胶州湾移植底播菲律宾蛤仔的生长和死亡特性

2004年5月至2005年4月对胶州湾菲律宾蛤仔（Rudimpes philippinarum）底播增殖区进行了逐月定点采样，将样品带回放于实验室内水族箱暂养，每站随机取样，共对3269个个体进行了基本生物学特性测定，研究了移植底播菲律宾蛤仔的生长、死亡等渔业生物学特性。结果表明，底播增殖菲律宾蛤仔苗种的平均个体质量0．26g、平均壳长11．1mm；底播蛤仔与野生蛤仔在生长规律上基本一致，春末至秋初（4～9月）是其主要生长期；1～3龄期间个体生长速度较快，1～2龄、2～3龄，个体质量分别增长3．88g和4．02g；1～2龄生物量增长最快，2～3龄由于死亡率增大，其生物量增长缓慢；1～3龄蛤仔软体部的生长速度快于贝壳，5～6月是菲律宾蛤仔的繁殖肥育期。根据个体生长特性，3龄为最佳采捕年龄；根据目前的养殖状况，2龄蛤仔已达到商品规格，从生物量上分析，采捕2龄蛤仔收益最高；6月是最佳的捕获时期。蛤仔生长具有明显的季节变化，水温是影响菲律宾蛤仔生长的主要环境因子。中国水产科学，2006，13（4）：642—649]

Growth and mortality of the transplant enhanced manila clam Ruditapes philippinarum in the Jiaozhou Bay

Manila clam Ruditapes philippinarum is one of the important marine mollusks in China.It ever distributed extensively in the Jiaozhou Bay.Due to overexploitation and environmental changes,local wild manila clam stocks declined badly.Presently the farmed and enhanced clams played an important role in the Jiaozhou Bay.For example,the enhanced area covered more than 10?000 hectare in the Jiaozhou Bay,and yield exceeded 320?000 tons,which accounting for above 45% of the total farmed output in the Jiaozhou Bay in 2003.The enhanced clam seedings were mainly from Fujian Province after 2000 in the Jiaozhou Bay,however,the fishery biology including growth and mortality of the transplant enhanced clams were not still examined yet.In this paper the growth and mortality of the enhanced manila clams were studied in order to provide some support for the sustainable development of the aquaculture and enhancement of the clams in the Jiaozhou Bay.Samples were collected monthly at 7 fixed sites in the Jiaozhou Bay from May 2004 to April 2005,and the samples were brought to laboratory breeding temporarily in the aquarium.The clams were sampled stochastically at each sampling site in each month,and the biological characteristics including weight,shell length,and flesh weight of 3?269 in total clams were measured,and then the growth and mortality of enhanced manila clam were examined.The results showed that the manila clam seedlings mainly from Fujian province had an average body weight of 0.26?g,and average shell length of 11.1?m.The enhanced clam had a similar growth trend with the local wild clams.The clams at different ages grew fast during May to September,and grew slower after October and even ceased growth between November and next January with the decreasing temperature.So the main growth periods lasted from April to September,which was same as that of the wild clams.As to the monthly growth rate,the gross weight was faster than that of shell length.The shell length,gross weight and flesh weight kept at relatively higher growth rates before October except for August,and the growth rates were low from October to next January and increased thereafter.A relative low growth rate occurred in August for clams of age 1 and age 2,which was probably due to the high temperature.The clams grew fast between age 1 and age 3,and the individual mean gross weight increments were 3.88?g and 4.02?g for age 1 and age 2,respectively.The biomass of age 1 had the fastest growth rate;the biomass increase was getting slower due to the increased mortality for age 2.The flesh grew faster than the shell between age 1 and age 3,and the main breeding period for the manila clam was from May to June.Based on the individual growth,the best harvest age was 3;according to the analysis of the highest biomass output,the best capture age was 2.The best harvesting period was June.The water temperature was the main environmental factor that affected the farmed clam growth in the Jiaozhou Bay,and there was an evident seasonal change in the growth.