Diversidade Ictiofaunística e Ecologia reprodutiva de uma espécie nativa de peixe da Bacia Piranhas-Assu, RN

The Caatinga biome is rich in endemic fish species fauna. The present study the results of fish faunal surveys conducted in the hydrographic basin of Piranhas-Assu of the Brazilian Caatinga biome. The fish samples collected were distributed in four orders (Characiformes, Perciformes, Siluriformes and Synbranchiformes), 11 families (Characidae, Curimatidae, Auchenipteridae, Anostomidae, Prochilodontidae, Erythrinidae, Cichlidae, Sciaenidae, Heptapteridae, Loricariidae, Synbranchidae) and 22 species, of which 17 are endemic and five have been introduced from other basins. The order Characiformes was the most representative in number of species (46,35% ) followed by Perciformes (35,38%), Siluriformes (17,44%) and Synbranchiformes (0,5%). The Nile tilapia, Oreochomis niloticus, the only exotic species, was most expressive in number of individuals (24.92%) followed by the native species piau preto, Leporinus piau (18,77 %). Considering the relative frequency of occurrence of the 22 species, 13 were constant, five were accessory and four were occasional. This study investigated the reproductive ecology of an endemic fish black piau, Leporinus piau from the Marechal Dutra reservoir, Acari, Rio Grande do Norte. Samplings were done on a monthly basis from January to December 2009, and a total of 211 specimens were captured. The environmental parameters such as rainfall, temperature, pH, electrical conductivity and dissolved oxygen of water were recorded. The sampled population showed a slight predominance of males (55%), however females were larger and heavier. Both sexes of L. piau showed positive allometric growth, indicating a higher increase of weight than length. The first sexual maturation of males occurred at smaller size, with 16.5 cm in total length than females (20.5 cm). During the reproductive period, the condition factor and gonadosomatic index (GSI) of L. piau were negatively correlated. This species has large oocytes with a high mean fecundity of 54.966 with synchronous oocyte development and total spawning

Avaliação da ecotoxicidade de percolados em áreas de disposição de resíduos na região metropolitana de Natal/RN

Leachates are effluent produced by decomposition of solid waste, they have complex composition and can be highly toxic. Therefore such percolated liquid should be collected and treated properly to avoid environmental contamination of soil and of water bodies. The objective of this study was to evaluate the toxicity through ecotoxicological tests with Ceriodaphnia dubia (Cladocera - Crustacea) of percolated liquids generated in two different systems of municipal solid waste (MSW) disposal in the city of Natal/ RN: A Sanitary Landfill in the Metropolitan Region of Natal/ RN, and in a dump off area. Furthermore, it was evaluated the possible contamination of the underground water of the dump off area. Two monthly samples were taken at four points between the months of May/2009 and January/2010. The Point "A" corresponds to the end of the pond leachate treatment in ASRMN; The Point "B" corresponds to a containment pond at the dump. The Point "C" is an area near one of the cells of the dump off area where the leachate outcrops; The Point "D" stands for an underground water well at the area. The last point, called "E" was sampled only once and corresponds to the slurry produced by temporary accumulation of solid waste in the open area of the dump. The ecotoxicological tests, acute and chronic, followed the ABNT 13373/2005 rules, with some modifications. The samples were characterized by measuring the pH number, the dissolved oxygen (DO), the salinity, BOD5, COD, Cd, Cu, Pb, Cr, Fe, Mg, Ni, and Zn. At Point A, the average number of EC50-48h ranged between 1.0% and 2.77% (v/v), showing a high toxicity of the leachate to C.dubia in all months. To this point, positive correlations were found between the EC50- 48 with precipitation. Negative correlations were found between the EC50- 48h with salinity. At point B there was no response of the acute exposure of organisms to the test samples. At point C the EC50-48h ranged from 17.68% to 35.36% in just two months of the five ones analyzed, not correlated meaning. Point D, the EC50-48h level ranged between 12.31% and 71.27%, showed a negative correlation with, only, precipitation. Although it was observed toxicity of underground water in the Landfill Area, there was no evidence of water contamination by leachate, however, due to the toxic character of this water, additional tests should be conducted to confirm the quality of water that is used for human supply. At point E there was no acute toxicity. These results support the dangers of inappropriate disposal of MSW to water bodies due to the high toxicity of the leachate produced highlighting the necessity of places of safe confinement and a treatment system more effective to it

