Reproductive biology of the freshwater goby Knipowitschia croatica Mrakovčić, Kerovec,Mišetić & Schneider 1996 (Actinopterygii,Gobiidae)

The reproductive biology and gonadogenesis cycle of the Vrgorac goby, Knipowitschia croatica is described [Conservation of Endangered Freshwater Fish in Europe, Birkhauser Verlag, Basel]. The species displays sexual dimorphism during the spawning period. Sexual maturity is achieved at an early age, with 50% of males and females sexually mature at total lengths of 40–45 mm. Fecundity of gravid females ranged from 188 to 593 eggs, with an egg diameter of 0.22–1.11 mm. Though the extended spawning period lasts from March to November, the highest intensity is observed from April to September. A comparison is made of the reproductive biology of this species with other sand goby species of the genera Knipowitschia and Pomatoschistus.     

Reproductive biology of Philodryas patagoniensis (Snakes: Dipsadidae) in south Brazil: male reproductive cycle

The male reproductive cycle of Philodryas patagoniensis in south Brazil was described through morpho‐anatomical and histological analysis of individuals deposited in zoological collections. Spermatogenesis occurred during late autumn–winter (June–September) and spermiogenesis occurred in spring–summer (October–March). The volume of the testes was smaller (quiescent) in winter, while the tubular diameter and the epithelial height of the seminiferous tubule were larger in summer (January–March). The ductus deferens presented spermatozoa all over the year and had no seasonal variation in diameter. The length of the kidney was larger in winter–spring (July–December), although the tubular diameter and epithelium height of the sexual segment of the kidney (SSK) were larger only in winter (July–September). Total testicular regression was observed in late autumn (May), simultaneously with the peak in SSK. Therefore, at the individual level, males exhibit a discontinuous cyclical reproduction. Considering the population level, the reproductive cycle is seasonal semisynchronous, with most of the individuals showing a reproductive peak in spring–summer (October–March). Here, we present evidence to support the importance of the microscopic approach to reproductive cycle studies. Finally, we discuss the intrinsic and extrinsic factors influencing P. patagoniensis reproductive patterns.     

Freshwater pearl mussel (Margaritifera margaritifera) glochidiosis in wild and farmed salmonid stocks in Scotland

The Corbicula of the Saone at Lyon were sampled every month from September 1996 to December 1999. These populations are characterised by a single annual reproduction period starting in May or June and ending in September or October in which two peaks of intensity can be distinguished; the presence of one or more cohorts according to year; low growth in spite of a growth period that generally lasts from March to October; and a lifespan of about 5 years. Although the effect of toxic substances can be considered, it appears that the reason for the low recruitment levels observed from 1997 to 1999 are above all due to the small quantities of food available, especially chlorophyll a.     

Annual cycle of liveweight and reproductive changes of farmed male fallow deer (Dama dama) and the effect of daily oral administration of melatonin in summer on the attainment of seasonal fertility

Entire bucks (N = 7) exhibited pronounced liveweight gains over spring and summer months (October-February), to reach a peak mean weight of 59.8 kg, and rapid liveweight losses over the rutting period (April-May) with a minimum mean liveweight of 54.2 kg. Mean neck girth and serum testosterone levels increased during late summer (January-March) and peaked at 387 mm and 12 ng/ml respectively immediately before the onset of the rut (April). Thereafter both measures declined during winter and spring months (June-December). Bucks castrated prepubertally (N = 11) exhibited similar but less pronounced changes in mean liveweight and neck girth, in the absence of any change in testosterone secretion. Peak mean testicular diameter of entire bucks (39 mm) occurred immediately before the rut and was followed by testicular regression over winter and spring months (June-November), such that the testes attained their minimum mean size of 18 mm diameter in early summer (November). Motile spermatozoa were absent from ejaculates collected in summer (November 1983, 1984; January 1984). However, ejaculates collected pre-rut (late March), immediately post-rut (June) and in early spring (September) contained successively increasing numbers of motile spermatozoa. A further 14 polled, entire bucks were given orally 5 mg (N = 7; Group A) or 20 mg (N = 7; Group B) melatonin at 15:30 h daily from 1 December 1983 to 14 January 1984 (45 days). Seven control bucks (Group C) received vehicle ration only. The measurements taken for bucks in Groups A and B were not significantly different (P greater than 0.1) on any sampling date and the data for these 2 groups were pooled. Mean serum testosterone concentrations and mean ejaculate volume were not significantly different between melatonin-treated and control bucks on any sampling date, although other measures exhibited significant differences (P less than 0.05) at various treatment or post-treatment dates: melatonin-treated bucks showed a transiently greater increase in neck muscle development during and immediately after treatment, a slight retardation of liveweight gain between 45 and 75 days after treatment, an earlier peak in maximum mean testicular diameter and an earlier onset of sperm presence in ejaculates.     

