Fig. 6

Mytilus edulis. Relationship between age (year-1 starts in spring of year of birth) and parameters of production and biomass. a Mean half-year production (in g AFDM m⁻², with 1 SE, n = 26) in the 1979–2005 period on Balgzand (means of all sampling sites). Black columns refer to production completed within the main growing season (March–August), white ones to the remaining part of the year. Production during the first growing season (left-most black column) was not actually measured, but arbitrarily set at two times the August spat biomass. b Mean biomass (in g AFDW m⁻², with 1 SE, n = 26). Black columns refer to late-summer samples and white ones to late-winter samples. c Mean P/B ratio values (in a⁻¹, with 1 SE, numbers of observations indicated in brackets). No value included for the first year of life, because of the arbitrary nature of the first-growing season estimate of P. Double asterisks denotes statistical significance (P < 0.01)