保安湖沙塘鳢的食性、繁殖、年龄及生长的研究

保安湖沙塘鳢１冬龄成熟,雌雄比１：１．３４,４月初至６月中旬繁殖;个体绝对繁殖力５４０—１９４３ｅｇｇ（１１５４±３１４ｅｇｇ）。渔获物中以体长８．０—１４．０ｃｍ,体重１０．０—４０．０ｇ,２、３龄个体为主。体长－体重关系为Ｗ＝０．０２１２９Ｌ３.０５８５。３龄前生长较快;雄鱼略快于雌鱼。肥满度冬春季较高,最高在３月。体长和体重与年龄的关系可用Ｂｅｒｔａｌａｎｆｆｙ生长方程描述,参数分别为：雌鱼Ｌ∞=１５．２９ｃｍ,ｋ＝０．４０７２,ｔ０＝０．１５９６,Ｗ∞＝８４．９ｇ;雄鱼Ｌ∞＝１６．７１ｃｍ,ｋ＝０．３７３６,ｔ０＝０．１０９５,Ｗ∞＝１１８．５ｇ;体重生长拐点年龄和拐点体重雌鱼分别为２．８６ａ和２５.１ｇ,雄鱼３．１３ａ和３５．４ｇ。     

瓣结鱼的繁殖习性以及精子的活力与寿命

经组织学观察，研究了性成熟瓣结鱼的性腺发育的周期性变化，并初步分析了瓣结鱼的和。其繁殖盛期在４月下旬到５月上旬，繁殖群体♀：♂＝１：９．１，繁殖季节具有雌雄二态性，雄鱼绝大多数在２龄性成熟，雌鱼多在３性成熟。不同浓度的ＮａＣｌ溶液对精子活力和寿命有较大影响，成熟精子在０．４５－０．５５％的ＮａＣｌ溶液中剧烈运动时间最长，平均为１７２．５秒。     

深圳湾大弹涂鱼种群结构与生殖特征

本文探讨了深圳湾大弹涂鱼种群结构和生殖特征。结果表明：该种群以１、２龄鱼组成为主,３龄鱼极少,表明种群结构简单,体长与体重的相关曲线方程为Ｗ＝４．１６１８×１０－５Ｌ２．７４５１（ｒ＝０．９５７６）。雌雄性比为３：２。一龄鱼开始性成熟。雌鱼性成熟最小生物学体长为６２ｍｍ,雄鱼为５９ｍｍ。个体绝对生殖力波动于１９５６—１４０５３粒,平均７２９３粒;个体相对生殖力Ｆ／Ｌ：２９．５—１００．５粒／ｍｍ,平均７９粒／ｍｍ;Ｆ／Ｗ：５１１．０—８０４．９粒／ｇ,平均７５２粒／ｇ。４—６月为繁殖盛期,７—８月为繁殖末期。雌性周年月平均成熟系数（ＧＳＩ）变动范围为０．２７％—４．３６％。大弹涂鱼在一个生殖季节中只能产卵一次,属于一次性排卵类型。     

山地麻晰繁殖生态的研究

１９９７年３月至１９９８年８月,在徐州市近郊的牛头山对山地麻晰的繁殖生态进行了研究。３～７月为繁殖期,其中４～５月为交配产卵盛期。雌雄性比为１１．６。从交配到产卵为２６天,卵白色、革质、椭圆形。长径平均为１．３７（１．２３～１．５３）ｃｍ,短径平均为０．８６（０．７～１．０６）ｃｍ,卵重平均为０．６（０．４～０．８５）ｇ,每窝平均产卵４．１（３～５）枚。孵化期为５０天。初孵出的小麻晰尾端为蓝绿色,     

长吻鮠的卵巢发育和周年变化及繁殖习性研究

本文报道了长吻卵巢发育与周年变化特点和繁殖习性。依外形和组织学特征,性成熟前至性成熟鱼卵巢的发育可分为卵原细胞期、单层滤泡期、卵黄泡期,卵黄充满期、成熟期和退化期６个时期,Ⅰ期性腺只存在于１龄内个体,Ⅱ期性腺持续２年左右,性成熟前发育至Ⅲ期,经Ⅳ、Ⅴ期发育至成熟并首次参与繁殖,最小性成熟个体３龄。性成熟后个体卵巢的发育只有后５个时期。繁殖期４—６月,产后卵巢很快退回到Ⅱ期,Ⅲ期卵巢越冬。一次产卵类型。卵壳膜源于滤泡细胞。卵粒的退化吸收分５步完成。     