Diagnóstico ecotoxicológico dos efluentes lançados no complexo estuarino do Jundiaí/Potengi, Natal/RN

Untreated effluents that reach surface water affect the aquatic life and humans. This study aimed to evaluate the wastewater s toxicity (municipal, industrial and shrimp pond effluents) released in the Estuarine Complex of Jundiaí- Potengi, Natal/RN, through chronic quantitative e qualitative toxicity tests using the test organism Mysidopsis Juniae, CRUSTACEA, MYSIDACEA (Silva, 1979). For this, a new methodology for viewing chronic effects on organisms of M. juniae was used (only renewal), based on another existing methodology to another testorganism very similar to M. Juniae, the M. Bahia (daily renewal).Toxicity tests 7 days duration were used for detecting effects on the survival and fecundity in M. juniae. Lethal Concentration 50% (LC50%) was determined by the Trimmed Spearman-Karber; Inhibition Concentration 50% (IC50%) in fecundity was determined by Linear Interpolation. ANOVA (One Way) tests (p = 0.05) were used to determinate the No Observed Effect Concentration (NOEC) and Low Observed Effect Concentration (LOEC). Effluents flows were measured and the toxic load of the effluents was estimated. Multivariate analysis - Principal Component Analysis (PCA) and Correspondence Analysis (CA) - identified the physic-chemical parameters better explain the patterns of toxicity found in survival and fecundity of M. juniae. We verified the feasibility of applying the only renewal system in chronic tests with M. Juniae. Most efluentes proved toxic on the survival and fecundity of M. Juniae, except for some shrimp pond effluents. The most toxic effluent was ETE Lagoa Aerada (LC50, 6.24%; IC50, 4.82%), ETE Quintas (LC50, 5.85%), Giselda Trigueiro Hospital (LC50, 2.05%), CLAN (LC50, 2.14%) and COTEMINAS (LC50, IC50 and 38.51%, 6.94%). The greatest toxic load was originated from ETE inefficient high flow effluents, textile effluents and CLAN. The organic load was related to the toxic effects of wastewater and hospital effluents in survival of M. Juniae, as well as heavy metals, total residual chlorine and phenols. In industrial effluents was found relationship between toxicity and organic load, phenols, oils and greases and benzene. The effects on fertility were related, in turn, with chlorine and heavy metals. Toxicity tests using other organisms of different trophic levels, as well as analysis of sediment toxicity are recommended to confirm the patterns found with M. Juniae. However, the results indicate the necessity for implementation and improvement of sewage treatment systems affluent to the Potengi s estuary

Projeto raia de fogo: aspectos populacionais da raia de fogo (Dasyatis marianae Gomes, Rosa & Gadig, 2000) e pesca de elasmobrânquios no complexo recifal do Parracho de Maracajaú

The species Dasyatis marianae inhabits coastal areas associated with coral reefs, considered endemic to the northeast of Brazil, occurring from the State of Maranhão to the south of Bahia. Specimens of this species are commonly sighted by divers and fishermen in the area of Maracajaú reefs, a complex reef that is part of the Environmental Protection Area of Coral Reefs (EPACR), which was developed in this study about the ecology and biology of the D. marianae, in order to characterize aspects of population structure in the area of the reef complex of Parracho de Maracajaú. We analyzed 120 specimens caught by artisanal fishing site of the size, weight, sex, stage of maturity and stomach contents. Most subjects were adult males (1.7:1) and was more abundant for rays with lengths between 25 and 29cm of LD, where females reach larger sizes, a feature common to other rays. The largest specimens were captured in the area of seagrass, which is preferred for the species. The distribution of species in the area showed an ontogenetic and sexual segregation, where the youthful occur near the beach, which is a likely area for nursery and growth of the adult females prevail in the seagrass, which apparently has a high prey availability, and Adult males are more distant, a higher proportion occurring in outlying areas, suggesting a habit more exploratory than the females. The evaluation of the reproductive system indicated 3 reproductive cycles per year, one young per pregnancy, and showed that the mature males were smaller than females. The cubs of D. marianae size at birth 12 to 15cm LD. As for diet, the species was characterized as carnivorous crustacean specialist. The performance of visual censuses in different localities allowed to evaluate the density of D. marianae in different environments of the complex. The species occurs in greater numbers in seagrass, environment very important for the conservation of the species. 100 individuals of D. marianae marked in reef complex area enrolled in a recapture rate of 3%. Some behavioral aspects were evaluated, as diurnal pattern of activity, interaction with cleaning and fish Pomacanthus paru followers as Lutjanus analis and Carangoides bartholomaei. Overall, much of the information obtained should be used for management of the species

