Fecundity studies on sprat, Sprattus sprattus L., from a fjord on the Norwegian Skagerrak coast. In: Flødevigen rapportserie no 1, 1992

Data were collected monthly from sprat caught with trawl in Frierfjord, during January-May in 1985 and 1986. Sprat used ranged from 7 to 15 cm and from 2.1 to 27.9 g. Ichthyoplankton was sampled to follow the spawning progress. Interannual variations in fecundity are indicated, which might depend on differences in spawning stock compositions. Absolute fecundity varied from 3825 to 78955 (mean: 21134) in 1985 and between 2939 and 42822 in 1986 (mean: 12260). Fecundity estimates are based on number of developing oocytes, i.e. equal or larger than 150 um, assumed to be shed during the spawning season (determinated spawning). The results indicate, however, that the spawning of sprat is indetermined and thus the fecundity estimates are underestimated. Atresia is not considered