Population studies on the Amphipoda of Mazoma Lagoon (Greece)

The life cycles of four amphipod species—Gammarus insensibilis, Dexamine spinosa, Microdeutopus gryllotalpa andCorophium insidiosum—were studied in the brackish-water lagoon Mazoma of the Amvrakikos Gulf, Ionian Sea.G. insensibilis has an annual life cycle with limited recruitment over the year and maximum reproductive activity in the winter months.D. spinosa exhibits continuous recruitment in the lagoon with a maximum in summer. Both species produce a single brood per female per yer. Continuous recruitment was observed during the summer months forM. gryllotalpa andC. insidiosum, and multiple breeding per female per year. Sex ratios varied considerably over the year, with a persisting preponderance of the females.