Thomas Saly N, Mandhir Sandhya Kavitha, Krishnankutty Harsha, Baby K A Mary, Ghosh K A Aishwarya
ICAR-Central Institute of Fisheries Technology, Kochi, Kerala, 682029, India.
Environ Sci Pollut Res Int. 2023 Mar;30(14):40062-40072. doi: 10.1007/s11356-022-25029-7. Epub 2023 Jan 6.
Abandoned, lost, or otherwise discarded fishing gear contributes considerably to global marine debris. These lost gears, mostly made of non-biodegradable synthetic materials, persist in the marine environment for longer periods of time and pose a great threat to marine life by entangling and killing target fishes and other non-target species such as turtles, birds, and mammals, a phenomenon known as ghost fishing. Other environmental impacts include physical impacts on aquatic habitats, transfer of microplastics into food web, and interference with fishing. Information regarding the catching efficiency and catch rates of lost nets in Indian waters is lacking. Ghost fishing capacity of simulated lost gillnets is being reported for the first time in India. This study investigates the ghost fishing capacity of lost gillnets through an experimental approach at Aroor, Vembanad lake, Kerala, India. Simulation studies using purposefully abandoned shrimp gillnets (32 mm mesh size) were conducted to understand the fishing capacity of lost gillnets during two seasons (monsoon and post-monsoon) as separate experiments. The gillnets maintained their catching efficiency until the 15th day during the first experiment and up to the 50th day in the second experiment. Catches showed an exponential reduction over time in both experiments. A total of 251 specimens comprising of 27 species were caught from both sets of experimental nets, and the state of catch in the nets showed different decaying stages from the second day itself along with fresh stages. As the days progressed, particulate matter and detritus began to accumulate on the experimental nets, increasing net visibility and reducing their catching efficiency. The results of the study on ghost fishing capability will contribute to the development of strategies for reducing the effects of lost nets on the aquatic ecosystem and for suggesting improved management strategies.
废弃、丢失或以其他方式丢弃的渔具对全球海洋垃圾的产生有很大影响。这些丢失的渔具大多由不可生物降解的合成材料制成，在海洋环境中持续存在较长时间，通过缠住并杀死目标鱼类以及海龟、鸟类和哺乳动物等其他非目标物种，对海洋生物构成巨大威胁，这种现象被称为“幽灵捕鱼”。其他环境影响包括对水生生境的物理影响、微塑料向食物网的转移以及对渔业的干扰。目前缺乏关于印度海域丢失渔网的捕捞效率和渔获率的信息。印度首次报道了模拟丢失刺网的幽灵捕鱼能力。本研究通过在印度喀拉拉邦韦姆巴纳德湖阿罗尔进行的实验方法，调查丢失刺网的幽灵捕鱼能力。使用特意废弃的虾刺网（网目尺寸32毫米）进行模拟研究，作为单独的实验来了解两个季节（季风期和季风后期）丢失刺网的捕鱼能力。在第一个实验中，刺网在第15天前保持其捕捞效率，在第二个实验中则保持到第50天。在两个实验中，渔获量均随时间呈指数下降。从两组实验网中共捕获了251个标本，包括27个物种，网中的渔获状态从第二天起就呈现出不同的腐烂阶段以及新鲜阶段。随着时间的推移，颗粒物和碎屑开始在实验网上积累，增加了网的可见度并降低了其捕捞效率。幽灵捕鱼能力的研究结果将有助于制定减少丢失渔网对水生生态系统影响的策略，并提出改进的管理策略。
