広塩性魚類マミチョグ胚・仔魚を用いた短期慢性毒性試験法の開発: 総排水毒性（WET）試験への適用を目指して

抄録

The early life stages of fish are particularly useful for chronic toxicity assessment of chemicals; however, thus far, only a few test methods have been established for marine fishes. The present study aimed to establish a short-term and chronic toxicity assay system using embryo and sac-fry stages of an euryhaline fish mummichog, Fundulus heteroclitus. To achieve this goal, we examined the optimal exposure duration and endpoints for the toxicity assay in seawater (30 PSU). The survival, hatchability, and dry weight of larvae were evaluated as endpoints after exposure to two typical toxicants, copper (Cu) and 3,5-dichlorophenol (3,5-DCP). In the Cu experiment, the lowest observed effect concentration (LOEC) was 0.3 mg/L for larval growth (dry weight), but even the maximum concentration (9 mg/L) had no effect on survival and hatchability. The LOEC of 3,5-DCP on larval growth was also lower than that of the other endpoints (1 mg/L vs. 3 mg/L). These LOECs for growth did not differ between the two test durations (embryonic to larval stage vs. only larval stage) for both toxicants. These results indicate that larval growth is the most sensitive and suitable endpoint for short-term and chronic toxicity assessments in this fish species.