RCAAP Repository

A survey for bivalves (Teredinidae) at several sites in the Escuro River and Comprido River at mangrove regions in Praia Dura , Ubatuba, SP was conducted. Nausitora fusticula was the most abundant species found in all collection sites at the border of Comprido River meaning that the species was well adapted to the intertidal regions and to the large variation in salinity (0 to 33 S). N. fusticula was found with Bankiafimbriatula, Bankiagouldi and Bankia rochi at the mangrove region in contact with the water. At the regions less influenced by the tides N. fusticula occurred with Neoteredo reynei and few specimens of the genus Banida already cited. The species of Teredinidae was found at the maximum limit of penetration of the sea water during the high tides. When the salinity was lower neither Banida species nor Neoteredo reynei occurred, but Psiloteredo healdi and AC fusticula were found.

The aim of this study was to establish the importance of the macrofauna as food for young fish species that inhabit the infralittoral adjacent to the lower marsh. The sampling site is located at Arrozal, Cananéia lagoon estuarine region (25º02'S and 47º56'W) and the collectings were realized monthly, during a year. The results suggest that the studied area could be considered as a nursery ground for young fish species. The local macrofauna is composed mainly by several groups of crustaceans and has a marked temporal variation. Mysids were dominant in Spring, copepods in Summer, mysids and bivalves were co-dominants in the Autumn and amphipods in Winter. Mysids, copepods, ostracods, tan aids and other epifaunal crustaceans were more consumed than other items. According to the trophic habits, the twelve fish species could be divided into three groups: the first and the third as mysids and copepods eaters respectively, and the second group with a balanced diet reflecting more than the other groups the seasonal variation of the macrofauna collected by the dredge. Benthonic and benthopelagic organisms were considered the major food source, being consumed by 75% of the analysed fish species, in Cananéia infralittoral.

Samples of Antarctic krill, Euphausia superba, collected from 18 locations in the Drake Passage, Bransfield Strait and on the west coast of the Antarctic Peninsula were analyzed for protein variation using enzyme electrophoresis. Of 19 enzyme loci studied, 14 (73,6%) exhibit allelic variations. Average heterozigosity for a station varies from 0,129 to 0,157. Five loci are with null alleles. Differences in allelic frequency related to sex and size of animal were not observed. No significant deviations from random mating expectation according to the Hardy-Weinberg principle were found in any locus at any station except Aph-1 at the stations 8 and 18; Est-1 at the station 9 and 11, and Mdh-1 at the station 18. These deviations are likely due to the difficulty in .analysing the enzyme pattern or to the small sample sizes. Analysis of allele distribution indicate that samples from all locations are homogeneous in all polymorphic loci. Genetic distances between samples vary from 0.000 to 0.002. These results suggest that specimens from all locations of the investigated region belong to a single genetically homogeneous population. The contribution of physical and biological factors to the homogeneity of krill in the region and the necessity of a detailed study utilizing not only electrophoresis but also another techniques were discussed.

Density and diversity patterns of the polychaetous annelids from the northern continental shelf of São Paulo State, Brazil, were studied. Polychaetous densities were higher in the inner shelf, mainly in the southern transect. Temporal variations were observed at the northern and central transects in the 20 and 35 m isobaths, with higher summer values. Diversity values were lower in summer and higher during winter in the outer shelf. The inner shelf presented more complex diversity patterns with seasonal fluctuations in lower depths. Muddy sediments presented higher densities; diversity and richness were higher in fine sand sediments. Coarser sediments presented the highest values of evenness but low diversity. The higher diversity values in the shallowest stations were due to the higher number of species and in the deepest stations to the great evenness.

The macrobenthic assemblages of Buenos Aires Province continental shelf were studied from samples collected by the R/V "Capitán Oca Balda" along a transect from 38 m to 218 m depth. Three faunistic areas were determined, corresponding to the coastal, central and external shelf, inhabited by species originate d from the Argentine and/or Magellanic Zoogeographical Provinces. These results confirm the presence of different ecological areas in the Argentine Continental Shelf.

