四川地区的鱼怪及其生殖特性的研究

本文对鱼怪(Ichthyoxenus japonensis)在四川的分布和生殖特性作了调查研究。材料于1980—1984年收集,共研究了2,100余个标本。 1.在四川主要分布于盆周丘陵地区,呈环形分布,如图1所示。 2.个体抱卵量的变化列示如图3—5。个体相对抱卵量的变化范围在13—22之间,平均为20粒。 个体抱卵量与体长呈指数函数关系,其关系式:R=5.5475L~(1·4583)(r=0.9584);其与体宽的回归方程式:R=32.805X-32.430(r=0.9327)。 3.育卵囊内抱卵量的多少随雌体的大小而有差异,较大的雌体抱卵量较多(曾发现最大雌体长22.5毫米,抱卵599个),还没有发现抱卵量随体长增长而减少的情况。 4.还对个体抱卵量变动与成长指标的关系及其所反映的种群生物学特性问题进行了讨论。     

杭州湾北部安氏白虾的繁殖生物学特征

采用2017年4月至2018年3月张网逐月采样数据分析杭州湾北部安氏白虾（Palaemon annandalei）的繁殖生物学特征。结果显示,安氏白虾体平均体长（32.0 ± 5.4）mm（14 ~ 51 mm,n = 3 210）,抱卵群体平均体长（36.3 ± 3.4）mm（27 ~ 51 mm,n = 375）。体重分布范围为0.016 ~ 1.700 g,n = 3 210,平均体重（0.565 ± 0.282）g,抱卵群体体重分布范围为0.400 ~ 1.700 g,n = 375,平均体重（0.868 ± 0.225）g。雌、雄个体间平均体长和平均体重都具有显著性差异（P < 0.01）;雌雄性比为1.27︰1,雌性个体数显著多于雄性个体数（P < 0.01）。繁殖期从4月下旬一直持续至10月下旬,6月和8月为两个繁殖旺期,抱卵率（B）和性比（S）具有显著线性相关关系（P < 0.05）,关系式为B = 41.80S﹣21.06（R2 = 73.9）。绝对繁殖力为17 ~ 179粒,平均绝对繁殖力（60 ± 26）粒,平均相对繁殖力（70 ± 24）粒/g,n = 375。绝对繁殖力（FA,单位粒）与体长（L,单位mm）、体重（W,单位g）均呈二次函数显著相关（P < 0.01）,关系式分别为FA = 0.29L2﹣18.52L + 342.67（R2 = 76.8）和FA = 97.32W2 ﹣100.75W + 71.66（R2 = 94.5）。卵长径分布范围为1.090 ~ 2.688 mm,平均长径（1.599 ± 0.158）mm,短径分布范围0.807 ~ 1.992 mm,平均短径（1.141 ± 0.118）mm,n = 2 787。研究表明,与20世纪80年代相比,安氏白虾个体朝小型化方向发展,繁殖周期延长,繁殖旺期由单峰型变为双峰型,这可能是生态环境持续恶化和高强度捕捞压力所致。     

三峡水库秀丽白虾生长与繁殖生物学特征研究

2012 年11 月至2013 年10 月逐月对三峡水库木洞江段秀丽白虾的生长和繁殖生物学特征进行了研究。结果显示秀丽白虾是一年生的虾类, 寿命为1214 个月。雌性个体的平均体长(37.727.92) mm 显著大于雄性(37.086.59) mm, 具有明显的雌雄异形现象。秀丽白虾的渐近体长(L)为59.33 mm, 生长系数(K)是1.6/年, 生长方程为:Lt=59.33-e-1.6(t+0.081)。雌虾繁殖季节从4 月上旬持续至9 月下旬, 繁殖高峰期为4 月中旬至6 月中旬, 由越冬虾和当年虾两个世代的繁殖群体组成。抱卵雌虾的体长为27.0753.71 mm, 平均体长(L50)为37.06 mm。雌雄性比月变化为1.112.36, 平均为1.46, 群体中雌性个体数量显著多于雄性(P 0.001)。绝对繁殖力(FA)为31294 粒, 相对繁殖力(FR)为(11522)粒/g。绝对繁殖力与体长呈幂函数关系(FA=0.0031L2.8632, r=0.72, n=106), 而与体重呈直线关系(FA=104.63W+9.9534, r=0.79, n=106)。卵径(D)平均值为(1215102) m。为合理保护和利用三峡水库秀丽白虾种群资源, 建议加强虾类捕捞管理, 繁殖期间(49 月)禁止捕捞虾类或限制捕捞强度。       

