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题名: 洪湖和洞诞湖鲫生活史特性的比较研究
作者: 沈建忠
答辩日期: 2000
导师: 曹文宣
专业: 水生生物学
授予单位: 中国科学院水生生物研究所
授予地点: 中国科学院水生生物研究所
学位: 博士
摘要: 人类活动对鱼类生活环境和种群结构产生了巨大的影响,分析环境变迁和开发利用对鱼类生活史的影响,具有重要的理论和实践意义。洪湖和洞庭湖是两个环境有明显差异、受自然和人为影响程度不同的水体,生活于其中的鱼类必然产生与之相适应的生活史对策,以保持种群的繁衍。比较研究这两个湖泊中鱼类生活史特性的适应性变化,对种群资源管理有一定的指导作用。本研究选择适应力强、在天然渔业中占有重要地位的鲫作为研究对象,通过野外取样,观测种群结构、生长、性成熟年龄和个体大小、性比、繁殖投入等主要生活史特性,比较分析存在的差异、形成的原因及其适应意义,并通过室内饲养野外种群和F 1代的实验研究,进一步分析两湖鲫生活史特性差异形成的根本原因。为此,在l 998年1月至1 999年9月期间,于东洞庭湖的岳阳、六门闸和洪湖新闸、瓦沟子,逐月或隔月进行取样,共采集样本5620尾。并于1 998年1 2月将这两个湖泊的野外鲫种群置于室内相同条件下进行饲养实验,持续至1 999年5月。1 999年9月至2000年5月又对这两个湖泊鲫F1代进行了实验研究,实验设计方案为2个种群、2种饲料(饲料A,以豆粕为主要蛋白源,蛋白含量32.22%;饲料B,以鱼粉为主要蛋白源,蛋白含量40.41%)、3个重复组。本研究所得主要结果总结如下: 1.鳞片材料适于鉴定年龄结构简单、生长快的洞庭湖鲫种群,而对洪湖那样年龄结构复杂、生长缓慢的鲫种群,则4龄以下个体的年龄较为可靠,随年龄提高(5龄以后),误差增大,与耳石相比,存在低估高龄个体年龄的问题。 2.鲫星耳石和微耳石均可直接用于年龄鉴定,与耳石磨片年轮读数完全一致的达80%以上,对高龄个体误差也不超过1龄。经耳石边缘年轮形成时期分析,证实耳石上一年形成一个年轮。耳石上、特别是耳石磨片上年轮清晰易辨,鉴定高龄个体年龄依然可保持很高的精确度,用于鉴定洪湖鲫种群年龄,两观测者年轮读数总吻合率可达92.6%。表明耳石是一种优于鳞片的年龄鉴定材料,对年龄结构复杂、生长缓慢的鱼类应采用耳石鉴定年龄,以提高年龄鉴定的准确性和可比性。3.不同龄组耳石重量有显著差异,分析耳石重量可作为验证年龄鉴定准确性的辅助手段,特别在判别大小相似个体的年龄时,作用更为明显。4.洪湖鲫种群年龄结构较复杂,由8个龄组组成,3龄以上个体占25%左右;洞庭湖鲫种群年龄结构较为简单,一般由3个龄组组成,而且3龄个体所占比例不到5%。 5.根据耳石上年轮退算的各龄平均体长结果表明,洪湖鲫种群生长显著慢于洞庭湖鲫种群,其3、5龄的平均退算体长分别相当于洞庭湖1、2龄时的平均退算体长。两湖鲫种群生长的差异可能与捕捞、凶猛鱼类压力、饵料资源、沉水植被状况不同有关。 6.洪湖鲫1龄约70%达性成熟,2龄约94%成熟,3龄以上才完全达性成熟;洞庭湖鲫种群性成熟较洪湖鲫种群早,1龄几乎全部性成熟。洪湖鲫生长缓慢是性成熟年龄推迟的主要原因;洞庭湖鲫成鱼死亡率高,生长快,性成熟早是对环境压力的适应。 7.洪湖和洞庭湖鲫种群雌雄性比分别为1.46:1和1.5 0:1,两者无显著差异。这两个湖泊鲫性比都随体长而变,体长增加,雌雄性比提高。性比与年龄的关系,两湖鲫的表现不同,洪湖鲫O-2龄平均为1.34:1,3-8龄平均为2.1 4:1;洞庭湖鲫年龄结构简单,各龄组性比变化不大。性比存在季节变化,与繁殖活动有关。 8.洪湖和洞庭湖鲫在繁殖投入上差异显著,表现在洞庭湖鲫的成熟系数和个体繁殖力显著高于洪湖鲫。但Ⅳ期卵巢最大卵径的测量结果表明,洪湖鲫繁殖力下降并不伴随卵质下降,反而显示出卵子质量高于洞庭湖鲫的倾向。洞庭湖鲫繁殖投入高,是对种群高死亡率的适应,符合生活史理论预言。9.从比较繁殖力的结果来看,洪湖鲫2、3龄组对种群补充的作用最大,其次是4龄组,其它龄组作用相对较小;洞庭湖鲫2龄组对种群繁殖力的贡献最大,1龄组和3龄组接近,3龄组在繁殖群体中组成比例虽低,但对种群补充的作用不可低估。l O.野外种群室内实验结果表明,洪湖鲫种群生长与洞庭湖鲫无显著差异,但在繁殖投入上依然表现出显著的差异,因此,可初步认为野外两种群生长上表现出来的差异可能是由环境造成的,无遗传基础;繁殖投入上的差异可能有遗传基础,是对各自环境压力长期适应的基因型反应。11.在两种人工饲料喂养条件下,洪湖鲫F1代生长均快于洞庭湖鲫F 1代,但在繁殖投入上,显著低于洞庭湖鲫F 1代,进一步说明野外洪湖鲫种群与洞庭湖鲫生长的差异可能来自环境的影响,而繁殖投入上的差异可能是遗传因素引起的。在生长和繁殖的折衷约束中,洪湖种群生长优先于繁殖,洞庭湖种群则繁殖优先于生长。1 2.饲料质量对洪湖和洞庭湖鲫生长的影响均显著,用饲料A喂养,鲫生长显著慢于以饲料B喂养,生长效率也显著低些。饲料质量对繁殖投入的影响则两种群表现不一,洪湖鲫在两种饲料条件下,繁殖投入无显著差异,繁殖投入不随生长率提高而提高;洞庭湖鲫在饲料B喂养下,繁殖投入显著高于以饲料A喂养的,表现出繁殖投入随着生长率的提高而提高。
英文摘要: Human activities have profoundly affected the environments and population structures of fishes. It is of great significance in the theoretic researches and practical application to assess the effects of alternation of habitats and exploitation on fish life histories. Honghu Lake and Dongting Lake, two important fisheries waterbodies have remarkably different biotic and abiotic environments, as well as different natural and human influences, so the fishes in these lakes may evolve the life-history strategies to adapt to their environments. It is important for management of the fish population resources to comparatively study the adaptive variations in life-history traits of fishes in the two lakes. Crucian carp, Carassius cturatus, a dominant fish species both in Honghu Lake and Dongting Lake, was selected to detect the differences in some of important life-history traits, such as population structures, growth, age and size at maturity, sex-ratio, and reproductive investments etc. and to analyze the causes of the variations in life-history traits and their adaptive significance. Field observations were carried