The effect of salinity (0-40 %o) and temperature (11-36ºC, at 5ºC intervals) variations on maximum growth rate (div d-1), maximum yield (logio cell number) and chlorophyll-α content (pg cell-1) of four planktonic algae was examined under laboratory conditions. Phaeodactylum tricornutum grew over the entire range of experimental salinities, at 11-26 ºC. The highest maximum growth rates ( 1.6 div d-1) occurred between 9-30 %o and 16-26 ºC. Optimum salinity range for maximum yield (7.0) was found at 9-35 %c, under 16 ºC. Tetraselmis gracilis reproduced from 4 to 40 %o at 11-31 ºC, with the highest values of maximum growth rate ( 1.6 div d-1) and maximum yield (6.1) occurring at salinities between 14-40 %o at 11-21 ºC and 11-16 ºC, respectively. Minutocellus polymorphic and Chaetoceros sp grew between 9-40 %o and 11-31 ºC. Their highest maximum growth rates (2.1 and 2.6 div d-1, respectively) were found at 31ºC, between 20-35 %o and 20-40 %o, respectively. The highest maximum yields for AT. polymorphic (7.2) were recorded between 16-21 ºC at 20-40 %o and for Chaetoceros sp (6.8), between 25-40 %o at 16-31ºC. Chlorophyll-a content per cell was not conspicuously associated to temperature and salinity for the four species. At low salinity extremes, when cell division was inhibited, an increase in the amount of chlorophyll-a per cell was detected.

Within the scope of the MAR-14 Project, part of the Brazil-Germany Bilateral Agreement in Marine Sciences, an oceanographic survey aboard the R/V Victor Hensen was carried out in Brazilian coastal waters between Santos (23º56'S) and Rio de Janeiro (22º54'S), from January 15 to January 22,1991. In this article we report results of preliminary analyses of the hydrographic data collected with CTD, STD, Nansen bottles and XBT's. These preliminary results show intense stratification in the first 200 m depth, and the penetration of the Brazil Current deep into the continental shelf region. Two eddy-like features were detected. The first one, anticyclonic, was located in the northern part of the domain and confined to the uppermost 200 m. The second, a cyclonic vortex, was found a little to the southwest below 200 m and extending downwards to about 800 m depth. Water mass analyses based on T-S diagrams suggest that the interface between the South Atlantic Central Water (SACW) and the Antarctic Intermediate Water (AIW) is located at about 500 m depth. One important aspect of this study is that this was the first time a high resolution survey with a CTD probe was realized along the eastern Brasilian Coast, south of Cabo Frio.

A three-dimensional, linear, barotropic and meso-scale numerical model is used for the southeastern Brazilian shelf, in order to represent the composition of the main astronomical tidal constituents, superimposed to extreme meteorological effects, for specific periods of interest. However, meteorological data relative to this area are very few and sparse, so that a methodology to provide meteorological conditions to the oceanic circulation model was used, based only on atmospheric pressure charts at the surface. The pressure field was well represented, while the calculated wind speeds were much larger than the observed winds at the coast. The model results indicate that it is possible to associate the predominant high pressure center in the South Atlantic and the correspondent surface elevations parallel to the coastline to an approximately geostrophic oceanic circulation system. On the other hand, the passage of cold fronts in the area induces transient systems that modify the geostrophic pattern, also changing the surface elevation isolines configuration.

This paper presents the simulation of the nine principal tidal constituents in the southeastern Brazilian shelf, through the processing of a hydrodynamical numerical model. The modeled area extends from Ponta do Vigia (SC) to Cabo Frio (RJ), from the coast up to approximately the 100 m isobath. The model used in the simulations is three-dimensional, linear, barotropic and of meso scale. Each principal tidal constituent was processed isolatedly, in order to define its characteristics in the area of interest, especificaly its cotidal lines and current elipses at the surface. The considered tidal constituents were: Q1, O1, P1, K1, N2, M2, S2, K2 and M3. The obtained amplitude and phase cotidal maps show the amplification and attenuation areas for the tidal waves, as well as their propagation directions. The surface currents elipses, on the other hand, indicate the behavior of the tidal currents in the modeled area, especially in terms of gyres, predominant directions and typical intensities. With the simulations results, it is possible to predict tidal elevations and tidal currents, at any location in this area, and for whatever required period.

