Caprella watch : new approach for monitoring butyltin levels in the shallow water ecosystem

The wide impact of tributyltin on non-target organisms has led several developed countries toplace restrictions on the use of TBT as an antifouling agent for coastal boats and aquaculture beds。A comparative study on the butyltin levels in various organisms showed that marked bioaccumulationoccurs in certain lower trophic levelsi.e., from seawater to phytoplankton and into caprellid amphipods, Caprella spp.，which inhabit algal communities and aquaculture beds in the subtidal zoneare small crustaceans with reduced movement ability and a shortened life-span of少于3 months。这些characteristics indicate Caprella spp. may be well-suited for monitoring butyltin改变较小的空间和气氛。Thus，我们在使用Caprella spp. to monitor temporal and spatial changes in monitor temporal and spatial changes of suitabilitybutyltins baseline concentrations of butyltins. We compared the acute toxicity of caprellid and gammaridamphipods,both collected from the shallow water ecosystem of Otuschi Bay. the results showafter 2 days of caprellids in 1.2-6.6 mg TBT/L are significantly lower than gammarids in 17.8-23.1mg TBT/L. We have collected Caprella spp. from various areas along Japanese coasts自1997. Thepreliminary results on the BTs （TBT）DBT and MBT) indicate that BTs vary from 1 ng/g wet weight in C. penantis R-type from TobishimaIsland in the Sea of Japan to 466 ng/g wet weight in C. decipiens from Amakusa Islands，western Kyushu. This indicates that the difference of BTs in Caprella spp. is in the range of atleast 500 times along Japanese coasts. The above relts indicate that Caprella watch is a usefulapproach for monitoring butyltin residues in the shallow water ecosystem。

The wide impact of tributyltin (TBT) on non-target organisms has led several developed countries to place restrictions on the use of TBT as an antifouling agent for coastal boats and aquaculture beds. A comparative study on the butyltin levels in various organisms showed that marked bioaccumulation occurs in certain lower trophic levels ; i.e., from seawater to phytoplankton and into caprellid amphipods, Caprella spp. Caprella spp., which inhabit algal communities and aquaculture beds in the subtidal zone, are small crustaceans with reduced movement ability and a shortened life-span of less than 3 months. These characteristics indicate that Caprella spp. may be well-suited for monitoring butyltin residue changes over small spatial and temporal scales. Thus, we propose the suitability of using Caprella spp. to monitor temporal and spatial changes in baseline concentrations of butyltins. We compared the acute toxicity of caprellid and gammarid amphipods, both collected from the shallow water ecosystem of Otuschi Bay. The results show LCィイD250ィエD2 at 20℃ after 2 days of caprellids in 1.2-6.6 mg TBT/L are significantly lower than gammarids in 17.8-23.1 mg TBT/L. We have collected Caprella spp. from various areas along Japanese coasts since 1997. The preliminary results on the BTs (TBT, DBT and MBT) indicate that BTs vary from 1 ng/g wet weight in C. penantis R-type from Tobishima Island in the Sea of Japan to 466 ng/g wet weight in C. decipiens from Amakusa Islands, western Kyushu. This indicates that the difference of BTs in Caprella spp. is in the range of at least 500 times along Japanese coasts. The above results indicate that Caprella watch is a useful approach for monitoring butyltin residues in the shallow water ecosystem.