鳗鲡(Anguilla japonica Temminck Schlegel)繁殖生物学研究——Ⅰ.下海鳗鲡雌雄性状差异和鉴别

通过比较鳗鲡的眼径、眼间距、吻形等外部特征能比较可靠地鉴别雌雄两性。这些形态上的测量数据经“判别函数”的计算,确定了两性之间的差别。运用形态上的差异鉴别400—600毫米体长组的雌雄鳗,准确率可达到90%。座标图表明体长的分布自然地区分为雌雄鳗,体长在600毫米以上者全为雌鳗,体长400毫米以下者全为雄鳗。雌雄两性体长和体重关系为W=0.0000001285L3.015。体长400—600毫米的鳗鲡的体长和体重的直线回归系数(b)依性别而有所不同。雄鳗为0.887(W=0.887L-280.20);雌鳗为1.150(W=1.150L-376.73)。雄性肥满度为1.15±0.052,雌性为1.42±0.053,以上两对数值在两性间都存在显著差异。       

巢湖安氏异钩虾生物学的初步研究

巢湖越年的安氏异钩虾交配季节为2—4月,水温10—18℃。从交配产卵至幼体孵出,需10天左右时间。雌性抱卵30—110枚,平均75枚,能重复产卵。在繁殖期间两性长时间抱对。 在实验室培养条件下,春季最早孵出的幼体,每经一次蜕皮,体长约增长0.5毫米,自3月下旬至5月上旬,蜕皮次数多,生长快,比较巢湖自然状态下与实验室培养条件下,幼体增长的速度,前者略高于后者。     

鸭绿江细鳞鱼的生物学

细鳞鱼是鸭绿江的重要经济鱼类。幽门垂数、鳃耙数及侧线鳞数与国内其他产地相比呈现明显交叉。支流十三道沟河口以上的5公里江段为主要产卵场。产卵期为4—5月,盛期4月末。成熟个体多数4龄,最小成熟雌鱼体长309毫米。体长285—438毫米,体重315—1098克的个体绝对怀卵量1629至3119(平均2194),与体长L的关系式N=9.54924 L-1297.3246,与体重W的关系式N=2.2207W 641.6345。卵径3.5—4.0毫米。水温5.3—9.0℃时,受精后625小时孵出。用鳞片测定年龄及生长。3龄鱼体长可达356毫米,5龄鱼体长一般为389毫米。体长与体重的关系式W_(?)=0.002486L~(2.9146),W_♀=0.004509L~(2.8978)。     

水丰水库的池沼公鱼生物学

本文报道了1942年横断鸭绿江而成的水丰水库的池沼公鱼生物学,内容包括性状变异、年龄和生长、食性、繁殖、群体结构、群体消长变化及渔业利用。水丰水库的池沼公鱼一龄体长(到尾叉的体长,后同)74毫米,体重3克;二龄体长99毫米,体重6.5克。体长体重关系式:logW=2.5306logL-1.7590。主要以浮游动物为食,但不同栖息地点食物组成有明显差异。一龄即达性成熟;性比为1♀:1.24♂;个体繁殖力905—19051粒,平均4330粒;个体繁殖力Y(百粒鱼卵)与体长L(厘米)的相关方程式为Y=58.4860L-402.7606;群体增殖速度(Vp)等于1494;4至5月在水库岸边产卵,卵粘性,水温10—15℃,约经12天孵出仔鱼。群体由1—3龄3个龄组组成,1321尾标本的平均年龄为1.15;65.1—80毫米体长组的个体为主要渔获对象,占整个渔获的65.5%。池沼公鱼是目前水丰水库第一位的经济鱼类,1982年鱼产量120万斤,占总鱼产的57.8%。       

雷山髭蟾繁殖生态初步研究

2014年10月—2016年6月,采用野外定点观察的方法系统观察雷山髭蟾Vibrissaphora leishanensis的繁殖生态习性。研究表明:雷山髭蟾求偶、交配、产卵均在水体中进行;繁殖期在每年的9月底至12月底,11月中旬最集中;雄性的体长和体质量均显著大于雌性;繁殖行为包括筑"巢"、鸣叫求偶、抱对、产卵,雄蟾单个鸣叫,抱对时雄蟾主动。有共用一个"巢"穴抱对产卵的习性和集群产卵的行为。卵群直径65.13~100.47 mm,平均77.73 mm±9.47 mm(n=54);窝卵数162~394粒,平均226.79粒±7.89粒(n=54);卵径2.06~5.18 mm,平均3.82 mm±0.91 mm(n=270);孵化期为107~157 d,平均127.71 d±7.38 d(n=54)。     

