SHANGHAI－A total of 130,000 fish, 1,000 kilograms of shrimp and 20,000 mitten crabs, were recently released into an artificial reef in the Yangtze River estuary.

The 13th marine life release since 2001 was done under an environmental restoration program affiliated to the Yangtze deepwater navigation channel project.

The artificial reef, with a total length of 147 kilometers, is a former embankment of the diversion channel, which was submerged after the navigation channel was built.

Since 2001, a total of 1.496 million fish, 2.15 metric tons of shrimp, 110,000 mitten crabs and 171 tons of shellfish have been released to restore the estuary's natural environment.

The Yangtze, the longest river in China, is regarded as the country's "golden waterway".

China has invested heavily to smooth out the deepwater channel of the lower stream of the river to allow container ships to travel upstream.

The throughput of standard containers shipped via the river in the first half of last year topped 9.4 million twenty-foot equivalent units, up 5.3 percent year-on-year.

"The Yangtze Estuary Deepwater Channel Project is the largest and most complicated estuary channel regulation project in the world. Since the beginning of its construction, great importance has been attached to ecological protection and restoration," said Chen Yaqu, an expert in restoring environments from the East China Sea Fisheries Research Institute, who participated in the release of the marine animals.

Chen, 82, has been participating in the restoration of the Yangtze River estuary for nearly 20 years.

He said from 2002 to 2004, the artificial oyster reef system in the estuary was constructed using a concrete dike as a substrate and replenishing the area with oysters.

So far, the aquatic resources have brought economic benefits.

Chen said the reef has become an important spawning ground and habitat for a number of aquatic animals including rare fish.

Local companies have joined in the restoration efforts. On Dec 23, the Shanghai Shenergy Chongming Power Generation also released marine animals into the estuary.