金沙江攀枝花江段白缘(鱼央)的繁殖生物学

为丰富白缘(鱼央)Liobagrus marginatus(Günther)的基础生物学资料,于金沙江攀枝花江段收集到729尾性腺可辨的样本,分析其年龄结构、性别比、初次性成熟个体大小以及繁殖力等繁殖生物学特征。结果表明:繁殖群体由1~4龄4个年龄组组成,其中2龄个体在数量上占绝对优势(63.83%),其对种群繁殖力的贡献为62.07%。在性成熟个体中,雌性和雄性分别为64尾和77尾,雌雄比=1∶1.20;符合1∶1理论比值(χ~2=1.199,P0.05);雌、雄最小性成熟个体体长分别为66.80 mm、67.32 mm,体质量分别为5.7 g、6.7 g。攀枝花江段白缘(鱼央)的繁殖季节为3—6月,绝对繁殖力平均值为161.2粒±55.1粒。Ⅳ期卵巢中卵子发育不完全同步,卵径变幅为0.29~3.86 mm。金沙江攀枝花江段白缘性成熟快,但繁殖力低,繁殖群体主要由低龄个体组成,种群资源亟需保护。     

乐山棒花鱼形态特征的两性异形和雌性个体生育力

测定了乐山棒花鱼(Abbottina kiatingensis)繁殖期形态特征包括体长、头长、头宽、头高、吻长、眼后头长、眼径、眼间距、体高、尾柄长、尾柄高、尾鳍长、背鳍基前距、背鳍基长、腹鳍基前距、腹臀间距、体重和去内脏体重的两性异形和雌性个体生育力。繁殖期雄性个体的数量显著多于雌性个体,雌雄两性个体的体长差异不显著。特定体长的雌性个体的头长、头宽、头高、吻长、眼后头长、尾柄高、背鳍基前距、背鳍基长和去内脏体重显著小于雄性个体,其余指标不存在明显的差异。回归分析表明,乐山棒花鱼的怀卵数量与体长和体重回归关系显著,雌性通过个体大小(体长和体重)的增加来提高个体生育力。     

棒花鱼形态特征的两性异形和雌性个体生育力

测定了棒花鱼(Abbottina rivularis)繁殖期形态特征包括体长、头长、头宽、头高、眼间距、鼻间距、背鳍基长、胸鳍长、胸鳍腹鳍间距、尾柄长、尾鳍长和体重的两性异形和雌性个体生育力。结果表明,雄性个体的数量显著多于雌性个体,雄性个体的体长显著大于雌性个体。特定体长的雌性个体的胸鳍腹鳍间距显著大于雄性个体,头长、头宽、头高、眼间距、鼻间距、背鳍基长、胸鳍长、尾柄长和尾鳍长显著小于雄性个体,雌雄两性体重不存在显著差异。棒花鱼的怀卵数量与体长和体重回归关系显著。偏相关分析显示,当控制第三者恒定时,怀卵数量与体长和体重呈正相关但不显著。棒花鱼存在个体大小和其他局部特征显著的两性异形,雌性个体主要通过腹腔容积的增加提高个体生育力。棒花鱼形态特征的两性异形是性选择和生育力选择共同作用的结果。     

鳇亚科棒花鱼属鱼类的分类与系统发育关系

逗亚科棒花鱼属鱼类的分类与系统发育关系尚未解决。研究选择线粒体Cyt b基因和核基因RAG1、MLH3及MSH6作为分子标记, 重建了棒花鱼属鱼类的系统发育关系, 并结合形态证据对该属鱼类进行了分类厘定。结果表明: 棒花鱼与钝吻棒花鱼是单系种。拉林棒花鱼与辽宁棒花鱼是并系种, 一起形成单系群。拉林棒花鱼+辽宁棒花鱼一起嵌套在小鳔逗属鱼类内部, 钝吻棒花鱼嵌套在片唇逗属鱼类内部。拉林棒花鱼+辽宁棒花鱼+钝吻棒花鱼+片唇逗属+胡逗属+小鳔逗属+琵琶逗属鱼类组成单系群, 它们一起与棒花鱼形成姊妹群关系。可量性状与可数性状均不能区分拉林棒花鱼和辽宁棒花鱼。结合系统发育关系与形态证据, 棒花鱼属鱼类的分类厘定如下: 棒花鱼属鱼类包括棒花鱼和平江棒花鱼(未取样); 辽宁棒花鱼是拉林棒花鱼的同物异名, 后者的分类位置有待进一步校订; 钝吻棒花鱼校订为钝吻片唇逗。     

