The Study Of Breeding Densities, Substratum, Predators On The Grown And Survival Of The Pinctada Martensii

There are abundant types of mari-cultured shellfish, among which, Pinctada martensii was considered to be the most important type, since it is the major mother-of pearl used in cultivation of mari-cultured pearl. Different cultivate environment and climate conditions create different influence on Pinctada martensii. Although most of Pinctada martensii shall be aquatic cultivated, subject to the location limit of Wuzhizhou Island, Pinctada martensii can only be grown in smaller seedling buckets with smaller water capacity. In order to enhance the cultivation production of Pinctada martensii in sea area of Wuzhizhou Island, an experiment in respect of cultivation of Pinctada martensii in Wuzhizhou Island has been conducted. Study results are as followed:1 Study on aquiculture density of Pinctada martensii. This experiment consists of two parts, outdoor and indoor. The outdoor part includes 4 groups, and each group repeated 3 times with 12 seedling buckets in total. Meanwhile, indoor part includes 4 groups, and each group repeated 3 times with 12 seedling buckets in total. We set the aquiculture density of larva as 0.5 individual/mL,1.Oindividual/mL,1.5individuals/mL and 2.0individuals/mL respectively. By monitoring hydration experiment, we ascertain hydration environment of sea area of Wuzhizhou Island, and through measuring the shell length and height of larva in each experimental bucket, we compare growth rates and survival rates under different aquiculture densities. Based on above experiment we achieve best aquiculture densities for indoor and outdoor cultivation, which are 0.5-1.Oindividual/mL for outdoor and 0.5-1.0 individual/mL for indoor. Considering the benefit maximum for cultivation, it is suggested to apply 1.Oindividual/mL outdoor cultivation.2 Influence of different seedling attached devices on attaching status of Pinctada martensii larva. We chose 5 different seedling attached devices, including (1) string made from twisted sunshade net; (2) rope seedling attached device (new thick string); (3) rope seedling attached device (old thick string); (4) packaging belt (broad-band type); (5) 5cm Havelock (flat, not twisted). We compare the attaching effectiveness of Pinctada martensii larva with different densities, obtaining the best aquiculture densities of 1.0-1.5individual/mL. In addition, we compare attaching effectiveness of different attached devices and the result shows that the best device would be string made from twisted sunshade net and lope seedling attached device (old thick string), following the rope seedling attached device (new thick string) and 5cm Havelock, which the worst one is packaging belt (broad-band type).