Luiz Fernando Loureiro Fernandes

Zooplankton community of the Vitória Bay estuarine system (Southeastern Brazil): Characterization during a three-year study

Com o objetivo de caracterizar a comunidade zooplanctonica no sistema estuarino Baia de Vitoria/Canal da Passagem, Vitoria, E.S., foram coletadas amostras em dez pontos amostrais, trimestralmente durante tres anos (1998-2000). Um total de 64 taxons foram identificados. Copepoda contribuiu com o maior numero de especies (49) na comunidade, destacando-se Acartia lilljeborgi,Acartia tonsa,Paracalanus parvus,Paracalanus quasimodo,Parvocalanus crassirostris,Temora turbinata,Oithona hebes,Oithona oculata e Euterpina acutifrons. A maior abundância ocorreu no verao do ano 2000. Os indices de diversidade foram maiores na entrada do estuario. A composicao do zooplâncton se caracterizou por apresentar especies estuarinas e costeiras, sendo a distribuicao destas especies influenciada principalmente pela variacao dos valores de salinidade no estuario.

Horizontal and vertical distribution of mesozooplankton species richness and composition down to 2,300 m in the southwest Atlantic Ocean

We describe the species richness, distribution and composition of mesozooplankton over the continental shelf and slope, and in the water masses in the Campos Basin, southwest Atlantic Ocean. We analyzed the mesozooplankton from two oceanographic cruises (rainy and dry seasons, 2009) with samples taken in five different water masses from the surface to 2,300 m depth. In the Subsurface Water (SS), in both sampling periods, more species were recorded over the slope (rainy: 100; dry: 128) than the continental shelf (rainy: 97; dry: 104). Over the slope, species richness decreased with increasing depth: the highest values were observed in the South Atlantic Central Water (SACW), and the lowest values in the North Atlantic Deep Water (NADW), in both sampling periods. We recorded 262 species in 10 groups (Hydrozoa, Siphonophora, Ctenophora, Branchiopoda, Copepoda, Euphausiacea, Decapoda, Chaetognatha, Appendicularia e Thaliacea), with 13 new occurrences for the southwest Atlantic. Copepoda was the group with the highest species richness, containing 138 species. In both periods, the samples from SS, SACW and Antarctic Intermediate Water (AAIW)/Upper Circumpolar Deep Water (UCDW) were clustered in different faunistic zones, based on species composition. This study confirmed that zooplankton richness in the southwest Atlantic Ocean is underestimated, and suggests that additional efforts must be directed toward a better understanding of this fairly unknown region.

Seasonal chaetognath abundance and distribution in a tropical estuary (Southeastern, Brazil)

This study focuses on the seasonal variation of the chaetognath species in the Vitoria Bay/Passage Channel estuarine system, Espirito Santo, Brazil, in terms of their abundance and distribution. Specimens of chaetognaths were collected between July 1997 and April 1998 at 10 sampling stations, with a cylindrical-conical plankton net of 200 µm mesh and 30 cm mouth, fitted with a mechanical flowmeter. Five chaetognath species were identified: Sagitta enflata, Sagitta decipiens, Sagitta hispida, Sagitta friderici and Sagitta minima. Most of them were distributed in areas of high salinity (e.g. at the stations closest to the outer estuary). The dominant species, S. enflata and S. friderici, were more frequent in the outer estuary where salinities varied from 32 (wet season - summer) to 28 (dry season - winter). S. friderici was the only species found right in the middle of the Passage Channel, at a station close to the main freshwater input into the estuary. Results showed that chaetognaths only enter the estuary due to the tidal effect, and that they are not typical residents of this system. This is to be expected because the group normally inhabits only truly marine regions.

Distribution and abundance of Cladocera (Branchiopoda) in the Paraíba do Sul River estuary, Rio de Janeiro, Brazil

