Winter A, Tosteson T R
Department of Marine Sciences, University of Puerto Rico, Mayaguez 00681-5000.
Bull Soc Pathol Exot. 1992;85(5 Pt 2):510-3.
The stable carbon and nitrogen isotope contents of the meat tissues of 27 identifiable fish found in the gut contents of 70 ciguatoxic and non-ciguatoxic barracuda caught along the southwest coast of Puerto Rico have been analyzed. The isotope ratios of those fish found in the stomach contents of ciguatoxic barracuda were significantly different than ratios determined in those fish found in the stomachs of non-ciguatoxic barracuda. The isotope ratios of the toxic dinoflagellate Ostreopsis lenticularis, a presumed vector of ciguatera in the Caribbean were found to be extremely light, particularly for nitrogen. The lightened nitrogen ratios of the herbivore (Doctorfish) and carnivore (Squirrelfish) fishes found in the stomach contents of ciguatoxic barracuda suggest that the dinoflagellate was in the food chain of these barracuda. Results indicate that the trophic pathway of ciguatoxins through the marine food chain from the presumed primary trophic level (dinoflagellates/bacteria) to ciguatoxic barracuda appears to be different than the pathway to non-toxic barracuda. Stable isotope ratios may be a very useful tool for tracing ciguatoxins in the food chain and the identification of ciguatoxic fish.
对在波多黎各西南海岸捕获的70条雪卡毒素中毒和未中毒的梭鱼肠道内容物中发现的27种可识别鱼类的肉组织中的稳定碳和氮同位素含量进行了分析。在雪卡毒素中毒梭鱼胃内容物中发现的那些鱼类的同位素比率，与在未中毒梭鱼胃中发现的那些鱼类所测定的比率有显著差异。有毒的双鞭毛藻——透镜状奥氏藻，被认为是加勒比地区雪卡毒素的一种传播媒介，其同位素比率被发现极轻，尤其是氮的比率。在雪卡毒素中毒梭鱼胃内容物中发现的草食性鱼类（医生鱼）和肉食性鱼类（松鼠鱼）的氮比率变轻，这表明双鞭毛藻处于这些梭鱼的食物链中。结果表明，雪卡毒素通过海洋食物链从假定的初级营养级（双鞭毛藻/细菌）到雪卡毒素中毒梭鱼的营养途径，似乎与到无毒梭鱼的途径不同。稳定同位素比率可能是追踪食物链中雪卡毒素以及识别雪卡毒素中毒鱼类的非常有用的工具。
