VESSEL CONVERSION | Zhedai Fishery and Breeding 60001 – Bulk carrier rebuilt for fish harvesting off eastern China
China State Shipbuilding Corporation subsidiary Shanhaiguan Shipbuilding Industry has handed over a converted oceangoing aquaculture vessel to local company Senhai Muge (Zhejiang) Marine Technology.
Zhedai Fishery and Breeding 60001 (浙岱渔养60001; Zhedai Yuyang 60001) has an LOA of 224.9 metres (737.9 feet), a beam of 32.2 metres (106 feet), a depth of 18.5 metres (60.7 feet), and accommodation for 30 personnel.
Fitted with an innovative seawater circulation system to simulate ideal breeding environments
The vessel boasts seven harvesting tanks with a total capacity of approximately 80,000 cubic metres (2.8 million cubic feet), which is the equivalent combined capacity of 200 deepwater fish pens. The annual output is expected to reach 2,800 tons, thus yielding a production value of more than CNY120 million (US$17 million).
The vessel was originally built as a Panamax bulk carrier. While retaining sufficient buoyancy and the original hull's structural strength, water inlet arrays were incorporated on either side of the hull to allow seawater to enter the harvesting tanks. The hull bottom meanwhile has four drainage outlets through which water in the harvesting tanks can be pumped out into the sea.
With the aid of wave motions, seawater is continuously circulated through the vessel 24 hours a day, thus resulting in a natural water exchange system as well as a “quasi-wild” environment in which fish could grow. According to the vessel’s breeding technicians, this approach will not only significantly reduce operating costs, but will also reduce the mortality rate of the harvested fish.
The hull has also been reinforced to have a service life of 20 years and to be able to withstand Beaufort force 17 conditions with wind speeds in excess of 108 knots.
Can be relocated as needed depending on weather and environmental conditions
The onboard monitoring room contains an array of computers that gather data on such parameters as water temperature and oxygen content in real time. The monitoring capability will help the crew ensure precise feeding by identifying areas with ideal water temperatures and then positioning the vessel in those areas before commencing harvesting.
Because the vessel is self-propelled, it is able to ensure the most suitable growth environment for the harvested fish by sailing to colder northern waters during summer and then heading south for warmer waters during winter, thus ensuring the water temperature is kept within the optimum range of 14 to 28 degrees Celsius.
This capability can help shorten the breeding cycle to just one year from the typical three years or more, as is the case in other regions such as Norway.
The self-navigation capability will also enable the vessel to avoid areas that are experiencing algal blooms or those that are in the path of approaching typhoons.
Design work for Zhedai Fishery and Breeding 60001’s conversion was undertaken jointly by the China Ship Development and Design Centre and the China Shipbuilding Group's 714 Research Institute in compliance with China Classification Society rules.
The vessel will be operated primarily off eastern China’s Shandong province in the summer and it will relocate to the waters off the provinces of Zhejiang, Fujian, Guangdong and Hainan during the other times of the year.
