CAJ | 학술논문

2008年7月至2009年7月研究了江西青岚湖圆顶珠蚌(Unio douglasiae)的种群结构与繁殖特征.从其种群结构的周年变动情况来看,该种群趋于稳定状态,壳长40-65 mm的个体占大多数.在采集的标本中,最大个体壳长为83.6 mm,最小个体壳长为20.3mm.圆顶珠蚌自然种群性比为1:1.20,性成熟最小雌体壳长为27.6mm,体重为2.62 g;最小雄体壳长为27.9 mm,体重为2.21 g;5至6月间繁殖盛期,检测到最小妊娠个体壳长为29.8 mm,体重为2.98 g,推断一周年的圆顶珠蚌可能达到性成熟.根据圆顶珠蚌生殖细胞的发育规律和滤泡的变化特点,性腺发育分为生长期和成熟期、排放期、恢复期:属多次产卵类型.育儿囊属外鳃型,胚胎在胶质索中发育,钩介幼虫成熟后,胶质索消失成黏液状,成熟钩介幼虫附在新形成的黏液丝上排出体外.妊娠母蚌在受到刺激后,易发生流产,提前排出胶质索.繁殖期为2至7月,4、5、6月为繁殖高峰期,妊娠率分别为80.43%、84.21%和78.05%.平均繁殖力为(183.72±6.43)千粒/个,最大繁殖力为344.64千粒/个,壳长为54.5 mm;最小繁殖力为49.95千粒/个,壳长为29.8 mm.繁殖力与壳长和体重显著相关.这些结果不仅可以丰富淡水蚌的生物学内容,也能为淡水蚌保护和湖泊与河流的规范管理提供理论依据.
2008년7월지2009년7월연구료강서청람호원정주방(Unio douglasiae)적충군결구여번식특정.종기충군결구적주년변동정황래간,해충군추우은정상태,각장40-65 mm적개체점대다수.재채집적표본중,최대개체각장위83.6 mm,최소개체각장위20.3mm.원정주방자연충군성비위1:1.20,성성숙최소자체각장위27.6mm,체중위2.62 g;최소웅체각장위27.9 mm,체중위2.21 g;5지6월간번식성기,검측도최소임신개체각장위29.8 mm,체중위2.98 g,추단일주년적원정주방가능체도성성숙.근거원정주방생식세포적발육규률화려포적변화특점,성선발육분위생장기화성숙기、배방기、회복기:속다차산란류형.육인낭속외새형,배태재효질색중발육,구개유충성숙후,효질색소실성점액상,성숙구개유충부재신형성적점액사상배출체외.임신모방재수도자격후,역발생유산,제전배출효질색.번식기위2지7월,4、5、6월위번식고봉기,임신솔분별위80.43%、84.21%화78.05%.평균번식력위(183.72±6.43)천립/개,최대번식력위344.64천립/개,각장위54.5 mm;최소번식력위49.95천립/개,각장위29.8 mm.번식력여각장화체중현저상관.저사결과불부가이봉부담수방적생물학내용,야능위담수방보호화호박여하류적규범관리제공이론의거.
Freshwater mussels are one of the most widespread and imperiled groups of animals in the world, which play a major part in the functioning of many freshwater ecosystems, however, their populations declined continually during the 20th century. Unio douglasiae, one important specie of Unionidae, is widespread in lakes, rivers and impoundments, but little is know about its population structure and reproductive traits. Investigations on the population structure and reproductive traits of Unio douglasiae were carried out in Qinglan Lake from July, 2008 to July, 2009. From the view of population structure, the population tended to be stable and shell length of individuals was mainly from 40 mm to 65 mm in the population. The maximum length and the minimum length of individuals were 83.6 mm and 20.3 mm in the specimens. The sex ratio of natural population was found 1 : 1.20, the sex ratio of each month was in close agreement with the expected value of 1 : 1 by X~2 test. The minimum mature female with a shell length of 27.6 mm and weight of 2.62 g, and which of the male with a shell length of 27.9 mm and the weight of 2.21 g were found. The minimum preg-nancy individual was found with a shell length of 29.8 mm and weight of 2.98 g in examined specimens. We concluded that the female and male individuals matured at the age of 1 year. Taking the developmental characteristics gametes in follicles and features of follicles into account, the annual cycle of maturation for both male and female could be divided into the following three periods: (1) growth and maturation period, October to January of next year, (2) spawning period, February to June, (3) recovery period, August to September. The female in maturation could spawn several rounds in one reproduction cycle. Two pieces of outer gills of the female were used as marsupium. Embryo developed in the con-glutinates. In the development process of embryo, the colour of marsupium changed from ivory white to light red, then became cardinal red after matured. Mature glochidia on a mucous thread released from the water column. After stimu-lated by stressed condition, pregnancy mussels would release the superconglutinate. The breeding season lasted from February to July. The breeding peak period occurred from April to June, the pregnancy rates were 80.43%, 84.21% and 78.05% respectively. The average fecundity reached about (183.72+6.43)×10~3 embryo or glochidia. The maximum fe-cundity was 344.64×10~3 embryo or glochidia and the length of individual was 54.5 mm. The minimum fecundity was 49.95xl0~3 embryo or glochidia and the length of individual was 29.8 mm. Fecundity was related significantly to both length and weight. This study may provide more information related to basic biology and guidance for conservation of freshwater mussels and science-based management of rivers and lakes.