The eggs and larvae of the New Zealand snapper Pagrus auratus are pelagic with early buoyancy provided by dilute body fluids. The swimbladder begins to develop on the third day after hatch from a dorsal evagination of the gut tube. Communication w1h the gut is lost on about the tenth day following pneumatic inflation at around day eight. At this age the gas gland system appears fully functional and capable of secreting gas. By the age of settlement at around 30 days the swimbladder is a fully functional replica of the adult form except for the lack of a resorbent capillary system which does not develop until later in juvenile life. The swimbladder of the adult is of the euphysoclist form with a dorsally located resorbent oval area and sits high in the pleural cavity. The ventral tunica externa is firmly attached to the connective tissue lining the pleural space. The adult swimbladder displaces 5.6% of the volume of the body and its volume is regulated to provide near neutral buoyancy. The connective tissue integument provides almost no restriction to volume changes brought about by vertical movements of the fish and the swimbladder obeys Boyle's Law for physiological pressure changes. The ability of the connective tissue of the tunica externa to accommodate large tissue strains is due to massive regular crimping of otherwise straight collagen fibrils allowing reversible extensions up to 130%. In all other respects however the tissue structure of the tunica externa is consistent with a tissue providing an active mechanical role. The fibrillar morphology and physicochemical properties of swimbladder collagen is consistent with the vertebrate type I form however there are interesting variations in collagen form distributed throughout the swimbladder. Fibrillar morphology of the highly extensible tunica interna is significantly different to that of the tunica externa and appears to play very little mechanical rote. The extensibilty of the tunica externa appears to be regulated by physiological stress and related to the past history of tissue strain.

