Investigations on demersal fish in the Barents Sea winter 2004 : detailed report

Abstract

The main results in 2004 were: - The abundance of the 2003 and 2001 year classes of cod are poor, the 2002 and 1999 year classes are below average, while the 2000 and 1998 year classes are near average. - The abundance of older cod (7 years and older) is above average. - Compared to the 2003 survey these results are more pessimistic for all the year classes 1998-2002, but more consistent for older fish. This tendency is most evident for the acoustic results. - Lengths and weights at age and weight increments are slightly less than those observed in the previous two years, for most age groups. - The survey mortality calculated from the swept area results indicates that the mortality in 2003 for age 2 and for ages 6 and older was similar to the mortality in 2002, while it has increased for the remaining age groups. - For haddock the 2003 year class appears to be below average, the 2002 year class to appears to be strong and the year classes 1998 to 2001 are indicated to be at or above average. The amount of age 7 and older is somewhat below average. - Length, and weight at age and weight increments indicate slightly reduced growth. - The abundance indices of the redfish species are among the lowest in the time series and there are no signs of improved recruitment. - Compared to the 2003-results the abundance indices of Greenland halibut for fish below 20 cm and fish in the size range 30 to 40 cm have increased slightly, while in the size range 20-30 cm and above 40 cm the indices have decreased.