out during January 1998 to September 1999, with a total 5620 samples collected. Moreover, in a attempt to make an insight into the underlying causes, the crucian carp sampled from the two lakes were reared in 'common garden' between December 1998 and May 1999, and Fl generations with triplicates from the two populations were reared by feed A(soybean cakes used as the main resources of protein, 32.22% crude protein ) and feed B (fishmeal used as the main resources of protein, 40.41% crude protein) during September 1999 to May 2000. The main results and conclusions summarized as: (1) Scales were reliable for determining the ages of crucian carp in Dongting Lake which showed a faster growth and a relatively simple age structure. The annuli on the scales were obvious and could be read easily. The agreement between two readers and between scales and otoliths reached 90.5% and 91.7%, respectively. However, it was difficult to read annuli when the ages of fish is above 4 and the percent agreement between two readers, and between scales and otoliths for age estimations of population in Honghu Lake are only 50.9% and 56.6%, respectively. It is suggested that scales is not well suitable for age estimation in populations which have slow growth and relatively complex age structure because it underestimate the ages of older individuals.(2) The whole or sectioned lapillus and asteriscus both could be used for age determination of crucian carp. Agreement between whole and sections of otoliths were above 80%, and the errors were minor, less than one year. It is demonstrated that the annuli are formed once in one year, by analyzing the opaque zone at the edge. The annuli on the otolith, especially in sectioned ones are very clear and can be read easily, and the agreement between two readers reached 97% for the population in Dongting Lake and 92.6% for the population in Honghu Lake. It is suggested that otolith is better than scale for age determination, particularly in populations with complex age-structure and slower growth. (3) The otolith-weight among different age groups were significantly different and could be used for validating the accuracy of age determination. It is of great value in separating the ages of the individuals with similar body-length.(4) The population of crucian carp in Honghu Lake had relatively complex age-structure with eight age classes and the individuals older than three-year-old accounted for about 25%. The age-structure in Dongting Lake was simple, generally composed of three age classes, and the individuals of age 3 accounted for less than 5% It showed that the population of crucian carp in Dongting Lake was confronted with a higher adult mortality than in Honghu Lake, which might result from the differences in environments, fishing methods and fishing intensities.(5) The mean back-calculated body-length-at-age, based on otolith, showed that the growth of crucian carp in Honghu Lake was significantly slower than in Dongting Lake. The back-calculated body-length at age 3 and age 5 in Honghu Lake were similar to that at age 1 and age 2, respectively, in Dongting Lake. The differences in growth rate between the two populations might be attributed to the different fishing and predation pressures, forage resources and aquatic macrophytes abundance.