1 Introduction

Crassadoma giganteabelongs to mollusca,Lamellibranchia,Pterioida,Pectinidae[1].The variety has the advantages of delicious taste[2],high nutritional value,muscles accounted for a large proportion of software,strong environmental adaptability[3],rapid growth[4],lack of natura l resources in North American countries,the market in short supply.Scallops large-scale aquaculturein China started in the eighties,the main species of Gulf scallops and shrimp yaki scallop were cited from the east coast of North America and Japan.After decades of development,Liaoning and Shandong,Hebei and other places to form a larger scale of farming,the local economy has made its contribution to the development.However,serious problems such as large-scale death of scallop farming have emerged for a variety of reasons in the recent decade.Among other reasons,the single breeding species is also one of the reasons.The rock scallop because of the many advantages described above,after all,one of the preferred varieties introduced.Then,Since 2012,Dalian Ocean University has introduced into China through its Canadian partners.Up to now,the researches on this variety at home and abroad mainly include artificial seedling technology[5],nutritional composition analysis[2],ecology[2,6-9]and heredity[10],the impact of temperature on its growth has not been reported.In this paper,the growth of rock scallop at different temperatures was studied in order to provide a theoretical basis for artificial seedling production,marine maintenance and artificial breeding.

2 Data and methods

Test materials for 200 juvenile rock scallops with shell height about 2 cm.The juveniles produced during the artificial breeding trials of the rock scallops in 2015 were temporarily raised to the age of 6 months from the Longwangtang sea area of Lvshun.Their parents were got from Vancouver Island,Canada in 2014.

加快文物旅游人才引进和培养，建设一支高素质的文物旅游人才队伍，是四川提升文物旅游层次的必然要求.文物旅游专业性强，对旅游服务人才的要求高.一方面，旅游管理部门要重点引进一批既精通文物知识,又懂旅游管理的人才；另一方面，要加强同有关高校的合作力度，共同制定人才计划，不断扩大四川文物旅游专门人才的培养规模，从而构建一支既具有较高文物理论修养，又懂文物旅游经营管理的人才队伍；要加强文物专业导游人员的培养力度，建设一支综合素养高,服务服务能力强，适应文物旅游发展要求的新型导游队伍.

信息化时代，学校教育教学中的制度化的管理模式被系统的信息内容所替代，这一模式的应用不仅使信息技术在学校管理系统中的应用得到了最大化的发展，还为学校管理工作带来了积极的深化作用。本文针对教育管理信息化展开论述，并直面挑战提出有效对策[1]。

Fig.1 Scallop feeding device

The experiment was carried out in the Key Laboratory of Hydrobiology in Liaoning Province.The test water is natural seawater of Dalian Heishijiao area which has been treated by sand filtration.The test container is an automatic temperature-control and disinfection circulating aquaculture aquarium (effective water volume in each aquarium is 160 L)produced by Dalian Huixintai Equipment Development Co.,Ltd.Rock scallops native to the island of Vancouver Island,the annual variation of water temperature in the region between 6℃~20℃.Our preliminary experiments show that the species of scallops in indoor circulating water culture conditions,the temperature below 10℃and higher than 20℃growth efficiency is very slow.There were four temperature gradients were set up:10℃,12.5℃,15℃and 17.5℃.Each group was set 5 parallel groups and packed with 80 mesh polythene mesh bags.Each parallelgroup was fed 10 individuals.During the whole experiment,suck the bottom once a day,then replenish the sea water corresponding to the temperature,and change the water twice a week for 1/2 times each time.

尽管内部控制上强调招聘人员要从职业道德修养和专业胜任能力双方面标准来选拔和聘用财务人员，但是行政事业单位很难做到。例如，在行政事业单位中，有部分会计与财务工作人员在工作时并未取得相关证书，理论和实践根本无法同步，导致相关内部控制政策执行起来困难。同时，在行政事业单位中从事会计工作的人员年龄层次普遍偏大，接受新事物的能力与意识相对缺乏，但社会快速发展下，会计制度与理论知识也同样在发展，学习能力低下的问题必然产生各种不良影响。

