Toxicity of puffers landed and marketed in Thailand

Toxicity of puffer fish Lagocephalus lunaris and Lagocephalus spadiuceus landed and sold in Samut Sakorn fish landing in Thailand were studied monthly for one year from August 2000 to August 2001. Lagocephalus spadiceus was not toxic while L. lunaris was toxic, although the toxicity levels varied greatly among the different fish and the organs. Marked seasonal variation was also observed in L. lunaris toxicity. They were toxic for 9 months from March to November and the highest ratio of toxic specimens (100%) and the highest toxic scores in all the organs were found in August. The maximum toxicity found was 148 MU/g in the skin, 243 in the muscle, 813 in the liver, 529 in the ovaries and 2920 in the testes. The gonad was consistently found to have the highest toxicity and the testes were more toxic than the ovaries. High-performane liquid chromatography (HPLC) analyses of toxic specimens showed the presence of tetrodotoxin, 4-epitetrodotoxin and 4,9-anhydrotetrodotoxin, but not paralytic shellfish toxins. Quantity of tetrodotoxin detected by HPLC well explained the toxicity observed in the mouse bioassay.