Habitat specificity of the acanthocephalan Acanthocephalus clavula (Dujardin, 1845) in eels Anguilla anguilla (L)

1982 ◽  
Vol 56 (2) ◽  
pp. 121-130 ◽  
Author(s):  
C. R. Kennedy ◽  
D. Lord
Keyword(s):  
Sex Ratio ◽  
Alimentary Canal ◽  
Alimentary Tract ◽  
Sea Water ◽  
Anguilla Anguilla ◽  
Habitat Specificity ◽  
The Mean ◽  
Posterior Migration ◽  
Gravid Females ◽  
Single Worm

ABSTRACTThe habitat specificity of the acanthocephalan Acanthocephalus clavula in the alimentary tract of eels was studied in natural infections and in fish maintained experimentally under different regimes. The parasite exhibited a preference for a particular region (55 to 65%) of the alimentary canal which did not differ in different species of host, but habitat specificity was not very precise as there was considerable variation between individual hosts and A. clavula was capable of surviving and maturing in all regions of the intestine. The mean position of males was slightly anterior to that of females, and the over-all sex ratio was in favour of females. At high levels of infection the range of the parasites was extended and the mean position was significantly more anterior when compared to single worm infections. The parasite remains in the same site throughout the course of an infection: there was no posterior migration and gravid females occurred in the same proportion in all regions of the intestine. The mean position of the parasite did not change when the host was starved, or maintained in 100% sea water or with reduced aeration or at high temperatures. The results were compared with the habitat specificity exhibited by other species of freshwater fish acanthocephalans, and it was concluded that A. clavula was as adaptable and hardy as its present host, the eel.

Measurements of the Osmotic Pressure in the Habitat of Polymorphus Minutus (Acanthocephala) in the Intensine of Domestic Ducks

1969 ◽  
Vol 50 (1) ◽  
pp. 69-77
Author(s):  
D. W. T. CROMPTON ◽  
S. J. EDMONDS
Keyword(s):  
Osmotic Pressure ◽  
Alimentary Tract ◽  
Intestinal Helminths ◽  
Domestic Ducks ◽  
General Application ◽  
Intestinal Contents ◽  
The Mean ◽  
Posterior Migration ◽  
Small Intestinal

1. The osmotic pressure in the environment of Polymorphus minutus in the alimentary tract of ducks has been measured. Samples of intestinal contents were collected through cannulae inserted at known positions into the parasite's environment. 2. Samples were recovered from two healthy living ducks, without inducing anaesthesia, from points at 60% and 80% of the distance along the intestine, and from ten freshly killed ducks at a point 70% of the distance along the intestine. 3. The mean osmotic pressures at 60%, 70% and 80% of the distance along the intestine were found to be 170.5, 171.6 and 178.2 mM-NaCl/1. respectively and the variance was found to be 154.84, 84.41 and 30.13 for the three positions respectively. 4. It is postulated that the greater fluctuations in osmotic pressure at the anterior end of the environment may be responsible for the posterior migration of the parasite during the course of the infection. 5. The method here described for investigating osmoregulation in P. minutus may be of general application for studying aspects of the biology of small intestinal helminths in vivo.

scholarly journals On the Fecundity and Sex-ratio of Labeo bata (Hamilton) (Cypriniformes: Cyprinidae)

2015 ◽  
Vol 11 (2) ◽  
pp. 43-48
Author(s):  
MAR Joadder
Keyword(s):  
Body Weight ◽  
Sex Ratio ◽  
Average Length ◽  
Total Body Weight ◽  
Total Length ◽  
Labeo Bata ◽  
The Mean ◽  
Total Body ◽  
Gravid Females ◽  
The Relationship

The fecundity and sex- ratio of 2200 Labeo bata (Hamilton) specimens were studied. The fecundity of 234 gravid females varied from 51,354( for a fish with total length of 127.3 mm and total body weight of 20.0 g) to 91,568( for a fish with total length of 256.6 mm and total body weight of 156.70g).The mean fecundity was recorded as 67,617.50±13,510.15 for the average length and weight of 192.98±41.06 mm and 87.79±49.07 g, respectively .The mean total length and weight of gonad was 67.62± 24.01 mm and 20.35±13.50 g, respectively .The relationship between fecundity ( F.) and other parameters such as total length ( TL ), Standard length ( SL),  total weight( TW),  gonadal length (GL),  gonadal weight (GW) and gonadal depth (GD) were studied. DOI: http://dx.doi.org/10.3329/jsf.v11i2.21595 Journal of Science Foundation, 2013;11(2):43-48

Morphological ontogeny and ecology of Adoristes ovatus (Acari: Oribatida: Liacaridae), with comments on Adoristes Hull

2017 ◽  
Vol 22 (12) ◽  
pp. 2038 ◽  
Author(s):  
Anna Seniczak ◽  
Stanisław Seniczak ◽  
Sławomir Kaczmarek ◽  
Bogusław Chachaj
Keyword(s):  
Sex Ratio ◽  
Cross Section ◽  
Body Length ◽  
Junior Synonym ◽  
Thin Line ◽  
Anal Opening ◽  
The Mean ◽  
Gravid Females

