Bottom trawling is a high-efficiency fishing technique in global coastal fisheries [1], but with negative effects on marine benthos [2]. Bottom trawling affects seabed environments by dragging a net on the seabed and suspending sediments [3]. In addition, this fishing activity threatens marine benthic biodiversity and destroys the structures of benthic ecosystems [4]. Fishers have been concerned with these impacts for 600 years [5]. Over the past half century, the impacts of bottom trawling have come to the forefront for scientists and governments [5,6]. To reduce the negative effects on benthic ecosystems from bottom trawling, the European Union has used a Vessel Monitoring System (VMS) to monitor the activities of all vessels greater than
…show more content…
According to the China Statistical Yearbook of 2013, more than six million tons of catch were generated by China’s 36,744 trawlers [11]. The Chinese Ministry of Agriculture began to invest in the construction of the Beidou fishing vessel position monitoring system (VMS) in 2006. At the end of 2014, more than 60 thousand fishing vessels had been outfitted with VMS. This system provides continuous records to support fishery management. Sixty percent of the trawlers in China are distributed in the Yellow Sea and the East China Sea. The Yellow Sea (YS) is a semi-closed area of the Northwest Pacific Ocean with an average depth of 44 m. The East China Sea (ECS) lies over the broad shelf of the Northwest Pacific Ocean with an average depth of 370 m. Trawling for Chinese fishery in the two seas mainly occurs in coastal waters or in seawater at depth to 300 meters. Based on our in situ investigation, the common warp length of trawlers in the YS and the ECS is several times longer than the seawater depth; thus, warps and nets inevitably plow the seabed when fishing. Consequently, these fishing activities can directly affect marine benthic environments. Moreover, several tows are done by a trawler during a single fishing trip. To investigate the impacts on these seas, the principle issue is to identify which regions are heavily affected by trawling. Few studies on this subject have been carried out in the China Seas, …show more content…
Bottom trawling vessels registered in this study are mainly single rig otter trawler, and operate the benthic fauna, including fish (e.g. Trichiurus japonica, Larimichthys polyactis), crustacean (e.g. Metapenaeopis lata), and cephalopod (e.g. Loligo kobiensi).In 2013, for the Xiangshan Port chosen in this study, there were 3139 fishing vessels, including 1403 bottom otter trawling, and the total landing was 0.44 million tons (fish: 0.34 million tons; crustacean: 58.40 thousand tons).
In addition, vessels with different engine power have different gear width. We collected the power data and their corresponding gear width in China trawlers (See S1 for the raw data). Furthermore, we gave the best fit function between the power and gear width for China trawlers. The functions were fitted using four types: linear, logarithmic, power, and saturating. The function with lowest AIC is expressed as the best fitted model (Table 1). For trawlers in China, the best relationship between power and gear width is expressed as equation
According to the China Statistical Yearbook of 2013, more than six million tons of catch were generated by China’s 36,744 trawlers [11]. The Chinese Ministry of Agriculture began to invest in the construction of the Beidou fishing vessel position monitoring system (VMS) in 2006. At the end of 2014, more than 60 thousand fishing vessels had been outfitted with VMS. This system provides continuous records to support fishery management. Sixty percent of the trawlers in China are distributed in the Yellow Sea and the East China Sea. The Yellow Sea (YS) is a semi-closed area of the Northwest Pacific Ocean with an average depth of 44 m. The East China Sea (ECS) lies over the broad shelf of the Northwest Pacific Ocean with an average depth of 370 m. Trawling for Chinese fishery in the two seas mainly occurs in coastal waters or in seawater at depth to 300 meters. Based on our in situ investigation, the common warp length of trawlers in the YS and the ECS is several times longer than the seawater depth; thus, warps and nets inevitably plow the seabed when fishing. Consequently, these fishing activities can directly affect marine benthic environments. Moreover, several tows are done by a trawler during a single fishing trip. To investigate the impacts on these seas, the principle issue is to identify which regions are heavily affected by trawling. Few studies on this subject have been carried out in the China Seas, …show more content…
Bottom trawling vessels registered in this study are mainly single rig otter trawler, and operate the benthic fauna, including fish (e.g. Trichiurus japonica, Larimichthys polyactis), crustacean (e.g. Metapenaeopis lata), and cephalopod (e.g. Loligo kobiensi).In 2013, for the Xiangshan Port chosen in this study, there were 3139 fishing vessels, including 1403 bottom otter trawling, and the total landing was 0.44 million tons (fish: 0.34 million tons; crustacean: 58.40 thousand tons).
In addition, vessels with different engine power have different gear width. We collected the power data and their corresponding gear width in China trawlers (See S1 for the raw data). Furthermore, we gave the best fit function between the power and gear width for China trawlers. The functions were fitted using four types: linear, logarithmic, power, and saturating. The function with lowest AIC is expressed as the best fitted model (Table 1). For trawlers in China, the best relationship between power and gear width is expressed as equation