3 Statistical analysis

20世纪90年代末，华盛顿州沿海地区的研究表明，森林和海洋环境之间有着十分重要的联系。研究发现，木材碎片与来自森林河流和溪流的土壤中含有大量的陆地有机碳，死去的树木是海底生态系统的重要能量来源之一，据估计，浅海水域中60%的有机碳以及1 000米以下深水区约1/3的有机碳都来自森林，即使是在远离海岸的深海区，也有15%的有机碳是漂流木带来的副产品。

4 Results

4.1 temperature on the growth of juvenile rock sca llops

As one of the important environmental factors,temperature has a significant impact on the survival and growth of bivalve molluscs[11-13].The reasons are manifold,including affecting theactivity of related digestiveenzymes,theexpression and activity of immune-related factors and so on.It was reported that in the water temperature range of 15-50℃,Mactraantiquatapepsinactivity increasedsignificantly withincreasing temperature[14].The optimal temperature for the amylase and cellulase of the Mimachlamys nobilis was 55℃and 45℃,respectively[15],Temperature is too high or too low will reduce the enzyme activity,and digestive enzymes activity will directly affect the digestion and absorption efficiency of shellfish,thereby affecting the growth.Immunologically,for shellfish,the temperature not only affects its heart rate,respiration,feeding,digestion,excretion and organ function,but also affect the transcriptional expression of various related factors[16].Sudden drop in temperature had a great effect on the SOD activity in the body of Ruditapes philippinarum,which showed no fluctuation in the process of slow decrease of water temperature[17].In the seawater environment, changes in water temperature can cause salinity,feed abundance,dissolved oxygen content and other changes,together affect the immunity and disease resistance of shellfish and health level.The ability of scallop to adapt to temperature is related to the heritability of the species and the individual's physiological status,but not to the size of the individual,and all individuals of the same species respond in the same way to changes in temperature[18,19].

It can be seen from fig.4 that the growth rate of the juvenile rock scallop in each group is firstly reduced and then increased,The growth rates of 15℃group and 17.5℃group were significantly higher than those of 10℃group and 12.5℃group (P<0.05).The 10-day growth rate of shell length is similar to that of shell height.

Variance analysis showed that the temperature had no significant effect on the survival of juvenile rock scallop in the temperature range of 10℃~17.5℃,and all the groups were close to or reached 100%.

4.2 Analysis of significance between groups

The results showed that the temperature had a significant effect on the growth of the juvenile rock scallop (P<0.05),the shell high daily growth rate of it in 15℃group was significantly higher than the other three groups,there was no significant difference in shell length and wet weight daily growth between the latter two groups,but both were significantly higher than the first two groups.The pre-test scallop daily growth rate increased with increasing temperature,when the temperature rose to about 15℃,the growth rate reached the maximum,The growth rate decreases when the temperature exceeds 15℃.There was no obvious rule of scallop growth rate at different temperature in late stage.

Throughout the test period,all test subjects were measured every 10 days and the number of deaths was counted,measurements include measuring the shell height and shell length using a digital vernier caliper and using a 0.01 g flu-weight scale to weigh its wet weight.Data were subjected to one-way analysis of variance (ANOVA)using SPSS 19.0 software to test the differences between groups,extremely significant level is set to 0.01,the significant level is set to 0.05.

Fig.2 Shell height at different temperatures

Fig.3 Shell length at different temperatures

Fig.4 Shell height 10-day growth rate of juvenile rock scallop

Fig.5 Wet weight 10-day growth rate of juvenile rock scallop

Those with the same letter showed no significant difference.

GroupDaily growth Shell high/mm Shell length/mm Wet weight/mg 10℃0.029 7±0.006 7c0.026 3±0.006 6c3.400 0±1.397 7b 12.5℃0.026 4±0.003 3c0.026 3±0.001 3c3.100 0±1.001 1cd 15℃0.055 8±0.004 6a 0.054 0±0.002 2a 5.900 0±1.351 9a 17.5℃0.046 8±0.004 3b 0.046 7±0.005 6a 4.733 2±0.894 4a

4.3 different temperature survival of juvenile rock scallop

It can be seen from fig.5 scallop wet weight changes,the initial wet weight growth rate is slow,the growth of 15℃group was the largest during the experiment period.

