Distribution of paracalanidae species (Copepoda, Crustacea) in the continental shelf off Sergipe and Alagoas States, Northeast Brazil

Abstract

The spatial and seasonal distribution of the Paracalanidae species were studied in eighteen stations in the continental shelf off Sergipe and Alagoas States, northeast Brazil, in December, 2001 and 2003, and in June, 2002 and 2003. The Paracalanidae family was constituted by coastal and shelf species such as Parvocalanus crassirostris, Paracalanus quasimodo, P. indicus and P. aculeatus and oceanic species, Calocalanus pavo and Acrocalanus longicornis. Density values were higher in stations located at 10 m isobath with respect to those located at 20 and 30 m depths. Paracalanidae abundance presented differences between seasons with values higher in June (2002, 2003) than in December (2001, 2002). All species were more abundant in the rainy season except Parvocalanus crassirostris. Paracalanus quasimodo was the dominant species with average densities of 949, 740 and 41 ind.m-3 in December months and 4231, 2389 and 1185 ind.m-3 in June months, at stations with local depths of 10, 20 and 30 m, respectively. Canonical correspondence analysis showed that salinity and temperature were the environmental variables that presented significant correlation with the distribution of Paracalanidae species, probably because these variables are influenced by the estuarine waters and by the dynamic of oceanic water masses in the continental shelf.<br>A distribuição espacial e sazonal das espécies de Paracalanidae foram estudadas em dezoito estações na plataforma continental dos Estados de Sergipe e Alagoas, nordeste do Brasil, em dezembro de 2001 e 2003 e junho de 2002 e 2003. A família Paracalanidae esteve constituída por espécies costeiras e de plataforma tais como Parvocalanus crassirostris, Paracalanus quasimodo, P. indicus e P. aculeatus e por espécies oceânicas, Calocalanus pavo e Acrocalanus longicornis. Os valores de densidade total foram mais elevados nas estações localizadas em isóbata de 10 m decrescendo nas estações localizadas em profundidades de 20 e 30 m. A abundância de Paracalanidae apresentou padrão de flutuação sazonal, com valores mais elevados em junho (2002, 2003) do que em dezembro (2001, 2002). Todas as espécies foram mais abundantes no período chuvoso com exceção do Parvocalanus crassirostris. Paracalanus quasimodo foi a espécie dominante, com densidades médias de 949, 740 e 41 ind.m-3, nos meses de dezembro e de 4231, 2389 e 1185 ind.m-3, nos meses de junho, em isóbatas de 10, 20 e 30 m, respectivamente. A análise de correspondência canônica mostrou que a salinidade e a temperatura foram os fatores ambientais que apresentaram relação significativa com a distribuição das espécies de Paracalanidae, provavelmente porque estes fatores foram influenciados pelas águas estuarinas e pela dinâmica das massas de água oceânicas na plataforma continental

Multiloci analyses suggest synonymy among Rhomboplites, Ocyurus and Lutjanus and reveal the phylogenetic position of Lutjanus alexandrei (Lutjanidae: Perciformes)

“…Therefore, even though both species depend on the estuarine environments during early life cycles, L. jocu is able to inhabit estuaries from northern Brazil which are characterized by remarkable salinity fluctuations influences by the outflow of large rivers from Amazon, with salinity levels close to zero during rainy seasons (Barletta-Bergan et al, 2002;Barletta et al, 2005;Asp et al, 2016). On the other hand, the estuaries from northeastern Brazil are characterized by high salinity levels (Schwamborn et al, 2001;Araujo, 2006;Silva et al, 2009).…”

Spatial and temporal variation of the zooplankton community in the area of influence of the Itajaí-açu River, SC (BRAZIL)

“…The indicator species of Tropical Water in these periods were copepods Paracalanus quasimodo, Parvocalanus crassirostris, Temora stylifera and T. turbinata (BJÖRNBERG, 1981), the cladocera Pseudoevadne tergestina and Evadne spinifera (RESGALLA;MONTÚ, 1993), the Chaetognatha Sagitta enflata and S. híspida (RESGALLA JR.;MONTÚ, 1995) and the salpidae (thaliaceas) Doliolum nationalis and Thalia democrática DAPONTE, 1999aDAPONTE, , 1999b. As for the dominant species in the area of study, P. quasimodo and P. crassirostris are the species which are typical of the Brazilian coast and abundant in waters with low salinity of regions under heavy influence of the continental inflow (ARAUJO, 2006;BJÖRNBERG, 1981). For the species of the genus Temora, the replacement of the native species T. stylifera for the invasive species T. turbinata on the Brazilian coast, has been highlighted by Ara (2002).…”

Diel variation in the zooplankton of a highly dynamic Amazonian estuary

“…A dominant species in most subtropical and tropical coastal zones of South America (Vega-Pérez and Hernandes, 1997;Araújo, 2006;Magalhães et al, 2009), P. quasimodo presents marine-euryhaline behavior, occurring preferably in areas with high salinity (Lopes et al, 1998) and dominated by tides (Lopes, 1994;Eskinazi-Sant'Anna and Tundisi, 1996). An ability to tolerate moderate levels of salinity may nevertheless explain the dominance of P. quasimodo in the late flood tide and early ebb tide, when polyhaline conditions -as defined by the Venice system of classification (Anonymous, 1959) -prevailed ( Figure 2).…”