Toxicity of the puffer Takifugu rubripes cultured in northern Taiwan

To monitor toxicity of cultured puffer Takifugu rubripes specimens were monthly collected from two aquacultural farm in Ilan County and one farm in Taipei County from November 1996 to October 1997. These specimens were dissected into various parts, and their toxicity was determined by the standard tetrodotoxin bioassay. All specimens collected from Ilan County were non-toxic (< 10 MU/g), while the specimens collected from Taipei County during the period from January to March 1997 showed toxicity in the ovary and liver. The toxicity was as follows: ovary 105 +/- 9 (mean +/- S.E.) MU/g and liver 13 +/- 3 MU/g in January, ovary 88 +/- 12 MU/g in February, and ovary 253 +/- 55 MU/g and liver 17 +/- 6 MU/g in March. The highest toxicity of ovary and liver was 624 MU/g and 119 MU/g, respectively. Further, among ten specimens of the flatworm Stylochus orientalis collected from the Taipei's farm in February 1997, four worms showed low toxicity (1-3 MU/specimen). Flatworms contained TTX-related substances as analyzed by HPLC and GC-MS.