Return of Norwegian spring spawning herring (Clupea harengus L.) to historical spawning grounds off southwestern Norway

From the mid-1940s to mid-1960s a northward displacement of\nthe spawning areas of the Norwegian Spring Spawning Herring\nwas observed. Further retraction of the population from\ntraditional feeding and spawning grounds occurred as the stock\ncollapsed in the late 1960s. The spawning grounds off\nsouthwestern Norway were abandoned after 1959. Ever since,\nspawning appears to have been restricted to a few coastal\ngrounds and offshore banks off mid-Norway, primarily off the\nMøre district.\nAt present, the abundance of the spawning stock remains\ncomparatively low; 1.5-2 mill. tonnes as compared with 7-10\nmill. tonnes in the 1950s. However, in the spawning seasons\nfrom 1989 onwards, spring spawners have again been observed at\nthe southwestern grounds. The herring at these southern\ngrounds in 1990 and 1991 were Norwegian Spring Spawners and\nutilized traditional spawning sites. The spawning time was\nabout a month later than in the 1930s but similar to that in\nthe 1950s. Results of acoustic surveys showed that of the\ntotal spawning stock, 1.5 - 2 % used the southwestern grounds\ni 1990 and 1991.