长吻wei的卵巢发育和周年变化及繁殖习性研究

本文报道了长吻ｗｅｉ卵巢发育与周年变化特点和繁殖习性。依外形和组织学特征,性成熟前于性成熟鱼卵巢的发育可分为卵原细胞期、单层滤泡期、卵黄泡期,卵黄充满期、成熟期和退化期６个时期,Ｉ期性腺只存在于１龄内个体,Ⅱ期性腺持续２年左右,性成熟前发育至Ⅲ期,经Ⅳ、Ｖ期发育至成熟并首次参与繁殖,最小性成熟个体３龄。性成熟后个体卵巢的发育只有后５个时期。繁殖期４－６月,产后卵巢很快退回到Ⅱ期,Ⅲ期卵巢越冬。一次     

长尾雀繁殖生态的研究

长尾雀在长白山为留鸟,是典型的“素食”瘪类,仅在育雏期有很少的动物性食物。繁殖期在筑巢适宜生境１．３对／ｈｍ＾２,冬季在繁殖期相同生境为０．０７４只／ｈｍ＾２．４月初开始有求偶追逐和争雌行为。５月下旬产卵。孵化期１２－１３ｄ．６日龄喂雏３５次／ｄ。６日龄喂雏３５次／ｄ,雏鸟在１０日龄后体温恒定,育雏期１３－１４ｄ。９月中旬后幼鸟换成成鸟羽色。     

赤眼鳟的繁殖生物学

对赤眼鳟(Squaliobarbus curriculus)的性腺发育、性征、繁殖力、性比、繁殖习性、胚胎发育和胚后发育进行了研究。赤眼鳟初次性成熟年龄为2冬龄。繁殖季节为4月下旬至8月上旬,以5~7月为盛产期。网箱饲养已达性成熟年龄的赤眼鳟性腺成熟系数大于池养及江河野生的。其相对繁殖力为252.8粒/g,高于池养者31.05%,高于野生鱼28.0%。雄鱼体形比雌鱼长,成熟雄鱼在繁殖季节胸鳍具有颗粒状珠星,非繁殖季节珠星消失。雌雄比接近1∶1。赤眼鳟属敞水性产卵类型,为不分批产卵鱼类。广西江河的赤眼鳟天然产卵场有11处,主要分布于郁江,左江和右江各有1处。在水温28~28.5℃的情况下,自受精到孵化所需时间为16 h 10 min,积温453℃.h。鱼苗经17 d发育,鳞片完全,体形、习性与成鱼相似。     

草兔繁殖生物学的初步研究

本文分析了１９９１年１－１０月获自山西省东南部丘陵山区以及１９９０－１９９３年１０月至翌年１月获自该省各地草兔的有关繁殖特征。草兔的繁殖季节为１－９月,雄性进入性活动的时间早于雌性。生殖腺测度有明显的季节变化,其峰值在４月和５月。当年兔３－４月龄时性可成熟,但达到性成熟月龄的当年兔只有５１．７％在７、８月参加繁殖。怀孕个体见于２－９月,３月怀孕率最高,此后逐渐下降。胎仔数１－７只,５月最多,年均值３．６只,每只雌兔年产幼兔１２．９只。     

洞庭平原黑线姬鼠繁殖特性研究

１９８６年１０月－１９９０年１０月在湖南省桃源县和汉寿县的稻作区逐月调查,夹捕黑线姬鼠长江亚种２７６８只,雌性占４５。６％。主要繁殖期３－１１月,研究期内的月平均怀孕率为４８．６±４．０％、平均胎仔数为５．３±０．２只。繁殖指数为２．３６±０．２９。以上３个参数及种群性性比有季节性变化,４－５月和７－１０月为２个妊娠高峰;雄性睾丸下位率和雌性怀孕率有同步变动的趋势。５年龄组之间,其性比、怀孕率和繁     

ON THE EXTRACTION OF SOME TIME DEPENDENT PARAMETERS OF AN ACOUSTIC SIGNAL BY MEANS OF THE ANALYTIC SIGNAL CONCEPT. ITS APPLICATION TO ANIMAL SOUND STUDY

ABSTRACT

When studying the acoustic signals of animals, it is often necessary to obtain the precise time structure of the frequency. It is also useful to extract the envelope of a signal or to modify a signal to obtain its frequency modulated part. This can be achieved digitally using the analytic signal concept.

