2种双壳贝类染色体的观察研究

[目的]为贝类的细胞遗传学研究提供基础资料。[方法]以等边浅蛤和江户布目蛤的鳃组织为研究材料,用植物血球凝集素和秋水仙素对2种双壳贝类的腮组织进行处理后,采用滴片-空气干燥法制片并观察其染色体数目。[结果]通过观察2种贝类的中期分裂相,发现等边浅蛤的染色体众数为36的分裂相细胞,占全部计数细胞的55.0%,说明其染色体数目(2n)为36。而江户布目蛤的染色体众数为30的分裂相细胞,占全部计数细胞的58.8%,说明江户布目蛤的染色体数目(2n)为30。[结论]从细胞水平上看,日本镜蛤(2n=30)和江户布目蛤有较亲密的亲缘关系,而青蛤(2n=36)和等边浅蛤也有较亲密的亲缘关系。     

温州沿海3种双壳类营养成分比较分析

测定了采自温州沿海的等边浅蛤、尖刀蛏和结蚶3种双壳类软体部的营养成分。试验结果表明,等边浅蛤、尖刀蛏和结蚶软体部干样中粗蛋白分别为58.11%、71.02%和59.17%,粗脂肪分别为14.98%、14.35%和10.62%,灰分分别为10.85%、9.05%和11.03%;总氨基酸分别为459.27、565.20mg/g和509.83 mg/g,必需氨基酸分别为157.33、197.03 mg/g和181.57 mg/g,呈味氨基酸分别为241.402、88.40 mg/g和258.60 mg/g;限制性氨基酸均为蛋氨酸+胱氨酸。等边浅蛤、尖刀蛏和结蚶软体部脂肪酸组成分别为22种、23种和21种,等边浅蛤和结蚶无C14:1,结蚶无C14:3;饱和脂肪酸分别为36.01%、28.85%和30.87%,不饱和脂肪酸分别为63.97%、71.25%和69.14%,单不饱和脂肪酸分别为23.18%、27.61%和26.20%,多不饱和脂肪酸分别为40.79%、43.64%和42.94%。3种双壳类均具有较高的食用价值和开发前景。     

Effect of tooth spacing on the contact selection and available selection of a dredge for the equilateral Venus clam <Emphasis Type="Italic">Gomphina melanaegis</Emphasis>

ABSTRACT:   The effect of various tooth spacing on the contact selection and the net-mouth available selection of a dredge for the equilateral Venus clam Gomphina melanaegis is evaluated by applying a contact-probability model based on the SELECT method to the data of paired-gear tests with a control dredge of 12-mm tooth spacing and four test dredges of tooth spacing 16, 20, 24 and 35 mm. A master selection curve was estimated to be s ( R ) = exp(−11.23 R  + 4.799)/(1 + exp[−11.23 R  + 4.799]) where, R is l / d , the ratio of the shell length, l , to the tooth spacing, d . The shell width of 50% retention was slightly smaller than the tooth spacing, which means that size selectivity of teeth was a type of contact selection which was dependent on the tooth spacing. Contact probability, δ, of the clams coming into contact with the teeth were 0.625, 0.467, 0.563, 0.670 and 0.976 for tooth spacing 12, 16, 20, 24 and 35 mm, respectively. This indicates that some clams entered the dredge bagnet without contacting the teeth as the sand clogging the tooth spacing carried them into the bagnet. Available selection curve of the dredge net-mouth with teeth was obtained as δ s ( R ) + 1 −  δ , and examined in terms of the legal landing size of the Venus clam.     

等边浅蛤人工育苗试验初报

2006年6月～2007年1月,对等边浅蛤的人工繁殖、胚胎发育和幼虫培育、变态附着及稚贝培育进行了研究。结果表明：等边浅蛤胚胎繁殖盛期是每年的7~8月,在盐度20～25,水温24～29℃,pH8.0的条件下,受精卵经过15h发育成D形幼虫。盐度20～25,水温24～29℃时,胚胎的孵化率和D形率最高。温度和盐度对幼虫的生长发育影响明显,浮游幼虫生长最适温度为24～29℃,最适盐度为20～25,34℃试验组,幼虫几乎不能存活,19℃组存活率最高,但生长速度慢于24℃组。幼虫在盐度15～25时存活率最高,但盐度20～25时生长速度最快,在盐度35时,幼虫几乎不能存活。研究发现金藻和角毛藻是等边浅蛤浮游幼虫生长的适宜饵料。