Comparative study on the reproductive biology of Torpedo torpedo (Linnaeus, 1758) and T. marmorata (Risso, 1810) in the central Mediterranean Sea

Consalvo, Iván; Scacco, Umberto; Romanelli, Michele; Vacchi, Marino

doi:10.3989/scimar.2007.71n2213

Cited by 24 publications

(24 citation statements)

References 11 publications

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“…A frequently observed larger size in female elasmobranchs facilitates the accommodation and nourishment of embryos (Hamlett 2005). Increased fecundity with increasing maternal size is also well documented (Cortes 2000;Consalvo et al 2007), which is consistent with conferring a selective advantage on largersized females.…”

Section: Discussionsupporting

confidence: 61%

Sexual dimorphism based on body proportions and ontogenetic changes in the Brazilian electric rayNarcine brasiliensis(von Olfers, 1831) (Chondrichthyes: Narcinidae)

Rolim¹,

Caltabellotta

Rotundo

et al. 2015

African Journal of Marine Science

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Sexual dimorphism in the Brazilian electric ray Narcine brasiliensis from the south-western Atlantic coast was evaluated based on body proportions and ontogenetic changes. All regions of the body were found to have differences in body proportions between the sexes, except the spiracles. The nature of allometric and isometric relationships differed mainly in terms of the six largest body dimensions. Some of these differences can be supported by the species' life history. Principal components analysis (PCA) and analysis of similarities (ANOSIM) distinguished the adults' body proportions by sex. Similarity percentage analysis (SIMPER) selected six variables that best discriminated between the sexes with a cumulative difference up to 70% (tail width, disc width, length between snout and first dorsal fin, pelvic fin width, length between snout and the widest part of the disc, and disc length). It was possible to select seven stable dimensions, both ontogenetic and sexual, that are recommended for use in taxonomic studies. These dimensions were interspiracular distance, spiracle length and width, upper and lower tooth band width, pelvic fin length, and length of posterior lobe of the pelvic fin. It is important to consider the differences in body proportions within a species in order to properly characterise the population and estimate its most reliable parameters.

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Section: Discussionsupporting

confidence: 61%

Sexual dimorphism based on body proportions and ontogenetic changes in the Brazilian electric rayNarcine brasiliensis(von Olfers, 1831) (Chondrichthyes: Narcinidae)

Rolim¹,

Caltabellotta

Rotundo

et al. 2015

African Journal of Marine Science

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“…In our study, we identified a female with a contracted cervix and a fecundity of 24 embryos, suggesting she did not abort any embryos, which provides support for our estimations. Lower fecundities have been observed in other Torpediniformes, such as Lesser Electric Ray (1-14, Moreno et al 2010), Pacific Electric Ray (17, Neer andCailliet 2001), and Marbled Electric Ray T. marmorata (3-16, Consalvo et al 2007), although all these species are smaller than the Giant Electric Ray and thus can be expected to have lower fecundities. In addition, in some species the number of embryos is related to embryo size, such as in Ocellated Torpedo, which has a fecundity of 28 small embryos (12.5 cm TL, Capapé et al 2000).…”

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confidence: 94%

Reproductive Strategy of the Giant Electric Ray in the Southern Gulf of California

Burgos-Vázquez¹,

Mejía‐Falla²,

Cruz-Escalona³

et al. 2017

Mar Coast Fish

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The objective of the present study was to describe and characterize macroscopic and microscopic aspects of the reproductive biology of the Giant Electric Ray Narcine entemedor, a viviparous elasmobranch targeted by commercial fishers in Mexico. A total of 305 individual rays were captured (260 females, 45 males); all males were sexually mature. The median size at maturity for females was estimated to be 58.5 cm TL, the median size at pregnancy was 63.7 cm TL, and the median size at maternity was 66.2 cm TL. The range of ovarian follicles recorded per female was 1–69; the maximum ovarian fecundity of fully grown vitellogenic oocytes was 17, and uterine fecundity ranged from 1 to 24 embryos per female. The lengths of the oblong ovarian follicles varied significantly among months, and the largest ovarian follicles were found in July, August, and September. Median embryo size was largest in August, and the size at birth was between 12.4 and 14.5 cm TL. Histological evidence of secretions from the glandular tissue of the uterine villi indicate that this species probably has limited histotrophy as a reproductive mode. Vitellogenesis in the ovary occurred synchronously with gestation in the uterus. The Giant Electric Ray has a continuous annual reproductive cycle; a period of ovulation occurs between May and September and two peaks of parturition, one in January and one in August, occur, suggesting that embryonic diapause occurs in some individuals. These results provide useful information for the management of this important commercial species in Bahía de La Paz, Mexico, and will allow possible modification of the current Mexican regulations to enable better protection of this species.

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“…Differences in ovarian fecundity and number of uterine eggs or embryos were observed for B.kreffti, as already reported for several elasmobranchs. Consalvo et al (2007) observed 2-22 ovarian follicles but 4-19 embryos in T. torpedo, whereas, for T. marmorata, ovarian follicles ranged from one to 35 and litter size was 3-16. These differences are probably a result of reabsorption events once not all follicles are ovulated and might undergo atresia (Conrath, 2005).…”

Section: Discussionmentioning

confidence: 83%

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

Martins

Gadig

2019

Neotrop. ichthyol.

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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.

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Comparative study on the reproductive biology of Torpedo torpedo (Linnaeus, 1758) and T. marmorata (Risso, 1810) in the central Mediterranean Sea

Cited by 24 publications

References 11 publications

Sexual dimorphism based on body proportions and ontogenetic changes in the Brazilian electric rayNarcine brasiliensis(von Olfers, 1831) (Chondrichthyes: Narcinidae)

Sexual dimorphism based on body proportions and ontogenetic changes in the Brazilian electric rayNarcine brasiliensis(von Olfers, 1831) (Chondrichthyes: Narcinidae)

Reproductive Strategy of the Giant Electric Ray in the Southern Gulf of California

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

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