东海哈氏仿对虾的数量分布和生长特性研究

根据1986－1990年和1997－2001年对东海26°00′－ 33°00′N,127°00′E以西海域拖虾调查资料,共测定哈氏仿对虾样品9468尾,对哈氏仿对虾的数量分布和生长特性进行研究。结果表明,东海哈氏仿对虾的平均渔获率为458.7/g•h,其中31°00′－ 33°00′N海域最高,达到990.9/g•h,高峰期出现在秋季。主要分布在20－60m水深海域,适温范围10－24℃,适盐范围30－34,为广温广盐性虾类。周年雌虾明显多于雄虾,雌雄性比为1：0.62。雌虾个体也大于雄虾,雌虾周年平均体长和平均体重分别为71.6mm,5.0g;雄虾为57.9mm,2.3g,最大值出现在5－7月,最小值出现在9－10月。繁殖期5－9月,繁殖盛期6－7月。周年出现两次快速生长期,第一次在10-12月,其相对增长率雌虾为9.3%－17.5%,雄虾为7.9%－13.9%,第二次在翌年4－7月,雌、雄虾的相对增长率分别为4.3%－13.8%和6.2%。为合理利用该资源,宜在捕捞群体平均体长、平均体重最小值出现阶段进行保护,以提高其经济效益和生态效益。     

长江口脊尾白虾繁殖生物学

2014年11月至2015年10月对长江口脊尾白虾(Exopalaemon carinicauda)繁殖生物学进行了研究。结果表明:长江口脊尾白虾体长在25~75 mm,优势体长范围为35~55mm,平均体长(48±9)mm;周年间月性比变化介于0.89~1.63,年平均性比为1.12±0.22,卡方检验雌雄数量差异不显著;长江口脊尾白虾繁殖期在3—10月,繁殖高峰期在5—8月;5—6月繁殖群体以越年虾为主,7月繁殖群体以当年虾为主;个体绝对生殖力(F)在660~8000粒,与体长(L)呈直线相关,F=68.86L-2072(R2=0.498);个体绝对生殖力与体重(W)也呈直线相关,F=318.5W+267.0(R~2=0.504)。     

罗氏沼虾繁殖行为的再描述

2007年6～9月对采自孟加拉国库尔纳专区羌纳县布苏尔河原产地罗氏沼虾(Macrobrachium rosenbergii)的繁殖行为进行了观察研究。配合摄像机录像技术,重点观察并记录了野生罗氏沼虾生殖过程中的主要行为特征。本文所涉及的繁殖过程特指在人工操控条件下,自两性遭遇、识别至雌虾抱卵为止这段时间。选择体重在80.0g以上的雄虾、40.0g以上的雌虾分别在当地河堤外侧的池沼中驯化适应15d,然后,在室内水泥池中观察其繁殖行为。罗氏沼虾在繁殖过程中呈现的典型行为主要有:两性遭遇及识别,雄虾的占位,雌虾的蜕壳,雄虾俘获雌虾及其交媾前的守卫、交媾及精荚传递,雄虾交媾后的守卫及释放雌虾,雌虾产卵及抱卵。其中,雄虾的配偶守卫行为是有效地保证两性生殖成功的交配策略之一。     

A Parental Care-Mating Dilemma? Potential Risks for Offspring in the Pholcid Spider When Egg-Carrying Females Accept Mating

Many species face a trade-off between additional mating opportunities and the offspring benefits (viability, quality) provided by parental care. Female Holocnemus pluchei spiders must abandon their egg-sac, which they otherwise carry with their chelicerae, to copulate. This may involve risks for the offspring, such as predation and fungal infection. We assessed whether (1) males discriminate between egg-carrying females according to the egg development stage, (2) females are influenced by the egg development stage in regard to their proneness to mate, and (3) offspring are less likely to survive, due to high humidity and/or predation, in the absence of egg-carrying females. Apparently, males did not distinguish between females according to the developmental stage of the eggs they carried. However, females were more likely to mate when carrying relatively mature versus immature eggs (14–18 days and 3–6 days post-oviposition, respectively). All egg-sacs hatched successfully when guarded by egg-carrying females because this avoided both fungal infections (at high humidity) and cannibalism by conspecific spiders. Thus, H. pluchei females may face a trade-off between mating and parental care. Further research should clarify why egg-carrying females mate and how females prevent their egg-sacs from being infected by fungi.     

