BEIJING -- Chinese police have solved over 6,500 criminal cases and captured more than 11,000 suspects in a campaign to protect the Yangtze River, the Ministry of Public Security said on Friday.

The ministry launched the campaign in March this year to clamp down on criminal activities involving fishing, sand mining, and water transport logistics in the Yangtze River Basin, Luo Ji, an official from the ministry, told a press conference.

Efforts to curb large-scale illegal fishing in the Yangtze River have yielded positive results, Luo said.

More than 5,600 criminal cases related to illegal fishing have been cracked by police this year, with 585 vessels and around 141,000 kilograms of catch involved in these cases seized.

In a six-month joint operation against illegal sand mining in the river, law enforcement authorities have cracked 232 cases involving a confirmed amount of 5.91 million tonnes of sand with an estimated value exceeding 250 million yuan (about $35.3 million).

The number of sand-related criminal cases in the river this year has dropped 33.2 percent from last year, marking a decline for three consecutive years, according to Luo.