scholarly journals Reproductive biology of the Brazilian blind electric ray Benthobatis kreffti (Chondrichthyes: Narcinidae)

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Mariana F. Martins ◽  
Otto B. F. Gadig

ABSTRACT This study provides information on the reproductive biology of the Brazilian blind electric ray Benthobatis kreffti, endemic to southern and southeastern Brazil. Individuals were caught by bottom trawl carried out in 2003 and 2007, at 492-501 m depth off the São Paulo State continental slope. A total of 152 females (115-299 mm) and 144 males (91-243 mm) were sampled. Maturity was first observed at 177 and 162 mm, with total length at 50% maturity of 191 and 176 mm in females and males respectively. Uterine fecundity ranged from 1-3 and was not related to female total length. Size at birth estimated from the largest near-term observed embryos and smallest free-swimming ray was 91-100 mm. The low fecundity observed is typical of deepwater elasmobranch species, as well as late maturity in comparison with costal species. The relatively large size-at-birth suggests that this species invests more in length of each embryo than in litter size, increasing the offspring’s survival chance. In this context, these parameters highlight the vulnerability of this and other deepwater species to non-natural death, mostly caused by deep-sea fisheries.

2007 ◽  
Vol 64 (9) ◽  
pp. 1829-1835 ◽  
Author(s):  
Fabio S. Motta ◽  
Rafael C. Namora ◽  
Otto B. F. Gadig ◽  
F. M. S. Braga

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.


2007 ◽  
Vol 65 (1) ◽  
pp. 81-102 ◽  
Author(s):  
David A. Ebert ◽  
Leonard J. V. Compagno ◽  
Paul D. Cowley

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.


Caldasia ◽  
2015 ◽  
Vol 37 (1) ◽  
pp. 197 ◽  
Author(s):  
Kelly Acevedo ◽  
Fabián Moreno ◽  
Marcela Grijalba-Bendeck ◽  
Arturo Acero ◽  
Jorge Paramo

<p>As for most batoid species, little is known about the basic biology of the Venezuela round stingray Urotrygon venezuelae (Urotrygonidae). This study presents information about the reproductive biology of the species, including fecundity, embryonic development stage, relationship between maternal size and fecundity, gonadosomatic (GSI) and hepatosomatic (HSI) indices, sex ratios, maturity size and size at birth. With all this information, a preliminary reproductive cycle is proposed. A total of 269 specimens were caught with beach seine in Salguero beach, Colombian Caribbean Sea, between August 2005 and October 2006. We propose for U. venezuelae a biological cycle with three reproductive peaks: November-December, March-April and August. Median sexual maturity size was calculated in 176 mm (total length) for females and 227 mm for males; fecundity ranged between one and six embryos per female. We found that cloacal diameter and liver weight were better predictors for fecundity than total length for U. venezuelae.</p>


Author(s):  
C. Capapé ◽  
A.A. Seck ◽  
A. Gueye-Ndiaye ◽  
Y. Diatta ◽  
M. Diop

Two species of genus Squatina were recorded off the coast of Senegal and Squatina oculata is the most commonly caught in the area. Adult males and females studied were over 820 and 890 mm total length (TL) respectively, with the largest male and the largest female recorded being 1450 mm and 1570 mm and weighed 37 kg and 39 kg respectively. The females were significantly heavier than the males. Size at birth was between 226 and 266 mm and weight at birth between 129 and 159 g. Weight of ripe oocytes ranged from 87·65 to 117·60 g (mean SD 101·73±&;8·65). Gestation lasts one year minimum. Squatina oculata is a lecithotrophic species. Counts of ripe oocytes, eggs, embryos and fully developed foetuses showed that ovarian fecundity is significantly higher than uterine fecundity. The former ranged from 8 to 20 (mean SD 12·04±5·80), the latter from 3 to 8 (mean SD 6·22±3·41). There is no relationship between size and the categories of fecundity. Adult males and females were more common than the other categories of specimens landed. Among adults, females were more numerous than males, mainly gravid specimens.


2002 ◽  
Vol 62 (2) ◽  
pp. 239-248 ◽  
Author(s):  
F. E. S. COSTA ◽  
F. M. S. BRAGA ◽  
C. A. ARFELLI ◽  
A. F. AMORIM

Uteri from four pregnant females and two newborn of shortfin mako, Isurus oxyrinchus, were collected in the southeastern region of Brazil, during September, October, and November of 1993 and 1994. All embryos were near-term with developing dentition and inner organs. Total length ranged from 64.5 to 72.0 cm, and the maximum number of embryos observed in a litter was 20. These observations further confirmed oophagy as a form of nutrition in this species, and its periodicity. The presence of teeth in the embryos' stomachs suggest that tooth replacement begins in the uterine phase.


