DALIAN -- Police in Dalian, a major port in China's northeast, have been busy over the past few weeks patrolling ports and harbors to monitor illegal fishing.
A four-month fishing ban ended on Sept 1 and thousands of fishermen have resumed their operations.
In May, China's Ministry of Agriculture ordered a one-month extension to the previous ban. From May 1 to Sept 1, fishing was prohibited in rivers and offshore areas during the spawning season for most aquatic life.
Starting from Aug 25, officers in Dalian have inspected 200 ports, and those who did not have approval documents were not allowed to set sail, said Song Xianguo, deputy Party secretary of the police department.
A total of 82 boats were seized after failing to obtain documentation, and about 100 people were found to have faked documentation, according to police.
China has carried out fishing bans for many years to preserve fish resources in major oceans, said Lin Shanqing, deputy director of State Oceanic Administration.
During the ban, police stepped up law enforcement and carried out awareness campaigns.
This year, Dalian police dispatched 9,000 officers to monitor illegal fishing. Over 500 boats were seized, more than 270 people were fined for providing logistics for the boats and 180 others were caught illegally ordering or purchasing the catch.
"We are trying to establish a system which records the data of all boats, fishermen, owners, captains and crew members, so that we can quickly discover malpractice cases," said Song.
So far, information has been collected on 2,400 boats and 3,300 people.
Over-exploitation of offshore fisheries has damaged the biodiversity of the sea, which can be seen around Haiyang Island in Changhai County, about 73 nautical miles from Dalian, one of the four largest fishery areas in China.
In the first half of the year, fish farming output has grown, but the wild fish catch in the county dropped by 25.9 percent.
"We hope, with the extension of the ban, the environment will be improved so that we can catch more high-quality fish and seafood," said Wang Huan, a fisherman who lives in Changhai.
Since 2013, Dalian has spent 184 million yuan ($27 million) to put fish fry, juvenile fish able to feed themselves, into the sea.
In Tianjin municipality, the fishery authority issued 400,000 yuan in fines during the ban and detained one person for violation.
A fishing ban in the South China Sea ended on Aug 16. During this period, 92 cases of illegal fishing were reported, down 30 percent from last year, according to Hainan provincial maritime and fishery authorities.
The authorities increased supervision and asked members of the public to report violations during the ban.