Sexual dimorphism and female reproductive cycle in the scincid lizard Trachylepis vittata (Olivier, 1804) in Lebanon (Reptilia: Scincidae)

Sexual dimorphism and the female reproductive cycle were studied in a population of the viviparous lizard Trachylepis vittata at 2000 m a.s.l. on Mount Sannine, Lebanon. Females have larger body sizes than males and males have relatively larger heads than females. Females reach maturity at 56 mm snout-vent length. They spend at least six months in hibernation, from October to March. Adult females emerge from hibernation in April. Fertilization occurs mid-May and gestation lasts for 8-10 weeks. All females collected on the same date had embryos at the same embryonic developmental stage. Females produced 1-4 embryos. There is a significant positive relationship between female body size and number of embryos. Parturition lasts for two weeks and new-borns achieve adult size within about ten months.     

2016年南极斯科舍海南极大磷虾种群结构的时空变化

斯科舍海是南极大磷虾资源分布最为密集的海域,也是磷虾的传统渔场,但该海域磷虾种群结构存在较为显著的年际、季节性与区域性差异.为了解该海域磷虾种群动态,本研究利用2016年1—9月由渔业调查随机收集的样本,对该海域磷虾种群结构的时空变动进行了分析.结果表明: 各月磷虾性比存在显著的差异,1—5月雌性明显占优,而6—9月则呈现相反的趋势.1—9月期间,仅1月出现幼体,且雌性成体的比例与2月相当,占比超过了40%;3—5月,雌性未成体的比例均超过了50%,而雌性成体的比例开始逐月下降;6—8月,雄性未成体的比例达到峰值;9月,雌性未成体的比例显著增加,而雄性成体的比例呈下降趋势.在布兰斯菲尔德海峡内,2—5月,雌性未成体的比例超过一半;1月,乔治王岛东北水域已排卵个体的比例(25.6%)显著高于其他个体,雌性临产个体的比例也较高;6—9月,南乔治亚岛东北水域雄性成体的比例约占一半,雌性成体的比例极低.性成熟度组成显示,1—2月为磷虾产卵盛期,而产卵场出现在乔治王岛东北水域以及布兰斯菲尔德海峡.     