梁子湖鲤鱼的生物学

鲤鱼Cyprinus carpio Linnasus是我国重要的经济鱼类,在淡水渔业产量上一向占很大的比重。根据梁子湖的渔业情况,它约占梁子湖鱼产量的40％;就全国范围来讲,其经济价值之大,可以想见。但是关于鲤鱼在我国天然水体中的生长情况,生活习性等问题,过去研究得很少,因此,1955年2月至1956年3月我们在梁子湖进行了鲤鱼的生态调查,     

金沙江中下游圆口铜鱼的繁殖生物学

根据2013—2014在皎平渡圆口铜鱼产卵场的定点亲鱼收集(n=206)和2006—2014年在金沙江中下游金安桥至巧家干流江段的流动亲鱼采集(n=70), 对圆口铜鱼的繁殖生物学进行了初步研究。定点亲鱼收集的结果显示: 圆口铜鱼雌性最小性成熟个体全长330 mm, 体质量441.0 g, 年龄4龄; 雄性最小性成熟个体全长352 mm, 体质量396.6 g, 年龄3龄; 50%个体达到性成熟的年龄和全长分别为雌性4.32龄 406 mm, 雄性4.44龄 412 mm; 繁殖群体雌雄性比为1.37﹕1, 繁殖群体中雌性年龄为4—7龄, 雄性年龄为3—7龄; 雌雄个体的性成熟系数平均值均以6龄个体最高, 分别为10.55%和3.45%; 平均卵径为0.16 cm, 卵径分布呈双峰型。定点和流动亲鱼收集的雌性性成熟个体的结果表明: 圆口铜鱼绝对繁殖力变动范围为4055—137900粒/尾, 平均值为22817粒/尾; 相对繁殖力变动范围为5—73粒/g, 平均值为20粒/g, 75.68%个体的绝对繁殖力在10000—30000粒/尾之间, 70.27%个体的相对繁殖力在15—20粒/g之间; 绝对繁殖力和相对繁殖力均随着体长和体质量的增加而增加, 其中全长、体质量与绝对繁殖力呈指数分布函数正相关, 而与相对繁殖力呈二次项函数正相关。研究结果可为长江流域圆口铜鱼资源的保护提供重要的基础数据支撑。     

生长液浓度对ZnO纳米棒水浴生长的影响

以预制的ZnO晶种层为基底,采用化学溶液生长法,在不同生长液浓度(Zn2+)条件下生长ZnO纳米棒,对制备得到的ZnO纳米棒的结构和微观形貌进行XRD和SEM表征,分析水浴生长法的生长液浓度(Zn2+)对ZnO纳米棒的影响机理,发现在生长液浓度(Zn2+)为0.05mol·L-1时生长得到的ZnO纳米阵列空间取向最优。     

棒络新妇生物学特性研究初报

棒络新妇１年一代，以卵在树干，叶片内越冬。卵期１９９－２２０天，４月下旬孵化。幼蛛八龄，８月中旬成熟，９月中旬产卵。幼蛛生活历期１２１．１天，成蛛寿命４７－６２天，雌雄比６：１。成蛛日食量０．７７３７克，是一些害虫的重要天敌。该蛛发生与气候，海拔高度，天敌等关系密切。采取封山林，禁止在林内使用化学农药，移动卵块庳大繁殖。     