The morphological ontogeny of Adoristes ovatus (C.L. Koch, 1839) is described and illustrated. The adult has the interlamellar seta shorter than the lamella and the translamella is usually absent, but can also be incomplete, or present as a thin line. The juveniles are unpigmented, oval in cross-section, with thin and smooth prodorsal and gastronotal setae, and with the anal opening in the posteroventral position, which is typical of xylophages. The legs and claws of juveniles are relatively thick, especially leg I, and the leg setae are smooth or with short barbs. All juveniles have a sclerotized semicircle located anterior to each prodorsal seta le. The larva has 11 pairs of gastronotal setae, the nymphs have 12 pairs, without the d-series. The mean body length of females is larger than males, but varies greatly among samples (445–735 μm) and the largest females can be 1.5 times longer than the smallest males. The sex ratio and the number of gravid females also vary among samples. We provisionally consider Adoristes (Gordeeviella) Shtanchaeva, Subías & Arillo, 2010 a junior synonym of Adoristes Hull, 1916.

Reproductive parameters of blue shark, Prionace glauca, and other sharks in the Gulf of Guinea

1995 ◽  
Vol 46 (6) ◽  
pp. 967 ◽  
Author(s):  
JA Castro ◽  
J Mejuto
Keyword(s):  
Sex Ratio ◽  
Fork Length ◽  
Reproductive Parameters ◽  
Gulf Of Guinea ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Embryo Number ◽  
The Mean ◽  
Gravid Females ◽  
The Right

In total, 1967 pelagic sharks of eight different species were sampled in waters of the Gulf of Guinea between June and August 1993 by commercial longline gear. Catches of Prionace glauca and Sphyma zygaena included a large number of pregnant females, making it possible to calculate some of their reproductive parameters. In total, 419 gravid females of P. glauca were caught, ranging in size from 170 to 260 cm fork length. The size at which 50% of females have embryos was determined to be 180 cm FL. Examination of the uteri from 128 of these females showed a higher number of embryos (59-60%) in the right uterus. The mean number of embryos was 37. Data on embryo size suggests that P. glauca may have a west-east migration to give birth along the Atlantic equatorial line. The embryonic sex ratio was 1 : 1. In the same catch there were 21 gravid females of S. zygaena. No difference in the number of embryos between uteri was found in this species. Mean embryo number was 33.5 and embryonic sex ratio was 1 : 1.

Structure and dynamics of a rainforest frog (Litoria genimaculata) population in northern Queensland

2005 ◽  
Vol 53 (4) ◽  
pp. 229 ◽  
Author(s):  
Stephen J. Richards ◽  
Ross A. Alford
Keyword(s):  
Sex Ratio ◽  
Fat Body ◽  
Sympatric Species ◽  
Operational Sex Ratio ◽  
Population Estimates ◽  
Adult Males ◽  
Reproductive Condition ◽  
Structure And Dynamics ◽  
The Mean ◽  
Gravid Females

We studied a population of the rainforest frog Litoria genimaculata over a 7-year period at Birthday Creek, an upland rainforest stream in northern Queensland. Estimated population size on a 60-m transect fluctuated seasonally, decreasing to zero during most winters and reaching a maximum of over 130 during most warmer spring and summer months with an influx of young adult males. Summer population estimates were much smaller during 1990–93, coinciding with the disappearance of two sympatric species. However the L. genimaculata population subsequently recovered to pre-‘decline’ levels. Females were rarely captured along the stream so the operational sex ratio of adult frogs was strongly biased in favour of males (overall sex ratio 1 : 0.04). Sexual dimorphism in this species is extreme. The mean weight of gravid females (23.35 g) was nearly five times that of males (4.68 g) and the ratio of female SVL to male SVL was 1.65. Reproductive and fat-body condition changed seasonally, with males reaching peak reproductive condition in late spring and summer when population densities were greatest. Our data suggest that Litoria genimaculata uses Birthday Creek largely or exclusively as a reproductive habitat. The extent to which this species uses habitats away from stream environments remains to be determined.

Population parameters of ringed seals (Phoca hispida Schreber, 1775) in the Svalbard area

1987 ◽  
Vol 65 (4) ◽  
pp. 1021-1027 ◽  
Author(s):  
Christian Lydersen ◽  
Ian Gjertz
Keyword(s):  
Sex Ratio ◽  
Ringed Seal ◽  
Adult Males ◽  
Population Parameters ◽  
Phoca Hispida ◽  
Age Class ◽  
Ringed Seals ◽  
Males And Females ◽  
The Mean ◽  
Sexually Mature