THE WINTERING AND MOULT OF RUFFS PHILOMACHUS PUGNAX IN THE KENYAN RIFT VALLEY

Some 5700 Ruffs were ringed in the southern Kenyan rift valley during 1967–79, mainly at Lakes Nakuru and Magadi. These have produced 15 recoveries outside East Africa, 14 in Siberia between 73° and 154°E and one in India. Adult males returned to Kenya mainly during August, and females during late August and early September. Females greatly outnumbered males at all times. Most wintering males departed late in March and early in April, but females not until about a month later. First-year birds appeared from the end of August, but remained in low numbers until late October or November. Most departed during April and May, but a few females oversummered. First-year birds typically accounted for about 25% of the wintering Nakuru females, but about 50% of those at Magadi. At both sites they accounted for a higher proportion of male birds than females. Most of the birds at Nakuru throughout late August to May appeared to be local winterers, and many individuals remained in the area for many months each year. Retrapping indicated that approximately 60% of each season's birds returned the following season. Adult males and most adult females commenced pre-winter wing moult before arrival, but completed most of it in Kenya. Males moulted 3–4 weeks ahead of females, and most had finished before December. Females typically finished during December and early January. Most second year birds timed their pre-winter moult similarly to older adults. Suspension was recorded in over 15% of all moulting birds examined. Adult pre-summer moult involved most or all of the tertials, some or all of the tail feathers, most of the inner wing coverts and the body and head plumage. It occurred mainly during January to March (males) or February to April (females), although tertial renewal commonly began a month earlier. Males showed no sign in Kenya of the supplementary prenuptial moult. First-year birds moulted from juvenile into first winter body plumage during late September to November. They underwent a pre-summer moult similar in extent and timing to that of adults, and again about a month earlier in males than females. Spring feathers acquired were often as brightly coloured as those of adults. About 15% of first-year birds renewed their outer 2–4 pairs of large primaries during January to April. Adult and first-year birds fattened before spring departure, commonly reaching weights 30–60% above winter mean. Weights of adult males peaked early in April, those of adult females early in May, and those of first-winter females later in May. Weights were relatively high also during August and September. This was due to the arrival of wintering birds carrying ‘spare’ reserves, and also apparently to the presence of a late moulting fattening passage contingent. The wing length of newly moulted adults was about 3 mm longer than that of newly arrived first-year birds, but there was no evidence of an increase in the wing kngth of adults with successive moults. Adult wing length decreased by 4–5 mm between the completion of one moult and the middle stages of the next. The migrations and annual timetable of Kenyan wintering Ruffs are discussed, and their moult strategy is compared with that of other Holarctic waders.     

Observations on the female reproductive cycles of captive Asian yellow pond turtles (Mauremys mutica) with radiography and ultrasonography

The annual reproductive cycle of 27 female Mauremys mutica was observed by radiography and ultrasonography from April 2006 to August 2007. Radiography was used to monitor clutch size and ultrasonography was used to monitor changes in the ovarian follicles. The follicles started to enlarge in September and became preovulatory in January. The mean maximum follicle diameter of ovulation was 18.30±1.44 mm, and ovulation occurred from March through August. Eggs were laid between April and August. Turtles entered latent period in early August and the maximum follicular size was at a low of 13.22±2.36 mm in late September. The vitellogenesis of the next reproductive cycle began in October. The 24 adult females laid 56 clutches containing a total of 227 eggs. Average clutch size was 4.05 eggs (range 1–8) and there were 2.33 clutches (range 1–4) per female. Egg shell images were first observed on the sixth or seventh day after ovulation. The oviductal period averaged 6.9 weeks (range 2–16 weeks) on the first clutch, 3.4 weeks (range 2–8 weeks) on the second, and 2.75 weeks (range 2–6 weeks) for the third. Radiography and ultrasonography are non‐invasive and convenient methods to evaluate the reproductive cycle of female M. mutica. They should be applicable to other turtles and should greatly enhance knowledge of reproductive physiology. Zoo Biol 29:50–58, 2010. © 2009 Wiley‐Liss, Inc.     

The epidemiology of fasciolosis in the inter-Andean valley of Cajamarca, Peru

Fasciolosis is recognised as a major problem in dairy cattle in parts of Peru. A longitudinal study of dairy cattle in Cajamarca, Peru was used to determine the annual pattern of infection with Fasciola hepatica. After a gradual increase from January, peak egg production occurred in August/September and then dropped rapidly. Indirect indicators of infection, eosinophil counts and serum liver-enzyme activities, indicated that the major period of new infection in cattle occurred from December to May each year. Examination of snails demonstrated that, although there was no clear annual cycle in snail abundance, the majority of snails infected with cercariae were found between January and March. Climatological data indicated that there was sufficient moisture for development of the parasite during a limited period each year, coinciding with the period of maximum abundance of cercaria-infected snails, but that irrigation could substantially alter the amount of water available. Infections in tracer-calves decreased from December to September, with little or no infection occurring between June and August, but suggesting that there could be significant infection prior to December. Thus a defined annual cycle of infection was observed, where cattle acquired infection from December to May and this infection matured to produce peak egg counts in August/September which were then available to infect the intermediate host for the next cycle of infection.     

