North-East Arctic Haddock Melanogrammus aeglefinus (Linne)

Year-class abundance of haddock aged 3 (1) and haddock annual catch (2) in

Long-term fluctuations of the mean annual temperature in the main stream of the Murman Current along the Kola Section (St.3-7) in m layer and the abundance of the Northeast Arctic haddock aged 3 in

Year-class distribution of the Northeast Arctic haddock with different strength depending on sea temperature in Year-classes temperaturetotal lowmediumhigh weak medium1135 strong-8614 Number of year-classes % of weak year-classes % of medium year-classes % of strong year-classes

Abundance of year-classes aged 3(1) and haddock spawning biomass (2) in

Long-term variations of year-class abundance of haddock aged 3 (1) and the spawning stock (individuals aged 6-8) (2) in

Strength of the year-classes aged 3 (1), as well as the portion of individuals aged 3-5 (2) and 6-8 (3) in the spawning stock of haddock in

Distribution of haddock year-classes with different strength depending on the size of the spawning stock of individuals aged 6-8 (thou.t) in Year-classesSpawning stocktotal lowmediumhigh weak medium1135 strong27514 Number of year-classes % of weak year-classes % of medium year-classes57251 % of strong year-classes

Year-class abundance of haddock aged 3 (1) and total abundance of immature individuals aged 3 and older in the year of the appearance of year-classes (2) in

Distribution of haddock year-classes with different strength depending on the density of population in , in normal and warm years Year-classesNumber of stocktotal lowmediumhigh weak55820 medium3115 strong86-14 Number of year-classes % of weak year-classes % of medium year-classes % of strong year-classes

1. Haddock is characterized by a very great difference in abundance of some year-classes and, as a result, by very abrupt year-to-year variations of commercial and spawning stock size. 2. In the most of cases, during the first years of haddock year-class life, water temperature was a reliable indicator of strength at age 3. In anomalous cold years, all the generations of haddock were very poor despite the level of spawning stock, density of population and other factors. In the normal and warm years, the effect of water temperature on haddock juvenile survival and year-class abundance becomes weaker. 3. Haddock year-class abundance, to a great extent, depends on the spawning stock size and structure. The individuals aged 6-8 spawning two and more times have the maximal influence on strength of haddock year-classes. 4. The immature stock abundance of haddock distributed in the Barents Sea also has an impact on the strength of the year-classes. The relationship of the year-class strength and the density of population is especially noticeable in the warm years, when the role of abiotic conditions was high.

Haddock spawning stock dynamics and deviations in the stock size as compared to the previous year level

Haddock commercial stock dynamics and deviations in the stock size as compared to the previous year level