To characterize the cladoceran community of the Paraiba do Sul River estuary, located in the district of Sao Joao da Barra, Rio de Janeiro, Brazil, cladocerans were collected monthly in nine sampling stations from September 2002 until August 2003. Samples were obtained by subsurface tows using a plankton net with a 30 cm opening mouth and 70 micron mesh size, fitted with a mechanical flowmeter. Environmental parameters such as salinity and temperature were also obtained. Seventeen species of Cladocera were identified: Pseudoevadne tergestina, Penilia avirostris, Macrothrix triserialis, Moina micrura, Simocephalus kerhervei, Simocephalus vetalus, Simocephalus latirostris, Simocephalus serrulatus, Alona rectangula, Alona quadrangularis, Bosmina longirostris, Bosminopsis deitersi, Camptocercus dadayi, Ceriodaphnia richardi, Diaphanosoma fluviatile, Kurzia latissima and Pleuroxus similis. The highest total abundance of Cladocera occurred in April in the marine zone of the estuary. The most abundant species during this period was Penilia avirostris. At the mixing and freshwater zones of the estuary, the most abundant species were Moina micrura, mainly in January; and Simocephalus vetalus and Bosmina longirostris during spring. From this scenario, it can be inferred that the cladoceran community of the Paraiba do Sul River estuary presents characteristics of marine, brackish and freshwater environments. Temperature and salinity seem to limit the occurrence and distribution of cladocerans in the estuary.

Acute copper toxicity in juvenile fat snook Centropomus parallelus (Teleostei: Centropomidae) in sea water

Tres experimentos foram realizados para avaliar o acumulo e toxicidade aguda do cobre (Cu) em juvenis de robalo-peva Centropomus parallelus. O primeiro experimento foi realizado para determinar a concentracao letal (96h-CL50) de Cu. O segundo experimento foi realizado para avaliar os efeitos de concentracoes subletais de Cu (0,47 e 0,94 mg/L), enquanto o terceiro permitiu testar a capacidade de recuperacao dos peixes expostos a concentracoes subletais do Cu e posteriormente mantidos em agua do mar sem acrescimo de Cu. O valor de LC50 encontrado para o Cu foi de 1,88 mg/L. Os peixes expostos as concentracoes subletais de Cu mostraram um acumulo significativo nas brânquias em relacao ao controle em 96 h de exposicao (0,43 µg/g Cu). Nenhuma diferenca significativa foi observada entre os peixes expostos a 0,47 mg/L de Cu (1,09 µg/g) e 0,94 mg/L de Cu (1,26 µg/g). A exposicao (24 e 96 h) para as concentracoes subletais de Cu induziram danos no DNA. Os resultados mostram que a exposicao aguda a concentracoes subletais induz o acumulo de Cu e danos ao DNA nas brânquias dos peixes, onde estes efeitos sao recuperados apos 240 h em agua do mar sem adicao de Cu.

Temporal and spatial variation of rocky shores intertidal benthic communities in Southeast Brazil

The relationships between environmental factors and temporal and spatial variations of benthic communities of three rocky shores of the state of Espirito Santo, Southeast Brazil, were studied. Sampling was conducted every three months, from August 2006 to May 2007, using intersection points. Chthamalus bisinuatus (Pilsbry, 1916) (Crustacea) and Brachidontes spp. (Mollusca) were the most abundant taxa, occupying the upper level of the intertidal zone of the rocky shore. The species richness was higher at the lower levels. The invasive species Isognomon bicolor (C. B. Adams, 1845) (Mollusca) occurred at low densities in the studied areas. The clustering analysis dendrogram indicated a separation of communities based on exposed and sheltered areas. According to the variance analyses, the communities were significantly different among the studied areas and seasons. The extent of wave exposure and shore slope influenced the species variability. The Setibao site showed the highest diversity and richness, most likely due to greater wave exposure. The communities showed greater variation in the lower levels where environmental conditions were less severe, relative to the other levels.

Distribution of the species of Lucifer Thompson, 1829 in the subtropical South Atlantic between parallels 20º and 30ºs

A distribuicao das especies de Lucifer Thompson, 1829 (Decapoda: Luciferidae) no Giro Subtropical do Atlântico Sul foi avaliada pela Comissao Transatlântico Brasil I, entre novembro e dezembro de 2009. As amostras foram coletadas em 83 estacoes, em dois perfis entre o Brasil e Africa (20o e 30o Sul). Foram realizados arrastos obliquos com rede cilindro-conica, ate 150 metros de profundidade. Observou-se uma relacao sexual distinta entre as duas especies encontradas. L. faxoni apresentou numero de femeas significativamente maior em relacao aos machos: 1:0.5 (X2 = 21,77, p = 0,0001), enquanto L. typus, teve proporcao sexual de machos significativamente maior que de femeas: 1.86:1 (X2 = 50,84, p = 0,0001). A distribuicao de L. typus variou entre as porcoes oeste e leste da cordilheira Mesoceânica. Essa distribuicao esteve relacionada significativamente com a salinidade (R2 = 0.13; F(3.79); p = 0,009), mais elevada a oeste da area de estudo. No presente trabalho as duas especies tiveram seus registros ampliados para o Giro Subtropical do Atlântico. De forma geral, os camaroes luciferideos foram mais frequentes e abundantes nas estacoes de coleta a oeste da Cordilheira Mesoceância, com L. typus sendo mais representativo tanto em abundância quanto em ocorrencia.

