A High Incidence of Imposex in Pomacea Apple Snails in Taiwan: A Decade after Triphenyltin Was Banned

Summary results of imposex surveys in localities where both Pomacea canaliculata and P. scalaris coexist. C, crop drainage; W, wastewater drainage; Pc, P. canaliculata ; Ps, P. scalaris ; n , sample size; VDS, vas deferens sequence; Stage 0, with no evidence of a male genital system; Stage 1, with a rudimentary penis; Stage 2, with a rudimentary penis and penile sheath; values are the mean ± SD Locality code Sex n Shell length (mm) Weight (g)Penile sheath length (mm)Penis length (mm)Rudimentary penis length (mm)VDS stagesVDS index0 1 2C11-Pc F 21 40.6 ± 3.7 16.5 ± 4.2 00 2.01 ± 0.35 0 21 0 1.00M 9 41.4 ± 3.1 16.3 ± 4.0 17.01 ± 1.87 33.7 ± 09.8C11-Ps F 18 38.3 ± 2.5 14.2 ± 3.3 00 1.52 ± 0.30 0 18 0 1.00M 10 37.9 ± 1.9 13.2 ± 2.0 12.66 ± 3.12 29.4 ± 05.3C12-Pc F 31 33.1 ± 3.6 06.4 ± 2.2 00 1.41 ± 1.19 11 20 0 0.65M 21 33.5 ± 3.5 06.7 ± 2.2 12.58 ± 3.33 36.1 ± 10.8C12-Ps F 26 37.2 ± 3.5 09.2 ± 2.3 00 1.71 ± 0.95 5 21 0 0.81M 16 38.0 ± 2.2 09.0 ± 1.2 12.75 ± 2.77 31.0 ± 08.3W7-Pc F 16 31.6 ± 1.8 06.4 ± 1.2 00 2.29 ± 0.48 0 16 0 1.00M 17 31.9 ± 3.2 05.8 ± 1.6 11.49 ± 2.63 35.0 ± 04.8W7-Ps F 24 36.7 ± 2.1 09.5 ± 1.4 00.09 ± 0.31 2.52 ± 0.73 1 21 2 1.04M 4 37.0 ± 2.6 08.3 ± 1.3 12.57 ± 4.17 26.3 ± 13.0