Moving in the right direction
Ground-breaking research into fish stocks, improved traceability and marine conservation have been the focus for Denmark’s fishing sector. Adrian Tatum reports.
You have to dig deep to find out the real stories that are behind the Danish fishing industry. Maybe that is partly because the Danish tend to be a nation that just goes about their business without any fuss and the fishing sector is very much the same. Or maybe it is because there is not much to report in an industry that is run effectively and efficiently. Whatever the reason, when you think of the Danish fishing and seafood sector you think of quality and that has been the basis and philosophy the industry has been run on for many years.
It was a part-time fishermen by the name of Jens Vaever who revolutionised the Danish fishing industry in 1848 when he tried out a new idea he had been thinking about. At the time fishermen stood on the shore and fished for eel and occasionally flatfish but Mr Vaever had the idea of going out on a boat and try fishing with a seine a way out from the shore. The technique - where the net was dropped in the sea and the boat was anchored - was known as anchor seine and was the start of proper commercial fishing in Denmark.
Fast-forward to now and we find Denmark continually trying to improve its fishing sector in a number of areas. “The key concern at the moment is to make the most of the quantity of fish available to us. This means to obtain maximum value from the catches of fish and to conserve resources. The employment of optimal fishing methods – conserving catch and limiting discards - is an important focal point,” says the Danish Ministry of Food, Agriculture and Fisheries.
“The potential for development is great in the field of aquaculture. Especially within saltwater breeding, more species will be farmed in the future. The greatest challenge in this production is to reduce the impact on the environment and eco-systems while maintaining economic viability.”
One focus in the last few years has been research - finding out more about stocks and marine systems in and around Denmark, what state they are in, and how they can be improved. Some of the research has been potentially ground-breaking.
Scientists at the Danish National Institute of Aquatic Resources (DTU-Aqua) have been working on a study which has concluded that many of the investigated 515 fish species have the potential to move north as temperatures rise. It says when the sea ice recedes, and there is food to be found in the previously inhospitable Northeast and Northwest Passages, the fish will be able to move here and, with time, spread into new waters. The gradually changing sea temperatures and feeding conditions will facilitate the interchange of many fish species between the Atlantic Ocean and the Pacific.
According to DTU Aqua, this applies, for example, to the traditional Danish New Year cod, or Atlantic cod, which is one of the top-ten commercial fish species, and which researchers expect will inhabit the Northwest and Northeast Passages by 2100. Here, the cod will provide the basis for a completely new fishery, says the Institute.
Professor Einar Eg Nielsen, a scientist at DTU Aqua says, “Today, there are relatively few fish which are found in both the Atlantic and Pacific. The opening-up of the two passages will lead to completely new meetings between northern species that have been isolated from each other for a very long time. Which species win the battle for space is difficult to predict. But it could lead to new and different fisheries for northern stocks.”
Both the Northeast Passage, which is the frozen polar sea north of Russia, and the Northwest Passage, which is the straight across the top of Canada and America, have acted as barriers in the past to the interchange of most marine organisms between the two oceans due to the ice, cold and lack of food for the fish.
However, it is known that in the past fish spread through the Northwest Passage on a smaller scale in warmer periods. But only 135 of the 800 fish species currently inhabiting waters north of 50° latitude are found in both the Atlantic and the Pacific. The coming interchange is expected to be far more extensive, and will primarily happen via the Northeast Passage, i.e. north around Russia, show the researchers’ calculations.
According to the researchers, the fish will reach the Northeast Passage in significant numbers from about 2050, when the interchange of species between the two oceans will accelerate. Looking ahead to 2100, 41 Atlantic species may have reached the Pacific, while 44 Pacific species could have migrated in the opposite direction.
“Those which will spread most easily are species such as Atlantic cod, blue whiting and herring which spawn in the open waters where their eggs can be carried with the currents to colonise new areas,” says Professor Einar Eg Nielsen.
Work has also been carried out by DTU Aqua on a research project which looks at fish behaviour in relation to changes in climate.
According to DTU Aqua, there has been speculation on whether future climate change will lead to an increased interchange of marine life through the Arctic passages. The fact that researchers are now able to provide answers is entirely due to recent developments, says senior scientist, Mary S. Wisz from DTU Aqua.
