Observations on the biology of the common torpedo (Torpedo torpedo, Linnaeus, 1758) and marbled electric ray (Torpedo marmorata, Risso, 1810) from Egyptian Mediterranean waters

1994 ◽  
Vol 45 (4) ◽  
pp. 693 ◽  
Author(s):  
SH Abdel-Aziz
Keyword(s):  
Reproductive Biology ◽  
Breeding Season ◽  
Reproductive Cycle ◽  
Strong Correlation ◽  
Maximum Size ◽  
Size At Maturity ◽  
Torpedo Marmorata ◽  
Food Items ◽  
The Common ◽  
Males And Females

The reproductive biology and diets of Torpedo torpedo and T. marmorata from Egyptian Mediterranean waters are described. Males and females reached a maximum size of 39.1 and 40.8 cm total length (TL), respectively, in T. torpedo and 38.6 and 61.2 cm TL, respectively, in T. marmorata. The size at maturity of males of T. torpedo and T. marmorata is 18 and 25.5 cm TL, respectively, and of females, is 22 and 35.5 cm TL, respectively. Both species exhibit aplacental viviparity. T. torpedo has a restricted breeding season, and individual females appear to breed annually, whereas T. marmorata females appear to have a more extended reproductive cycle (probably breeding every two years). In both species, males are capable of mating every year. In T. torpedo, mating occurs between December and February, ovulation in March-April, and parturition in late August and September after five to six months of gestation. Individuals of T. marmorata mate between November and January, ovulate between December and February, and give birth the following December after 10-12 months of gestation. Mean embryos sizes are 7.3 cm TL (range 4.6-8.2 cm TL) for T. torpedo and 8.5 cm TL (range 5.8-10.1 cm TL) for T. marmorata. Observations in Egyptian Mediterranean waters show a strong correlation between ovarian and uterine fecundity and the length of the mother in both species. Fish are an important component of the diet of the two species, as, to a lesser extent, are crustaceans for T. torpedo and cephalopods for T. marmorata. Juveniles eat a wide variety of food items, whereas adults feed only on fish.

The Diet of the Common Toad (Bufo bufo) around a Pond in Mid-Wales

1987 ◽  
Vol 8 (1) ◽  
pp. 13-17 ◽  
Author(s):  
S.P. Gittins
Keyword(s):  
Bufo Bufo ◽  
Adult Males ◽  
Common Toad ◽  
Food Items ◽  
Inorganic Matter ◽  
Significant Difference ◽  
The Common ◽  
Males And Females ◽  
Toad Bufo ◽  
Toad Bufo Bufo

AbstractThere was no significant difference between the number of food items obtained by stomach-flushing toads caught in pitfall traps and from the dissection of corpses found on nearby roads. The frequencies of the different food categories were similar using the two methods. 97 % of the toads entering the pond in the spring had not recently fed, whereas 25% of toads leaving the pond had started to feed. Sloughed skin was found in 7% of stomachs. Vegetable matter was found in 15% of stomachs and inorganic matter in 6% of stomachs. The diet of the toad was found to be very varied, and the main food items were beetles, collembolans, millipedes, harvestmen and spiders. The diets of males, females and young toads were very similar, and only slight changes in diet were observed throughout the year. The size of food items ranged from 1 mm to 40 mm with most around 7 mm. There was no significant relationship between the size of the food item and the size of the toad for adult males and females, but there was for juveniles.

scholarly journals Reproductive biology of the Brazilian sharpnose shark (Rhizoprionodon lalandii) from southeastern Brazil

2007 ◽  
Vol 64 (9) ◽  
pp. 1829-1835 ◽  
Author(s):  
Fabio S. Motta ◽  
Rafael C. Namora ◽  
Otto B. F. Gadig ◽  
F. M. S. Braga
Keyword(s):  
Reproductive Biology ◽  
Positive Relationship ◽  
Ovarian Follicles ◽  
Southeastern Brazil ◽  
Brazilian Coast ◽  
Marine Science ◽  
Size At Maturity ◽  
Total Length ◽  
Males And Females ◽  
Using Data

