ABSTRACT
Birgitta Norberg1*, Inger-Britt Falk-Petersen2, Torstein Harboe1, Terje van der Meeren1 and Anders Mangor-Jensen1
The Atlantic cod (Gadus morhua L.) is considered a promising species for cold-water marine aquaculture. In addition, cod is one of the most economically important species for the fisheries and an average of more than 100,000 metric tons are harvested each year. In spite of the large catches of wild cod, the market has responded very positively to the farmed alternative, presumably due to high quality and freshness, and year-round availability. However, there are several important criteria that have to be fulfilled to approve a species candidature for aquaculture. The most important among these is a stable, seasonally independent production and the basis are methods for effective juvenile production. Cod farming is far from new. Towards the last part of the nineteenth century, trials with hatching of cod larvae in small incubators for releasing
C H A P T E R
yolk sac larvae into the Norwegian fjords were commenced at Flødevigen Biological Station. This program was sustained for nearly a decade, although the documented impact on the local stocks was questionable. To overcome criticism about survival potential of the released yolk sac larvae in the sea, in 1886 the Norwegian captain G.M. Dannevig performed a startfeeding trial with cod in a 2500 m3 large concrete enclosure on land (Rognerud, 1887). The intention was not aquaculture, but he managed to produce several thousands of cod fry in this system. Inspired by the results of Dannevig and other Norwegian pond experiments with plaice (Pleuronectes platessa) and flounder (Platichtys flesus) in the 1930s, the idea of producing marine fish for aquaculture purpose in enclosure systems was developed in the 1970s (0iestad et al., 1976). The method was further escalated to large-scale production of cod fry in lagoon systems at the aquaculture station of the Institute of Marine Research at Austevoll, Norway, with a breakthrough in 1983 when 60,000 cod fry were harvested from the 60,000 m3 enclosed lagoon "Hyltropollen" (Kvenseth and øiestad, 1984). The lagoon method diversified into the semi-intensive method where cod larvae were start-fed in floating plastic bag enclosures or large tanks on land, with the lagoon as a plankton production unit where copepods were fractionated and concentrated by means of wheel filters (van der Meeren and Naas, 1997). Towards the millennium, Canada succeeded with large-scale intensive production methods of cod juveniles based on production of warm water marine fish. Based on both the Norwegian experience and the Canadian results, Norway produced around 8 million cod fry in 2004, among this one million in lagoon systems.
