湖光山色下的哀愁--由漂浮的琵琶鼠魚探討外來入侵種與放生行為

摘要或動機

本研究自2005 年12 月開始，以臺北市內湖區大湖自公園死亡的漂浮琵琶鼠魚(Many-rayed Sailfin Sucker Catfish )為主要研究對象，探討外來物種與放生行為對大湖生態系的影響。 研究期間共觀察到死亡的琵琶鼠魚隻數計有1085 隻，可記錄到個體形質資料的隻數為910 隻，背鰭棘數則有11 棘、12 棘、13 棘與14 棘四種，分析四種不同棘數的琵琶鼠魚後發現：在體長、頭寬及吻到背鰭長度均無差異(p>0.05)，因此判斷所記錄的個體應是棘甲鯰科(Loricariidae) Pterygoplichthys 屬中的同一種魚種。由檢視魚體並分析記錄數量與環境因子相關性後推測：琵琶鼠魚死亡主因是劇烈起伏的溫度差異，其次是人為因素的刻意傷害。 所記錄到大湖池塘水棲動物有：環節動物、軟體動物、節肢動物、魚類、兩棲動物及爬行動物等六大類共34 種，其中外來物種有16 種，本地入侵物種有3 種，而這些外來動物進入大湖的主要管道應是由個人的棄養或放生行為所造成。琵琶鼠魚因繁殖能力強、具攻擊性、吞食其他魚種卵塊、可適應高污染水體及垂釣客對魚種的篩選等因素，而成為最具生存競爭能力的優勢魚種。不但造成大湖池塘呈現嚴重魚種單一化，更可由靜止水域大量擴散至流動水域。未來如何將政府相關部門、學術研究單位與民間社團等力量結合，共同防範大湖琵琶鼠魚的持續蔓延、宣導民眾正確的放生觀念、積極改善大湖水體污染狀況，並訂定完整之外來物種移除計畫，以期恢復大湖池塘物種歧異度，都將是刻不容緩的重要生態課題。;This research began in December of 2005. Focusing on dead floating Many-rayed Sailfin Sucker Catfish in Dahu Park, Nei-hu Distrct, Taipei city. We discuss the impacts of Alien and of behaviors of the release of captured animals on Dahu Park’s ecosystem. During observation period, there were totally 1085 dead Many-rayed Sailfin Sucker Catfish, of which 910 bodies were found. The number of the thorn bushes on dorsal fins includes 11, 12, 13,and 14. After analyzing four kinds of different thorn bushes, we find that no differences exist in Total length, Head width, Predorsal length (p>0.05). We hence conclude that the recorded object should be species with identical with Loricariidae Pterygoplichthys. With the inspection of the fish’s body and the analysis of the relevance of the recorded quantity and the environmental factor, we infer that the main reason of the Many-rayed Sailfin Sucker Catfish’s death is violent temperature differences and the second is attributed to human’s intentional abuse. The aquatic animals of Dahu Park amount to 34 kinds and six classes such as Annelida, Mollusca, Arthropoda, Pisces, Amphobian, and Reptilia. Among them, 16 kinds that are Alien and 3 kinds are Native Invasive Species. Intentional abandon and release behavior channel of these Alien to Dahu Park. Many-rayed Sailfin Sucker Catfish are highly productive, aggressive, and adaptable to highly polluted water. Besides, they eat ovums from other fishes. Moreover, they are not the fisher’s preference and hence often thrown back into pond once hooked . Thus, they become the most competitive survival fish species in Dahu Park. The high competitive ability of Many-rayed Sailfin Sucker Catfish causes Dahu Park to present a serious unification of fish species. This serious unification of fish species could also be spread from static water areas of Dahu Park to flowing water areas. According to our research, certain urgent ecological issues in Dahu Park are to take precautions against the spread of Many-rayed Sailfin Sucker Catfish, to promote the correct idea of releasing captured animals, to improve Dahu Park’s water pollution, and to stipulate a complete plan about eliminating Alien. Our research suggest that government’s relevant departments, academic research units, and folk corporations should be cooperated to achieve the above four goals. Once the four goals are achieved, we believe that the fish species of Dahu Park will be full of varieties again.

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檔案名稱	檔案大小	格式
湖光山色下的哀愁--由漂浮的琵琶鼠魚探討外來入侵種與放生行為	3 MB