Mussel culture in China

Abstract

The southernmost limit of the distribution of the common mussel, Mytilus edulis L., along the mainland coast of Asia is in the northern part of the southern Yellow Sea, including Jiaozhou Bay where they occur rarely. There are two breeding seasons a year, spring and autumn. The development of their population may be limited primarily by benthic predators and the high summer temperatures in the intertidal zone. The use of rafts in culture can overcome these problems. In China, commercial mytiliculture was initiated in the early 1970s. In order to solve the problem of seed mussel shortage, we carried out research on the collection of natural seed with the aim of increasing their production and on hatchery techniques aimed at attaining large-scale rearing. The two primary factors that contributed to the successful establishment of seed grounds along the Shandong Peninsula (e.g., Jiaozhou Bay) were leaving the kelp longline rafts in the water after their harvest to serve as attaching substrata for collecting spat and maintaining sufficient adult mussels for larvae production. Over the past few years, several reports on the artificial rearing of spat have been published in China. Recent research has resulted in the improvement of collectors used in the rearing tank, amelioration of larval food supply, inhibition of bacterial growth in the rearing water with the use of cheaper drugs, etc. As a result, over 10 million spat averaging 350–400 micra in length can be steadily produced per cubic meter of tank water by the method we have devised. Floating raft culture is now the most popular method employed. Each raft is 50 or 60 m long, mostly with glass floats. Mussels are cultured for a period of about 6 months or 1 year and are harvested in March and April or in September and October. Each raft can produce 750–2500 kg of fresh mussels; rafts in Jiaozhou Bay generally produce 1500 kg.