Sexual maturity of the alien redlip mullet, Liza haematocheilus (Temminck & Schlegel, 1845) in north Aegean Sea (Greece).

Summary The objective of the study was to identify the potential of Liza haematocheilus to establish self-sustaining populations along the coast of the North Aegean Sea (Greece). The sexual maturity was described histologically from 32 specimens (43–74.4 cm, TL) aged from 3 to 8 years old which were caught between 2003 and 2009 from fishery by-catches. Testicular and ovarian development was synchronous. Males were either maturing (spermatogenesis stage, September to March), mature (spermiating, April to July) or post-mature (recovery stage). Females were in previtellogenesis or maturing (early vitellogenesis, October to January) or mature (late vitellogenesis, July). Mature males (spermatids mean size: 1.5 ± 0.05 μm) were captured from April to July and mature females (late vitellogenic oocytes mean diameter: 499.4 μm) during July, indicating that spermiation and spawning in North Aegean Sea take place from April to July. Contrary to the other grey mullets which overwinter in the sea, the redlip mullet tolerates low water temperatures and migrates to freshwater where competition with other mullets is lacking. The issues of establishing population and evidence for its spawning success still remain open.