| In this study,we studied effects of suspended particle matter,hydrostatic pressure and explore conditions on P.yessoensis,which can provide a theoretical guide on selection of the bottom of scallop seeding and evaluate sustained and healthy breeding of scallops.Based on spatial-temporal variation of suspended particulate matter in Zhangzidao marine ranching and indoor controlled experiments,we used P.yessoensis as experimental material to investigate the effects of suspended particle matter,exposure and hydrostatic pressureon on feeding physiology,enzyme activity and the lethal of juvenile.The results as follows:1.Spatial-temporal distribution of suspended particulate matter in Zhangzidao Island and adjacent area.(1)Concentrations of TPM and POM in Zhangzidao island ranged from 16.76-97.54mg/L and 2.20-17.0 mg/L,respectively,the annual average were(31.65±9.58)and(6.97±2.08)mg/L each.The PCOM ranged from 8.69% to 37.09%,with an average of22.25±4.18%.(2)The seasonal trend of TPM concentration was autumn > spring >summer > winter.The highest TPM concentration was found in surface layer in autumn.However,the highest and lowest POM concentrations and organic contents appeared in summer and winter.(3)The POM and TPM concentrations were uniformly distributed horizontally in most area.Higher POM was found in the central area compared to the surrounding investigated seas in spring and summer,and an opposite situation was found in autumn and winter.Vertically,POM and TPM in bottom water were significantly higher(P<0.01)than in surface water in summer,and for the other seasons there was no significant difference(P>0.05).2.Studies on the effects of suspended particles on the feeding physiology of P.yessoensis.We studied the effects of suspended particles on the feeding physiology of scallop:(1)the effects of suspended particles on clearance rate CR,ingestion rate IR and absorption efficiency AE were investigated in different concentrations of suspended particles using experimental ecological method.The results showed that the total suspended particle had significant effect on CR,IR and AE(P<0.05).The CR and IR increased with the rise of concentrations of TPM and decreased when the TPM exceeded a definite concentration.The CR reached the maximum value of 0.82 L/g/h at a concentration of 53.01 ± 6.81mg/L and the minimum value of CR(0.05 L/g/h)at concentration of 622.9±14.13mg/L.The AE decreased with the increase of suspended particle concentration and the minimum value appeared at the concentration of 13.04±0.89 mg/L.In conclusion,TPM had significant effect on feeding physiology of P.yessoensis.The high concentration of suspended particles could limite the feeding physiology of scallop.(2)Feeding selectivity was studied in the suspended particulate matter in the natural seawater.The results showed that the filtering efficiency of scallops increased with the particle size was bigger,and scallops can completely filter out particles at the diameter of 3.84 ?m.With the increase of sediment sediment in water(mainly increase the particle 1.4-2 ?m),filtering efficiency of scallops on different size particles increased with the particles size were bigger,and maintain relatively stable was4-5 ?m.The filtering efficiency of scallops for 2-4 ?m particles in high concentration of suspended particulate matter was slightly higher than the low concentration.3.The lethal effects of suspended particulate matter and its effects on the activity of GP x and GST,and effects of exposure on the juveniles of P.yessoensis.The results showed:(1)During 12 days of experiments,suspended particulate matter has chronic lethal effect on juvenile.The mortality of P.yessoensis at high and low concentration groups was significantly different on 7th day,and the mortality rate increased with the increasing concentration of suspended particulate matter and the experiment time.(2)Gills and and visceral mass of scallop were sampled when exposed to various concentrations for 1 d,4 d,8 d,12 d and restored 2d in fresh sea water to investigate the effects of suspended particulate matter on its activity of GP x and GST.Results showed that the activity of GP x and GST in gills and visceral mass presented the downward trend after rising first with the concentration of suspended particulate matter and the extension of exposure time;GP x activity is significantly higher than GST;(3)At temperature of 10?,the survival rate of juveniles decreased significantly compeared with 20?.The juveniles have no death under the condition of wet and dry when explored for 8 hours at the temperature of 10?;The survival rate of dry groupand wet group was significantly different(P < 0.05)when explored for 12 hours;survival rate of juvenile in wet group was decresed more slowly than the dry group at temperature of 20?.4.The effects of hydrostatic pressure on the feeding rate,oxygen consumption rate and ammonia excretion rate of P.yessoensis.The simulation experiment was applied to explore the effects of different hydrostatic pressure(0,0.1,0.2,0.3,0.5 MPa)on the feeding rate,oxygen consumption rate and ammonia excretion rate of two different sizes P.yessoensis.The results showed that the hydrostatic pressure had significant effects on feeding rate,oxygen consumption rate and ammonia rate of two sizes of scallop(P < 0.05).(1)With the increase of the hydrostatic pressure,the feeding rate showed a trend of decrease,oxygen consumption rate and ammonia rate showed a trend of increase.This suggested it gained less energy and consumed more energy,So it was not conducive to the growth of scallop.(2)The results showed that increase of hydrostatic pressure in short time had different influence on different sizes of P.Yessoensis,and the small size scallop was more sensitive to the changes of hydrostatic pressure. |
PDF Full Text Request