Os cromossomos de 3 espécies de peixes da família Ariidae - Netuma barba, Genidens genidens e Arius parkeri - foram estudados após coloração convencional com Giemsa. As três espécies apresentaram número modal diplóide de 2n = 56. O cariótipo de N. barba compreende 18 pares de cromossomos metacentricos (m), 18 submetacêntricos (sm), 18 subtelocêntricos (st) e 2 telocêntricos (t); o de G. genidens compreende 12 pares m, 20 sm, 20 st e 41; o de A.parkeri compreende 16 m, 16 sm, 22 st e 2 t. Os resultados obtidos são comparados entre si e com os de outros ariídeos encontrados na literatura.

Dois testemunhos obtidos no Saco da Ribeira e Saco do Perequê-Mirim, locais situados na Enseada do Flamengo, foram estudados. No primeiro local foram observadas muitas carapaças de foraminíferos preenchidas por pirita. No outro local, além das carapaças preenchidas por pirita, foram notadas carapaças impregnadas com limonita e monossulfeto de ferro, as quais se relacionaram com níveis fortemente bioturbados. Essas informações mostraram que o Saco da Ribeira é caracterizado por condições mais redutoras do que no Saco do Perequê-Mirim. Através da quantificação de carapaças de foraminíferos impregnadas com hidróxido/óxido e/ou preenchidos por sulfeto ferroso foi possível estimar algumas diferenças em potenciais de oxirredução desses dois locais na Enseada do Flamengo.

The distribution of chaetognath species off Ubatuba region, São Paulo State, Brazil, was studied during a program of multidisciplinary research. Ten species belonging to the genera Sagitta, Krohnita and Pterosagitta were identified. S. enflata was the dominant species followed by S.friderici and S. hispida. The species S. enflata, S. hispida, S. tenuis, S. bipunctata and JC pacifica were found in the Shelf water whereas S. serratodentata, S. minima, S. hexaptera and P. draco in the Tropical water. Only S. friderici was found associated to Coastal water. Hydrological conditions affected population structure, size of individuals and abundance.

The feeding habits and the diel feeding periodicity of the searobin Prionotus punctatus were investigated at Ubatuba region (22º30'S) in the western South Atlantic. The samples were collected during consecutive 3 h periods over 24 h in January, 1987 and July and December, 1988. The diel feeding activity analysis indicated that Prionotus punctatus was a daytime feeder with afternoon tendency, permitting to bring up the hypothesis of the Orcadian rythm. The main food items were Portunidae crabs in Summer, and Portunidae and Penaeidae shrimps in Winter. The diet composition was very similar during the feeding activity time in Winter (July 1988), whereas it showed some variation in Summer (January 1987 and December 1988).

A year's survey conducted at a seagrass (Halodule wrightii Ascherson) bed and an adjacent bare sand area, on Codó Beach, Ubatuba, southern Brazil, showed that the macrobenthic species composition was different at the two habitats. Surface deposit feeder infaunal polychaetes were the dominant species in the Halodule site and omnivorous/carnivorous and filter feeder polychaetes, in the bare sand. These differences could be explained mainly by the characteristics of the sediment and the stability of the bottom and, secondly, by the presence of Halodule. The presence of vegetation has no effect on density of macrobenthos, probably due to the small size of Halodule plants, which do not support an abundant epifauna. Despite that fact, both number and diversity of species were higher in the seagrass area than in the unvegetated site, as was epifaunal abundance. Significant patterns of temporal fluctuations of macrobenthos abundance and species diversity were not observed, but diversity was the highest in Spring at both habitats. The temporal fluctuations of abundance differed in the two habitats. At the unvegetated site instability of the substrate seems to be responsible for the observed fluctuations in densities. At the Halodule site only light fluctuations occurred, though they did not follow those of macrophyte biomass. Macropredator effects are suggested to be one of the controling factors of macrobenthos density at the vegetated habitat.