Novelty response in the weakly electric fish Gymnotus carapo: seasonal differences and the participation of the telencephalon in its modulation

The arousal or novelty response (increased frequency of electric organ discharge in the presence of an electric stimulus delivered by a pair of electrodes placed in the water of the experimental chamber) and its habituation were studied in Gymnotus carapo, a weak field electric fish, in different seasons (September and March) and in animals with extensive or restricted telencephalic lesions. The novelty response was reduced but not abolished by repeated stimuli at fixed intervals in normal animals both in September (pre-mating season) and in March (beginning of the dry season). The magnitude of the novelty response did not differ between sham-operated animals and animals with extensive (detelencephalization) or restricted telencephalic lesions (dorsocentral area) within their respective groups (September or March). The novelty response to the first applied stimulus was significantly greater in normal, sham-operated, and derelencephalated animals in September compared to March, although baseline firing rate did not differ. The maximum extent of response reduction occurred after the 18th stimulus in September for all three experimental groups, whereas in the 4 groups tested in March the maximum reduction occurred between the 16th and 72nd stimulus, indicating that in March there is a greater fluctuation in the arousal level.     

Reproductive biology of Coilia mystus (Linnaeus) from the Yangtze Estuary,China: responses to overexploitation

Fishery harvest of Coilia mystus in the Yangtze Estuary has declined dramatically since the late 1990s. A full understanding of the reproductive biology of this species is essential for effective management of the population. A total of 1072 females of C. mystus collected from the Yangtze Estuary area between May 2006 and September 2007 were analyzed to reveal the general reproductive biology of the population. Females with increased gonadosomatic index (GSI) and gonads developed to stages IV and V occurred mainly from March through August, indicating a major spawning season in this period; there were also a few females with increased GSI and developed gonads observed in November and January. Absolute fecundity (AF) ranged from 3093 to 36 786; and increased with both body weight (BW) and age. The relationship of AF to BW was fitted to a linear function AF = 924.72 × BW?414.17 (r² = 0.82, n = 134, P < 0.05). Relative fecundity was 871 eggs per gram. Oocyte diameter (OD) of mature females ranged from 0.55 to 0.90 mm with a mean (±SD) of 0.71 ± 0.05 mm (n = 3927), independent of BW. The frequency distribution of OD showed a single mode and histological examination demonstrated that the development of oocytes was synchronous within an ovary, suggesting that C. mystus is a single spawner. Compared to previous studies, females in this study tended to produce more but smaller eggs. This increased fecundity may represent biological compensation for the decline in abundance of the population due to overexploitation.     

Settlement of bivalve spat on artificial collectors in Eyjafjordur, North Iceland

The seasonal pattern of bivalve spat settlement in Eyjafjordur, North Iceland, was investigated using artificial collectors of monofilament netting over 14 months (March 1998–January 2000) at 5, 10 and 15 m depth. SCUBA divers replaced the collectors at 4-weekly intervals. Twelve bivalve species settled on the collectors but only Mytilus edulis and Hiatella arctica were present throughout the year; they were the most abundant bivalve taxa. Of the remaining species, only Chlamys islandica, Heteranomia spp., Arctica islandica, Serripes groenlandicus and Mya spp. were sufficiently abundant to enable statistical analysis. All settled in late summer and autumn. Peak settlement of M. edulis, in September, consisted mainly of primary settlers (0.25–0.5 mm) although secondary settlers (>0.5 mm) were present in all samples. Mytilus edulis settled mostly at 5 m depth, especially larger individuals, possibly reflecting stronger currents at shallower depth and the proximity of mussel beds in the intertidal zone. Primary (<1 mm) and secondary H. arctica settlers (>1 mm) were present in most months, with the former being most numerous in September, 1999; settlement was equally abundant at 5 and 10 m depth. Primary settlement of C. islandica and S. groenlandicus occurred in autumn (mainly in September), and secondary settlers were very scarce and only seen in winter. Arctica islandica, Heteranomia spp. and Mya spp. settled mainly in September 1999 at 10 m depth, except for A. islandica, which was more numerous in August.     

