Termohaline tolerances of Rapana venosa (Gastropoda: Muricidae) larvae under experimental conditions: implications for range expansions in coastal waters of Argentina

GIBERTO, D.A.; SCHIARITI, A.; MONTOYA, N.; BENAVIDES, H.; BRUNO, L.I.

Punta del Este

Congreso; V Congreso Latinoamericano de Ciencias del Mar (COLACMAR); 2013

Aceptado

The gastropod Rapana venosa is one of most conspicuous exotic species in the Río de la Plata, inhabiting mixohaline and marine waters. The invasion to the adjacent waters of the region can be boosted by propagule pressure. The planktonic larvae of R. venosa is capable of endure 20 to 80 days in the water column. So to understand the potential expansion zones of the species we studied the larval survival under different salinity and temperatures values usually recorded in coastal waters of Argentina. Larvae were subjected to different combinations of salinity (5, 17, 35, 34), temperature (10°C, 15°C, 20°C) and salinity changes (gradual, abrupt) treatments during 48 hs (72 experimental units in total) and analyzed by an ANOVA. Average survival values for all larvae were 91%. Significant differences in survival were found only for temperatures of 20°C (77%), while survival was similar for all salinity conditions, even after being exposed to an abrupt change of 30 units. Larvae with the lowest survival values were those exposed to 20°C and salinity of 5 (55.37% ± 16.6). The oceanographic regime of the Río de la Plata is characterized by a southern net current during the reproductive period of the species in summer, potentially transporting larvae to adjacent waters. So larvae must be considered as a potential key responsible of the dispersion trough coastal waters of Argentina.