Samples were taken from 284 ringed seals (Phoca hispida) in the Svalbard area during April–July 1981 and March–April 1982. The age of 283 seals was determined by reading annuli in the cementum of the canine teeth. The mean age of the males was 11.3 years, and of the females, 14.9 years. Females were found to be significantly older than males. The mean length of sexually mature ringed seals was 128.9 cm for both sexes. The mean weight of adult males and females was 53.5 and 61.4 kg, respectively. Females were found to be significantly heavier than males. The sex ratio was 47.8% males and 52.2% females. Studies of microscopic sections of testis and epididymis from ringed seal males showed that 63, 75, and 80% of 5-, 6-, and 7-year-old animals, respectively, were sexually mature. The weights of testis and epididymis, diameters of tubuli, and the size of testis all showed a marked increase in the 5-year age-class. Macroscopic sections of ovaries from ringed seal females showed that 20, 60, and 80% of 3-, 4-, and 5-year-old animals, respectively, were sexually mature. The size of the ovaries showed a marked increase in the 5-year age-class. The ovulation rate of ringed seals from Svalbard was calculated to be 0.91.

scholarly journals Reproductive Biology of Round Sardinella (Sardinella Aurita) (Valenciennes, 1847) in Senegalese Coastal Waters

2018 ◽  
Vol 9 (1) ◽  
pp. 31
Author(s):  
Ismaïla NDIAYE ◽  
Alassane SARR ◽  
Alioune FAYE ◽  
Modou THIAW ◽  
Malick DIOUF ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Coastal Waters ◽  
Sexual Maturity ◽  
Reproductive Parameters ◽  
Monthly Variation ◽  
Relative Fecundity ◽  
The Mean ◽  
Sardinella Aurita ◽  
Somatic Index

In this study, a total of 1068 specimens Sardinella aurita of which 553 females and 515 males were examined. The objectif of this study was to determine the reproductive parameters of Sardinella aurita. The sex ratio was significantly in favor of females (55%). The size at first sexual maturity was estimated at 18.9 cm for females and 18.0 cm for males. The monthly variation of sexual maturity stages and gonado-somatic index (GSI) allowed to locate the reproduction periods from February to June and from September to December. The mean absolute fecundity was estimated at 110.794 ± 7582 oocytes whereas relative fecundity was about 422 ± 26 oocytes per gram of female.

scholarly journals Biology and parasitic potential of Doryctobracon areolatuson Anastrepha fraterculus larvae

2011 ◽  
Vol 46 (6) ◽  
pp. 669-671 ◽  
Author(s):  
Adrise Medeiros Nunes ◽  
Dori Edson Nava ◽  
Fernanda Appel Müller ◽  
Rafael da Silva Gonçalves ◽  
Mauro Silveira Garcia
Keyword(s):  
Biological Control ◽  
Sex Ratio ◽  
Adult Emergence ◽  
Parasitism Rate ◽  
Anastrepha Fraterculus ◽  
The Mean ◽  
Parasitoid Development

The objective of this work was to study the biology and parasitic potential of Doryctobracon areolatus on larvae of Anastrepha fraterculus. The egg-adult period, the sex ratio, the longevity, the pupal viability, and the parasitism rate of D. areolatus were determined in laboratory, using A. fraterculus as host. The parasitoid development from oviposition to adult emergence required 25.00±1.70 days, the sex ratio was 0.62±0.09, and the mean longevity was 16.36±3.62 days for males and 10.24±1.71 days for females. The mean parasitism rate was 53.50±8.93%, varying from 41.60 to 68.60%, which shows the potential of this parasitoid for biological control of A. fraterculus.

scholarly journals Seasonal Population Structure of the Copepod Temora turbinata (Dana, 1849) in the Kuroshio Current Edge, Southeastern East China Sea

2021 ◽  
Vol 11 (16) ◽  
pp. 7545
Author(s):  
Yan-Guo Wang ◽  
Li-Chun Tseng ◽  
Bing-Peng Xing ◽  
Rou-Xin Sun ◽  
Xiao-Yin Chen ◽  
...  
Keyword(s):  
Sex Ratio ◽  
East China Sea ◽  
Sea Water ◽  
Seawater Temperature ◽  
East China ◽  
Northwest Pacific ◽  
Coastal Current ◽  
Northwest Pacific Ocean ◽  
China Sea ◽  
Average Abundance

The abundance of adult males, females, and copepodites, and sex ratio of a Temora turbinata population and seawater hydrology were studied from 2018 to 2019 in waters off northeast Taiwan, northwest Pacific Ocean. The hydrological parameters showed significant differences between sampling months caused by interactions of Kuroshio, East China Sea water, and the China Coastal Current. The highest average abundance was recorded from the June 2018 cruise with 2903.92 ± 3499.47 (inds. m−3), followed by a cruise in June 2019 with an average abundance of 1990.64 ± 1401.55 (inds. m−3). The sex ratio ranged between 0.25 and 2.33; the records were significantly higher in samples of June 2018 than during other sampling cruises (one-way ANOVA). The spatiotemporal distribution of T. turbinata showed a clear pattern of seasonal changes among sampling stations and distribution zones. Abundance of females and copepodites correlated significantly positive (r = 0.755, p < 0.001), whereas sex ratio (r = 0.247, p = 0.119) did not correlate significantly. The present study revealed that the abundance of T. turbinate was highest in June and was positively correlated with seawater temperature; furthermore, this is the first time the in situ sex ratio of T. turbinata in western Pacific waters has been reported.

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