Reproductive biology and diet of the longtail butterfly ray Gymnura poecilura (Shaw, 1804) along western Bay of Bengal

2020 ◽  
Vol 100 (3) ◽  
pp. 461-470
Author(s):  
Muktha Menon ◽  
G. Maheswarudu ◽  
K. Sree Ramulu ◽  
Shoba Joe Kizhakudan
Keyword(s):  
Reproductive Biology ◽  
Maximum Size ◽  
Female Size ◽  
Feeding Intensity ◽  
Disc Width ◽  
The Mean ◽  
Index Of Relative Importance ◽  
Western Bay Of Bengal ◽  
Gravid Females ◽  
Size At Birth

AbstractThe reproductive biology and diet of the longtail butterfly ray Gymnura poecilura is described based on 630 specimens (N = 377 females and 253 males). The mean disc width (WD) of females and males was 576.7 mm (range = 190–920 mm) and 416.3 mm (230–550 mm), respectively. Sexual dimorphism in size was seen, with the maximum size of males being only 60% of the maximum female size. The disc widths at 50% maturity (WD50) were estimated to be 506.5 mm (females) and 435.9 mm (males). The mean uterine fecundity was 3.3 (range = 1–8). The size at birth was between 190 and 220 mm WD. Year-round reproduction was indicated, due to the presence of mature males and gravid females throughout the year, neonates in multiple months and large variations in embryo size within months. Feeding intensity increased with body size. Fish accounted for 80.9% of the diet (Index of Relative Importance, IRI), followed by crustaceans (18.9%) and molluscs. The species was found to be a specialized feeder.

Distribution, size and sex composition, reproductive biology and diet of sharks from Northern Australia

1991 ◽  
Vol 42 (2) ◽  
pp. 151 ◽  
Author(s):  
JD Stevens ◽  
KJ McLoughlin
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Annual Cycle ◽  
Post Partum ◽  
Austral Summer ◽  
Size Composition ◽  
Maximum Size ◽  
Northern Australia ◽  
Average Size ◽  
Size At Birth

The distribution, size composition, sex ratio, reproductive biology and diet of 17 species of shark from the families Triakidae, Hemigaleidae and Carcharhinidae from northern Australia were examined. In most of these species the sex ratio of the embryos is 1 : 1, whereas in the post-partum populations there were significantly more males than females. The results indicate four broad reproductive strategies among these sharks. In most species reproduction was distinctly seasonal with individual females giving birth each Austral summer (annual cycle) after a gestation period of 9-12 months. A second group had a very similar cycle except that individual females gave birth every second year (biennial cycle). A third group had an annual cycle but breeding was continuous throughout the year, these were mostly small bottom-associated sharks. One species had a seasonal cycle but gave birth twice each year (biannual cycle) after a 6-month gestation. The average size at birth varied from 27 to 75 cm and the average litter size varied from 2 to 34. The size at birth was about 40% of the size at maturity, which in turn was about 70% of the maximum size. Diets ranged from omnivorous to highly selective. Fish was an important component of the diet in all but one species. There was evidence of partitioning of food resources among sympatric, morphologically similar, sharks.

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.

Near-term embryos and gravid females of Lusitanian cownose ray (Rhinoptera marginata) in Mersin Bay, eastern Mediterranean Sea

2018 ◽  
Vol 69 (9) ◽  
pp. 1365
Author(s):  
E. Mümtaz Tıraşın ◽  
Nuri Başusta
Keyword(s):  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Sampling Location ◽  
Eastern Mediterranean Sea ◽  
Cownose Ray ◽  
Disc Width ◽  
Relative Closeness ◽  
Near Term ◽  
Gravid Females ◽  
Sexually Mature