Life cycle and population dynamics of Annina mesopotamica (Ahmed), (Isopoda, Flabellifera) in the Shatt Al-Arab Region, Basrah, Iraq

A population of the intertidal, ovoviviparous, cirolanid isopod Annina mesopotamica was studied at the Al-Chibassy tributary of the Shatt Al-Arab river from 14 May 1973 to 29 April 1974, and at the Garmat-Ali river of the Shatt Al-Arab, Basrah, Iraq from 5 November 1984 to 30 June 1986. Population density varied between 128 to 5760 individuals m^–2 with a mean of 1218 m^–2. Highest numbers occurred between June and September. Breeding extended for most of the year except November/January to February/March, although ovigerous females were present throughout the year. The incubation period varied with season, and was ca. 2 weeks during the warmest period, and about a month at lower temperatures. Egg numbers varied between 4 to 66 with mean 24. Brood size was linearly proportional to female size. The size frequency distribution of the population was polymodal with a predominance of females over males. Four different types of growth curves were found: exponential, concave, convex, and intermediate between concave and convex. Growth rate varied between 0.63 and 2.19 mm month^–1. Mortality was higher among summer cohorts. Life span varied between 5 and 11 months.     

珍稀濒危植物金花茶种子繁殖和生物学特性研究

对金花茶进行种子繁殖和生物学特性研究。结果表明:以含水6%湿沙贮藏,采用粒径大的种子(2.05cm×1.51cm×1.92cm)于3月进行播种繁殖,其发芽率最高,且幼苗长势健壮。金花茶从北热带季雨林中引种到中亚热带桂林雁山的自然环境条件下,植株能正常生长及开花结实。物候期比原产地推迟40d左右。成龄植株通常每年只有一次秋梢,于9月下旬开始展叶抽梢,10月中旬新梢停止生长。6月下旬至7月上旬开始现蕾,1月上旬至2月上旬为开花始期,2月下旬至3月中旬为开花盛期,3月下旬至4月上旬为开花末期。果实于11月下旬至12月成熟,生长期约9～10个月。17年生实生苗平均高(313.60±15.92)cm,基径(4.51±0.71)cm,平均冠幅(东西×南北)277.6cm×219.2cm。金花茶主要病害有赤叶枯病、炭疽病、白绢病等,4～6月高温湿热季节容易发病。虫害主要有蚜虫、卷叶蛾、天牛和木囊蛾等。     

Reproductive and larval cycle of the scallop Argopecten purpuratus (Ostreoida: Pectinidae), during El Niño-La Niña events and normal weather conditions in Antofagasta, Chile

Seasonality, amplitude, and magnitude of spawning events were determined for Argopecten purpuratus in the La Rinconada marine reserve, Antofagasta, Chile, between December 1995 and January 2004. During the same period, samples of scallop larvae were obtained in vertical plankton hauls recovered within this reserve in an area routinely exposed to circular, gyre-like currents which helped retain the larvae within the bay. The reproduction of this population in normal or cool (e.g. "La Ni?a", 1998-2000) years occurred throughout the year, with a more active period between September and April, declining in June and August; this contrasted with the warmer "El Ni?o" oceanographic period of 1997-98 in which reproductive activity was more intense and prolonged throughout the entire year. The reproductive events in this population were mostly synchronous, although one asynchronous period occurred each year following the more intense March to May spawnings. This reproductive activity generated a continuous presence of larvae in the area in which no strict relation could be found between the intensities of spawning and numbers of larvae in the water. Larval presence was, however, generally correlated with active spawning periods. Important increases in larval numbers recorded at the end of 1999 and the beginning of 2003 were correlated with census data showing a higher percentage presence of broodstock over 90 mm in shell length during these years. An adequate stock of this size class is needed for a successful seed capture program in the reserve (for mass culture).     

Behavioural observations of interactions in a free-ranging lynxLynx lynx family at kills

The behaviour of a free-ranging female lynxLynx lynx Linnaeus, 1758 and her kittens at 12 different kills was studied for 44 hours of observation from September 1996 to March 1997. The development of interactions at kills of a lynx family group showed the following pattern: until the end of September we often observed two lynx, usually both kittens, feed from the kill at the same time. After the age of four months aggression between kittens was observed frequently, with the bigger kitten being dominant. From September the kittens were never again seen feeding together at the kill. However, we never observed fighting, and aggressive behaviour did not increase with the age of the kittens. Whereas until December one of the kittens was always first at the kill, from January onwards it was mostly the adult female who ate first. She introduced her kittens to the home range of a neighbouring female where the family break-up occurred. The kittens were last seen together with their mother on 26 March. Dispersal seemed to be initiated by the female abandoning the kittens.     