Haemulidae, modelo cariotípico de estase evolutiva

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Efeito dos nutrientes (nitrogênio e fósforo) sobre o desenvolvimento da Gracilaria birdiae: crescimento e possível uso como biofiltro

Marine shrimp farming has grown exponentially during the last years in Brazil. In spite of the promising economical situation, this activity is facing an increasing criticism due to its environmental impact. Thus, the necessity of alternatives to mitigate environmental degradation caused by this activity. An alternative that is being studied is the policulture that is the integrated culture of two or more organisms, normally one of them a filtering organism. Among filtering organisms, macroalgae are very practicable because they are efficient in the removal of the exceeding nutrients of the water and do not leave residues in the water. Besides, the integrated culture with macroalgae allows the economical exploration of the seaweed (for the manufacture of jelly and jam, for the dairy industry, pharmaceuticals, etc.) along with possibility of a sustainable aquaculture. In the present experiment, the development of the seaweed Gracilaria birdiae, the influence and tolerance of this species to the environmental parameters, and its absorption efficiency in relation with the three kinds of macronutrients (NH4+, NO3- and PO4-3) found in the effluents of marine shrimp farming was studied. The experiment was divided in two parts: a laboratorial part and one part carried under natural conditions. The water used in the laboratory trial was collected in the shrimp ponds of Tecnarão farm and distributed in aquaria containing 20 g of G. birdiae. In the field trial, 0.5 kg of G. birdiae was inserted in PVC cages cultivated in the farm. The results of the study showed a modest growth of G. birdiae, probably due to its low tolerance to highly eutrophicated environments. However, the removal of nutrients was very expressive. Ammonia was reduced in approximately 34 %. Ortho-phosphate showed a reduction of 93.5 %. The capacity of biofiltration of the NO3- by the macro algae was of 100 %, showing that G. birdiae is a seaweed-filtered with a high level of removal for this nutrient under laboratorial conditions. In spite of the low growth of the macro algae in the experiment, the results in relation to the removal of nutrients of the water was encouraging, suggesting that this species can be an efficient biofilter and thus, a strong candidate to be used in a sustainable aquaculture

Diversidade de macroalgas marinhas bentônicas dos recifes de Maracajaú, área de preservação ambiental dos recifes de corais, Rio Grande do Norte, Brasil

Despite the importance of coral reefs to humanity, these environments have been threatened throughout the world. Several factors contribute to the degradation of these ecosystems. The Maracajaú Reef Complex, in Rio Grande do Norte state is part of the Coral Reefs Environment Preservation Area in northeastern Brazil. This area has been receiving an increasing influx of tourism and the integrity of the local reefs is a matter of concern. In this study, the reef macroalgae communities were studied and compared within two areas distinguished by the presence or absence of tourism activities. Two sample sites were chosen: the first one, where diving activities are intense; and the other, where these practices do not occur. Samples were collected at both sites within a quadrate of 625 cm2 of area randomly thrown 5 times along a 10 meters transect line. Richness, Shannon-Hill diversity and Simpson dominance indices were determined based on biomass data. Similarity between sites was analyzed with Bray-Curtis similarity and distance index. Fifty-eight macroalgae species were observed, including 7 Chlorophyta, 13 Phaeophyta and 38 Rhodophyta. In the non-disturbed site, 49 species were found, while at the disturbed site, there were 42 species. Dictyotaceae and Corallinaceae were the most representative families at the non-disturbed site, and Rhodomelaceae and Dictyotaceae at the disturbed site. The non-disturbed site presented a higher biomass and the greatest richness and diversity indices. In the disturbed site the dominance index was greater and Caulerpa racemosa was the dominant species. The dendogram based on similarity index showed two major clusters, and an isolated element at the center that corresponds to a sample from the disturbed site. In the first cluster, samples from the non-impacted site were predominant and fleshy brown algae were more conspicuous. The second cluster was composed primarily of samples from the impacted site, where C. racemosa and red filamentous and erect calcareous algae associations (turf forming) were observed covering large extensions. These associations are represented by groups of algae adapted to environments where disturbances are frequent. They can grow rapidly on substrate where benthic community was removed and do not allow the establishment of other species. The results of the present study show that tourism activity is an impacting factor that has been causing shifts in macroalgae communities in the Maracajaú Reef Complex