Batoid chondrichthyans are vulnerable to commercial fisheries even though they are often not targeted. A greater understanding of their reproductive biology is important to facilitate their conservation. In February 2013, 89 female and 40 male Lusitanian cownose ray (Rhinoptera marginata) specimens were accidentally caught in Mersin Bay in the eastern Mediterranean Sea. Thirty-six fish were gravid, each bearing one embryo. Of the remaining females, 39 were sexually mature but not gravid and 14 were immature. There were 28 mature and 12 immature males. The average disc width (DW) of both mature females (80.2cm) and males (74.2cm) was significantly higher than that of immature females (60.7cm) and males (60.3cm). For all rays, DW and total weight (TW) were in the range 55.7–98.2cm and 1802–13600g. The DW and TW measured for all 16 female and 20 male embryos were in the range 15.6–29.2cm and 57–281g. Such a large single haul sample, including many gravid specimens and mature males, indicates a schooling formation at capture. The location in Mersin Bay near the estuaries of the Tarsus and Seyhan rivers, and its relative closeness to the sampling location of a previously reported neonate, suggests that this region may be a nursery area for Lusitanian cownose rays in the eastern Mediterranean.

scholarly journals Probing airway conditions governing ventilation defects in asthma via hyperpolarized MRI image functional modeling

2009 ◽  
Vol 106 (4) ◽  
pp. 1293-1300 ◽  
Author(s):  
Lisa Campana ◽  
Jennifer Kenyon ◽  
Sanaz Zhalehdoust-Sani ◽  
Yang-Sheng Tzeng ◽  
Yanping Sun ◽  
...  
Keyword(s):  
Computational Models ◽  
Maximum Size ◽  
Measured Data ◽  
Lung Imaging ◽  
Small Airways ◽  
Functional Modeling ◽  
Airway Constriction ◽  
The Mean ◽  
Hyperpolarized Mri ◽  
Central Airway

Image functional modeling (IFM) has been introduced as a method to simultaneously synthesize imaging and mechanical data with computational models to determine the degree and location of airway constriction in asthma. Using lung imaging provided by hyperpolarized 3He MRI, we advanced our IFM method to require matching not only to ventilation defect location but to specific ventilation throughout the lung. Imaging and mechanical data were acquired for four healthy and four asthmatic subjects pre- and postbronchial challenge. After provocation, we first identified maximum-size airways leading exclusively to ventilation defects and highly constricted them. Constriction patterns were then found for the remaining airways to match mechanical data. Ventilation images were predicted for each pattern, and visual and statistical comparisons were done with measured data. Results showed that matching of ventilation defects requires severe constriction of small airways. The mean constriction of such airways leading to the ventilation defects needed to be 70–80% rather than fully closed. Also, central airway constriction alone could not account for dysfunction seen in asthma, so small airways must be involved.

The reproductive biology of Plutonaster Bifrons, Dytaster Insigns and Psilaster Andromeda (Asteroidea: Astropectinidae) from the Rockall Trough

1982 ◽  
Vol 62 (4) ◽  
pp. 869-887
Author(s):  
P. A. Tyler ◽  
S. L. Pain
Keyword(s):  
Reproductive Biology ◽  
Reproductive Strategies ◽  
Egg Size ◽  
Food Source ◽  
Maximum Size ◽  
Reproductive Synchrony ◽  
Sea Bed ◽  
Rockall Trough ◽  
Sperm Development ◽  
Surface Production

Examination of the reproductive biology of three closely related sympatric astropectinid asteroidshas revealed two distinct reproductive strategies. In Plutonaster bifrons and Dytaster insignis the gonads are serially arranged and open at gonopores located at the tip of genital papillae found on the dorsal arm surface between the bases of the paxillae. The ovaries of these species produce numerous small (ca. 120/«n diameter) eggs which in Plutonaster bifrons appear to show a distinct synchrony of production. Initiation of gametogenesis occurs in June to August of each year with oocyte growthcontinuing until March with a spawn-out in the period March to early June. In specimens where spawningdoesnot occur, there would appear to be internal oocyte degeneration, or after spawning relict oocytesundergo phagocytosis. In males initiation of spermatogenesis may occur in August/September of eachyear but after this synchrony of sperm development is not evident. In Psilaster andromeda gonads are located at the base of the arms and each gonad opens at a single gonopore. A number of small (<300 /«n) oocytes are produced by each gonad. Some of these are phagocytosed and some undergo vitellogenesis and grow to a maximum size of 950 fim before being spawned. Unspent oocytes undergo internal degeneration. In neither females nor males is there any evidence of reproductive synchrony. From these egg sizes, fecundities and gametogenic strategies, we infer indirect planktotrophic development for Plutonaster bifrons, the transfer of a seasonal surface production to deep water providing a food source for developing larvae. The egg size and or close to the sea-bed, as there is no evidence of brooding in this species.

