Reproductive Parameters of the Pelagic Stingray, Pteroplatytrygon(Dasyatis) violacea
| Reproductive parameter | Med. Sea (1) | Western Atlantic (2) | Eastern Pacific (3) | Western Pacific (4) |
|---|---|---|---|---|
| Mating | ||||
| Ovulation | ||||
| Egg capsule dimension | 3 x 1.5 cm | 8 x 4 cm | 4 x 3 x 1.5 cm (a) | |
| Number of eggs | 2-6 | up to 13 | 7 (a) | |
| Size of egg | 1.9 g | 1.0 g (a) | ||
| Embryo development | aplacental viviparity, trophonemata of uterine wall produce rich (13 % organic) "mother-milk" after egg-yolk has been used up | |||
| Litter size | 5-6 | 4-7; 10 (b) | 4-9 | |
| Gestation | 2 months | 2 - 3 months | ||
| Parturition | Aug./Sep.; Oct. 20, 1995 in captivity (5) | Aug./Sep.? | Winter (far off coast of Central America); Nov. 15, 1995 in captivity | Nov. - March in captivity |
| mean litter diskwidth at birth | 14.3-17.5 cm | 19.0 cm | 16.1-24.1 cm | |
| mean litter weight at birth | 150-175 g | 178 g | 155-463 g | |
| Male Maturity | 37.5 cm (6) | no data | < 41 cm (7), age 2? | |
| Female Maturity | 3.50-3.75 kg (8) ~46-48 cm DW | 40 - 50 cm | 40 - 50 cm?, age 3? | |
| Max. Size Male | 54 cm | 68 cm, 12 kg; age 6-7 yr; captive specimens |
||
| Max. Size Female | (61.4 cm) 9.010 kg | 80 cm | 96 cm, 46 kg; age 7-8 yr |
|
1) Lo Bianco 1909, Ranzi
1932, Ranzi 1933, Ranzi
and Zezza 1936,
2) Wilson and Beckett 1970,
3) This study (captive MBA data), M. Shaw (personal communication, captive data)
4) K. Chai (personal communication, captive data), Nishida and Fujino (manuscript
to be published, captive data)
5) Rod Haynes 1996. Personal commun.
6) Tortonese 1976, Last
1979
7) Julie Neer 1999. Personal communication.
8) Ranzi (1932)
a) Scott Greenwald found an eggcase with 7 eggs on June 8, 1996 in a holding
tank with 4 female and 2 male pelagic rays. We suspect that the eggcase (with
likely infertile eggs) was aborted for unknown reasons soon after ovulation.
Except for the smaller size, the eggcase (and eggs) was similar to the one described
by Wilson and Beckett (1970).
b) A large pelagic stingray (DW over the curve 1.06 m, DW ~ 1.0 m, M = 33.6
kg) which was captured in July 1994 at age 1-2 yr died on 3 June, 2005 at age
~12-13 yr. The left uterus contained 10 early-term embryos without pigmentaton
(DW range 5.5-7.0 cm, mean 6.25 cm). (Ann Coleman personal communication).
Created March 1996, (Slide shown at June 1996 AES meeting in New Orleans);
updated March 2005.
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