A Comparative Study On Physiological Metabolism And Growth Characteristics Of Scapharca Broughtonii From China And South Korea

Scapharca broughtonii, commonly known as the hairy clams, ark shell, blood clam, belong to Mollusca, Lamellibranchia, Arcoida, Arcidae, and Arca. In the past, duing to improper exploitation and resource planning unreasonable, natural resources of ark shell declined sharply. In recent years, people carried out some artificial activities of sowing cultivation to increase natural resources of ark shell. Adult of ark shell is large and tasty and has broad market value. In the 1990 s, our country had carried out arkshell in aquaculture. However, due to the breeding environment, breeding technology and diseases and other reasons, there is no large-scale promotion. In recent years, many regions have introduced ark shell from South Korea to breeding and aquaculture and the survival rate of ark shell could improve. But the basic research of growth, physiological characteristics about arkshell from China and South Korea is the lack of. This paper selected sub generation of the ark shell from China and South Korea. In Sanggou Bay, the oxygen consumption, ammonia excretion, feeding and other physiological parameters of Scapharca broughtonii from China and South Korea were measured to study the growth, physiological metabolism, energy distribution characteristics, in order to provide the basic data for aquaculture. The main results are as follows:1.The oxygen consumption rate and ammonia excretion rate of S. broughtonii in different seasonsDuring the period from May 2015 to November 2015, when the temperature of sea area reaches a certain temperature(15, 20, 20, 15, 25℃), the experiment of respiration and excretion by the method of still water and running water was made to study the physiological state of ark shell from China and South Korea. From May in spring to November in autumn, the parameters of mariculture area were as follows: the range of temperature was 15.35 to 25.23℃, the range of salinity was 31.4 to 32.2, the range of p H was 8.01 to 8.31, the range of dissolved oxygen was 6.24 to 9.21 mg/l. The meat condition increased gradually from May in spring to July in summer; and declined from August to September,gradually picking up from October to November in autumn. During the period of spring and summer(from May to September), oxygen consumption rate(ROw) of ark shell from two country decrease with the increase of temperature in different month and the trend of ROw was 15℃>20℃>25℃.From September to November in autumn, ROw gradually reduced and the trend was 25℃>20℃> 15℃. The oxygen consumption rate of ROn was increased with the increase of temperature, and the trend of ROn was 15℃< 20℃< 25℃. From September to November in autumn,the trend of ROn was 25℃>20℃>15℃.RNw and RNn reached the highest value in the summer of 25℃.2. The feeding rate and energy balance of Scapharca broughtonii from China and South Korea in different monthsThe energy budget equation of ark shell in different seasons are as follows:Korea:2015.05 15℃ still water 100C=10.92R+0.22U+74.93F+13.93P2015.06 20℃ still water 100C=2.02R+0.20U+61.25F+36.53P2015.09 25℃ still water 100C=13.18R+2.76U+80.10F+3.96P2015.10 20℃ still water 100C=12.33R+0.99U+81.14F+5.54P2015.11 15℃ still water 100C=12.46R+0.78U+70.74F+16.02P2015.05 15℃ running water 100C=11.02R+0.25U+65.06F+23.67P2015.07 20℃ running water 100C=3.40R+0.26U+64.60F+31.74P2015.08 23℃ running water 100C=3.16R+0.20U+80.38F+16.27PChina:2015.05 15℃ still water 100C=11.57R+0.34U+78.52F+9.57P2015.06 20℃ still water 100C=1.86R+0.14U+65.59F+32.42P2015.09 25℃ still water 100C=14.24R+3.35U+84.59F-2.18P2015.10 20℃ still water 100C=15.82R+1.17U+79.14F+3.87P2015.11 15℃ still water 100C=8.52R+1.24U+74.31F+15.93P2015.05 15℃ running water 100C=20.44R+0.69U+69.95F+8.92P2015.07 20℃ running water 100C=2.63R+0.20U+66.01F+31.16P2015.08 23℃ running water 100C=5.48R+0.28U+81.70F+12.54PThe in each season, faeces energy accounted for the highest, the lowest proportion was excretion energy. The faeces energy of ark shell from South Korea was 61.25% ~ 81.14%, and the faeces energy of ark shell from China was 65.59%~84.59%. The proportion of faeces energy and excretion energy for ark shell from South Korea in each season was generally lower than that for Chinese ark shell. While the proportion of growth energy for ark shell from South Korean in different seasons was generally higher than that for Chinese ark shell. The growth energy of ark shell from South Korea was 3.96%~36.53% and the growth energy of ark shell from China was-2.18%~32.42%. For the period of high temperature(25℃) in September, growth of Chinese ark shell is negative, and the adaptability of Chinese ark shell on high temperature was poor. In addition, the law of running water is similar to that of the static water in different seasons.3. Effects of careshell on growth of Scapharca broughtonii from China and South KoreaThe effect of careshell on growth and survival of Scapharca broughtonii was investigated by field study in Sanggou bay from April 6 to October 26, 2015. According to the ratio of careshell and the weight of Scapharca broughtonii, the experiment was set up four treatments. The initial weight of Scapharca broughtonii of every group was 160 g. The weight of the added careshell was 0g(control,C0), 80g(C1),160g(C2) and 320g(C3) respectively and 0g(control, K0), 13.5g(K1), 27g(K2) and 54g(K3) respectively. Every 40 days, the growth parameters(shell length, shell width, shell height, wet weight) of Scapharca broughtonii in each experiment group were measured and the number of deaths were recorded. The experiment lasted 200 days. Specific growth rate and mortality rate were calculated at different stages(every 40 days). The results showed that the growth parameters of Scapharca broughtonii for C3 group were significantly higher than the control group C0(P<0.05), but the difference with C2 and C1 was not significant(P>0.05). After 200 days, the specific growth rates of shell length, shell width, shell height and wet weight for C3 were 0.34±0.01%/d 、0.46±0.02%/d、0.39±0.01%/d、1.11±0.002%/d, which was significantly higher than that of C0(P<0.01). The average increase rate of SGR was 17.9%、20.3%、18.1%、16.7% than C0 and the difference was very significant(P<0.01). The mortality rate of C3 group was 19.6±5.6%, which was lower than the control group C0(26.1±2.5%), but the difference was not significant(P>0.05).