– When we trawl, we get as much fish as ten years ago. Ketil Hylland is a professor of marine biology and toxicology. He works at the Department of Life Sciences at the University of Oslo (UiO). Since 2010, he has monitored the fishing life in the Inner Oslo Fjord on behalf of the Professional Council for the Inner Oslo Fjord. – The Oslo Fjord is not dead, he says. Four times a year, a trawl is towed at a depth of 100 meters at the Steilene archipelago at Nesodden. Researchers do not want to trawl too much. It can strain the fish populations. – We make a trawl haul in each of the seasons. This is to have a general impression of what the fjord looks like. – What do you think when you hear or read that the Oslo Fjord is dying? – I think it is a statement that may not be entirely based on reality. – The cod is on its way back It is a fact that the cod stock in the Oslo Fjord has been at a historically low level. After UiO started its investigations, they caught fewer and fewer cod. Six or seven years ago, it reached its absolute bottom level. – At a time when there was actually no cod in our catches, Hylland says. Researchers from the University of Oslo pull a trawl at Steilene in all four seasons. Photo: Jason Lee Anders / UiOPhoto: Jason Lee Anders / UiO But in recent years, the catch of cod has gradually increased. When they were out this winter, they caught 15 to 20 cod in the trawl. And a few weeks ago the catch was very good. – We counted 40 cod on a trawl haul. It is on a par with what we got 10 years ago. The professor believes that this shows that the cod population in the Inner Oslo Fjord is on the rise. And he thinks the cod will also eventually be visible in shallow water. Immigrated cod The inner Oslofjord has had its own cod stock. Professor Ketil Hylland thinks the cod they now get in the trawl is a different type than the Oslofjord cod. Professor Ketil Hylland at UiO inspects the trawl. Photo: University of Oslo Photo: University of Oslo – It looked a little different and had slightly different parasites. It looks like it is almost gone, and that what we now get in is cod that has migrated into the fjord. He does not know if it spawns in the Inner Oslo Fjord. – It may be that it only uses the fjord as a growth area. But it shows that the fjord is attractive to cod. – It probably migrates into the Inner Oslo Fjord because it finds food here. There is a lot of fish, krill and shrimp. More whiting in the fjord Ketil Hylland does not know whether the mixture of fish species in the Oslo Fjord has always been as it was when they started trawling twelve years ago. They have also seen another change. There is much more whiting in the fjord than before. – Whiting now dominates our catches. Both in number and quantity, says Hylland. Why it is like that, they do not know. Whiting belongs to the cod family. It is a predatory fish that can supply itself with other species. It is often called the sea chicken. In this tub there is a lot of whiting. In addition to cod, the researcher gets eyeballs, sypike and silver cod, as well as flounder fish such as flounder, occasional plaice and flounder in the catch. Photo: Jason Lee Anders / UiOPhoto: Jason Lee Anders / UiO The fish they get are mostly in good shape. – Continued signs of illness The Norwegian Institute for Water Research believes it is good news that cod is on its way back to the Inner Oslo Fjord. NIVA researcher André Staalstrøm agrees that the fjord is not dead. – But the state of health is not satisfactory. André Staalstrøm is a researcher at NIVA’s section for marine biogeochemistry and physical oceanography. Photo: Private He points out that there are still too many environmental toxins and nitrogen in the Inner Oslo Fjord. According to the researcher, there are several dangers that threaten. And that action is needed. We must not fish too much We must not destroy seaweed and kelp (build piers, artificial beaches, etc.) We must not release too much fertilizer and environmental toxins (sewage and emissions from agriculture) At the top come climate change that makes the fjord warmer and darker than before. The condition in the Inner Oslo Fjord has been worse. In the 70’s. Great measures were taken. There are also a lot of environmental toxins on the bottom in Ytre Oslofjord. The NIVA researcher believes there is hope for the Oslo Fjord. – But now the pressure is so great that we have to do even more. Large variations Researchers at the Norwegian University of Life Sciences, NMBU, monitor life in shallow water below 20–25 meters at Drøbak and between Nesodden and Bærum. They agree that the Oslo Fjord is not dead, but believe it is too early to state that the cod is on its way back to the Inner Oslo Fjord. Thrond Oddvar Haugen is a professor at the Faculty of Environmental Science and Nature Management at NMBU in Ås. Photo: Birger Sætre The variations are large. – While there is a lot of cod in the area by Nesodden, the situation is completely different inwards towards Bærum, says Professor Thrond Oddvar Haugen at NMBU. Some of the cod they find near Bærum is also in a terrible condition. – They are thin and have much more parasites than you should expect. – Is there hope for the Oslo Fjord? – Yes, yes, yes. There is hope. But it does not come by itself. It is a big job that needs to be done. There is no doubt about that, says Haugen. Hope for cod fishing Today, it is forbidden to fish for cod in the Oslo Fjord all year round. The professor believes that the cod population must be allowed to grow more before fishing can be allowed again. – If this positive development continues, then I will not say any number of years. But then it should be possible if not too long, I think, says Professor Ketil Hylland. Researchers at the University of Oslo are excited about the catch they will get when they go out again in the autumn. Photo: University of Oslo Photo: University of Oslo
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– Oslofjorden is not dead – news Oslo and Viken – Local news, TV and radio