Hatching responses of subsocial spitting spiders to predation risk

The carrying of eggs often renders parents vulnerable to predators due to increased conspicuousness or decreased mobility. Nonetheless, egg-carrying parents can escape from the predators to which they are vulnerable. Previous studies have demonstrated heavy predation by spider-eating jumping spiders (Portia labiata) on egg-carrying spitting spider (Scytodes pallida) females, but little predation on eggless females. If the timing of hatching is phenotypically plastic, then both S. pallida females and their eggs could reduce the risk of predation by hatching early. Hence, this study examines the hatching responses of S. pallida to chemical cues from P. labiata, both in the laboratory and in the field, and addresses the following questions. (i) Do cues from predatory P. labiata influence the hatching traits of S. pallida? (ii) Are the olfactory cues from predators sufficient for predator detection by S. pallida ? (iii) Are hatching responses to predatory P. labiata controlled by egg-carrying S. pallida females, or directly by their embryos? The study provides evidence of hatching as a life-history switch point, which shows an adaptive plasticity in response to predation risk in egg-carrying S. pallida. Egg-carrying S. pallida females, but not unattended eggs, adjust egg-hatching time (the interval between oviposition and hatching) in response to the threat of predation on both the female and her eggs by P. labiata. In the presence of P. labiata, eggs that are carried by females hatch sooner; the hatchlings of these eggs are therefore smaller than hatchlings born in the absence of P. labiata. Chemical cues that are released from the draglines of P. labiata are sufficient to elicit changes in the egg-hatching traits of S. pallida. Hatching early in response to this predator may benefit both females and their offspring. To my knowledge, this is the first direct experimental study to demonstrate predator-induced hatching plasticity in spiders and, in particular, in animals with parental care.     

Reproductive pattern of the freshwater prawn Pseudopalaemon bouvieri (Crustacea,Palaemonidae) from hypo-osmotic shallow lakes of Corrientes (Argentina)

Pseudopalaemon bouvieri undergoes complete abbreviated development. The reproductive cycle (proportion and size of the sexually mature population and juvenile recruitment), fecundity and egg size of this prawn were examined in three subtropical shallow lakes. The reproductive cycle was seasonal; gonadal maturation occurred during the winter, ovigerous females were abundant in the spring and breeding occurred at the end of spring. Females produced small numbers of eggs (9–55) of relatively large sizes (1.0–2.1 mm). The proportion of ovigerous females with respect to the total number of females, the fecundity and egg size differed among the lakes according to the trophic state of the environments. Pseudopalaemon bouvieri has a reproductive strategy similar to other Palaemonidae species that inhabit nutrient-poor inland waters.     

Reproductive biology and recruitment in an amphidromous prawn Macrobrachium australe in Reunion Island

Macrobrachium australe is a widespread, medium‐sized amphidromous prawn which like many other species within this genus is exploited by fisheries. As such, they are vulnerable to overexploitation as well as to environmental modifications that impact connectivity between spawning and rearing habitats. An informed understanding of reproductive biology is essential for a responsible management of stocks in species with such a complex life circle. This study reports the results of a 1‐year investigation of the reproductive biology of M. australe in the Langevin River, Reunion Island, southwest Indian Ocean. Males attained a larger size than females. The smallest ovigerous female recorded during the study was 36 mm, and females >42 mm in length were ≥50% more likely to be ovigerous. Although reproduction occurred throughout the year, there was an increase in the reproductive activity from November to May. The highest rates of ovigerous females were observed from December to March, corresponding to elevated water temperatures and, to a lesser extent, elevated river flow. Recruitment mainly occurred in the months after high female reproductive activity (January to April).     

Different reproductive success at low salinity determines the estuarine distribution of two Palaemon prawn species

The two prawn species Palaemon adspersus Rathke and P. elegans Rathke differ in their distribution patterns in estuaries: P. adspersus occurs at lower salinities and also extends further into the Baltic than P. elegans . Yet, at low salinities adult survival does not differ between the two species. Reproductive success was, however, substantially reduced in P. elegans at low salinity, but not in P. adspersus . Berried P. elegans females from the Swedish west coast hatched significantly fewer clutches at 10%‰ than did P. adspersus females from the same locality. Furthermore, larval survival in P. elegans was significantly lower at 5 and 7.5‰ than in P. adspersus . At higher salinities (10 and 24.5‰) no interspecific differences in larval survival were found, except in one experiment where P. elegans larvae had a lower mortality. It is concluded that the different estuarine distributions of the two palaemonid prawn species result from these interspecific differences in reproductive success at low salinity.     

