadian Journal of Fisheries and Aquatic Sciences.

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Published 18.05.2016

Paper of the Month - The herring genome revealed

The herring genome provides new insight on how species adapt to their environment

How species genetically adapt to their environment is a central question related to the evolution of biodiversity. In a new study scientists at Uppsala University and their colleagues, including Hjort Centre researcher Professor Arild Folkvord, report that whole genome sequencing of Atlantic and Baltic herring revealed hundreds of loci underlying adaptation to the brackish Baltic Sea or timing of reproduction. The study was published 3 May in eLife.

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Published 08.04.2016

Paper of the Month - Reproductive tactics of fish in hypoxic sea

Fish in naturally hypoxic marine habitats such as the Eastern Boundary Upwelling Ecosystems of the norhern Benguela have evolved behaviourally and physiologically to tolerate this extreme environmental challenge. Studies of field collections of bearded goby (Sufflogobius bibarbatus) from research ship surveys that were combined with controlled behavioural and physiological experiments have provided evidence for its behavioural, physiological and reproductive adaptations. 

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Published 03.03.2016

Paper of the Month - Climate warming

A recent paper by Fossheim et al (2015) examined how the fish fauna in the Barents Sea has responded to recent warming in the period 2004-2012. It was found that the spatial distribution of fish communities had expanded northwards. This was explained by an increased abundance and distribution of large, migratory predatory fish.

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Published 18.02.2016

Paper of the Month - Simple models of simple brains

Why do fish behave the way they do? Biologists find intrinsic value in understanding behaviour and being able to explain it, while others have more applied motivations and are interested in behaviour to promote conservation or designing effective fishing gear. In either case, theoretical models are a helpful tool because they can provide interpretation and prediction. But how should a model be constructed to describe decision-making in a tiny fish brain?

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Published 21.12.2015

Paper of the Month - The role of water clarity in Norwegian Coastal waters

An article by Dag L. Aksnes (UiB, Hjort Centre) is now available online in ICES Journal of Marine Science. The article describes how the murky inshore Bay of Fundy gave rise to the critical depth concept and elucidates how water clarity influences key properties in Norwegian Coastal Water and North Atlantic water.

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Published 23.11.2015

Paper of the Month - Predictive potential of Individual Based Models

An article by Ute Daewel (NERSC/Hjort Center), Corinna Schrum (UiB, Hjort Center) and Alok K. Gupta (UniResearch) has been released in Marine Ecology Progress Series, presenting for the first time a long term integration of  a spatially explicit individual based model. The model results were analysed to identify processes relevant for inter-annual to decadal changes in larval cod survival in the North Sea, and to discuss the predictive potential of the method.

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Published 19.10.2015

Paper of the Month - How fish eggs float in the ocean

An article by Svein Sundby and Trond Kristiansen at IMR/Hjort Centre has just been released in PlosOne presenting a holistic conceptual framework for vertical distribution of pelagic fish eggs in the world oceans depending upon characteristic salinity profiles in the different waters along with the specific gravity of the eggs. Associated with this they also present the new term “the critical spawning depth” below which eggs will settle out and be ultimately lost.  

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Published 11.05.2015

Paper of the Month - Balanced exploitation and coexistence of interacting, size-structured fish species

In their article in Fish and Fisheries (Law et al (in press), Jeppe Kolding and co- authors explored how to best organize exploitation of an aquatic ecosystem. It was found that while conventional fisheries management can induce stock collapse, harvesting balanced on the basis of productivity at each body size and across species exerts a strong force countering stock collapse. Additionally there is less disruption to size-structure, increased resilience, and substantially greater biomass yields are possible.

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Published 03.03.2016

Paper of the Month - Ecosystem processes are rarely included in tactical fisheries management

An extensive recent review in Fish and Fisheries by Skern-Mauritzen et al. (2015) (link) considering assessment reports for 1200 fish stocks worldwide finds that environmental variation is largely overlooked in fisheries management, at least based on the available information found in writing. This is despite the fact that ecosystem drivers affect stock productivity, which is one of the bearing pillars in international conventions on Ecosystem Approach to Fisheries (EAF).

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Published 09.02.2015

Paper of the Month - Life of cod in changing environments

The ocean environment in our seas has been changing a lot over the last century. On top of the typical pattern of decadal fluctuations in temperature, man-made climate warming has contributed to the last decade being the warmest on record. This has caused reduced extent of the sea ice in the Barents Sea and adjacent waters, which opens up new ice-free areas to cod and other fish. On top of this, the last century has seen industrial fishing becoming ever more efficient. How do cod cope with an environment that is changing on many fronts?

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