Dioecious species with sexual dimorphism. This is an oviparous species with external fertilization. A. iberus shows a reproductive strategy adaptated to unstable environments, reaching maturity early (in the first few months of life) and showing a high reproductive effort.
It is a multiple spawner that releases batches of eggs between May and August in the Ebro delta, although two moments appeared to stand out as most important (Vargas & De-Sostoa 1997). The spawning period is longer in its southern localities (Mar Menor coastal lagoon). This species showing an extraoridanry plasticity on its gonads and gametogenesis, sometimes occurring two or one developed ovaries or testes (Garcia-Alonso et al. 2009).