The impact of no-take marine reserves on spiny lobster, Jasus edwardsii, populations and the adjacent lobster fishery was assessed in a study that determined: the response of lobster populations to protection, if lobsters within marine reserves moved out into the surrounding fishery, examined the behavioural characteristic of lobsters that contributed to their recovery and spillover, and contrasted catch characteristics around a north-east New Zealand marine reserve with 2 unprotected sites. Surveys of 4 no-take marine reserves of different ages and 4 unprotected control sites confirmed that J. edwardsii increase in mean size and abundance within protected areas. Total lobster density was estimated to increase by 6.1% per year of protection. The relationship between age of reserve and the density of lobsters above the legal size limit (>100 mm carapace length) was complicated by depth related interactions between reserves, due to seasonal changes in the depth distribution of lobsters and differences in the timing of surveys among locations. However, density increases in legal sized lobsters were greater than those of the overall population. Mean size of protected lobsters increased in a non-linear fashion, reflecting the asymptotic growth characteristics of the species. Mean carapace length of lobsters increased by 11.24 mm after 3 years of protection and only by 16.25 mm after 2l years of protection. Corresponding increases in biomass (kg.500 m-2) and egg production (eggs.500 m-2) were estimated to be 7.4% and 6.6% respectively per year of protection. A tag recapture program indicated that the limited scale of movements and relatively high site fidelity of mature J. edwardsii aided the recovery of lobster populations in protected areas. Of 737 lobsters tagged in and around the Leigh Marine Reserve,212 were subsequently resighted. Seventy percent of resighted lobsters were relocated less than 250 m along the shore from their initial site after a mean period of liberty of 146 (se = 13.42) days. However, seasonal offshore movements took lobsters beyond the seaward boundary of the reserve where they were susceptible to capture. Of the 521 lobsters tagged on inshore reefs within the Leigh Marine Reserve. l.9% were caught over the seaward boundary by commercial fishers, and 14.4% of the 181 lobsters tagged over the seaward boundary were resighted on inshore reefs within the reserve. Movements into or out of the reserve across the longshore boundaries were also recorded for 7 out of the 27 lobsters moving further than 250 m along the shore. Acoustic tracking confirmed that J. edwardsii have a high site fidelity, with tracked lobsters spending a median of 84% of their time at their home site. Twenty one percent of the 26 lobsters fitted with acoustic tags never left their tagging site and, of those that did leave 56% eventually returned. Lobsters moved up to 3.1km away from their home sites but managed to find their way back after periods of 1 to 103 days away. Five lobsters had strong associations with two separate sites and made repeated movements between these alternate home sites. The straight line distance between alternate home sites ranged from 200 m to 1.3 km, and the period between visits to their primary or secondary home sites ranged from 1 to 93 days. Movement activity varied throughout the year, and seasonal patterns differed between males and females. Females displayed one peak in movement activity per year, around the time of larval release in September-October. Males displayed a summer peak centred on January, and a winter peak centred on July. The onset of high movement activity was often accompanied by a shift to deeper water and l0 of the 14 lobsters tracked for over 6 months spent periods away from the inshore reef system. Exposed groups of lobsters were observed aggregating in offshore areas of sand and low lying patch reef during the day. Offshore aggregations were observed over 7 months of the year and lobsters within the aggregations displayed behaviour consistent with the use of mutual defence. The sexual composition of the aggregations reflected seasonal patterns in male and female movement rates. Male J. edwardsii dominated the aggregations in winter and summer; times when peak feeding rates of males held in captivity were also recorded. Females dominated the offshore aggregations in September-October when larvae are released. Seven of the 26 lobsters fitted with acoustic tags moved over the boundaries of the Leigh Marine Reserve and Tawharanui Marine Park during offshore movements. Despite the fact that there is no fishing access to inshore reefs within the Leigh Marine Reserve, no significant difference was detected between the catch per unit effort (kg.trap haul-1) of lobsters caught around the reserve, nearby coastal Leigh or Little Barrier Island. However, catches around the marine reserve contained fewer (P=0.0009) but larger lobsters than at Little Barrier Island. The catch characteristics of lobsters from coastal Leigh were intermediate between the other two sites. As access to inshore reefs around the Leigh Marine Reserve was limited to a small area at either end of the reserve, traps tended to be set in offshore locations and the sexual composition of the total catch around the Leigh Marine Reserve reflected the seasonal movements of males and females into, and out, offshore areas. At coastal Leigh and Little Barrier Island the location of traps was not restricted and greater use was made of coastal fringing reefs. As a result the sexual composition of the catch at these locations did not reflect the movement of various components of the lobster population into and out of specific habitats or locations. Overall, the results of this study suggest that relatively small (~ 5 km2) no-take marine reserves increase lobster biomass and egg production, without adversely affecting catch rates in the surrounding fishery. Marine reserves may therefore represent a viable management tool, which if used in conjunction with other management regimes, could provide a more precautionary approach to the management of the J. edwardsii fishery at minimal cost to the industry.

The effects of seawater inflows and macrophyte beds on community metabolism and phosphorus dynamics in the seasonally-closed Swartvlei estuary were investigated. Metabolic rates were determined by diurnal oxygen curve analysis. Gross primary production ranged from 0,7 to 14,9 g 0₂ m⁻² day⁻¹, and respiration from 0,9 to 25,2 g 0₂ m⁻² day⁻¹. The highest production rates were recorded inside the dense beds of Zostera capens is Setchell (x- = 7,8 g 0₂ m⁻² day⁻¹ ). Metabolism was positively correlated to submersed macrophyte cover, and decreased upstream of the mouth region. No seasonal variation in gross production could be detected, and mouth closure had no detectable effect on metabolic rates. Growth of the green alga Enteromorpha sp. in winter, and the effect of decay of this alga on dissolved oxygen, total inorganic carbon and total dissolved phosphorus in the water column is discussed. High day-time respiration values, measured in a darkened polythene enclosure, indicate that photorespiration occurs in Zostera. Apparently the annual amount of oxygen respired throughout the estuary exceeded that produced by 2 7100 tonnes, i.e. the estuary was heterotrophic. This is discussed in relation to the effectiveness of the diurnal curve method as a way of measuring metabolic rates, and to the possibility of organic matter input via river inflows. There is a net gain of up to 17,4 kg of particulate phosphorus over mean tides. Diurnal phosphorus studies indicate that Zostera releases phosphate into the water column in the light. Enteromorpha takes up phosphate in the morning, which it appears to release over the rest of the day. The cycling of phosphorus between seawater, sediments, macrophytes and the water column is discussed.

