In recent years, there has been a sharp fall in the number, as well as the size, of salmon returning to western Norway from the Norwegian Sea. Possible causes include a lack of food, high levels of sea lice and smolt predation in the fjords. Since 2001 The Institute of Marine Research has been releasing tagged smolt into the River Daleelv in Hordaland, and the results of that work may now help to explain what is happening.

Once again in 2010, the MAREANO project will carry out two three-week scientific missions with the research vessel “G. O. Sars”. The first one starts on 24 July, and the second one starts on17 September. This year’s activities start off North Cape and finish in Nordland VI, south-west of the Lofoten Islands. The aim is to map biodiversity, geology and biotopes in an 18,500 square kilometre area. Once completed, the MAREANO programme will have mapped a continuous area of sea including Troms I, Troms III, Troms II, Nordland VII and parts of Nordland VI.

- The four pillars of sustainable fisheries management are: science, fisheries legislation, control of fishing activities, and violation sanctions, said Åsmund Bjordal, panelist at the “United Nations Open-ended Informal Consultative Process on Oceans and the Law of the Sea” this week. 

When fish farms are placed in optimal locations, there is little evidence that they result in  excessive fertilization of large areas. Over the past fifteen years, Norwegian salmon and trout production has almost quadrupled, from 220,000 tonnes in 1994 to 820,000 tonnes in 2008. Meanwhile, the quantity of dissolved chemical nutrients released into the water has increased by 20%.

In Hardangerfjorden, sea lice infection rates increased in June in relation to May, particularly on sea trout in the outer part of the fjord. An increase in sea lice levels was also observed in Herdlefjorden (Hordaland) and off Namsenfjorden (Trøndelag). In the other fjord systems studied, results show that sea lice levels on wild salmonids remain low.

The quota advice for Northeast arctic haddock is the largest since the quota advices first were given, and 25 percent more than the 2010 advice. The quota advice for Northeast arctic cod is 703 000 tonnes, an increase of 96 000 tonnes (16 percent) from 2010. If the quota advice is followed, the norwegian quota vil increase with 40 000 tons from 2010. 
 

Tourist fishers in the business sector in Norway catch about 3 300 tons of fish a year, scientists at the Institute of Marine Research estimate. Earlier non-scientific estimates have suggested far higher numbers.    

Provisional results show that, in May, sea lice numbers were low in Hardangerfjorden. The small number of sea lice found on the fish that we examined is probably due to the low water temperature. The situation may change quickly when the temperature rises over the course of the summer. Sea lice levels in Hardangerfjorden are being monitored throughout June, and tomorrow we will look at new samples. It also appears that this year the smolt migration is taking place slightly later than usual, which means that it is unclear whether the smolt will get out of the fjord before the potential increase in lice numbers.

Yet another introduced species, the Asian sea squirt Styela clava, appears to have established itself in Norway. It has been found in several locations along the coast, and has become relatively common in the Stavanger area. The Styela clava populations may be found in  densities of 500-1500 individuals per square metre, and can outcompete local species.