Zootaxa ◽  
2008 ◽  
Vol 1861 (1) ◽  
pp. 44 ◽  
Author(s):  
ULISSES CARAMASCHI ◽  
RENATO N. FEIO ◽  
VINÍCIUS A. SÃO-PEDRO

A new species of Leptodactylus belonging to the L. fuscus species group, and related to the L. mystaceus complex, is described from the Lagoa das Bromélias (20 o 53’S, 42 o 31’W; 1,227 m above sea level), Parque Estadual da Serra do Brigadeiro, Municipality of Ervália, State of Minas Gerais, Southeastern Brazil. Leptodactylus cupreus sp. nov. is characterized by the large size for the group (SVL 50.1–55.1 mm in males) and color pattern. The new species has a non-pulsed advertisement call, with call rate about 12 calls/s and a dominant frequency between 2,800 and 3,058 Hz.


2006 ◽  
Vol 23 (2) ◽  
pp. 314-322 ◽  
Author(s):  
Érika R. de Alvarenga ◽  
Nilo Bazzoli ◽  
Gilmar B. Santos ◽  
Elizete Rizzo

Reproductive biology and feeding of Curimatella lepidura (Eigenmann & Eigenmann, 1889) were studied in Juramento reservoir, São Francisco River basin, Southeastern Brazil. Histological analyses and gonadosomatic indexes revealed females and males in reproductive activity from October to March and total spawning occurring from January to March coupled with the peak of spermiating males. In the dry season, the fishes accumulated energetic reserves for reproduction during a short rainy season. The species presented sexual dimorphism, being females larger than males and sexual maturation occurring close to 7.7 cm standard length for females and 7.1 cm for males. C. lepidura presented iliophagous feeding habit, ingesting mainly sediment/detritus and a small amount of acari, algae, Tricoptera insects and Ostracoda crustaceans, suggesting a probable role in nutrient recycling of the Juramento reservoir.


2017 ◽  
Vol 15 (1) ◽  
Author(s):  
María L. Estalles ◽  
María R. Perier ◽  
Edgardo E. Di Giácomo

ABSTRACT This study estimates and analyses the reproductive parameters and cycle of Sympterygia bonapartii in San Matías Gulf, northern Patagonia, Argentina. A total of 827 males and 1,299 females were analysed. Males ranged from 185 to 687 mm of total length (TL) and females from 180 to 742 mm TL. Sexual dimorphism was detected; females were larger, heavier, exhibited heavier livers, wider discs and matured at lager sizes than males. Immature females ranged from 180 to 625 mm TL, maturing females from 408 to 720 mm TL, mature ones from 514 to 742 mm TL and females with egg capsules from 580 to 730 mm TL. Immature males ranged from 185 to 545 mm TL, maturing ones from 410 to 620 mm TL and mature males from 505 to 687 mm TL. Size at which 50% of the skates reached maturity was estimated to be 545 mm TL for males and 594 mm TL for females. According to the reproductive indexes analysed, S. bonapartii exhibited a seasonal reproductive pattern. Mating may occur during winter-early spring and the egg-laying season, during spring and summer.


2020 ◽  
Vol 54 (3) ◽  
pp. 336
Author(s):  
Andrés Reátegui-Quispe ◽  
Daniel Pariona-Velarde

Blue shark Prionace glauca is one of the most important elasmobranch species landed and consumed in Peru. Due to its importance as fishery resource, were evaluated lead (Pb), cadmium (Cd), mercury (Hg) and Total Volatile Base Nitrogen (TVBN) in the muscle tissue of 25 specimens, captured in the southern zone of Peruvian sea. These analytes were compared with current regulations and were determined its relationship with sex and total length (TL). We obtained ranges between 0.04-0.25, 0.01-0.04 and 0.09-0.50 mg kg-1 for Pb, Cd and Hg, respectively. TVBN values were between 38.50-94.60 mg TVBN 100 g-1. Analytes did not have differences with TL and gender. Pb was positive correlation with TL, while the Cd, Hg and TVBN did not. This study provides sanitary information of blue shark muscle from Peruvian waters.


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