Acute toxicity effects of salinity stress on the invasive golden apple snails

Objective To study the salt tolerance of black and yellow golden apple snails, Pomacea canaliculata.

Method The acute toxicity test was taken to observe golden apple snails' behaviors under salinity stress.The 50% lethal concentration(LC₅₀)values were calculated.Golden apple snails cultivation experiments at low salinities(0, 5 and 10 g·L^-1)lasting 1 month were did to obtain their growth and survival parameters.

Result and conclusion The black and yellow golden apple snails were inhibited immediately with hermetization of their mantle cavity when they were put into high saline artificial water(15 and 20 g·L^-1).Snails escaped from unfavourable conditions with slow response under the medium salt stress(10 g·L^-1).At the low salt stress(5 g·L^-1), the snails crawled leisurely with sensitive response and movement, just like the control.The regression equation of yellow snail between the mortality at 48 h and the salt concentration was y ＝ 4.143x -14.762(R² ＝ 0.842), LC₅₀ ＝ 15.632 g·L^-1; while black snail at 48 h:y ＝ 3.958x -13.152(R² ＝ 0.866), LC₅₀ ＝ 15.956 g·L^-1.Low salinity(0, 5, 10 g·L^-1)aquaculture growth experiments showed that 2 shell colored snails in the salinity 10 g·L^-1 had the highest mortality after 1 month growth.The absolute growth mass were 0.954, 1.278 and 0.683 g for yellow snail at salt concentration of 0, 5 and 10 g·L^-1 respectively, while 0.845, 1.073 and 0.877 g for the black snail.They both expressed negative growth at the beginning of sampling, and expressed excellence growth at 5 g·L^-1.The research suggest that golden apple snails can tolerate certain salt stress, which means they can grow well in salt water with lower salinity.This phenomenon demonstrates a possibility of invasive risk for estuaries.