The Reproductive Cycle of the Invasive Bivalve limnoperna forlunei (Dunker, 1857) (Mytilidae) from a Neotropical Temperate locality

DARRIGRAN, G. A.; PENCHASZADEH, P. E.; DAMBORENEA, C.

Toronto

Conferencia; 10th International Aquatic Nuisance Species and Zebra Mussel Conference; 2000

Limnoperna fortunei (Dunker, 1857) is a dioecious, freshwater species, native of rivers and creeks of China andsoutheastern Asia. It was first recorded in the Americas in Bagliardi Beach (34°55'5 - 57°49'W), in the Argentinianlittoral zone of the Río de la Plata, in 5eptember 1991, at a density of 4 to 5 specirnens/rnz. During 1993, maximaldensities of about 80,000 specimens/rnz were recorded in this same locality. Its current density reaches 150,000specirnens/rnz, similar to the densities of populations of the rocky shore rnarine mytilid Brachidontes rodriguezi d'Orb. found in Mar del Plata (38°00'5 - 57°33'W).The reproductive biology of this invasive species is analyzed for the first time in its neotropical habitat.L. fortunei invaded the Hong Kong area in the late '60s, and japan in the '70s. In the Americas, this species isfound currently in the rivers Río de la Plata, Paraná and Paraguay. It causes an important impact in the human environment(the principal problems caused by larval invasion, settlement and maturity of L. fortunei, into waterdistribution systems, are: reduction of pipe diameter; blockage of the pipeline; decreased water velocity caused byfriction; accumulation of empty shells; contamination of water pipelines by mass mortality and filters occlusion) andnatural environment (affecting the taxocenosis of autochthonous molluscs, favoring the settlement of other macroinvertebratefauna not common in the environment).Up to now, the reproductive cycle of L. fortunei is only known in subtropical habitats of Hong Kong. The HongKong population of L. fortunei is dioecious and semelparous, and no cases of hermaphroditism have been reported.In the Neotropical region, L. fortunei is a dioecious species, and unlike what Morton observed in Hong Kong, 0.55%of hermaphrodites were recorded.The gametogenesis was continuous in the study population and major and minor spawning events occurredduring the study periodoThe results of this study demonstrate a correlation between environmental temperatures and the reproductivecycle of Limnoperna fortunei in Baqliardi Beach.