Distribution of the mesozooplankton at continental shelf off Sergipe, Brazil

Abstract

The purpose of this work was to study the composition and abundance of the mesozooplankton at two stations at the continental shelf off Sergipe. At each station, oblique plankton tows were carried using plankton nets with 200 µm mesh size, in six hours intervals during three consecutive days. One hundred and three taxa were identified and Copepoda was the dominant group with fifty one species. The mesozooplankton assemblage was composed by coastal, neritic and oceanic tropical species. There were significant differences in composition and abundance between the two studied stations (p<0,05) but not between tidal stages. At station 1, the most abundant species were Creseis acicula, Oikopleura spp., Temora stylifera, Paracalanus quasimodo and Aglaura hemistoma, and at station 2 Paracalanus quasimodo, Paracalanus spp., Siphonophora, Gastropoda and Decapoda larvae. Coastal species such as Parvocalanus crassirostris, Acartia lilljeborgi, Euterpina acutifrons and Corycaeus giesbrechti occurred only at the last station, located close to the mouth of the São Francisco River, where surface salinity and transparency values were low. In this station the salinity average value at surface was 30,8±1,9 and at the bottom layer was 35.0±0.3 PSU. Mesozooplanhton density values ranged between 124 ind.m -3 and 2,658 ind.m -3 at station 1, and from 734 ind.m -3 to 3,061 ind.m -3 at station 2. A Monte Carlo test based on a canonical ordination revelead that local depth and water transparency were significantly correlated to the mesozooplankton distribution.Key words: zooplankton community, Copepoda, shelf off Sergipe, tropical. DISTRIBUIÇÃO DO MESOZOOPLÂNCTON NA PLATAFORMA CONTINENTAL DE SERGIPE, BRASIL RESUMOA proposta desse trabalho foi estudar a composição e abundância do mesozooplâncton em duas estações, na plataforma continental de Sergipe. Em cada estação, arrastos oblíquos de plâncton foram feitos utilizando-se uma rede de plâncton de 200 µm de abertura de malha, em intervalos de seis horas, durante três dias consecutivos. Cento e três táxons foram identificados e Copepoda foi o grupo dominante com cinqüenta e uma espécies. A assembléia mesozooplanctônica foi composta por espécies tropicais costeiras, neríticas e oceânicas. Houve diferença significativa na composição e abundância entre as duas estações estudadas (p<0,05), mas não entre os estágios tidais. Na estação 1 as espécies mais abundantes foram Creseis acicula, Oikopleura spp., Temora stylifera, Paracalanus quasimodo e Aglaura hemistoma e na estação 2, Paracalanus quasimodo, Paracalanus spp., Siphonophora e larvas de Gastropoda e Decapoda.

Spatiotemporal distribution of zooplankton in relation to some abiotic variables in the waters of the Kribian Atlantic coast (South Cameroon)

“…[32] and [33] point out that copepods are the most abundant group of multicellular metazoan zooplankton in the oceans and even on Earth. The dominance of copepods in the zooplanktonic population of the Kribian coast obtained in this study is in line with the results observed in the bibliographic synthesis on the zooplankton of the neritic waters of the Atlantic Ocean on the coasts of Côte d'Ivoire (58%) [28], Brazil (approximately 50%) [29], the Atlantic coasts of Morocco (73%) [30] and Senegal (27 to 93%) [34]. The spatio-temporal distribution of abundance showed an overall abundance of copepods in all stations and during all months with a predominance of the families Paracalanidae, Oithonidae and Euterpinidae.…”

“…The spatio-temporal distribution of abundance showed an overall abundance of copepods in all stations and during all months with a predominance of the families Paracalanidae, Oithonidae and Euterpinidae. These observations partially corroborate those made on the Brazilian continental shelves in the State of Sergipe and in Ivory Coast where ( [29] and [28] respectively observed the predominance of the family Paracalinidae in their work.…”

“…This taxonomic richness is close to that obtained in Casamance (56 taxa) by [27] or in Côte d'Ivoire (52 taxa) by [28]. However, it remains much lower than the species richness recorded by [29] on the Brazilian continental shelf (130 taxa) and the taxonomic richness obtained on the continental shelf of Morocco, on the Atlantic Ocean side (78 species) by [30]. These differences in taxonomic richness could be linked to the types of environment, the physico-chemical properties of the water, the regional climate and the hydrology of the water bodies [31].…”

Characterization of the zooplankton in the continental shelf of the Brazilian Equatorial Atlantic

“…This large number of Copepoda recorded in the CSM is similar to that in other tropical regions of Brazil. Araujo and Ribeiro (2008) 2010) say that large, medium, and small crustacean copepods are the main food resources for fish, while carnivorous individuals (such as gelatinous individuals) compete with other organisms to obtain food, and their energy may not be efficiently transferred to higher trophic levels.…”