Kristine Bonnevies hus
Marine systems are characterised as highly complex, being subject to multiple drivers (e.g. climate change or fishing pressure) and being riddled by high uncertainties. Yet, we still manage to come up with models to simulate ecosystem dynamics or establish fishing quotas. In order to achieve this we rely on experts and their judgements. Especially in situations where empirical data is scarce experts are often the best or even only source of information. Experts help to make sense of ambiguous data or, in case of no data, are able to provide input due to their acquired learning and experience. These expert judgments are indispensable but it pays to be aware that they are not perfect. While the idea that people are not always rational agents has been widely accepted, it is often overlooked that experts are humans, too.
Many animals migrate for various reasons, for instance to find new feeding grounds, survive harsh climate, or reproduce. Northeast Arctic cod is a fish that is of high economic importance to Norway and Russia and which undertakes annual migrations. Here, I will talk about its spawning migration and highlight some of its costs and benefits.
The upcoming Brexit has European fishermen worrying that they cannot continue to fish in British waters as they have been doing for centuries. If British waters would truly be closed to European fishermen, it would deal a strong blow to the European fisheries, since many fish are caught in British waters. Here we raise the questions: do fish really care about these country borders, and is it valid from a biological viewpoint for the UK to claim ‘their fish’?
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.
For the second time this summer, an intense heat spell is on the rise in many European countries as temperatures go beyond 40 C. Official heatwave warnings and instructions are issued repeatedly for european citizens who often flee to the sea breeze to cool off. But exactly how cold is the water that we are turning to for a bit of comfort in days like that? We are all familiar with the idea of global warming, but have you ever wondered what happens once such extreme heat penetrates the sea surface into the marine world? Does the ocean ever develop heatwave ''fever ''?
Past studies on high-latitude abundances and distributions shifts under climate change have largely focused on food availability and temperature. In a new model linking physics to biology, published in Global Change Biology, we quantify how sea-ice loss will improve visual fish foraging efficiency. Ecological and evolutionary consequences for polar marine ecosystems would follow.
Conventional fishing management by governmental regulation often oversimplifies the complex interplay of power relationships between fishers and other stakeholders. In a recent study published in Ecology and Society (Kininmonth et al. 2017), we looked how the fishing-traders relationships may affect fishing patterns in light of market or ecological changes.
Everyone who is working or living around the Baltic Sea has heard of the round goby. Fishermen swear on them because they have become more and more abundant in their catch replacing other fish species. Round gobies originally come from the Ponto-Caspian region and amongst others in the Baltic, they are present as a non-indigenous species, meaning that they have colonized and spread outside their native range. Theory is that they were introduced through the ballast water of ships.
Food web describe the diversity of species and their feeding relationships. In theory, building a food web comes down to listing trophic relationships. In practise, building a comprehensive food web is challenging and comes at some cost. Nonetheless, our methodology presented hereinbelow can be used to find the best trade-offs.
Funded by NASA's InterDisciplinary Science (IDS) program
Conference for young marine researchers
13 to 15 September 2017 in Kiel, Germany
12 to 16 June 2017 at the Institute of Ecosystem Study
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.
In March 2016, a Memorandum of Understanding for Seas of Norden Research School (SEANORS) promoting collaborative marine research and training in the Nordic countries was signed by the rectors of 9 Nordic universities.
The first MARmaED Progress Report for the European Commission was delivered, on schedule, at the end of October 2016.
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).
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.
Five of our Early Stage Researchers will be presenting papers and posters at the ICES Annual Science Conference (ASC) in Riga, Latvia. The details of the talks and posters can be found below.
11-13 September 2016, Hamburg, Germany