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dc.contributor.advisorJaureguizar, A.J.
dc.contributor.advisorGuerrero, R.A.
dc.contributor.authorBarretto, A.C.
dc.coverage.spatialAtlántico Sudiccidental, Argentina, Uruguay, Río de la Plata, Golfo San Matías, El Rincón
dc.date.accessioned2009-04-07T09:35:16Z
dc.date.available2009-04-07T09:35:16Z
dc.date.issued2007
dc.identifier.urihttp://hdl.handle.net/1834/3017
dc.description.abstractThe age-class distribution of the Brazilian flathead Percophis brasiliensis in relation to environmental variables in spring and winter, and the growth of both sexes, were studied in the SW Atlantic Coastal System (SACS)(34°S-31° S). Growth was studied from 1449 individuals (n=853, spring (1998 + 2000), n=596, winter (2004)) to which size (TL), sex, and age were determined. Age was determined considering that an opaque plus a hyaline band (present in the transverse section of the sagitta otolith) represented 1 year of life. The age-class distribution in spring and winter was established through hierarchical clustering and non-metric multi-dimensional scaling (nMDS analysis). This analysis grouped sampling stations (n=109, spring 1998; n=160, winter 2004) with similar sex-age classes structure. The BIO-ENV analysis was used to estimate the association between the distribution of these groups and environmental variables (depth, temperature and salinity of bottom). Although oceanographic regimes differed from their average geographical distribution, P. brasiliensis was present in both seasons in marine coastal waters with lower temperatures and higher salinities and depths; its distribution showed in turn, N-S seasonal changes related to the combined influence of the Río de la Plata (mainly) and El Rincón estuarine regimes. Even though this species is present in the SACS in both seasons P. brasiliensis shows migratory movement, emigrating towards the winter and returning (specially to southern SACS) towards spring to spawn. In this season a marked age-classes ordination associated to salinity is observed whereas in winter this ordination is less evident. In spring, other adults (5-8 year old males, 7,8 year old females) were distributed in higher salinity waters of San Matías Gulf/El Rincón (external coastal zone), younger adults in lower salinity waters of El Rincón (internal coastal zone), and juveniles (0,1 year old males; 0 year old females) in the intermediate coastal zone. In winter, the studied area is more homogeneous with respect to spatial distribution of age-classes mainly characterized by younger adults (2-5 year old males and females). The marked age-classes ordination given in spring would be a mechanism to reduce intraspecific competition for food resources, given the high degree of overlapping between juvenile and adult diets, and the high densities that take place in this season. In both seasons juveniles showed preference for high temperature marine coastal waters, whereas adults tend to occupy colder waters during spring (warmer spawning season); these habitats are suitable for a fast growh of juveniles, and to minimize metabolic costs of adults which may thus allocate more energy to reproductive activity. The degree of overlapping between juvenile and adult habitat is consistent with the 'general concept' of spatial distribution of ontogenetic stages established by Beck et al.(2001).en
dc.description.sponsorshipUniversidad de Buenos Aires (UBA). Facultad de Ciencias Exactas y Naturales (Argentina)
dc.language.isoes
dc.titleInfluencia ambiental en la distribución espacial de las clases de edad de pez palo (Percophis brasiliensis) en el Sistema Costero del Atlántico Sudoccidental (34°-41° S)es
dc.title.alternativeEnvironmental influence in age-class spatial distribution of the Brazilian flathead (Percophis brasiliensis) in the southwestern Atlantic Coastal Ecosystem (34°-41° S)en
dc.typeTheses and Dissertations
dc.description.notesTesis (Licenciatura). Realizada en el INIDEP (Instituto Nacional de Investigación y Desarrrollo Pesquero- Mar del Plata, Argentina)
dc.description.otherPercophis brasiliensis, pez palo, grupos por edad, composición por edad, factores ambientales, efectos ambientales, distribución geográfica, estructura poblacional, crecimiento, aguas costeras
dc.format.pages61
dc.subject.agrovocAge compositionen
dc.subject.agrovocEnvironmental factorsen
dc.subject.agrovocGeographical distributionen
dc.subject.agrovocPopulation structureen
dc.subject.agrovocGrowthen
dc.subject.agrovocAge groupsen
dc.subject.agrovocCoastal watersen
dc.subject.asfaAge groupsen
dc.subject.asfaAge compositionen
dc.subject.asfaEnvironmental factorsen
dc.subject.asfaGeographical distributionen
dc.subject.asfaPopulation structureen
dc.subject.asfaGrowthen
dc.subject.asfaEnvironmental effectsen
dc.subject.asfaCoastal watersen
refterms.dateFOA2021-01-30T18:47:52Z


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