Abstract Motta, F. S., Namora, R. C., Gadig, O. B. F., and Braga, F. M. S. 2007. Reproductive biology of the Brazilian sharpnose shark (Rhizoprionodon lalandii) from southeastern Brazil. – ICES Journal of Marine Science, 64: 1829–1835. The reproductive biology of the Brazilian sharpnose shark, Rhizoprionodon lalandii, off southeastern Brazil was investigated using data from gillnet landings. The size-at-maturity for males and females was estimated to be 59 and 62 cm total length (LT), respectively. Ovarian fecundity ranged from 3 to 7 follicles (mean = 4.54), and uterine fecundity from 1 to 5 embryos (mean = 3.3). There was a slight positive relationship between female LT and the number of ovarian follicles, but uterine fecundity was not related to female LT. Embryonic growth is fast following fertilization during summer and autumn. Gestation requires 11–12 months, and peak parturition is between August and September. A comparison of size-at-maturity between animals from northeastern and southeastern Brazil suggests the existence of at least two stocks of R. lalandii along the Brazilian coast.

scholarly journals Aspects of the reproductive biology of skates (Chondrichthyes: Rajiformes: Rajoidei) from southern Africa

2007 ◽  
Vol 65 (1) ◽  
pp. 81-102 ◽  
Author(s):  
David A. Ebert ◽  
Leonard J. V. Compagno ◽  
Paul D. Cowley
Keyword(s):  
Reproductive Biology ◽  
Southern Africa ◽  
Sexual Maturity ◽  
Size At Maturity ◽  
Total Length ◽  
Large Size ◽  
Disc Width ◽  
New Information ◽  
Males And Females ◽  
First Maturity

AbstractEbert, D. A., Compagno, L. J. V., and Cowley, P. D. 2008. Aspects of the reproductive biology of skates (Chondrichthyes: Rajiformes: Rajoidei) from southern Africa. – ICES Journal of Marine Science, 65: 81–102. New information is presented on the reproductive biology of 22 southern African skate species. Sex ratios for most species were relatively even. Sexual dimorphic differences in disc shape were evident in all species, but the total length (LT) to disc width (D) relationship was significantly different in only three species, and the LT to weight (W) relationship significant in just five species. Sexual dimorphism relative to maximum total length (LTmax) was absent in all but the two largest species. Males and females of the same species grow to a similar LTmax except those whose LTmax is >1.5 m LT. Size at first and 50% (LT50) sexual maturity was approximately the same for both sexes in all but the two largest species. First maturity occurred at >60% of LTmax for all species for which sufficient data were available, and most (n = 18) matured at >75% LTmax. The large size at maturity relative to LTmax suggests that growth slows or is partially suspended following sexual maturity. The egg cases of 15 species are described, and a key to their identification is presented. Egg cases in utero were observed throughout the year suggesting that most species reproduce year-round.

Reproductive Biology of the Black Dogfish,Centroscyllium Fabricii, Collected From Waters off Western Greenland

1995 ◽  
Vol 75 (2) ◽  
pp. 285-310 ◽  
Author(s):  
Kazunari Yano
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Breeding Season ◽  
Litter Size ◽  
Reproductive Organs ◽  
Normal Female ◽  
Size At Maturity ◽  
Free Living ◽  
Near Term ◽  
Female Reproductive Organs

The reproductive biology of 1124 male (165–760 mm TL) and 1476 female (175–898 mm TL) black dogfish,Centroscyllium fabricii, was examined. The sharks were caught off western Greenland with bottom otter trawls. Size at maturity was about 550 mm TL in males and 650 mm TL in females. Ovarian ova did not continue to develop during gestation. The sex ratio of embryos was 1:1. Litter size ranged from 4 to 40, with a mean of 16–4. The total number of mature ova, fertilized ova, or embryos tended to increase with size of the females. Development of black dogfish embryos is dependent solely on yolk reserves. Near-term embryos (152–192 mm TL) had completely absorbed their external yolk sacs. The smallest free-living specimens collected in this study were 165 mm TL for males and 175 mm TL for females. The black dogfish does not seem to have a well-defined breeding season. This species displayed a well-defined pattern of depth segregation by size. The sex ratios in five shallow depth strata (500–599, 600–699, 700–799,800–899, and 900–999 m) were 1:1, but those of three deeper depth strata (1000–1099,1100–1199, and 1200–1299 m) contained a significantly greater number of females than males. Four abnormal hermaphrodites possessed gonads containing both testicular and ovarian tis-sues. Two specimens had normal female reproductive organs (e.g. ovaries, oviducts, nidamental glands, and uteri) as well as claspers.