Avaliação da toxicidade de florações naturais e de cultura de cianobactérias: efeitos sobre Ceriodaphnia silvestri (Crustacea, Cladocera)

The incidence of toxic cyanobacterial blooms is one of the important consequences of eutrophication in aquatic ecosystems. It is a very common phenomenon in reservoirs and shrimp ponds in the State of Rio Grande do Norte (RN), Brazil. Cyanobacterias produce toxins which can affect aquatic organisms and men trough the food chain. Aiming to contribute to the studies of cyanobacterias in RN, we propose: a) to evaluate the toxicity of isolated cyanobacterias in important fresh-water environments; and b) to verify the effects of both natural and cultured blooms occurred in reservoirs for human supply and in the cladoceran Ceriodaphnia silvestrii. This study was carried out using samples of natural blooms occurred between March and October of 2004 in Gargalheiras Dam (08º L e 39º W), in July of 2004 in Armando Ribeiro Gonçalves Dam (06o S e 37o W) and in commercial shrimp ponds (Litopenaeus vannamei) located in fresh-water environments. The samples were collected with plankton net (20µm.) for identification, isolation and obtaining of phytoplanktonic biomass for liophilization and later toxicity bioassays. The toxicity of cultured samples and natural blooms was investigated through bioassays in Swiss mice. Quantification of cyanobacteria in samples was conducted following the Ütermol method, with 300mL samples fixed with lugol. The toxicity test with Ceriodaphnia silvestrii followed ABNT, 2001 recommendations, and were accomplished with natural hepatotoxic bloom s samples and cultured samples of both non-toxic and neurotoxic C. raciborskii. In this test, five newborns, aged between 6 and 24 hours, were exposed to different concentrations (0 a 800 mg.L-1) of crude cyanobacterial extracts during 24 and 48 hours. Three replicates were used per treatment. The pH, temperature and dissolved oxygen at the beginning and after 24 and 48hours from the test were measured. We estimated the CL50 through the Trimmed Spearman-Karber method. The blooms were constituted by Microcystis panniformis, M. aeruginosa, Anabaena circinalis, Cylindrospermopsis raciborskii and Planktothrix agardhii, producers of mycrocistin-LR confirmed with HPLC analysis. Samples of hepatotoxic blooms registered toxinogenic potential for C. silvestrii, with CL50-24h value of 47.48 mg.L-1 and CL5048h of 38.15 mg.L-1 for GARG samples in march/2005; CL50-24h of 113,13 mg.L-1 and CL5048h of 88,24 mg.L-1 for ARG July/2004; CL50-24h of 300.39 mg.L-1 and CL50-48h of 149.89 mg.L-1 for GARG October/2005. For cultured samples, values of CL50-24h and CL50-48h for C. raciborskii toxic strains were 228.05 and 120.28 mg.L-1, respectively. There was no mortality of C. silvestrii during the tests with non-toxic C. raciborskii strain. The toxicity test with C. silvestrii presented good sensitivity degree to cyanotoxins. The toxicity of natural hepatotoxic blooms samples (microcystins) and cultured neurotoxic saxitoxins producer samples analyzed in this study give us strong indications of that toxin s influence on the zooplanktonic community structure in tropical aquatic environments. Eleven cyanobacteria strains were isolated, representing 6 species: Anabaenopsis sp., Cylindrospermopsis raciborskii, Chroococcus sp., Microcystis panniformis, Geitlerinema unigranulatum e Planktothrix agardhii. None presented toxicity in Swiss mice. The strains were catalogued and deposited in the Laboratório de Ecologia e Toxicologia de Organismos Aquáticos (LETMA), in UFRN, and will be utilized in ecotoxicológical and ecophysiological studies, aiming to clarify the causes and control of cyanobacterial blooms in aquatic environments in RN. This state s reservoirs must receive broader attention from the authorities, considering the constant blooms occurring in waters used for human consumption

