SHANGHAI, Dec. 27 (Xinhua) -- A vessel carrying 130,000 fish, 1,000 kg of shrimp and 20,000 mitten crabs has released the creatures into an artificial reef in the waters of the Yangtze River estuary.

The 13th activity held since 2001 is an ecological restoration program affiliated to the Yangtze deepwater navigation channel project.

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

Since 2001, 1.496 million fish, 2.15 tonnes of shrimps, 110,000 mitten crabs and 171 tonnes of shellfish were released to restore the estuary's ecological environment.

The Yangtze, the longest river in China, is dubbed as the country's "golden waterway." China has invested heavily to smooth out the deep-water 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 H1 topped 9.4 million TEU, 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 ecological restoration expert from the East China Sea Fisheries Research Institute, who boarded the ship to participate in the release of the sea creatures.

Chen, 82, has been participating in the ecological 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 the 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 ecological efforts. On Dec. 23, the Shanghai Shenergy Chongming Power Generation Co., Ltd. also released aquatic animals into the estuary.