SELECTIVE BREEDING OF SWIMMING CRAB PORTUNUS TRITUBERCULATUS IN CHINA

Ping Liu ^a,b,*, Jian Li ^a,b, Baoquan Gao ^a,b, Jianjian Lv^a,b, Xianliang Meng ^a,b
^a Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture, P.R.China, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 266071 Qingdao,China.
^b Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, No. 1 Wenhai Road, Aoshanwei Town, Jimo, Qingdao, China.

* E-mail: liuping@ysfri.ac.cn

The swimming crab, Portunus trituberculatus (Crustacea: Decapoda: Brachyura) is widely distributed in the coastal waters of Asia-pacific countries. The farming of P. trituberculatus has been developing rapidly in China over the last decades and the highest yield of 100,000 tons with 40,000-ha farmed area. However, the swimming crab harvests have declined drastically with frequent outbreaks of disease. Moreover, the wild fishery ground and fishery season of this crab are almost disappeared in many regions since 1990s. In order to enrich this resource, scientists at the Yellow Sea Fisheries Research Institute (YSFRI) worked to select and breed a new variety of P. trituberculatus with improved growth performance since 2005. In 2010, they have produced a fast-growing population called "Huangxuan No.1" after five generations of selection. Further new species selective-breeding research is ongoing.

The goal of the breeding program is to develop a faster-growing cultured crab (P. trituberculatus) through population selection strategy. In 2005, a mating design is applied. The base selective population was established after finishing the combining ability test and genetic structure analysis. Each generation selective intensity was around 5% to select the bigger ones. After mating, the females migrate to the pond indoor for overwintering. Females extrude a brood of fertilized eggs with stored sperm, then moved to the cultivate pond indoors. The released larvae, termed zoea, are advected to indoor farming pond where they go through four zoea-stage larvae, one megalopa and juvenile stage. At juvenile II stage stage, randomly sampled animals were moved to the ponds outdoor separately. The ponds were separated into several parts with net.

Till date, the new variety "Huangxuan No. 1" for fast-growthing of P. trituberculatus was selected successfully in 2010 after five generation selection from four geographical population, and the body weight increased 20.12% and survival rate increased 32.00%, respectively, compared with the unselected population.