摘要:
用壳高15～21mm的墨西哥湾扇贝(Argopecten irradians concentricus)稚贝作为实验材料,控制水温在16和24℃条件下进行对盐度的耐受力实验.实验结果表明,当温度在24℃时,稚贝存活的盐度范围为18.5～44.4,低盐度对稚贝的存活影响明显.稚贝可生长的盐度范围是21.2～41.0(日增长率r>4.0),适宜的生长盐度为24.0～32.0(日增长率r>8.0),其中26.0～28.0的盐度为最佳生长盐度.在16℃条件下,最初8h内,其生存盐度范围为17.4～46.4,但是48h后稚贝的存活盐度范围与24℃温度条件时无明显差别,显示出低温条件会使稚贝对极限盐度的反应速率减缓.当盐度处于接近极限范围时,盐度变化幅度过大易导致稚贝死亡.墨西哥湾扇贝对盐度的适应能力与原生境盐度有关,稚贝预先在盐度为19.5和44.9中适应9d后,再过度到14.3和48.5中,48h后,存活率为78.3%和100%,而若是从盐度为32中直接移到3和48.5中,48h后存活率分别为0和27.3%.显然,通过中间驯化或适应过程,稚贝会提高耐盐能力.此结果表明,在高温多雨的南方海域,应避免在易受淡水中冲击的河口、海湾区域开展墨西哥湾扇贝养殖.
关键词:
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墨西哥湾扇贝 /
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温度 /
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盐度 /
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耐受力
Abstract:
The range of salinity tolerance of the southern bay scallop.A.radians concentrycus was studied in laboratary.All experimenu were carried out with the spats,15-21 mm in height,by exposing the spats to various salinities for periods of 48h or more,with the aim of explaining the observations about the mortality in nature and deciding the farming sites for this species culture.The survival range of salinity is 18.5-44.4 at 16 and 24℃.The effect of lower salinity on the survival rate is more obvious.The salinity range for growth of the spats is 21.2-41.0(the daily growth rate,r > 4.0),suitable 24.0-32.0(r > 8),and optimal 26.0-28.0.If the salinity fluctuates strongly,the survival rate decreases seriously when the salinity is close to threshold value.The salinity tolerance of the scallop relates of the envitaanental salinity,too.The species is more resistant to salinity variation at decreasing temperature in a short time,but cannot increase its tolerance range in the lasting time.Results show that the species can survive and normally grow in the sourhem China seaarea,but it is unsuitable to planting in the estuary or the faming areas when the scallops may expose to freshwater.
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