Use of the copepod Oithona hebes as a bioencapsulator of essential fatty acids

The advantages of using copepods in aquaculture include nutritional superiority, high digestibility and broad spectrum of sizes, with the possibility of bioencapsulation of nutrients, probiotics and medicines. This study aimed to compare the effects of feeding copepods with a microalgae diet and two commercial inert diets on the copepod culture performance and their fatty acid profile. Wild copepods were collected in the estuarine system of Piraque-acu River, Aracruz, Espirito Santo, Brazil, with a conical net of 60 cm in diameter and 200 μm mesh with a blind cup end, towed through the subsurface layer at a speed of 1 knot for 5 minutes. Once collected, the material was sieved in order to select only Oithona hebes. The experiment was conducted in nine cylindrical-conical tanks with a 60 L capacity, salinity of 25.8 ± 1.3, temperature of 25.5 ± 0.5 oC and weak aeration, stocked with a density of 1.5 copepod/mL. Treatments were made in triplicate and consisted of: Treatment 1 (Control) fed with microalgae Chaetoceros gracilis and Nannochloropsis oculata (1:1) with 50,000 cells.mL-1each; Treatment 2 with S.Parkle® INVE (1g.million-1); and Treatment 3 with freeze-dried spirulina (1g.million-1). The mean final population was compared by a Tukey test (p < 0.05). Results showed higher population growth for copepods treated with S.parkle, which was the only treatment that presented copepodites. S.parkle was a good source of total lipids (9.54 g.100g-1 dry weight), high availability of DHA, EPA and had a good DHA:EPA:ARA ratio of 12.4:3.4:1.0. Copepods that were fed S.parkle had the highest DHA levels and a DHA:EPA:ARA ratio of 15.4:2.2:1.0. This study showed that S.parkle is a good inert food for rearing the copepod O. hebes, demonstrating the ability of copepods to bioencapsulate nutrients, allowing their transfer in the food chain.

Crescimento e produtividade de juvenis de robalo-peva a diferentes temperaturas e taxas de alimentação

O objetivo deste trabalho foi avaliar o efeito da temperatura e da taxa de alimentacao sobre o crescimento e a produtividade de juvenis de robalo‑peva ( Centropomus parallelus ). Utilizou-se experimento fatorial com duas temperaturas (25 e 28 o C) e duas taxas de alimentacao (3 e 6% da biomassa ao dia), com tres repeticoes para cada combinacao de temperatura e taxa. Os peixes (9,80±0,41 g; 9,86±0,14 cm) foram alimentados duas vezes ao dia durante 60 dias. A cada 15 dias, foram realizadas amostragens para corrigir a quantidade de racao oferecida. Nao houve mortalidade durante o experimento. Maior crescimento em peso e comprimento foi obtido nos animais submetidos a temperatura de 28 o C. Ganho de peso, biomassa final, conversao alimentar aparente e taxa de crescimento especifico foram influenciados pela taxa de alimentacao e pela temperatura. A oferta de 3% da biomassa ao dia a 28 o C proporciona melhores indices de crescimento e produtividade para juvenis de robalo‑peva.

Interannual Variability in Tropical Estuarine Copepod Assemblages off Northeastern Brazil

Abstract We studied copepod assemblage variability among years, seasons, and tidal states in the Mucuri River estuary (Bahia State, Brazil). Zooplankton samples were collected seasonally through five years (2002-2006) at three sampling stations, one of which was sampled over a complete tidal cycle (two ebb and two flood tides). Temperature, salinity, river flux, and rainfall data were collected. Winter and summer represented dry and wet seasons, respectively. Copepod abundances ranged from 40 to 63% of the total zooplankton assemblage and comprised 46 taxa, among which, common estuarine species such as Temora turbinata (first record for the studied area), Parvocalanus crassirostris, Acartia lilljeborgi, Oithona hebes were the most abundant (euryhaline species). Interannual and seasonal variations were most marked in stenohaline species, e.g., Notodiaptomus sp. and Thermocyclops minutus; density variations of euryhaline species, which made up the majority of the abundant taxa, were most closely related to tides. Diversity and richness also followed an intertidal pattern of variation.