scholarly journals Biological traits of Quadrastichus mendeli (Hymenoptera, Eulophidae), parasitoid of the eucalyptus gall wasp Leptocybe invasa (Hymenoptera, Eulophidae) in Thailand

Parasite ◽  
2019 ◽  
Vol 26 ◽  
pp. 8
Author(s):  
Benjakhun Sangtongpraow ◽  
Kosol Charernsom
Keyword(s):  
Developmental Time ◽  
Egg Load ◽  
Biological Traits ◽  
Female Size ◽  
Gall Wasp ◽  
Potential Fecundity ◽  
The Mean ◽  
Leptocybe Invasa ◽  
Eucalyptus Gall Wasp ◽  
Honey Solution

Quadrastichus mendeli Kim & La Salle, a parasitoid of Leptocybe invasa Fisher & La Salle, is a uniparental species. This study assessed the biological traits of Q. mendeli in the laboratory at a temperature of 27 ± 1 °C. Diets had a highly significant effect on the mean longevity of female Q. mendeli. Feeding honey solution prolonged the mean longevity of the parasitoid to 4.80 days. The estimated 50% survival period was 3 days. The mean potential fecundity in all ages was 8.85 eggs per female. Age had a highly significant effect on the mean egg load. There was a positive relationship between egg load and female size. The mean of realized fecundity throughout the life span was 2.47 progenies per female. The mean developmental time of Q. mendeli from the egg to adult stage was 27.06 days. The shorter developmental time of Q. mendeli in comparison to its host can be considered a reason for the successful control of L. invasa in Thailand.

Aspects of the post-larval life history of Limnadia stanleyana King (Crustacea : Conchostraca)

1968 ◽  
Vol 16 (5) ◽  
pp. 885 ◽  
Author(s):  
JA Bishop
Keyword(s):  
Life History ◽  
Maximum Size ◽  
Isolated Populations ◽  
Growth Rings ◽  
Initial Stage ◽  
History Of ◽  
The Mean ◽  
Genetically Determined ◽  
Larval Life History ◽  
Moulting Cycle

L. stanleyana occurs in some rainwater pools near Sydney, N.S.W.. A study of the life history permits description of some aspects of the growth and morphological variation of the species. No growth rings are formed on the carapace during the initial stage of post-larval development. After this a ring is formed at each moult. Animals moult at regular intervals during the period of rapid growth which continues until after maturity. Moulting then occurs less frequently and eventually ceases in aged animals. The increment in size during each moulting cycle varies. It is greater in immature than is adult animals so although the increase in number of growth rings is linear the increase in size at this time is near exponential. The maximum size attained varies from generation to generation even in the same pool. There are sexual differences in the proportions of the carapace and damage due to injury increases markedly in aged animals. At 7.5�C third- and fourth-stage nauplii did not mature and scarcely grew during incubation for 336 hr. At 16, 20, and 25�C similar larvae grew to maturity in about 349, 161, and 109 hr respectively. The mean number of spines on telsons of animals from one pool is different from that of those from other pools. This situation merits further examination since the biological characteristics of the species facilitate the study of this quantitative, probably genetically determined, character in reproductively isolated populations.

scholarly journals Reproductive Biology in Northern Prickly Ash

2018 ◽  
Vol 143 (1) ◽  
pp. 72-83
Author(s):  
David A. Munter ◽  
James J. Luby ◽  
Neil O. Anderson
Keyword(s):  
Reproductive Biology ◽  
Reproductive Strategies ◽  
Economic Importance ◽  
Reproductive Barriers ◽  
Pollen Stainability ◽  
Dioecious Species ◽  
Zanthoxylum Americanum ◽  
The Mean ◽  
Northern Forests ◽  
Autonomous Apomixis