Importance of photoperiods in determining temporal pattern of annual testicular events in rose-ringed parakeet (Psittacula krameri).

Male rose-ringed parakeets (Psittacula krameri) were transferred to a long photoperiod (LP; LD 16:8) or a short photoperiod (SP; LD 8:16) for 45 or 90 days on four dates corresponding to the beginnings of different reproductive phases in an annual testicular cycle, and testicular responsiveness was evaluated by comparison with the testicular volume, weight, seminiferous tubular diameter, and germ cell profiles of birds in a natural photoperiod (NP). Exposure of birds to LP during the progressive phase (November) led to precocious maturation of testes after 45 days, but induced regression at 90 days. After showing retarded gametogenic functions at 45 days, parallel (November) SP birds exhibited an accelerated rate of germ cell formation at day 90. During the prebreeding phase (January), there were no remarkable differences in any features of testes among NP. LP, and SP birds at 45 days, but gonadal involution in LP parakeets and active spermatogenesis in SP birds occurred after 90 days. The testes did not show any response to LP or SP for 45 and 90 days when the birds were transferred to altered photoperiods during the breeding (March) and preparatory (June) phases, indicating that the parakeets were photorefractory for at least 6 months (March through September). The results also suggest that initiation and termination of seasonal gametogenic activity in parakeets are possibly functions of endogenous rhythmicity or extraphotoperiodic environmental factors. Duration of light may have certain influences on the attainment of annual peak in spermatogenesis, but in all probability the species has a low photoperiod threshold for induction of testicular growth.     

Vegetative propagation and spore-based recruitment in the carrageenophyte Chondracanthus chamissoi (Gigartinales, Rhodophyta) in northern Chile

In the present study we compared vegetative and spore‐based propagation for Chondracanthus chamissoi (C. Agardh) Kützing. Monthly field observations were made over a 1‐year period at Puerto Aldea, Tongoy Bay, Chile. Data were collected both outside and within a bed of C. chamissoi. Vegetative propagation was assessed via attachment of drifting fronds to shell‐encrusted concrete blocks at both sites. Germination of spores was recorded on the same shell substrates. Substrate re‐adhesion varied seasonally between sectors. Highest averages occurred within the algal bed between January 1997 and March 1997. The number of sporelings showed two peaks of maximal recruitment in spring and summer months (January‐March 1997 and September 1997‐January 1998). Spore‐based propagation is an important mechanism of seasonal regeneration of biomass in the C. chamissoi bed; however, re‐attachment of fronds may have been important in maintaining production of the bed during the period of maximum biomass accumulation.     

Aspects of the population ecology of Lucinomaborealis (L.) (Bivalvia) in Raunefjorden,Western Norway

2194 Lucinoma borealis (L.) were obtained from 99 quantitative (0.2 m²) samples of substratum (stratified random sampling) collected between November 1975 and October 1976 in the archipelago of Eggholmane ≈20 km south of Bergen. The depth range of the 20900 m² area was 0.3–13.3 m, and the bottom sediment (fine to very coarse sand) was rich in calcium carbonate. The highest density was found in the deep (≈ 8–13 m) sub-areas, with fine sediment (median grain-size diameter ≈ 0.3–0.5 mm). L. borealis was the most abundant bivalve species in the area studied (59.6%, by number). The average density was 22.2 (C.I. ± 5.4) ind. · 0.2 m ^?2, and the biomass was 690 (C.I. ± 116) mg AFDW · 0.2 m ^?2. The average size of animals found in shallow water (coarse sediment), with low abundance, was markedly larger than that of those from deeper water. Adults from shallow water consisted of 49.5% females, but in deep water the corresponding figure was only 38.6%.According to the data, spawning in deep water occurred in June, August–September, and possibly also in January–February. The spawning period in shallow water was more diffuse and uncertain. The egg diameter of 123.75 (C.I. ± 1.59) μm, indicates a lecithotrophic development. Maturation occurred at a shell length of 10–13 mm, and the largest animal found was 34.3mm long. The shell of L. borealis grows allometrically.