Reproductive biology of the banded guitarfish, Zapteryx exasperata, from the Gulf of California, México

2009 ◽  
Vol 89 (8) ◽  
pp. 1655-1662 ◽  
Author(s):  
María-Del-Pilar Blanco-Parra ◽  
J. Fernando Márquez-Farías ◽  
Felipe Galván-Magaña
Keyword(s):  
Reproductive Biology ◽  
Reproductive Cycle ◽  
Gulf Of California ◽  
Average Length ◽  
Common Species ◽  
Management Plans ◽  
Males And Females ◽  
One Year ◽  
Gravid Females ◽  
Critical Aspects

The banded guitarfish, Zapteryx exasperata, is a common species in the artisanal elasmobranch fisheries in the Gulf of California. Fishery-derived specimens were examined to determine critical aspects of the reproductive biology of this poorly known group of rays. Two functional testes and ovaries were found in males and females respectively. Median size at maturity (L50%) for males was 64 cm total length (TL) and for females 69 cm TL. Average length of gravid females was 78.8±3.8 cm TL. Histological analysis showed no evidence of sperm storage in the oviducal gland. Gestation was estimated to occur over a five to six month period (February–July) and was concurrent with vitellogenesis. Mean uterine fecundity was estimated as 7 (range 2–13, SD. = 3). The sex-ratio of embryos was 1:1. The reproductive cycle for Z. exasperata from the Gulf of California was estimated to last one year with parturition, ovulation and copulation occurring during the summer months. Differences found in the reproductive cycle of Z. exasperata between the Gulf of California and the west coast of Baja California could have implications in the future management plans for this fishery in the Gulf of California.

Reproductive cycle of the common guitarfish, Rhinobatos rhinobatos (Linnaeus, 1758), in Alexandria waters, Mediterranean Sea

1993 ◽  
Vol 44 (3) ◽  
pp. 507 ◽  
Author(s):  
SH Abdel-Aziz ◽  
AN Khalil ◽  
SA Abdel-Maguid
Keyword(s):  
Embryonic Development ◽  
Mediterranean Sea ◽  
Reproductive Cycle ◽  
Egg Size ◽  
Gonadosomatic Index ◽  
Maximum Size ◽  
Reproductive Rate ◽  
Gestation Period ◽  
Monthly Basis ◽  
The Common

The common guitarfish, Rhinobatos rhinobatos, is an ovoviviparous fish having a gestation period of about nine months and a mean reproductive rate of 8 to 14 progeny per pregnancy. Data on gonadosomatic index, maximum ovum diameter, size frequency of ova, and ovarian and uterine contents for 438 specimens (236 females and 202 males), analysed on a monthly basis, indicated a distinct seasonal reproductive cycle for R. rhinobatos. Females reached a maximum size of 181 cm and 20 kg, whereas the maximum size of males was 172 cm and 16 kg. Lengths at which 50% of specimens were mature were 87 and 70 cm for females and males, respectively. Ovarian egg size and male gonadosomatic index both peaked in July and August, indicating that mating occurred in summer. Uterine eggs were present from late February through July, but no embryonic development was evident. Females with full-term embryos were observed in late August, and parturition was followed immediately by ovulation. Ovarian fecundity ranged from 8 to 27 (mean 18) eggs per fish, whereas uterine fecundity ranged from 8 to 14 (mean 12) eggs or embryos per fish.

scholarly journals Reproductive aspects of the oceanic whitetip shark, Carcharhinus longimanus (Elasmobranchii: Carcharhinidae), in the equatorial and southwestern Atlantic Ocean

2013 ◽  
Vol 61 (2) ◽  
pp. 161-168 ◽  
Author(s):  
Mirna Regina dos Santos Tambourgi ◽  
Fábio H.V. Hazin ◽  
Paulo G.V. Oliveira ◽  
Rui Coelho ◽  
George Burgess ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Reproductive Biology ◽  
Reproductive Cycle ◽  
Size At Maturity ◽  
Southwestern Atlantic ◽  
Total Length ◽  
Southwestern Atlantic Ocean ◽  
Longline Fisheries ◽  
Fishing Area ◽  
Pelagic Longline

The present study sought to study the reproductive biology of the oceanic whitetip shark, Carcharhinus longimanus, in the equatorial and southwestern Atlantic Ocean. A total of 234 specimens were collected as bycatch during pelagic longline fisheries targeting tunas and swordfish, between December 2003 and December 2010. The fishing area was located between latitudes 10N and 35S and longitudes 3E and 40W. Of the 234 individuals sampled, 118 were females (with sizes ranging from 81 to 227 cm TL, total length) and 116 males (ranging from 80 to 242 cm TL). The reproductive stages of the females were classed as immature, mature, preovulatory and pregnant, while males were divided into immature, maturing and mature. The size at maturity for females was estimated at 170.0 cm TL, while that for males was between 170.0 and 190.0 cm TL. Ovarian fecundity ranged from 1 to 10 follicles and uterine fecundity from 1 to 10 embryos. The reproductive cycle of this species is most likely biennial, with parturition occurring once every two years.