Utilização da macroalga Ulva lactuca linnaeus na redução de nutrientes (NH4+,NO3- e PO4-2) provenientes da carcinicultura

Dentre as macroalgas capazes de absorver altas concentrações de N e P dissolvidos na água, destaca-se a Chlorophyta Ulva lactuca, bastante adaptável e resistente às adversidades ambientais, como grandes variações de temperatura, salinidade, matéria orgânica e metais pesados. Trata-se também de uma espécie bastante comum nas áreas intertidais do litoral norte-riograndense. Devido a suas características ecológicas, fisiológicas e nutricionais, foi avaliado nesse estudo, o seu potencial como biofiltro na redução de NH4+, NO3- e PO4-2, tanto em condições controladas como também em um viveiro de camarão. No experimento laboratorial, foram utilizados quatro aquários de vidro de 30 x 20 x 20cm com 10L de água, sendo três aquários experimentais contendo 20g de U. lactuca e um controle. O acréscimo de biomassa foi de 2,92g (22,92 ± 6,29g; p < 0,05) em relação ao inóculo inicial de 20g, sob temperatura (28,50 ± 0,58ºC), salinidade (35,00 ± 0,00 ), pH (8,26 ± 0,02) e luz constante (250 μmol.m2s-1). O crescimento positivo (1,78 ± 4,38%dia-1; p < 0,05), juntamente com a alta eficiência de absorção de amônio (83%; p < 0,001), nitrato (83%; p < 0,001) e ortofosfato (53%; p < 0,001), demonstrou que, nessas condições, a Ulva lactuca absorveu os nutrientes e aumentou sua biomassa. Já no experimento de campo, realizado na fazenda TECNARÃO, situada no município de Arez/RN (06° 11 40 Latitude Sul, e 35º 09 37 Longitude Oeste), foram utilizadas três gaiolas de PVC, posicionadas a 12cm da superfície da água, cada uma com dimensões de aproximadamente 59 x 59 x 15cm, onde foram colocadas 200g de U. lactuca. O ganho de biomassa de 3g (203,00 ± 41,02g; p < 0,001) foi muito semelhante às condições controladas, demonstrando a adaptabilidade da espécie em condições ambientais variáveis, onde, apesar da temperatura pouco variável (27,45 ± 0,64ºC), houve progressiva diminuição de salinidade (25 - 15 ), devido ao período de fortes chuvas (34,70 ± 23,78mm). Somado a isso, foram observados vários fatores biológicos interferindo no viveiro, como a presença de epífitas, organismos endofíticos, fouling e a herbivoria por parte dos próprios camarões. Houve aumento nas concentrações de NH4+ (4,36 ± 1,69 μmol.L-1), NO3- (0,17 ± 0,25μmol.L-1) e PO4-2 (0,41 ± 0,13μmol.L-1), coincidindo com o crescimento da espécie até a terceira semana. Todos os parâmetros ambientais analisados, assim como a biomassa e a Taxa de Crescimento Relativo (TCR), obtidos no campo, apresentaram variações altamente significativas (p < 0,001). As correlações observadas entre biomasa e NH4+ (r = 0,82; p < 0,001) e entre biomassa e PO4-2 (r = 0,87; p < 0,001), indicam que esta espécie é capaz de ter um crescimento satisfatório nas condições eutróficas de um viveiro de camarão, sendo possível seu uso como biofiltro.