It has been reported that temperature has a great influence on the growth rate of scallops[20].Assuming that the scallops gain energy through ingestion,the ingestion can equal the sum of growth energy and respiratory metabolic energy.Within a certain range,the respiratory metabolism of scallopsintensifieswith increasing temperature[21].As respiratory metabolism increases,theamount of growth energy used to grow will inevitably decrease.However,the intake of scallops is not constant,and in the range of proper temperature,feeding increaseswith increasing temperature.At first,asthe temperature rises,feeding increases more than the growth of respiratory metabolism,and the growth rate of scallops also increases,after reaching a certain temperature,food intake can be reduced,respiratory metabolism can stillincrease,so growth is reduced.

Fig.6 Wet weight 10-day growth rate of juvenile rock scallop

5 Discussion

From fig.2 and fig.3,it can be seen that in shell height and shell length,the juvenile rock scallops in each group are in the growth state,and the final growth amount in 15℃group is the largest,significantly higher than the other three groups(P<0.05).

The test temperature is decreased by 1℃daily until the preset temperature.Weighing (wet weight)every 10 days after the temperature reaches the preset value and measuring the shell height,shell length,the test period of two months.Other aquaculture conditions during the experiment were salinity:32,pH:7.89~8.25,and continuous aeration to maintain dissolved oxygen levels above 3.7 mg/L.Feed 6 times a day,adjust the amount of each group to feed 2 h after feeding finish.The feeds were fresh unicellular algae,includingNitzschia closterium,Isochrysis zhanjiangensis and Platymonas subcordiformis.

不论是行为上的自由还是思想上的自由，若没有桎梏本身的存在，则自由也就不再有意义，正因为生活中有太多无奈，才更显得自由的美好，也才更显得勇于追求自由的可贵。

The results showed that the temperature had a significant effect on the growth rate of the scallop shell,and the growth was the best when the temperature was 15℃.Although the final growth rate in 17.5℃group was similar to that in 15℃group,the final growth rate was lower than that in 15℃because the initial growth rate was slightly lower.The growth rates of 10℃ group and 15℃ group were significantly lower than those of the other two groups.According to the author's opinion,this is related to the weakened life activity of the baby scallop at low temperature,including breathing,metabolism and other energy required to reduce,Reduced food intake,growth rate will naturally be reduced.Thus,too high or too low temperature will reduce the growth rate of juvenile rock scallop.The growth rate of all groups appeared to decrease and then increase,it is speculated that the scallop's ability to adapt to temperature is poor at the beginning of the experiment.

From the test results,in the temperature range of 10℃~17.5℃,the survival rate of the juvenile rock scallop is very high under different temperatures,all of which are more than 90%,and the death are mostly caused by mechanical damage,rather than temperature.Among them,the survival rates of juvenile rock scallop at 12.5℃and 15℃were 100%.The significance analysis showed that temperature had no significant effect on the survival rate in the experimental temperature range.The above results appear because the test temperature is within the normal range of rock scallop growth(6℃~20℃).

Studying the influence of temperature on the survival and growth of rock scallop had important guiding significance for the artificial breeding and cultivation of this species.It can be used as a reference for the future research and discussion of rock scallop culture technology.The variation of annual water temperature in the Yellow Sea of Dalian is roughly in the range of 1℃~25℃.Compared with the origin (6℃~20℃),although the upper and lower limits of water temperature are higher or lower,more than half of the water temperature in the rocky scallop.We believe that after continuous domestication,rock scallops should be able to gradually adapt to the environment of Dalian sea area,expanding its temperature range,to have a good prospects for the cultivation of new varieties of scallops.

Acknowledgments

This study was supported by Liaoning Provincial Education Department Project(NO.L201624).

References:

[1]Coan,E.V.Bivalve Seashells of Tropical West America.Marine Bivalve Mollusks from Baja California to Northern Peru[M].Valentich-Scott,P.(2012),2,1258.

[2] Cao Shanmao,Wang Hao,Chen Wei.Analysis,evaluation and comparison of nutritive composition in rock scallop Crassadoma gigantean with three Chinese scallops[J].Dalian Ocean University,2016.

