Riau Islands became one of the coral reef conservation sites in Indonesia. Examples of coral reef conservation sites in the Riau Islands are Karang Alangkalam and Karang Bali. The area's marine life has made the Natuna Sea into a scuba diving destination. While there were once threats towards the coral reefs in the region, such as blast fishing, a survey by the Indonesian Institute of Sciences found that most of the coral reef ecosystems and mangrove forests in a number of locations in the waters around Batam are in a good condition. Nevertheless, there are some threats that might endanger the ecosystem in the province, such as plastic waste which is mostly produced by households that are thrown into the sea. Illegal fishing is also one of the factor that damages the ecosystem in the region. The sea around the Natuna Islands in the previous years has been home to illegal fishing due to weak law enforcement in the region. Under the Widodo administration, the Natuna Sea has been frequently patrolled by the Indonesian Navy and the Indonesian Maritime Security Agency to prevent illegal fishing. This has resulted in the arrest of hundreds of fishing boats and their crews from countries such as Malaysia, Vietnam and China.