Encalhes de Cetáceos ocorridos no período de 1984 a 2005 no litoral do Rio Grande do Norte, Brasil

Strandings of live or dead aquatic mammals constitute an important instrument to provide information regarding the occurrence, biology and ecology of these species. The aim of this study was to register the stranded species of cetaceans, the frequency and the spatial-temporal distribution of theses strandings during the period of 1984 to 2005, in the coast of Rio Grande do Norte. Data was acquired through the monitoring of strandings in the north, north-west and south coast of RN, and through information obtained from institutions and newspaper archives of the State. A total of 122 strandings of cetaceans were registered along the coast of Rio Grande do Norte. Of the 14 species of cetaceans registered, four species had higher frequencies: Sotalia guianensis (n= 65), Steno bredanensis (n = 6), Globicephala macrorhynchus (n = 6) and Physeter macrocephalus (n = 7). Out of 118 strandings, 93 occurred in the south coast (78.8 %), 23 in the north coast (19.5%) and 2 (1.7%) in the north-west coast of the State. The highest frequency of strandings occurred during the months of August to March and the maximum number of strandings occurred from 2000 onwards, as a consequence of the intense monitoring of the Pequenos Cetáceos Project in Rio Grande do Norte

Ecomorfologia de dez espécies de peixes marinhos mais abundantes de Galinhos/RN

Ecomorphology is a science based on the idea that morphological differences among species could be associated with distinct biological and environmental pressures suffered by them. These differences can be studied employing morphological and biometric indexes denominated Ecomorphological attributes , representing standards that express characteristics of the individual in relation to its environment, and can be interpreted as indicators of life habits or adaptations suffered due its occupation of different habitats. This work aims to contribute for the knowledge of the ecomorphology of the Brazilian marine ichthyofauna, specifically from Galinhos, located at Rio Grande do Norte state. 10 different species of fish were studied, belonging the families Gerreidae (Eucinostomus argenteus), Haemulidae (Orthopristis ruber,Pomadasyscorvinaeformis,Haemulonaurolineatum,Haemulonplumieri,Haemulonsteindachneri), Lutjanidae (Lutjanus synagris), Paralichthyidae (Syaciummicrurum), Bothidae (Bothus ocellatus) and Tetraodontidae (Sphoeroidestestudineus), which were obtained during five collections, in the period time of September/2004 to April/2005, utilizing three special nets. The ecomorphological study was performed at the laboratory. Eight to ten samples of each fish specie were measured. Fifteen morphological aspects were considered to calculate twelve ecomorphological attributes. Multivariate statistical analysis methods such as Principal Component Analysis (PCA) and Cluster Analysis were done to identify ecmorphological patterns to describe the data set obtained. As results, H.aurolineatumwas the most abundant specie found (23,03%) and S.testudineusthe less one with 0,23%. The 1st Principal component showed variation of 60,03% with influence of the ecomorphological attribute related to body morphology, while the 2nd PC with 23,25% variation had influence of the ecomorphological attribute related to oral morphology. The Cluster Analiysis promoted the identification of three distinct groups Perciformes, Pleuronectiformes and Tetraodontiformes. Based on the obtained data, considering morphological characters differences among the species studied, we suggest that all of them live at the medium (E.argenteus,O.rubber, P.corvinaeformis,H.aurolineatum,H.plumieri,H.steindachneri,L.synagris) and bottom (S.micrurum,B.ocellatus,S.testudineus) region of column water.

Avaliação espaço-temporal do zooplâncton da laguna estuarina de Guaraíras (RN, Brasil)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Utilização de embriões liofilizados e flocos de Artemia na diversificação nutricional de pós-larvas do camarão marinho Litopenaes vannamei (Boone, 1931)

