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

The reproductive biology of Torpedo torpedo (n = 535) and Torpedo marmorata (n = 385), collected in coastal waters of Latium (central Mediterranean Sea, Italy) between September 2000 and October 2001, was studied and compared. Males and females reached a maximum length of 445 and 477 mm TL in T. torpedo and 364 and 553 mm TL in T. marmorata. Males and females of T. torpedo reached length at sexual maturity (TL50%) at similar sizes (249 mm TL and 258 mm TL respectively) whereas TL50% in females of T. marmorata was greater than that of males (312 and 251 mm TL respectively). Analysis of the gonadosomatic index (GSI) and maximum oocyte diameter (MOD) in mature females suggested that gestation lasted about 6 months in T. torpedo and 9 to 10 months in T. marmorata. Fecundity was positively correlated with length in both species and, comparing ovarian and uterine fecundity, T. torpedo had a greater reproductive potential than T. marmorata. Size at birth of T. torpedo was smaller than that of T. marmorata and embryos of the latter showed a higher rate of mass increment with size than those of T. torpedo.

Abstract licence: CC BY

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