幽靈漁具的潛在影響與衝擊：以台灣北部海域蟹籠漁業為例

簡向農、王世斌

國立臺灣海洋大學海洋事務與資源管理研究所

摘要

海洋塑膠垃圾的污染在近年受到相當的關注；這些塑膠可能捕獲、纏繞、窒息或殺死海洋動物，其中“被遺棄、遺失或丟棄的漁具”，或所謂的幽靈漁具又特別的致命。該漁具因持續不斷的捕魚，但漁獲卻無法為人所用，故形成幽靈漁業的現象。幽靈漁具可能對敏感棲地產生衝擊，也可以透過纏繞而威脅海洋生物生存。幽靈漁具產生的可能原因包括人為破壞、惡劣天候、碰觸海底礁石、漁民作業疏失、與其他漁具衝突、船隻經過割斷浮標與故意丟棄…等。這些漁具一旦遺失將對海洋環境、物種保育、人類健康、旅遊、地區經濟等產生多重層面的影響。本文以臺灣北部蟹籠漁業為例，探討該漁業漁具遺失量及其經濟損失，並評估其潛在幽靈漁業的影響。結果發現在台灣西北漁場作業的蟹籠船，其籠具遺失量與遺失率四季有所不同，並以秋季為最高。而西北海域與北部沿岸作業船隊每船年總計籠具平均遺失量分別為2,899與1,761個，約佔其年產值的5%，而遺失籠具所可能造成的幽靈漁業損失可達年捕獲量的5-22%或6-27%。西北船隊的主要遺失肇因在春秋冬季皆為漁具衝突(49-53%)，但在夏季則為作業疏失所致；而衝突對象77%為中國大陸拖網船，23%為臺灣拖網船。但沿岸船隊籠具遺失肇因的前三名則分別為船隻經過纏繞(28%)、漁具衝突(27%)與惡劣天候(19%)。針對台灣北部蟹籠漁業所得結果，本文提出：依漁業特性研擬因應對策，清除現有幽靈漁具讓棲地重生，建構完善的漁具遺失通報與回收處理系統，以及研究與教育宣導等並重的倡議，做為台灣未來施行籠具漁業管理之重要參考依據。

關鍵字

幽靈漁業、遺失漁具、蟹籠漁業、沿近海漁業管理

Potential Impacts of the Ghost Fishing Gears: an Example of the Crab Trap Fishery Operating in the Northern Waters off Taiwan

Xiang-Nong Jian, Shyh-Bin Wang

Institute of Marine Affairs and Resource Management, National Taiwan Ocean University

Abstract

Pollutions by marine plastic debris have received great attention in recent years. Marine plastic debris although may catch, entangle, asphyxia and killed marine animals, the abandoned, lost, and discarded fishing gears or “ghost fishing gears” are especially lethal to marine life. Ghost fishing occurs when this lost gear continues to catch and kill marine life. No longer catching for human consumption. Ghost fishing gears not only kill marine life but could also impact on the marine habitats. There are many reasons why fishing gear may ends up ghost gears including theft and vandalism、severe weather events、entanglement with other fishing gear、snagging on the seabed or operational errors and poor maintenance, or even intentional discarded. Once these gears are lost or abandoned, it may exert multiple impacts on marine environment, species conservation, human health, tourism and local economy. This study examined both gear and economical losses based on the data collected from crab trap vessels operating in the northwestern (NW) offshore waters (thereafter NW fleet, NWF) and coastal waters off northern Taiwan (thereafter NC fleet, NCF). Results indicated that mean number of trap lost and lost rate per vessel for the NWF were different among seasons, with the highest occurred in the fall. The annual trap lost per vessel were estimated to be about 2,899 for NWF and 1,761 for NCF, and valued at about 5% of the catch’s revenue for both fleets. The loss of the crab biomass possibly induced by the lost traps (i.e., ghost fishing) were estimated to be about 5-22% and 6-27% of the annual catch per vessel for NWF and NCF, respectively. The main cause of the trap loss for NWF in spring, fall and winter seasons was gear conflict (49-53%), mainly with trawlers from China (77%) and Taiwan (23%), while it was the operational errors in summer. For NCF the main causes of trap loss were differ from those of the NWF, and were entangled by passing vessel (28%), gear conflict (27%) and bad weather (19%). Based on these results, the development of a fishery-specific countermeasures, a trap clean-up program to rejuvenate the habitats, and a trap loss self-reporting and recovery systems, as well as a research and educational propaganda were proposed and recommended for fulfill the need of future management of trap fishery in Taiwan.

Keywords

Ghost fishing, lost gears, crab trap fishery, costal fishery management