We deal here with the method. Definition and computation are described, its application is discussed and the performances are compared to those of sonagraph and zero- crossing methods. This paper presents a method enabling precise AM and FM analysis of different animal vocalisations. The method has also been used for the purpose of synthesis by extracting the frequency modulated part of a signal. It is found to be a powerful means of modifying some parameters of a natural signal without altering other features.     

Variations in the spawning periodicity of eight fish species in three English lowland rivers over a 6 year period, inferred from 0+ year fish length distributions

The spawning periodicity of eight fish species was investigated in three English lowland rivers over a 6 year period from patterns in 0+ year fish standard length ( L _S) distributions. A single cohort of 0+ year dace Leuciscus leuciscus , roach Rutilus rutilus and perch Perca fluviatilis was observed each year, suggesting that these species spawned only once annually. By contrast, populations of chub Leuciscus cephalus , bleak Alburnus alburnus , bream Abramis brama , gudgeon Gobio gobio and minnow Phoxinus phoxinus were inferred to spawn on more than one occasion each year. Annual and intercatchment variations occurred in the L _S distribution patterns of some of the fish species. In chub, for example, although a minimum of two 0+ year cohorts occurred in all years in the River Trent, 'multiple' spawning (either at the individual or population level) was most apparent in 1999, 2003 and 2004. By contrast, 'multiple' spawning events were not evident in all years in the Warwickshire Avon and Yorkshire Ouse, with recruitment presumably based upon a single spawning event in some years. There is effectively a trade-off between early spawning (extended growing season), and the possibility that environmental conditions will impact upon recruitment success, and the potential for reduced overwinter survival of smaller individuals with lower lipid resources from later spawning events. Notwithstanding, fishes as small as 15 mm L _S survived the winter in some years, suggesting that progeny from later spawning events may make important contributions to fish recruitment success.     

Diel spawning periodicity of red snapper Lutjanus campechanus in the northern Gulf of Mexico

Ovaries of red snapper Lutjanus campechanus were examined histologically to determine rates of oocyte maturation, diel spawning periodicity and whether lunar cycle influenced spawning rhythm. Hydration of red snapper oocytes began during the mid‐morning hours; c . 5 h was necessary for oocytes to become fully hydrated and ovulation occurred no more than 5 h after oocytes attained full hydration. Appearance of fresh postovulatory follicles after 1330 hours and the absence of hydrated oocytes after 1830 hours signified that red snapper spawning occurred during this 5 h period. In addition, evidence of a peak in spawning was seen near 1600 hours. Postovulatory follicles degenerated within a 24 h time period. A lunar spawning cycle was not evident.     

东海带鱼春、夏和秋季产卵群体的生殖周期特性与种群问题

东海带鱼有春、夏和秋季生殖之别,秋季并出现分群现象。带鱼第一个生殖周期与其出生季节相适应;从第二个生殖周期开始则消失了与出生季节的相应关系。根据种群结构的组成特性以及耳石相对生长的分析,从种群概念上阐明了不同季节出生的带鱼群体的相互关系。论证了春、夏和秋季产卵群体系为同一种群的不同生物学群。文中讨论了种下阶元的不同分化程度和位置:繁殖群(种群)——繁殖下群——生物学群。     

长江刀鲚亲鱼强化培育及自然产卵规律研究

试验研究了人工饲养条件下长江刀鲚亲鱼培育的水温及主要水化学指标、饵料投喂策略及经强化培育后刀鲚自然产卵的规律。结果表明,刀鲚亲鱼培育池周年水温变化范围为5-34℃,刀鲚常年摄食,采用“鲮鱼苗+细足米虾”的系列活饵进行饲育期、越冬期、促熟期分阶段的投喂策略,雌性亲鱼强化培育后成熟系数可达16.5%,发育较佳,总体成活率为97.6%。5-6月是刀鲚产卵的高峰期,产卵时间集中在20:00-20:30,受精率为80%-92%,试验期间收集刀鲚受精卵56.9万粒。刀鲚的产卵与水温关系密切,最适产卵水温为20-28℃。     

Prey resources before spawning influence gonadal investment of female, but not male, white crappie