四湖总干渠环境雌激素不同浓度江段鱼繁殖生物学比较研究

选取湖北四湖总干渠污染水平不同的3个江段(A、B、C), A离源头较近, B位于一农药厂排污口下方, C位于一城镇居民排污口下方, 比较鱼繁殖群体的生物学特征。A江段水体中未检测出环境雌激素, 而B、C两江段主要含有壬基酚和双酚A, 两种污染物总浓度在20 μg/L左右。与A江段相比, B、C江段鱼繁殖群体中雌性个体的比例明显较高, 卵粒较小; 雄性个体精巢组织间隙增大, 精原细胞和精子细胞密度低; 肝体指数增大、肝组织出现大量空泡, 肝细胞密度降低等特点。壬基酚和双酚A已被证明具有显著的雌激素活性和生殖毒性。因此, B、C江段壬基酚和双酚A环境雌激素浓度较高可能是导致鱼繁殖群体生物学特征改变的重要原因。     

Biology of the Galapagos shark,Carcharhinus galapagensis, in Hawai'i

Synopsis Catch records from the Hawai'i Cooperative Shark Research and Control Program, which operated in Hawai'i from 1967–1969, were examined and data on the Galapagos shark,Carcharhinus galapagensis were analyzed. A total of 304 Galapagos sharks was caught, predominantly with longlines. More female sharks were caught than males, and the catch was skewed geographically. On the island of O'ahu the highest catch rates occurred along the north and south coasts. High catch rates also occurred near points of land, where longshore currents converge. Average depth of capture was greater for juveniles (45.1 m) and mature males (60.2 m), than for subadults (38.8 m) and mature female sharks (34.2 m). Males appear to reach maturity between 205 and 239 cm total length, and females between 215 and 245 cm. Litter size ranged from 4 to 16 pups, with an average of 8.7. In Hawaiian waters Galapagos sharks are born at just over 80 cm total length. Mating and parturition apparently occur early in the year, and gestation is estimated to be about 12 months. Stomach contents consisted mainly of teleosts and benthic prey, and ontogenetic changes in diet occurred as sharks increased in size. Sharks consumed a smaller proportion of teleosts and more elasmobranchs with increasing size. Dietary diversity also increased with increasing size of shark.     

Conservation genomics in the fight to help the recovery of the critically endangered Siamese crocodile Crocodylus siamensis

Endangered species are often characterized by low genetic diversity and it is imperative for conservation efforts to incorporate the knowledge obtained from genetic studies for effective management. However, despite the promise of technological advances in sequencing, application of genome‐wide data to endangered populations remains uncommon. In the present study we pursued a holistic conservation‐genomic approach to inform a field‐based management programme of a Critically Endangered species, the Siamese crocodile Crocodylus siamensis. Using thousands of single nucleotide polymorphisms from throughout the genome, we revealed signals of introgression from two other crocodile species within our sample of both wild and captive‐bred Siamese crocodiles from Cambodia. Our genetic screening of the Siamese crocodiles resulted in the subsequent re‐introduction of 12 individuals into the wild as well as the selection of four individuals for captive breeding programmes. Comparison of intraspecific genetic diversity revealed an alarmingly low contemporary effective population size in the wild (<50) with evidence of a recent bottleneck around Tonle Sap Lake. We also projected a probable future extinction in the wild (within fewer than five generations) in this population in the absence of re‐introduction efforts. However, an increase in the number of potential breeders through re‐introductions, including the one resulting from this project, could counter this trend. Our results have been implemented in ongoing re‐introduction and captive breeding programmes, with major implications for the conservation management of Siamese crocodiles, and provide a blueprint for the rescue effort of other “terminally ill” populations of critically endangered species.     

The effects of stimulus type on consistency of responses to conflicting stimuli in Siamese fighting fish

Individuals must often decide among a range of behavioral responses in a given situation and individuals will likely vary from one another in the choices they make. A rarely explored example of this is when both a male and a female are present simultaneously and a male must decide to fight or court. Consistent individual differences have been found in decision-making in Siamese fighting fish; however, dummies were used to explore this question and it is possible that individuals respond differently in this situation when faced with live stimuli as a result of feedback. Therefore, this study investigated whether males behave similarly to dummy and live stimuli by exposing them to male and female conspecifics both simultaneously and separately. Subjects were tested first with dummies and then in the same situations using live conspecifics. It was hypothesized that males would respond in the same manner to both the dummy and live fish. The results indicated that individuals behaved similarly to the dummy fish and the live fish in corresponding conditions. In addition, repeatability levels suggest that individuals behaved similarly across trials of a given treatment type while differing from one another in their responses. This study demonstrates that males are consistent in their responses even when receiving feedback from conspecifics and supports the continued use of dummy stimuli as an effective tool.     

