开阔型港湾紫菜埕地轮养菲律宾蛤仔的研究

A RESEARCH ON ROTAIONAL CULTURE OF THE CLAM RUDITAPES PHILIPPINARUM AND PORPHYRA IN OPEN BAY

利用开阔型港湾紫菜养殖理地空闲季节，进行小型试验并指导大面积轮养菲律宾蛤仔。选择含沙量80％～90％的沙泥稳定底质，海水比重1．016～1．022，大潮于露2～4小时，流速80～100厘米／秒，饵料丰富的海区，1～2月份播种壳长2．0～2．2厘米的一龄大蛤苗，密度1000个／米2，养成期间药杀蛇鳗，围网防害，在水温12～27．5℃，滩养4～5个月，7月份台风季节前可收获壳长达3厘米以上商品蛤，成活率68％左右，1．3公顷的平均产量37．5吨／公顷。比较淹水时间短、流量低的养殖条件．商品合格期提前2个月，成活率提高23％，平均每公顷增加产量14．4吨，效益非常显著。

This paper reports both results of the small experiment carried out on culture field of Porphyra in open bay in idle season and conduction for rotational culture of Ruditapes philippinarum (Adams et Reeve) in a large area in 1996 and 1997. The conditions selected stable sand and mud bottom sediment containing 80 - 90% sand, seawater specific gravity 1. 016- 1. 022, exposed sediment for 2-4 hours at spring tide, seawater flow rate at 80- 100 cm/sec, one year'spats in shell length 2.0-2. 2cm were seeded at density 1000 ind/ m2 from January to February in sea area with abundant feeds. Killing worm eels with medicine and preventing harmful animals with enclosure must be done during culture period.The clams were cultured on beach for 4- 5 months at water temperature 22- 27- 5℃. Commodity clams can be harvested in shell length of over 3cm and survival of about 68% before typhoon coming in July. Average yield of 1. 3 hm2 is 37. 5t/hm2. Comparison of culture way with all through the ages showed present way had exposed sediment for long time(6 hours),slow flow rate(40 cm/sec), seeding moderate spats (shell length of less than 1. 8cm). The time for commodity clams up to standard has been moved up for 2 months. Survival has been raised 23%. Average yield per hectare has been increased 14. 4t. Beneficial result is remarkable.