The introduction of the alien amphipodGammarus tigrinus Sexton, 1939 (Crustacea, Amphipoda) in The Netherlands and its competition with indigenous species

Abstract

In oligohaline watersGammarus tigrinus has a much greater reproductive capacity than any of the three indigenous (sub)speciesG. d. duebeni, G. zaddachi orG. p. pulex. The most important factors that enable this recently introduced species to compete the local species are: (a) its favourable reproductive period during the warm summer months, (b) its very short egg-incubation period, and (c) its very short time needed to reach sexual maturity.