The objective of the current study was to evaluate the zootechnical performance (survival and growth) of Litopenaeus vannamei post-Iarvae fed an artificial shrimp diet supplemented with Artemia flakes or freeze-dried Artemia embryos. For that purpose, 20 culturing units were individually stocked with 50 shrimp post-Iarvae (average dry weight of 0,3 ± 0,03 mg) at a stocking density of 20 post-larvae per liter, and fed the experimental diets to satiation during 20 days. The experimental design consisted of four diets (T1, T2, T3 and T4) with five repetitions each. For treatments T1, T2 and T3, dietary supplements of 5mg of Artemia flakes (T1), freeze-dried Artemia embryos (T2), and of the commercial shrimp diet (T3) were offered 2 hours after the shrimp were initially fed the commercial shrimp diet. For treatment T4 (control), no additive was offered 2 hours after the initial feeding. Shrimp survival, absolut (GPA) and relative increase in weight (GPR), and specific growth rate (TCR) were used as evaluation criteria. After the experimental period, no significant statistical differences (p>0,05) in survival were observed. Regarding growth, the dietary treatment which used freeze-dried Artemia embryos as an additive (T2) presented the best results for GPA (6,7 ± 0,7 mg). There were no statistical differences within treatments T1, T3 and T4 (p>0,05). AIso, post-larvae fed freeze-dried embryos (T2) showed a relative increase in weight (2241,4%) which differed significantly (p<0,05) from T4(1911,7%) but not from T1 (1801,6%) or T3 (1946,7%). In conclusion, the results of the current study indicate that an artificial shrimp diet supplemented with freeze-dried Artemia embryos fulfils the nutritional requirements of post-larvae L. vannamei and promotes a better growth than diets not supplemented with Artemia flakes

Caracterização ecológica dos peixes recifais do Atol das Rocas

The present work was carried out at the Atol das Rocas (3º 51 S; 33º 49 W), the only atoll of the South Atlantic and the first Brazilian marine protected area. It was guided by the following hypothesis: the composition of the fish communities varies in agreement with the position of the pools; in other words, with or without permanent ocean connection. To test the validity of this hypothesis, the fish abundance was estimated in the connected pools (Barretinha/Barreta Falsa) and unconnected ones (Cemiteriozinho/Âncoras), carrying an ecological characterization of the fishes that inhabit these pools. Additionally, the structural complexity of the sampled places was also evaluated intending to verify the variations of the abundance and diversity of fishes in function to this factor. By the fact of this research was being carried out through the limits of a conservation unit, the samples was realized using visual census techniques. The results generated through uni and multivariate analytic techniques allowed the evidence that decisive factor in the density, richness and diversity variations of fishes are linked to the substratum type (Hard / Soft bottom) and not by the fact that the pool are or are not connected permanently to the ocean. In relation to the structural complexity; 58% of the variations in the diversity of fishes were attributed to changes in the structural complexity, while 12% of the variations in the abundance were attributed to the structural complexity

Estudo do crescimento, eficiência de biofiltração e cinética de absorção de nutrientes (N-NH, N-NO e P-PO4³) da macroalga Gracilaria cervicornis (Turner) J. Agardh

The objective of this study was to examine the growth of Gracilaria cervicornis cultured in a shrimp (Litopenaeus vannamei) pond and to determine the absorption efficiency and the kinetics parameters (Vmax, Ks e Vmax:Ks) of this macroalgae for the nutrients N-NO3-, N-NH4+ and P-PO4-3, aiming at its use as bioremediatory of eutrophicated environments. For this study, two experiments (field and laboratory) were developed. In the field study, the seaweed was examined in relation to the growth and the biomass. In the laboratory experiment, the absorption efficiency of G. cervicornis was measured through the monitoring of the concentration of the three nutrients (N-NO3-, N-NH4+ e P-PO4-3) during 5 hours and the kinetic parameters were determined through the formula of Michaelis-Menten. The results obtained in this study demonstrated that G. cervicornis benefited from the available nutrients in the pond, increasing 52.4% of its biomass value after 30 days of culture. It was evidenced that the variability of the biomass could be explained through the salinity, availability of light (transparency and solid particle in suspension) and concentration of N-NO3- in the environment. In the laboratory experiment, the highest absorption efficiency was found in the treatments with low concentration (5 µmol.L-1), being evidenced a reduction of up to 85,3%, 97,5% and 81,2% of N-NH4+, N-NO3- and P-PO43-, respectively. Regarding the kinetic parameters, G. cervicornis presented better ability in absorbing N-NH4+ in high concentrations (Vmax = 158,5 µmol g-1 dry wt h-1) and P-PO43- in low concentrations (Ks = 5 µmol.L-1 e Vmax:Ks = 10,3). The results of this study show that G. cervicornis could be cultivated in shrimp ponds, presents a good capacity of absorption for the tested nutrients and is a promising candidate for biorremediation in shrimp pond effluent