Marine Science blog - Page 2

Published May 7, 2018 10:28 AM

Many heavily fished fish stocks are dominated by young and small fish. The reason is simple: the chance to reach old age is small. If the fisheries selectively target large fish, the dominance of young and small fish becomes even larger. Such skewed age and size distributions can make the fish populations more sensitive to detrimental effects of oil spills.

Published Apr. 10, 2018 11:47 AM

Spawning migration is a prevalent phenomenon for the major fish stocks in the Barents Sea. While many of them migrate to the coast of Norway to spawn they are doing so to different areas. We have studied the Northeast Arctic haddock variability in spawning grounds to understand what drives the observed shifts over time.

Published Feb. 2, 2018 3:20 PM

In a study recently published in Ecology we find apparent competition between major zooplankton groups in a large marine ecosystem. Apparent competition is an indirect, negative interaction between two species or species groups mediated by a third species other than their prey.

Published Aug. 22, 2017 3:27 PM

Since Hjort in 1914 it is accepted that recruitment variation is a major source of variability in the biomass of adult fish. In a recent study published in Marine Ecology Progress Series (Durant & Hjermann 2017) we investigated how external forcing and age structure alter the effect of the year-to-year recruitment variability on population growth for some key fish species which occupy different trophic levels in an Arcto-boreal marine ecosystem.

Published Jan. 27, 2017 11:20 AM

High fishing pressure tends to lead to proportionally fewer old and large individuals in fish stocks. It is feared that these demographic changes make the fish stocks more sensitive to climate variability and change. Statistical analysis of long-term survey data on cod eggs throws new light on the possible mechanisms.

Published Nov. 8, 2016 9:49 AM

Spawning time and location are important factors affecting the reproductive cycle for migratory fish by potentially affecting offspring survival and growth. We examine this relationships by using a drift model for early life stages (eggs to age 1) of the Northeast Arctic cod combined with empirical estimates of spatial variation in mortality at two different life stages (Langangen et al. 2016).

Published Oct. 11, 2016 9:14 AM

The Marine Group of CEES was created in august 2005 as a platform where people with common interest meet and exchange ideas. In 2015 we were about 20 post-docs and PhDs financed on project money. I think it is time after more than a decade to look at the success and failure of our group, generally share experience, and maybe brag a little.

Published June 8, 2016 9:05 AM

Mass mortality events are events that cause elevated mortality that may reduce the population size over a short period. Such events are likely on the rise across the globe and for several taxa (Fey et al. 2015). We recently investigated how such events may affect the community of interacting species in the Barents Sea. For this investigation, we constructed a multi-species model of a key component of the Barents Sea ecosystem consisting of fish and zooplankton

Published May 2, 2016 9:50 AM

It is notoriously difficult to estimate mortality rates for zooplankton populations in the open ocean. In a new paper, Kvile and colleagues demonstrate that mortality estimation can be improved using a statistical regression approach (SRA) that takes into account advection and spatiotemporal trends in recruitment. Using this method on Calanus finmarchicus survey data from the Norwegian Sea–Barents Sea, they find indications of increased mortality for the oldest copepodite stage pair (CIV–CV), possibly reflecting higher predation pressure on larger copepodites.

Published Apr. 15, 2016 1:31 PM

Growing evidence suggests that the telomeres’ length (a non-coding DNA sequence localized at the end of the chromosomes) is related to individual breeding performances and survival rates in several species.

Published Mar. 6, 2016 7:07 PM

The development of haddock embryos is highly impacted by oil exposure as discussed in a previous post. In a new study Sørhus et al. explored the link between transcriptional changes and developmental processes such as pattern formation and organogenesis. The question is to understand the abnormal development in fish.

Published Feb. 5, 2016 11:21 AM

A recently paper published in PNAS,  members of the CEES Marine Group explore potential climate effects on Calanus finmarchicus, a key zooplankton species in the North Atlantic. The paper shows how the combination of shallow mixed-layer-depth and increased wind apparently increases chlorophyll biomass in spring, and in turn C. finmarchicus biomass in summer. These findings strongly suggest bottom-up effects of food availability on zooplankton, and highlight the need to consider climate effects “beyond temperature” when projecting zooplankton dynamics under climate change.

Published Jan. 22, 2016 1:00 AM

Marine phytoplankton contribute nearly 50% to global primary production, support zooplankton production and play a vital role in regulating Carbon sequestration. Phytoplankton productivity fluctuations are caused by various direct and indirect effects of temperature, the balance of which show large-scale geographical patterns. 

Published Dec. 18, 2015 1:00 AM

Friday 11 December 2015, Kristina Øie Kvile has defended her PhD about the climate effects on Calanus finmarchicus dynamics with success. 

Published Dec. 4, 2015 1:00 AM

Penguins are highly visible species for the public. Their life has been portrayed in many movies. Unfortunately they are also species impacted by climate change. In a recent publication a team led by Charles Bost used long-term data to relate the large-scale climatic anomalies in the Southern Hemisphere to the foraging behaviour and population dynamics of the king penguin.

Published Nov. 12, 2015 7:05 PM

Interdisciplinarity is a central focus for many funding agencies. The argument for this is that only with scientists working together that some of the major questions of today could be answered. In a recent paper, a collection of students and post-doc from the NorMER network explored the difference of perception of scientists in function of their discipline: social science or natural science.

Published Sep. 4, 2015 1:00 AM

Opening the sea areas around Lofoten and Vesterålen islands for petroleum activities is a highly debated topic. One of the main concerns has been to what extent an accidental oil-spill may affect the ecologically and economically important species of fish that spawn in the area. We have investigate how an increased mortality event at the egg and larval stage in cod may affect the population.

Published June 5, 2015 1:00 AM

A fundamental challenge for European Marine Science is to deliver scientific impact, global leadership and sustainable blue growth for Europe in times of overexploitation, climate change and other anthropogenic stressors. The Marie Sklodowska-Curie Innovative Training Networks MARmaED project makes important steps to answer this challenge by connecting science, policy and people, thus transcending national borders, disciplinary barriers and sectorial divides.

Published May 22, 2015 10:41 AM

Spatial Ecosystem models can be useful but need to be validated with data. Our study validates for the first time the spatial version of the commonly used Ecopath with Ecosim ecosystem modelling suite. We find that spatial distribution of fish species is well predicted by the model, but fishing effort distribution is not.

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