During 1982 benthic and floating filamentous algal mats appeared in the maturation ponds of the Grahamstown Sewage Disposal Works. These mats clogged the ponds and reduced the efficiency by which the effluent was purified. As they continued to be a problem despite numerous efforts to remove them, this study was initiated to investigate the alga, establish why it was successful in the pond environment, and how its growth could be controlled. The physico-chemical environment of a representative maturation pond was characterised while laboratory studies were conducted to investigate the growth, photosynthetic and respiratory characteristics in the alga. The alga was identified as Rhizoclonium riparium (Roth) Harv. although its morphological variability was greater than that reported in the literature. Growth and photosynthetic studies indicated that the alga favoured temperatures between 20 and 30⁰C and relatively high light intensity (700μE.m⁻².s⁻¹) and that it was highly productive. In addition, the alga exhibited photoadaptive ability, although it seemed to be sensitive to photoinhibition. Its success in the maturation pond was attributed to the favourable physico-chemical environment, particularly the high transparency of the effluent which allowed the penetration of PAR to the pond floor and to the alga's ability to adapt to the change in environment when it floated from the pond floor to its surface. Although the algal mats contribute to the oxidation of the effuent within the maturation pond, they are generally detrimental to the system because they shade the water column and inhibit wind-induced mixing. Recommendations on methods of controlling of the mats are presented. / KMBT_363 / Adobe Acrobat 9.53 Paper Capture Plug-in

1. The development of estuarine research in South Africa has been reviewed, and the present state of knowledge assessed. Little is known about many abundant estuarine species, and a previously unstudied prosobranch Nassarius kraussianus (Dunker), was selected for investigation. 2. The study area, a mudflat on the Bushmans River estuary, was divided into three habitat types: supratidal, intertidal and subtidal, each with a particular substratum and pattern of vegetation cover. The distribution of N. kraussianus is associated with the nature of the substratum and the degree of Zostera capensis Setchell cover. 3. A brief review of pertinent literature indicated the necessity of relating population parameters to environmental conditions. 4. The population biology of N. . kraussianus was investigated, and the size frequencies, sex ratios, and male/female size frequencies were recorded over three distinct periods: pre-flood, post-flood and recovery. 5. The Bushmans River flooded in July and August 1979, and the results of the flood have been described. The most immediate result was a period of low salinity, but the most persistant result was the deposition of silt, which had an important effect on the substratum and the Z. capensis beds. 6. The pre-flood population was characterised by patchy distribution, and by a large number of mature adults in relation to juveniles. Females were generally larger than males, and the sex ratio was 1:1. The presence of juveniles in consistantly low numbers indicated that reproduction may have been continuous, but that intraspecific adult/juvenile competition may have kept juvenile numbers low. 7. The post-flood period was characterised by extreme physical conditions, and the survival of a few adults. Juveniles were completely annihilated, and were absent until a few were spawned by the surviving adults towards the end of 1979 . Sex ratio was biased, and females predominated. 8. The recovery period began abruptly with the arrival of a large number of juveniles in the 2, 3 and 4 mm size classes. Recolonisation coincided with habitat recovery, and reqeneration of the Z. capensis cover. Recolonising juveniles grew quickly, reaching adult size in three months. After that, juveniles were spawned on the mudflat by the new population. During this period the sex ratio did not return to the pre-flood 1:1, but remained female biased. Males and females grew at the same rate over the period measured, but females were consistantly larger, indicating that at some stage female growth may be faster. 9. The recolonising juveniles arrived in a regenerated habitat, at a time when temperatures were high, and conditions for growth probably optimal. If intraspecific competition was a feature of the pre-flood population it would have been elimianted in the recovery phase, by the absence of adults. 10. N. kraussianus is apparently omnivorous and proabably not food limited. However, carrion, a limited resource, may be essential for growth to reproductive maturity. Adults and juveniles may compete for this resource, and any juveniles deprived of access to carrion may be stimulated to leave the parental habitat. 11. N. kraussianus is ovoviviparous, and carries up to 5 egg cases within the uterus. Each triangular egg case contains 1 egg which hatches after approximately 3 weeks, as a free swimming veliger. Yeligers metamorphose, and settle after 4-7 days, assuming a benthic mode of life. Ovoviviparity protects the developing embryo from the rigours of environmental extremes, and ensures that embryos are not swept out to sea . Additionally, veligers have a high probability of settling in the parental habitat. 12. This reproductive strategy has been compared with other prosobranchs, and the evolutionary trends within the Prosobranchia, and particularly the Nassariidae, have been related to their dispersal potential. 13. Developmental strategy is intimately related to recolonisation potential. Ovoviviparity, and the lack of pelagic larvae, did not limit the recolonisation potential of N. kraussianus, and recolonisation was probably effected by post-larval juveniles, which may disperse from neighbouring estuaries and coastal pools, by floating in coastal and tidal currents. Post-larval juveniles have two important advantages over larvae. They are less vulnerable to physical extremes, and they have a sturdy crennellated shell which probably affords them protection from predators. 14. Examples of larval recolonisation in estuarine populations have been reviewed, and the most fundamental conclusion of this work is that recolonisation is an important, and probably widespread, adaptation to estuarine conditions in South Africa.