Population ecology of the Australian frog Crinia signifera: adults and juveniles

1996 ◽  
Vol 23 (3) ◽  
pp. 249 ◽  
Author(s):  
CM Bull ◽  
I Williamson
Keyword(s):  
Breeding Season ◽  
Population Ecology ◽  
South Australia ◽  
Adult Mortality ◽  
Large Size ◽  
Early Emergence ◽  
The Common ◽  
Males And Females ◽  
A Site ◽  
Breeding Seasons

A population of the common Australian frog Crinia signifera Girard, 1853 was studied over a 3.5 year period at a site near Bridgewater in South Australia. In this population, C. signifera are long lived and iteroparous, with some individual males and females participating in at least four consecutive breeding seasons. Adult survivorship was high (up to about 70% per annum) for both males and females. Metamorphosis occurred from October to January and some individuals reached maturity within a year. However, most individuals reached maturity in the second breeding season following metamorphosis. Survival of juveniles ranged from 5 to 72% per annum, with individuals emerging early having higher survival than those that metamorphosed late. However, it was not clear whether increased survival was associated with early emergence or large size at emergence. The data support the argument that iteroparity is favoured in situations in which preadult mortality is higher and less predictable than adult mortality.

scholarly journals Breeding in wild populations of a small dasyurid marsupial, Planigale ingrami, in north-western Queensland using a novel method for collection of specimens

2014 ◽  
Vol 36 (1) ◽  
pp. 81 ◽  
Author(s):  
P. A. Woolley ◽  
C. Elliott
Keyword(s):  
Reproductive Biology ◽  
Breeding Season ◽  
Reproductive Strategies ◽  
Breeding Cycle ◽  
Wild Populations ◽  
Reproductive Structures ◽  
Identification Of Species ◽  
Novel Method ◽  
Males And Females ◽  
North Western

The reproductive biology of the long-tailed planigale (Planigale ingrami) is less well known than that of its congeners P. gilesi and P. tenuirostris. Aspects of the anatomy of reproductive structures and the pattern of reproduction of P. ingrami were established by examination of specimens extracted from the stomachs of feral cats shot in north-western Queensland. This species has an extended breeding season that commences in August and probably ends in December, and both males and females may live to breed in more than one season, providing support for the similarity of the reproductive strategies of these three species of Planigale. Females of P. ingrami have twelve nipples in the pouch, the form of which may differ from that of other planigales. Pouch morphology may prove useful in the identification of species of Planigale providing observations are made on the appearance of the pouch throughout the breeding cycle.

scholarly journals Diet of Leptodactylus fuscus (Amphibia: Anura: Leptodactylidae) in the Pantanal of Miranda river, Brazil

2012 ◽  
Vol 12 (1) ◽  
pp. 99-104 ◽  
Author(s):  
José Luiz Massao Moreira Sugai ◽  
Juliana de Souza Terra ◽  
Vanda Lúcia Ferreira
Keyword(s):  
Body Size ◽  
Prey Size ◽  
Maximum Size ◽  
Diet Overlap ◽  
Generalist Predators ◽  
Adult Males ◽  
Intrinsic Factors ◽  
Skull Shape ◽  
Food Items ◽  
Males And Females

Amphibians are usually generalist predators, and their diet is influenced by extrinsic (e.g. food availability) and intrinsic factors (e.g. body size and skull shape). This study aims to describe the diet of adult males and females of Leptodactylus fuscus in the Pantanal of the Miranda river and to answer the following questions: i) Are prey's maximum size and number of food items explained by the anuran's body size? ii) Are richness of morphospecies and number of food items explained by frog sex? iii) Is there diet overlap between male and female? We recorded 62 food items, belonging to seven orders of Arthropoda, and one individual of Annelida. The diet of L. fuscus was dominated by Orthoptera, followed by Coleoptera, Araneae, Hymenoptera, Blattaria, Hemiptera and Diptera. Frog's body size did not influence prey size or number of food items consumed. The number of prey and richness of morphospecies did not differ between males and females. There was low diet overlap between the sexes. Our results provide evidence for the opportunistic and generalist feeding behavior of L. fuscus.

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