Ecological studies on the population of isaza,Chaenogobius Isaza Tanaka,in Lake Biwa,with special reference to the effects of population density upon its growth

1. In order to get the knowledge on the age composition of “isaza” population in Lake Biwa and the effect of population density on growth, monthly distribution of mean body length and mean body weight has been analyzed on the basis of monthly haul by “isazabiki” trawl during 1949 to 1953 and also 1960 to 1965.
2. There is no apparent sex difference in the growth in the first and second years of life.
3. “Isaza” population is composed of two age groups, age 0 and 1 groups (1+fish), the latter occupying by far the greater part in commercial catch.
4. During the growth season fishes of both ages feed mainly on zooplankton, though in winter frequently take chironomid larvae, gammaridae and others in volume.
5. The growth season falls in the period from April to October in both age groups.
6. A considerable yearly variation occurring in growth is in close connection with the fluctuation of population density of all ages.
7. The influence affected by the density of age 1 group is larger than that by age 0 group.

     

Parameters of rewards on choice behavior in Siamese fighting fish (Betta splendens)

Five experiments were conducted with Siamese fighting fish (Betta splendens) to investigate how choices in a T-maze were affected by parameters of a social reward (aggression display to another male): presence or absence, amount, delay and distance traveled. Bettas showed a preference for the side associated with the presence of another male rather than the side associated with nothing (Exp 1), a greater length of time of the reward (Exp 2) and shorter delay (Exp 3). The animals were indifferent when one side offered a longer delay to a longer reward time compared with a shorter delay to a shorter reward time (Exp 4). What was most surprising, however, was that fish preferred to choose the side that was associated with swimming a greater distance to reach an opponent male (Exp 5). These experiments demonstrate that, while some parameters of a visual reward affect behavior in predicable ways (greater amount, shorter delay), the complex motivations underlying inter-male aggression can produce what appear to be paradoxical results.     

Quantification of catch composition in fisheries: A methodology and its application to compare biodegradable and nylon gillnets

When evaluating fishing gear catches, the focus is often on a few species as opposed to the entire catch. In some fisheries this can lead to ignoring major part of catch composition. Thus, there is a need for a more holistic approach when evaluating the ecological impact of using a specific fishing gear and when comparing two or more gears. In this context, it is relevant to have a method that describes the total catch and quantifies proportions of the catch being wanted and unwanted. In this study, we outline such a method and demonstrate its applicability to catch data from a small-scale coastal gillnet fishery targeting European plaice (Pleuronectes platessa, Linnaeus, 1758) by comparing catch composition when using nylon and biodegradable gillnets. The results showed no significant differences in catch composition between gillnets made of the two materials. Therefore, the catch composition obtained using the more environmentally friendly biodegradable materials does not represent a barrier in this specific gillnet fishery. However, species selectivity of gillnets is still of concern as the primary target species constituted only half of the total catch composition in numbers while the rest was unwanted catch. The presented approach for quantifying and inferring the differences in catch composition can be further applied for assessing the performance of different fishing gears and their modifications.     

据于矢耳石Sr/Ca值的长江日本鳗鲡迁移格局多样性分析(英文)

长江口是中国日本鳗鳗苗的主要产区和仅存的成鳗渔业水域。日本鳗自长江河口至上游金沙江近3000km干流及许多支流中都有分布,但其迁移行为却不为人了解。该文分析了2008年9～11月采自长江靖江段(31o30′N,120o42′E)的153尾银色鳗样本的生物学特征,测定了其中27尾标本的矢耳石Sr/Ca值。结果显示,153尾样本中有雌性85尾、雄性68尾,雌雄性比1:0.8。雌性由3～7(平均5.52)龄组成,平均体长(669±80)mm,体重(555±229)g,丰满度1.77±0.22,性腺指数(GSI)1.32±0.31。雄性由3～5(平均4.38)龄组成,平均体长(518±51)mm,体重(234±76)g,丰满度1.62±0.18,GSI0.21±0.11。雌性的这些生物学参数均显著大于雄性(P<0.05)。依据矢耳石线鳗标志轮平均Sr/Ca值(7.99±1.05)×10-3进行判断,有17尾(即62.96%个体)为"淡水型",10尾(即37.04%个体)为"河口型"。16尾雌性中有13尾(即81.25%)为"淡水型",3尾为"河口型"。11尾雄性中仅36.36%为"淡水型",63.64%为"河口型"。对每个生长层组的Sr/Ca值分析表明,雌雄间2龄时无显著差异,但3龄、4龄和洄游龄组都有显著或极显著的差异,预示着2龄时两者的栖息水域比较一致,但后来出现了明显栖息地分化。     

