從九○年代初期、引發環保人士對於代表自由貿易體制的關稅暨貿易總協定（General Agreement on Tariffs and Trade，以下簡稱GATT）之不滿的鮪魚／海豚案，到世界貿易組織（World Trade Organisation，以下簡稱WTO）成立後的小蝦／海龜案，為了環境保護的目的所採取的貿易限制措施—亦即是所謂「環保貿易措施」（environmental trade measures, trade-related environmental measures (TREMs)）--於GATT/WTO中所引發關於貿易規則與環境保護間的爭端，至今尚無定論。環保貿易措施於GATT/WTO下所引發的爭端，特別是依據國際環境公約（multilateral environmental agreements，以下簡稱MEAs）所採取之環境貿易措施，一般包含兩方面的法律爭議：第一，實體規則之衝突：GATT/WTO賦予會員之權利與義務，以及MEAs下賦予締約國之權利與義務，兩套實體規則間可能發生潛在的衝突；第二，管轄權之衝突：WTO下的爭端解決機制，以及MEAs下之爭端處理機制，均可能針對環保貿易措施所引發的法律爭端取得管轄權。於前者，目前尚未於WTO之下發生相關爭端。而於二○○○年一件關於歐盟與智利問涉及劍魚之保育的爭端，發生同時繫屬於WTO下的爭端解決機制以及聯合國海洋法公約下所成立之國際海洋法庭的狀況，顯示出管轄權之衝突已經由「潛在衝突」變成「實際的衝突」。因此，本文將針對此一管轄權之衝突，進行下列議題的討論與分析：環保貿易措施之適用所引發的爭端，是否因其性質，可訴諸於WTO下以及MEAs下的爭端解決場域？同一爭端同時繫屬於兩個以上的爭端解決場域之機率為何？若有一個以上的爭端解決場域時，誰擁有優先管轄權？若上述之數個爭端解決場域係屬於平行存在，並沒有誰擁有優先管轄權的情形時，此對於環保貿易措施之適用以及國際法秩序將可能造成哪些衝擊？

From the legendary tuna/dolphin case that triggered the launching of a campaign against the General Agreement on Tariffs and Trade (GATT) by environmentalists, to the shrimp/turtle case after the establishment of the World Trade Organisation (WTO0, trade-related environmental measures (TREMs)—trade restrictive measures for the protection of the environment—continue to generate vigorous debate over trade vs. environment within the GATT/WTO context. Two types of legal controversies have arisen in the context of disputes concerning the application of TREMs under the GATT/WTO, especially TREMs adopted in accordance with multilateral environmental agreements (MEAs). The first one is characterized by a potential conflict between two sets of substantive rules: the relationship between international trade rules under the GATT/WTO and international environmental rules under MEAs. Secondly is the potential conflict between jurisdictions: the dispute settlement mechanisms of both the WTO and th e MEAs can obtain jurisdiction concerning disputes arising from the application of TREMs. Cases concerning the first type of potential conflict have yet to arise. A dispute between the EU and Chile concerning the conservation of swordfish was simultaneously brought before the Dispute Settlement Body of the WTO and the International Tribunal of the Law of the Sea set up by the UN Convention of the Law of the Sea. This dispute has served to ‘substantialise’ the ‘potential’ conflict between competing jurisdictions. This article, thus, will focus on the following issues concerning conflicting jurisdictioins over such disputes: can disputes arising from the application of TREMs be settled under the dispute settlement mechanisms of both the WTO and of the MEAs? Is it likely that such disputes will be subjected to multiple dispute settlement mechanisms? If the answer is yes, does one of them have sole and/or primary jurisdiction? If none of them has primary jurisdiction, what, then are the implications of parallel jurisdictions over such disputes on the application of TREMs and international law?