[3] Cao Shanmao,Liang Weifeng,LI Xiaoyu,et al.Effects of Different Ecological Factors on Oxygen Consumption Rate and Ammonia Excretion Rate in Young Puffer Scallop[J].Journal of Dalian Ocean University,2016,3(32).

[4] Leighton D L．A growth profile for the rock scallop Hinnites multirugosus held at several depths off La Jolla,California[J]．Marine Biology,1979,51(3):229-232．

[5] Cao Shanmao,Wang Jian,Wang Qian.Artificial breeding of introduced rock scallop Crassadoma gigantea[J].Journal of Dalian Ocean University,2017,1.

[6] Culver C S,Richards J B,Page H M．Manipulation of the cementing process of the purple-hinge rock scallop,Crassadoma gigantea[J]．Journal of Shellfish Research,2000,19(6):651-652．

[7]Phleger C F,Rossi S S．Dissolved organic matter accumulation by juveniles of the purple-hinge rock scallop,HinnitesmultirugosusGale [J].Comparative Biochemistry and Physiology．Part A:Physiology,1982,71(3):453-456．

[8] Malachowski M．The reproductive cycle of the rock scallop Hinnites giganteus (Grey)in Humboldt Bay,California[J]．Journal of Shellfish Research,1 988,7:341-348．

[9] Cao Shanmao,Liang Weifeng,Wang Jian.Foundation of filtration rate of juvenile rock scallop[J].Journal of Dalian Ocean University,2016,6.

[10]Laurén D J．Oogenesis and protandry in the purple-hinge rock scallop,Hinnites giganteus,in upper Puget Sound,Washington,U．S．A．[J]．Canadian JournalofZoology,1982,60(10):2333-2336．

[11]Wang Danli,Xu Shanliang,Yuo Zhongjie,et al.The effect of temperature and salinity on the incubation of Cyclina Sinensis and survival,growth metamorphosis of C.sinensis larvae and juveniles[J].Acta Hydrobiologica Sinica(Acta Hydrobiol Sin),2005,29(5):495-501.

[12]Liu Zhigang,Wang Hui,Li Zhimin,et al.Upper incipient lethal temperature of Argopecten irradians concentricus Say[J].Journal of Fishery Sciences of China,2007,14(5):778-785.

[13]Lin Bishui,Wu Tianming.Huang Bingzhang.Effects of Temperature and Salinity on Growth and Development of(Rudipates Philippinarum)Spats and Clam[J].Journal of Fisheries,1983(1):15-23.

[14]Dong Zhiguo,et al.The effects of temperature,pH and feeding time on pepsin activity of Coelomactra antiquate[J].Journal of Shanghai Fisheries University,2005,14(4):397-400.

[15]Zhang Lingfei,Li Junhui.Effects of temperature and pH on amylase and cellulase activities of Huagui scallop Chlamys farreri[J].Aquaculture,2008,5:4-6.

[16]Xu Youqing,et al.Effect of Temperature on Immune System and the Mechanism in shellfish[J].Aquatic Sciences,2012,31(3):176-180.

[17]Li Runling.Changes of environmental factors in sea ice and seawater and their effects on the activities of enzymes related to immunity of shellfish in Madongdong Bay[D].Da Lian:Dalian University of Technology,2016.

[18]He Yichao,Zhang Fusui,Wang Ping,et al.Salinity tolerance of the southern bay scallop Argopecten irradians concentricus[J].Chinese Journal of Oceanology,Chinese Version,1999,21(4):87-91.

[19]You Zhongjie,Lu Tongxia,Ma Bin et al.The Temperature on the Growth and Survival of Argopecten irradians Concentricus Larvae and Juveniles[J].Aquatic Sciences,2003,22(1):8-10.

[20]Dall W,Hill B J,Rothlisberg P C．The Biology of the Penaeidae [M].Blaxter J H S,Southward A J．Advances in Marine Biology．New York:Academic Press,1990．

[21]Dalla Via G J．Salinity Responses of the Juvenile Penaeid Shrimp Penaeus Japonicus:I．Oxygen Consumption and Estimations of Pro-ductivity[J].Aquaculture,1986,55:297-306．