Reproductive biology of female franciscana dolphins (Pontoporia blainvillei) from Argentina

PANEBIANCO, MARÍA V.; DEL CASTILLO, DANIELA L.; DENUNCIO, PABLO E.; NEGRI, MARÍA F.; BASTIDA, RICARDO; FAILLA, MAURICIO; VITULLO, ALFREDO D.; CAPPOZZO, HUMBERTO L.

JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM

CAMBRIDGE UNIV PRESS

Año: 2016 vol. 96 p. 831 - 840

0025-3154

The ovaries of 31 franciscana dolphins (19 immature and 12 mature) by-caught in coastal waters of Argentina were examined to describe the reproductive biology. No ovarian polarity was found, both ovaries were functional and showed similar amounts of corpora. A positive trend was observed between the number of corpora and age (3-8 years old), indicating that ovulation scars are detectable for at least 4 years, and a ovulation rate of 0.39 was found for the sampled population. Age, length and weight at sexual maturity were estimated at 3.92 ± 0.09 years, 133.47 ± 11.11 cm and 32.68 ± 2.72 kg, respectively. The annual pregnancy rate was 0.36 ± 0.02 (95% CI = 0.10-0.65). The proportion of lactating and resting females found were 0.25 and 0.33 respectively. These outcomes constitute the first reproductive and life history information on franciscana dolphins from the southernmost population and are important in relation with adequate conservation management plans for this small cetacean.