Length frequency analisys were applied for sardine data collected from commercial catches throughout the southeastern Brazilian coast in 1977-1987. Age/length keys were obtained by otolith ring countings and utilized to transform length into age composition. Growth parameters were estimated by the von Bertalanffy growth equation using age and length data for each year and for all the period of investigation. The mean growth parameters for the entire period were estimated as L∞ = 271 mm and K= 0.59 year-1. Instantaneous total mortality (Z) coefficients per year were estimated using catch curves and methods based on the mean length of the fish caught. Total mortality rate for the entire period was obtained through the average of the annual values. Natural mortality (M) was estimated using the Paul/s empirical equation (1980a), and fishing mortality (F) by the difference between total and natural mortality values.The results were Z = 3.6 year-1; M = 0.96 year-1; and F= 2.6 year-1.

Preliminary experiments were carried out to estimate the potential toxicity of an effluent derived from petroleum to be dumped into São Sebastião channel through a submarine emissary which is being built at the Maritime Terminal "Almirante Barroso" (TEBAR). Two simulated samples of this effluent (denominated A and B) were supplied by PETROBRÁS. The toxicity of sample A was tested with young and adult Promysis atlántica (Crustacea, Mysidacea) and the toxicity of sample B only with young individuals of the same species. In relation to Effluent-A, concentrations between 1% and 5% increase significantly the rate of mortality of animals in short term tests (24-96 hrs). The results also indicated that, in this case, adults are less resistant than youngs. Concentrations of 0.075% of Effluent-B are at the maximum limits of no effect observation for short term expositions of young animals (96 hrs). The two effluent samples are different from each other. Both of them are very toxic, but the second is about 10 times more toxic than the first one. The toxicity of the samples also varies in function of time of storage. It seems that this variation is not predictable as the results indicated that the toxicity increased with storage for sample A and diminished for sample B. Other possible effects of the effluent on the ecosystem are discussed.

No summary/description provided

One hundred species of benthic foraminifera were found in the study area (25ºS - 48ºW). The surface sediment of this lagoon contains from 0 to 3,000 tests per 50 cm³ and up to 32 species. The foraminifera fauna of the lagoonal system of Iguape-Cananéia is the richest among those described in other paralic environments of Brazil. The richness of foraminifera fauna can result from the strong marine influence in the Baía de Trapandé. The foraminifera distribution in the study area is characterized by the occurrence of marine assemblages nearby the mouth, with a gradual increase in agglutinating species, such as,Ammotiwn salsum and Gaudryina exilis. In the confined areas, with low salinity, the assemblages are oligospecific and Milammina earlandi Is dominant. The abundance of Pararotalia in the Mar de Cananéia shows that this environment is less restricted than Mar de Cubatão, where the genus is absent. The distribution of foraminifera species shown to be also influenced by urbain sewages.

A linear three-dimensional hydrodynamical numerical model, Heaps type, was implemented to the continental shelf of Maranhão State, aiming the simulation of the circulation generated by astronomical and meteorological effects in that area. Five runs of the model were performed, in order to compute the circulation in the shelf due to the following effects: principal lunar semi-diurnal component (M2), composition of the principal astronomical components in the area, mean summer meteorological conditions, mean winter meteorological conditions and tidal forcing in specific periods of interest. M2 cotidal maps and currents ellipses were obtained, that one being the most important component in the tidal circulation. Mean seasonal elevations and currents are generally much smaller than the astronomical ones, allowing the use of tidal forcing only in hydrodynamic predictions.The model simulations were satisfactory in the platform and less precise within bays and internal shallow areas, where significative delays are observed, due to effects of smaller scale than the one adopted by the model.

The diet of chaetognath species were studied by examining the gut contents of 9466 specimens collected off Ubatuba region, São Paulo State. The greatest proportion of chaetognaths (7119 individuals) showed their gut contents empty. Copepods, mollusc eggs, appendicularians, cladocerans and annelids were the most common food items in the gut contents of juveniles and mature stages. Cannibalism occurred in low frequency. In Summer the copepods Temora stylifera and Paracalanus spp were more abundant, whereas Oncaea spp and mollusc eggs were heavily preyed in Winter. There was a clear trend of increasing prey size with the developmental stage.