Spatial and temporal distribution of ''curvina'' larvae (Plagioscion squamosissimus HECKEL, 1840) and its relationship to some environmental variables in the upper Paraná River floodplain, Brazil

Abstract

With the objective of studying the spatial and temporal distribution of "curvina" Plagioscion squamosissimus larvae and verifying respective spawning sites, monthly sampling was carried out from March 1993 to February 1994 on the Upper Paraná River floodplain. Using a conical-cylindrical plankton net (0.5 mm mesh), samples were taken from the surface of the water bodies, and in the marginal vegetation a strainer and a dragnet ("picaré") were used. Water samples were collected for environmental variable analysis (temperature, dissolved oxygen, water pH, and electrical conductivity). Water level data were obtained from hydrometric stations. High average density of larvae was found from December 1993 to February 1994 due to high temperature and water level. The Baía sub-area was shown to be the most important in the larvae catch, probably due to its semi-lotic characteristics. Larvae size distribution was shown to be more frequent in the 4.0 mm standard length class, indicating that the sampling stations were next to the spawning sites.

Spatio-temporal distribution of fish larvae in relation to ontogeny and water quality in the oligohaline zone of a North Brazilian estuary

“…3 adults spawn in calm areas where the young larvae would remain. As they reach a more advanced development stage, the individuals move towards areas of stronger water flow and use the currents to reach other nursery grounds (Baumgartner et al 2003, Bialetzki et al 2004. All the remaining larval species that were absent from the juvenile/adult catches (Viana et al 2010) counted very few individuals suggesting that their presence was accidental or that Guajará Bay was on their migration route.…”

Carnivory during Ontogeny of the Plagioscion squamosissimus: A Successful Non-Native Fish in a Lentic Environment of the Upper Paraná River Basin

“…squamosissimus was the most abundant species, being essentially represented by immature individuals [ 26 ]. In addition, the period of highest cannibalism (stomach contents in late January and March) coincided with the sudden increase in the availability of juveniles, a fact supported by the occurrence of spawning and high densities of larvae of this species in the Upper Paraná River floodplain, especially during the high water-level season associated with high temperatures [ 10 , 53 , 54 , 55 ]; ii)the intake of prey being advantageous for growth and development, thus maintaining the energy within the population. In this aspect, conspecifics represent a diet of high nutritional quality, with minerals and amino acids in the optimal proportion for maximal growth [ 51 , 56 ].…”

Abundância e distribuição temporal de larvas de <em>Pachyurus bonariensis</em> Steindachner, 1879 (Perciformes, Sciaenidae), em uma baía do pantanal matogrossense

“…Desta forma, é possível que exista uma temperatura limite acima de 21ºC, como observado nos meses frios, na qual a reprodução desta espécie se torna viável. De acordo com Vazzoler (1996) e Baumgartner et al (2004), a temperatura da água influencia diretamente nas diferentes fases do ciclo de vida dos peixes, sendo um dos principais fatores a determinar o início e a duração do período reprodutivo, bem com a distribuição sazonal das larvas (PALLER;SAUL, 1996). Assim, a presença de larvas nos meses de inverno, primavera e verão sugere que a atividade reprodutiva de P. bonariensis é um processo contínuo.…”

“…Esse comportamento pode ser um mecanismo para minimizar a competição intraespecífica (SANTIN et al, 2004;OSTERGAARD et al, 2005) e evitar predadores planctófagos visuais (BAUMGARTNER et al, 1997;. No entanto, principalmente as larvas em pré-flexão foram encontradas na subsuperfície da água durante o dia e também à noite.…”

“…Estudos que abordam a ecologia das larvas são escassos em ambientes aquáticos continentais, destacando-se no Brasil os trabalhos de Oliveira (2000) e Araújo-Lima et al (2001) para a região Amazônica; Baumgartner et al (2003;, , 2008) Situa-se em uma área de relevo aplainado, numa planície fluviolacustre, em zona de média inundação (FRANCO; PINHEIRO, 1982), conectando-se a oeste com o rio Cuiabá, por meio do Canal Boca do Leme e a leste recebe as águas da bacia do rio Mutum. As encostas apresentam-se com baixa declividade.…”