Zanthoxylum americanum is a common understory species in the northern forests of Minnesota and surrounding regions. It has potential economic importance for its citrus fragrance, pharmacological or insecticidal properties, and produces peppercorns similar to those of the related Zanthoxylum species. Zanthoxylum americanum is a dioecious species but has been reported to have aberrant flowers with autonomous apomixis instead of other potential reproductive barriers. The reproductive biology of Zanthoxylum americanum was investigated in two native Minnesota populations. Determinations of male fertility, whether autonomous apomixis was the predominant floral reproductive mechanism, the presence of seedless fruit (parthenocarpy/stenospermocarpy), and the occurrence of hermaphrodism were made over 2 years. Sex ratios (female:male plants) within each population differed. The mean pollen stainability was 95.8% ± 0.3% (fresh) and 78.6% ± 1.1% (stored 18 months). Parthenocarpy did not occur in either population. Autonomous apomixis was not the primary floral reproductive mechanism. Stenospermocarpy (seedlessness) occurred in 13% of the female fruit clusters. Although commonly described as being dioecious, two additional reproductive strategies were identified: 1) plants with functional protandrous flowers with rudimentary pistils and 2) hermaphroditic flowers with fully functional pistils (protogynous) and anthers. As many as 10% to 30% of the male plants bore at least one fruit/plant each year. One clonal stand had both hermaphroditic and functionally staminate flowers on the same plant. Two evolutionary pathways to dioecy in Z. americanum are proposed.

scholarly journals Reproductive Biology of the Booroola Merino Sheep

1984 ◽  
Vol 37 (3) ◽  
pp. 163 ◽  
Author(s):  
BM Bindon
Keyword(s):  
Reproductive Biology ◽  
Litter Size ◽  
Single Gene ◽  
Ovulation Rate ◽  
Physiological Characteristics ◽  
Merino Sheep ◽  
Sheep Breeds ◽  
The World ◽  
Lamb Survival ◽  
Size At Birth

This paper reviews the genetic and physiological characteristics of the Booroola Merino, one of the four most prolific sheep breeds in the world, and which was acquired by CSIRO in 1958 from a commercial sheep property, 'Booroola', Cooma, N.S.W. The exceptional prolificacy of this genotypee. g. mean flock ovulation rate in 1982 of 4�2 (range 1-10) and mean litter size of 2� 5 (range 1-7)is largely attributable to a single gene (F) of uncertain origin which increases ovulation rate. Crosses of the Booroola with other Merinos produce progeny which have a 47-87% increase in ovulation rate, a 45-56% increase in litter size at birth, and a 1-33% reduction in lamb survival relative to control Merinos. This represents a 16-37% increase in the number of lambs weaned per ewe joined in favour of the Booroola crosses.

Reproductive biology of the pelagic stingray, Pteroplatytrygon violacea (Bonaparte, 1832), in the equatorial and south-western Atlantic Ocean

2014 ◽  
Vol 65 (11) ◽  
pp. 1035 ◽  
Author(s):  
D. P. Veras ◽  
F. H. V. Hazin ◽  
I. S. L. Branco ◽  
M. T. Tolotti ◽  
G. H. Burgess
Keyword(s):  
Sex Ratio ◽  
Atlantic Ocean ◽  
Reproductive Biology ◽  
Sexual Maturity ◽  
Pregnant Female ◽  
Longline Fishery ◽  
Western Atlantic ◽  
Pregnant Females ◽  
Size At Birth ◽  
Tuna Longline

From October 2005 to March 2010, a total of 480 pelagic stingray, Pteroplatytrygon violacea, specimens, 188 females and 292 males (0.64 female : 1 male), were taken in the equatorial and south-western Atlantic by the commercial tuna longline fishery and their reproductive biology was studied. Disc widths (DW) ranged from 28.0 to 66.0 cm for females and from 34.0 to 59.6 cm for males. Size at first sexual maturity was estimated at ~48.0 cm DW (first pregnant female) for females and ~41.0 cm DW for males. Ovarian fecundity, considering only follicles larger than 0.5 cm in diameter, ranged from 1 to 17 follicles per female, while the uterine fecundity of embryos in pregnant females in Stages 2 and 3 ranged from 1 to 5 embryos per female. The sex ratio between the embryos was almost equal (1.08 female : 1 male) and the size at birth was 19.0 cm DW.

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