INVESTIGADORES
CRESPO Enrique Alberto
artículos
Título:
Growth and age at sexual maturity of South American sea lions. Mammalian Biology.
Autor/es:
GRANDI, M.F., S. L. DANS, N.A. GARCÍA & E. A. CRESPO
Revista:
JOURNAL OF MAMMALOGY
Editorial:
ALLIANCE COMMUNICATIONS GROUP DIVISION ALLEN PRESS
Referencias:
Año: 2010 vol. 75 p. 427 - 436
ISSN:
0022-2372
Resumen:
The averageageatsexualmaturity(ASM) isanimportantparameterforevaluatingthereproductivepotentialor status ofapopulation.SouthAmericansealions, Otariaflavescens in Patagonia(Argentina)wereexploitedand reduced tolessthan10%ofpre-exploitationnumbers.Atpresent,thepopulationisrecoveringatarateof6%.Inthis paper, westudiedgrowthandageatsexualmaturityofSouthAmericansealionsinthesouth-westernsouthAtlantic by examining219individuals(femalesandmales)collectedbetween1989-2008.Individualswereagedbycounting growthlayergroupsintoothsections,standardbodylengthwasmeasuredandmaleandfemalereproductiveorgans were examinedmacroscopicallyandhistologicallytoestablishindividualsexualmaturity.Maximumrecordedlength for malesandfemaleswas264cmand200cm,respectively,andmaximumages19and21yrs. ASM definedastheage where50%offemalesaremature,wasestimatedat4.870.5 yearsold,correspondingtoameanSLof147cm,about 81% oftheirasymptoticlength.Firstobservedovulationoccurredduringthe4thyear,firstbirthmayoccurbetween4 and 5yearsold.Malesphysiologicallymaturebetween4-6years,butthesizeofthetestesshowsthatallmalesbecame sexuallymaturebytheageof9yearswhentheyreachameanSLof212cm,about86%oftheirasymptoticbody length.Thepresentinformationon ASM andgrowthof O. flavescens willimprovethedevelopmentofpopulation dynamicsmodels,toinvestigatetheimpactofrecoveringsealionspopulationsonitsmarineenvironment,aswellasits trophicinteractionswithcommercialfisheries. ASM) isanimportantparameterforevaluatingthereproductivepotentialor status ofapopulation.SouthAmericansealions, Otariaflavescens in Patagonia(Argentina)wereexploitedand reduced tolessthan10%ofpre-exploitationnumbers.Atpresent,thepopulationisrecoveringatarateof6%.Inthis paper, westudiedgrowthandageatsexualmaturityofSouthAmericansealionsinthesouth-westernsouthAtlantic by examining219individuals(femalesandmales)collectedbetween1989-2008.Individualswereagedbycounting growthlayergroupsintoothsections,standardbodylengthwasmeasuredandmaleandfemalereproductiveorgans were examinedmacroscopicallyandhistologicallytoestablishindividualsexualmaturity.Maximumrecordedlength for malesandfemaleswas264cmand200cm,respectively,andmaximumages19and21yrs. ASM definedastheage where50%offemalesaremature,wasestimatedat4.870.5 yearsold,correspondingtoameanSLof147cm,about 81% oftheirasymptoticlength.Firstobservedovulationoccurredduringthe4thyear,firstbirthmayoccurbetween4 and 5yearsold.Malesphysiologicallymaturebetween4-6years,butthesizeofthetestesshowsthatallmalesbecame sexuallymaturebytheageof9yearswhentheyreachameanSLof212cm,about86%oftheirasymptoticbody length.Thepresentinformationon ASM andgrowthof O. flavescens willimprovethedevelopmentofpopulation dynamicsmodels,toinvestigatetheimpactofrecoveringsealionspopulationsonitsmarineenvironment,aswellasits trophicinteractionswithcommercialfisheries.
