Figure 3.

The effects of size-selective fishing gear on optimal age at maturation in the Northeast Arctic cod Gadus morhua. The left-to-right axis is the fishing mortality f_max [year⁻¹] in the feeder fishery at the sizes where selectivity is 1, and the front-to-back axis is the fishing mortality f_max [year⁻¹] at the spawning grounds. (A) Unselective fishing mortality; all sizes have the same probability of being caught (selectivity U is always 1). (B) Sigmoid trawl selectivity, where the size-selectivity of the fishery increases with the fish’ body size (here at maximum from L_max = 70 cm onwards). (C) Bell-shaped size-selectivity is typical for gillnets (here with maximum selectivity at L_max = 90 cm).