(6) In Honghu Lake, about 70% females reached maturity at age 1, 94% at age 2 and 100% at age 3. while nearly all the females in Dongting Lake matured at age 1. It might be related to variation in growth and different environmental pressures.(7) The sex-ratio of crucian carp was 1.46:1 in Honghu Lake and 1.50:1 in Dongting Lake, with no significant difference. The sex-ratio was length-dependent in both populations and would increase with the body-length. The sex-ratio in Honghu Lake was age-dependent, and the average of the sex-ratio for age 0 to age 2 was 1.34:1 and 2.14:1 for age 3 to age 8, the sex-ratio in Dongting Lake showed little variation among age groups. The sex-ratio also changed seasonally in relation to reproductive activities.(8) The reproductive investments, indicated by gonadosomatic index and fecundity, for crucian carp in Honghu Lake was significantly lower than in Dongting Lake. However, cmcian carp in Honghu Lake showed a tendency to produce relatively larger eggs than in Dongting Lake, based on measurements of the egg diameter in the ovary at stage IV . The higher reproductive investments in Dongting Lake was a adaptation to relatively higher adult mortality, which is in agreement with the life-history theory prediction.(9) Based on the comparative spawning power, the individuals of age 2 and age 3 made greatest contribution to the recruitment, age 4 the second, the other age groups relatively low in Honghu Lake. Meanwhile, age 2 played a most important role in the recruitment, age 1 and age 3 are nearly the same. The contribution to the recruitment can't be underestimated although the individuals of age 3 had the lowest percentage in the spawning stock in Dongting Lake,(10) The experimental results under indoor 'common garden' condition showed that there were no significant differences in growth, but significant differences in reproductive investments between the populations from Honghu Lake and Dongting Lake. It was suggested that the differences in growth between the two populations in the field might be caused by environmental factors, not by genetic factor, but the differences in reproductive investments might be genetically-controlled (11)The Fl crucian carp from the population in Honghu Lake displayed a significantly higher growth rate, but lower reproductive investments than that from the population in Dongting Lake, either fed by feed A or feed B. The results support the preliminary conclusions of the previous experiment. The population from Honghu Lake exhibited growth priority over reproduction, but the reverse in Dongting Lake.(12)The feed quality affect the growth of Fl crucian carp from the two populations. The groups fed by feed A displayed a lower growth rate and growth efficiency than that by feed B. However, the two populations showed a remarkably different response to the feed quality in the reproductive investments. Fl from Honghu Lake displayed no significant differences either fed by feed A or feed B, but Fl from Dongting Lake displayed significant differences between two feeds, the higher investments in the groups fed by feed B were observed.
语种: 中文
内容类型: 学位论文
URI标识: http://ir.ihb.ac.cn/handle/342005/12538
Appears in Collections:中科院水生所知识产出(2009年前)_学位论文

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洪湖和洞诞湖鲫生活史特性的比较研究.沈建忠[d].中国科学院水生生物研究所,2000.20-25
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