Biology of the western pygmy perch,Edelia vittata,and comparisons with two other teleost species endemic to south-western Australia

Synopsis This paper provides data on the movements, spawning times and localities, size and age composition, growth and diet of the western pygmy perch,Edelia vittata, in a south-western Australian river. The results of this study are compared with those recorded previously for two other locally endemic species (Galaxias occidentalis andBostockia porosa) to ascertain the extent to which these three species utilise the same resources, and whether they are similarly adapted to the highly seasonal flow regime. A total of 3396Edelia vittata was collected with a 3 mm mesh seine net from the Collie River in south-western Australia at 3–6 week intervals over a period of 26 months. During the winter, fish moved from the river into either adjacent flood waters or tributary creeks. The trends shown by gonadosomatic indices, oocyte growth and prevalence of post-ovulatory follicles, demonstrate that spawning takes place between late winter and late spring (July–November). Sexual maturity was attained by both sexes at the end of the first year of life. Although 99% of the fish belonged to the 0+, 1+ and 2+ age classes, representatives of the 3+, 4+ and 5+ age classes were also caught. The respective von Bertalanffy growth curve parameters for L, K and t₀ were 54.9, 1.178 and -0.210 for males and 57.9, 1.124 and -0.198 for females. At the end of the first and second years of life, the lengths predicted from the von Bertalanffy growth equations were 42 mm ( 0.8 g) and 51 mm ( 1.4 g) for males and 43 mm ( 0.9 g) and 53 mm ( 1.6 g) for females. The diet consisted of a wide range of small benthic invertebrates, especially dipteran larvae, ostracods and cyclopoid copepods. The peak time, duration and predominant locality of spawning, the time of day when maximum activity occurs and the diet ofEdelia vittata differs from those previously recorded forGalaxias occidentalis andBostockia porosa. These differences would be likely to minimize any potential competition amongst these three species. The growth rates, age at first sexual maturity and pattern of oocyte development also differ amongst the three species.     

Faunal utilization of constructed intertidal oyster (Crassostrea rivularis) reef in the Yangtze River estuary,China

An intertidal oyster reef (～260 ha) was created by planting hatchery-reared seed oysters (Crassostrea rivularis) on an artificial concrete modular reef in the Deepwater Navigation Channel Regulation Project of the Yangtze River estuary. We examined the development of reef communities (oyster, barnacle and motile epibenthic macrofauna), characterized nekton use and assessed the habitat value of the constructed reef. The C. rivularis oyster population showed a rapid exponential increase with time and reached maximum density (3410 ± 241 ind./m²) and biomass (3175 ± 532 g/m²) after one year of restoration. The barnacle Balanus albicostatus was the most abundant sessile macrofauna and had a significantly greater density in the high intertidal zone than in the low intertidal zone (P < 0.05). The reef also supported diverse motile epibenthic macrofauna (11 mollusks, 11 crustaceans, 4 annelids and 2 fishes), and the reef-associated communities were numerically dominated by Neanthes japonica, Perinereis aibuhitensis, Nerita yoldi and Littorinopsis intermedia. A total of 50 nekton species (31 fishes, 9 shrimps and 10 crabs) utilized the constructed intertidal oyster reef, and grass shrimp Palaemon spp. dominated the nekton communities in term of abundance. Since the constructed intertidal oyster reef supports a variety of reef communities and abundant nektons, it should be recognized as an important and protective fish habitat in the Yangtze River estuary.