Biological parameters of franciscana dolphins, Pontoporia blainvillei, bycaught in artisanal fisheries off Argentina.

NEGRI, M.F.; PANEBIANCO, M.V.; DENUNCIO, P; RODRIGUEZ, D; CAPPOZZO, H.L.

JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2011

0025-3154

Franciscana dolphin (Pontoporia blainvillei) is an endemic small coastal dolphin of the Southwestern Atlantic Ocean. Incidental captures of this species in fishing gillnets occur all along itsgeographical distribution. The aim of this paper was to determine the biological parameters of the franciscana dolphin bycaught in the artisanal coastal fishery of the southern Buenos Aires province,Argentina. Between 2003 and 2009, the carcasses of 54 incidentally entangled franciscanas were collected. The age, sexual and physical maturity as well as the body condition of each specimen was determined. In the studied area, the sex ratio of the bycaught dolphins did not differ from 1:1 and, consistent with other areas, juveniles less than 4 years old were in high proportion (69%). Inaddition, 74% of the entangled animals was sexually immature and the 85% physically immature. Also, there was a predominance of sexually immature dolphins during spring time, coinciding with the breeding season. From the body condition analyses, it might be inferred that the condition of the bycaught franciscanas were good and, thus, entanglement were not associated with a disease or physiological disorder. The data presented here are of importance to assess the impact of artisanal fisheries on the population of franciscana dolphin in the southernmost area of its distribution.