In this study, an outdoor pool experiment was used to evaluate the effect of prey resources during 4 months before spawning on the gonadal investments of male and female white crappie Pomoxis annularis , a popular freshwater sportfish that exhibits erratic recruitment. Fish were assigned one of three feeding treatments: starved, fed once every 5 days (intermediate) or fed daily (high). All measurements of male testes ( i.e. wet mass, energy density and spermatocrit) were similar across treatments. Conversely, high-fed females produced larger ovaries than those of intermediate-fed and starved fish, and invested more energy in their ovaries than starved fish. Compared to pre-experiment fish, starved and intermediate-fed females appeared to increase their ovary size by relying on liver energy stores ('capital' spawning). Conversely, high-fed females increased liver and gonad mass, implying an 'income'-spawning strategy (where gonads are built from recently acquired energy). Fecundity did not differ among treatments, but high-fed fish built larger eggs than those starved. Females rarely 'skipped' spawning opportunities when prey resources were low, as only 8% of starved females and 8% of intermediate-fed females lacked vitellogenic eggs. These results suggest that limited prey resources during the months before spawning can limit ovary production, which, in turn, can limit reproductive success of white crappies.     

Spawning migrations of the chub in the River Spree, Germany

Out of 52 chub Leuciscus cephalus tagged with internal radio‐transmitters, 46 migrated to spawning grounds in the River Spree, Germany. All chub started their first spawning migration on 21–22 May in both years of study, 1995 and 1996. They arrived at three different spawning grounds within a day and left after 1 to 6 days to return to their original sites. On 17 and 18 June 1995 and 1996 chub started their second spawning migration with the same pattern as the first. About 60% of all migrating chub moved between 1 and 13 km upstream to the nearest spawning ground. Some exceptions were observed: a few chub did not use the nearest spawning ground, some chub used different spawning grounds at first and second spawning or moved downstream to a spawning ground. Spawning grounds were characterized by 0·4 m s⁻¹ current velocity, shallow depth (0·1–0·8 m) and a stony bottom, where most eggs adhered.     

催产时黄鳝性类固醇激素含量变化的研究

本文首次报道哺乳动物促黄体生成素释放激素类似物（ＬＨＲＨ－Ａ）诱导黄鳝排卵过程中,血浆雌二醇（Ｅ２）、孕酮（Ｐ）和睾酮（Ｔ）含量变化的规律。根据１７２尾黄鳝血样放射免疫测定结果,试验组雌鱼于排卵前相继出现Ｅ２和Ｐ浓度高峰（Ｐ〈０．０１）;雄鱼于催产后２４ｈ出现Ｔ浓度峰值（Ｐ〈０．０１）;试验组雌鱼的Ｔ含量与对照组无显著差异（Ｐ〉０．０５）。在对照组,雄鱼的Ｅ２和Ｐ浓度及雄鱼的Ｔ含量差异不显著（Ｐ〉     

Reproductive Biology and Protandrous Hermaphroditism in Acanthopagrus latus

Detailed macroscopic and histological studies of the gonads of a full size and age range of Acanthopagrus latus from each season in Shark Bay, Western Australia, demonstrate that this species is a protandrous hermaphrodite in this large subtropical embayment. Although our scheme for the changes that occur in the ovotestes of A. latus during life is not consistent with some of the conclusions drawn for this species elsewhere, it is similar to that of Pollock (1985 J. Fish. Biol. 26: 301–311) for the congeneric Acanthopagrus australis. The ovotestes of males develop from gonads which contain substantial amounts of both testicular and ovarian tissue. The testicular component of the ovotestes of all males regresses markedly after spawning. During the next spawning season, the ovotestes either become gonads in which the testicular zone again predominates and contains spermatids and spermatozoa (functional males), or gonads in which the ovarian zone now predominates and contains mature oocytes (functional females). Once a fish has become a functional female, it remains a female throughout the rest of its life. In Shark Bay, A. latustypically spawns on a limited number of occasions during a short period in late winter and early spring and has determinate fecundity. The mean potential annual fecundity was ca. 2000000. The total length of 245mm, at which, during the spawning period, 50% of A. latus become identifiable as males, is very similar to the current minimum legal length (MLL) of 250mm, which corresponds to an age of ca. 2.5 years less than that at which 50% of males become females. Thus, although the spawning potential ratio suggests that the present fishing pressure is sustainable, the current MLL should be reviewed if recreational fishing pressure continues to increase.