“The huge amounts of data on the distribution of fish species which are now available in databases such as fishbase.org, the projections of sea temperature, salinity and currents which we can obtain from models of oceanographic conditions, and finally the statistical tools for modelling have enabled us to pool the information to find out exactly how different species will react to changed environmental conditions,” explains Ms Wisz, who has brought together the interdisciplinary group of researchers from DHI, DTU, Aarhus University and the University of Copenhagen.
“Our original assumption was that the interchange would primarily take place via the Northwest Passage. However, our models showed that the Northeast Passage might well play an important role in future,” says Ms Wisz.
DTU Aqua has also created a new model that can predict what the relative numbers of large and small species should be in different areas of the ocean. According to the Institute, in the sea, body size determines position in the food chain and who eats who to a much greater extent than on land. This in turn provides a number of clear and relatively simple rules for determining how many small and large animal organisms there can be within a given marine area. Now a new study has demonstrated that these rules can also explain diversity, i.e. the number and sizes of the species that inhabit the area. In the longer term, this may provide one of the long-sought-after keys to better understand the regulation of biodiversity and how to preserve it, which is a goal of the EU’s marine strategy and a high priority in international treaties that seek to protect marine life.
While marine diversity has been studied for many years, there are surprisingly few explanations as to why there are generally more small species than large, and a poor understanding of why species richness or biodiversity across the vast majority of animal classes increase as you move from the poles to the equator, says DTU Aqua.
Professor in Fisheries Biology at DTU Aqua, Henrik Gislason, says, "Many researchers have attempted to explain these patterns, but without any great success. Although we are aware of numerous differences between north and south, for example that seasonal temperature variations in northern and southern waters result in uneven food production, while production is more evenly distributed over the year at the equator, no-one has been able to determine just how this affected biodiversity.
“Now, however, we have constructed a model – based on fundamental principles for how marine animals feed on each other – that can predict what the relative numbers of large and small species should be in different areas and how these numbers depend on differences in temperature and the size of the area considered.”
The research highlights the fishing sector’s need to invest in research to make sure it has a sustainable future and is current in its approach right now. As well as monitoring fish stocks Denmark has made strides in helping to restore marine life in the very oceans that its vessels have fished.
The last few years has also seen the testing of new fishing gear at the Dogger Bank region. DTU Aqua has been working with the Danish Fishermen’s Association with the aim of finding out if fishing with pelagic doors and lighter trawling gear reduce impacts on the seabed and marine life. Scientists have been comparing the effects of a conventional bottom trawl compared to the new fishing gear with effects measured by a combination of side scan sonar and under water video recording, and by determinations of the amount, sizes and diversity of living organisms in the sediment.
As a result, the Danish Minister of Food, Agriculture and Fisheries, Dan Jorgensen and The Danish Minister of Environment, Kirsten Brosbol have recently submitted a joint proposal to establish six new Marine Protected Areas (MPAs) in the region of Kattegat to protect its soft-bottom habitats, which currently remain unprotected. One of the biggest threats is bottom trawling which damages the seabed and can take years before soft-bottom habitats recover once a trawl has passed by.
But the move has been met with criticism. “The government’s proposal is simply not enough to address many years of destruction of the Kattegat. Although it is positive that the government is finally taking steps towards protecting marine habitats, there is need for a much more ambitious protection of marine biodiversity,” says Mette Blæsbjerg of WWF.
“The proposal by the government protects only relatively small areas from bottom trawling. Bottom trawling is the single greatest threat to soft bottom habitats in the Kattegat today. Bottom trawling disturbs the seabed and its wildlife, and takes a very long time to recover after,” says Christina Abel of Oceana.
The sector has also made attempts to improve traceability at ports and through the whole fish supply chain. An electronic seafood traceability system now covers all of Denmark's seafood supply chain. Since its launch in 2011, the SIF system has accumulated data on some 100,000 metric tons of seafood sold in Denmark in its database.
Nine Danish auctions, as well as major processors and traders, are using its online electronic system, and more than 4,000 retail stores have joined. The initiative has been implemented for four years and has received around €5 million in funding from the European Union.
Under SIF, parties across the supply chain have to submit information with an electronic device to a database, which can be accessed by them. Data can be tracked using a barcode or lot number and details required for input include data on when the fish is caught, sorted, packaged and sold. The data collection is recorded as close to the moment of catch as possible, and is automated to prevent human error and make it as reliable and relevant as possible. SIF’s platform can also provide marketing information, such as information on certification to be used for retailers to prove where the fish came from.
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