Ecophysiology of the invasive aquatic mudsnail Potamopyrgus antipodarum under stressful environmental conditions

ERIK V. THUESEN; PAOLUCCI, ESTEBAN

Dublin

Conferencia; 10th International Conference on Biological Invasions: New Directions in Invasion Biology; 2018

Invasive freshwater species, such as the exotic mollusc Potamopyrgus antipodarum (New Zealand Mudsnail), can frequently survive under harsh conditions, including brackish and hypoxic environments. We experimentally assessed the effects of salinity (0, 10, 20, 25 and 30 psu) and temperature (environmental water temperature and 20ºC) on mortality and physiology of P. antipodarum collected at Capitol Lake, Olympia, WA USA. We measured metabolic rates and enzymatic activities (Malate Dehydrogenase, Lactate Dehydrogenase, Alanopine Dehydrogenase, etc.) in snails after different acclimation periods (2, 4, 6 and 10 days). Significantly higher mortalities were observed at 25 and 30 psu than under other salinities, with the strongest effects when snails were collected at the end of winter, and exposed to 30 psu and 20ºC (100% mortality in 3 days). These snails lasted 5 days at 30 psu when the environmental water temperature was set at 5ºC. When snails were collected during the spring, 100% mortality was observed after 40 days at 30 psu and 20ºC, and mortality was much less at 30 psu and 10ºC, reaching 74±24% after 105 days. At 0 psu and 10°C, mortality was only 5%. Metabolic rates were significantly lower when snails were exposed to salinities of 25 and 30 psu, even after 10 days of acclimation. Enzymatic activities showed small but significant declines after 10 days at higher salinities, and metabolic rates maybe affected at the biochemical level under stressful environmental conditions.