Sex and reproductive stage differences in the growth,metabolism, feed,fecal production,excretion and energy budget of the Amazon River prawn (Macrobrachium amazonicum)

The aim of this study was to evaluate differences in various physiological measures (growth, fecal production, feed intake, nitrogenous excretion, oxygen consumption, energy substrate used, and energy budget) among males, ovigerous females and non-ovigerous females of the freshwater prawn Macrobrachium amazonicum. This species exhibits pronounced sexual dimorphism and different male morphotypes and has the potential for use in aquaculture. Males and non-ovigerous females were studied for 30?days. Ovigerous females were studied for 10?days. Prawns were fed commercial prawn food, and all males were of the Translucent Claw (TC) morphotype. The results demonstrate physiological differences both between males and females and between females of different reproductive stages. Males had higher rates of ingestion, growth and oxygen consumption and less fecal loss than females. We postulate that in the absence of other morphotypes, TC males may exhibit increased growth rates. Males and females used protein as an energy substrate. Males channeled approximately 9% of their energy budget into growth, whereas non-ovigerous and ovigerous females channeled only 1.4?±?0.4 and 0.07?±?0.07%, respectively. Whereas males and non-ovigerous females channeled 9.0?±?9.74 and 61.8?±?3.0%, respectively, of the energy ingested into metabolism, ovigerous females channeled 97.7?±?4.7% into metabolism, likely due to the frequent beating of their pleopods, which oxygenates and cleans the eggs. As reported for marine prawns, males and non-ovigerous females of M. amazonicum lost approximately 5% of their ingested energy in exuviae. The physiological differences observed between the sexes and between females of different reproductive stages might reflect corresponding differences in patterns of activity, growth, and reproduction.     

Female egg dumping and the effect of sex ratio on male egg carrying in a coreid bug

Phyllomorpha laciniata Vill (Heteroptera, Coreidae) is uniqueamong terrestrial insects in that females glue eggs on the backsof other conspecifics. Egg carrying byP. laciniatamales haspreviously been considered as paternal care. We explored femaleoviposition with respect to previous mating experience of femalesand tested whether sex ratio affects male egg-carrying. Thehypothesis that male egg-carrying is a form of paternal carepredicts that a male should always accept eggs after matingwith a female. However, if male egg-carrying is a form of postcopulatorymate guarding rather than paternal care, egg carrying shouldincrease in the presence of other males. When two couples wereplaced together, females laid eggs on the backs of all individualsenclosed, including the backs of other females. However, whena female was accompanied by 2 males, 22 out of 26 females ovipositedon their mating partner. Thus, sexual competition rather thanpaternity alone, affects a male's eagerness to carry eggs. However,even if males sometimes carry their own eggs, females lay eggson the backs of all conspecifics they can easily acquire. Thus,egg carrying in P. laciniata is partially voluntary and partiallythe result of female egg dumping     

Sex differences in habitat distribution of a planktonic copepod, Eudiaptomus gracilis

The spatial distribution of adult males and females in a population of the copepod Eudiaptomus grachs ; was studied throughout one year The sexes were markedly segregated in spring and under ice in late winter This skewed distribution was mainly due to a strong concentration of females in deep water in the lake centre Males were more evenly distributed but dominated in relative terms strongly over females near the surface and the littoral zone Among females, those carrying eggs were most concentrated in deep regions Also during summer, females in the lake centre showed a marked abundance peak in deep water but the distribution of egg-carrying females did not differ from other females During autumn and early winter, differences in the distribution of the sexes were minor The distribution of the sexes is discussed in relation to predators, temperature, food, and mates Female copepods are susceptible to fish predation when carrying eggs Fish may contribute to the over-representation of females in deep regions by eating or scaring away this category of vulnerable prey from littoral areas and from the surface waters The fish predation hypothesis does not accurately predict the seasonal occurrence of the skewed distribution, however Feeding rate of fish is most likely low under ice Reproductive advantages in the warmer deep water may have contributed to female choice of habitat in late winter In spring and late winter proportionally fewer females near the surface and shore carried eggs, but they earned more spermatophores This indicates that these females were more receptive to matings Phytoplankton biomass was higher near the surface Thus, males may have gamed mating advantages and more food by avoiding deep water in the centre of the lake