x, 106 leaves : ill., maps ; 29 cm Notes Typescript Thesis (Ph. D.)--University of Oregon, 1986 Includes vita and abstract Bibliography: leaves 98-106 Another copy on microfilm is located in Archives

vii, 97 leaves : ill., maps ; 28 cm Notes Typescript Thesis (M.S.)--University of Oregon, 1985 Includes vita and abstract Bibliography: leaves 92-97 Another copy on microfilm is located in Archives

Com o objetivo de aplicar e avaliar a viabilidade de uso dos métodos disponíveis com organismos marinhos, no controle da toxicidade de efluentes líquidos que são lançados em ambientes estuarinos, foram realizados testes de toxicidade aguda com os crustáceos Mysidopsis juniae, Artemia sp, Temora stylifera e Acartia IiIljeborgi e testes de toxicidade crônica de curta duração com o equinodermo Lytechinus variegatus, utilizando-se os efluentes industriais de uma indústria siderúrgica, COSIPA e uma fábrica de fertilizantes, ULTRAFÉRTIL/JARDIM SÃO MARCOS, ambos lançados no estuário do Rio Cubatão. Dentre os organismos-testes utilizados, para avaliação do efeito tóxico agudo, o misidáceo M. juniae foi o mais sensível para ambos os efluentes, sendo que Artemia sp foi o menos sensível. Testes de toxicidade crônica com L. variegatus também se mostraram bastante úteis para avaliação de efeitos subletais. Os efluentes analisados apresentaram grande variabilidade durante o período de estudo, o que foi evidenciado através do cálculo do coeficiente de variação para testes com M. juniae. Foi avaliado, também, o efeito da salinidade sobre a sensibilidade dos crustáceos M. juniae e Artemia sp a agentes químicos (zinco e DSS) e aos efluentes industriais. A salinidade não interferiu significativamente nos resultados observados, com exceção de um experimento realizado a 15x10-3 com Artemia sp, com o efluente da COSIPA. Verificou-se, ainda, o possível efeito da utilização de salmoura obtida através dos processos de congelamento e evaporação da água do mar, sendo que o primeiro processo foi indicado para salinização de efluentes. / Acute toxicity tests with the crustaceans Mysidopsis juniae, Anemia sp, Temora stylifera e Acartia lilljeborgi and short-term chronic toxicity test with the echinoderm Lytechinus variegatus were conducted with the objective of evaluating the appropriateness of their application for the control of liquid effluents disposed off in estuarine environments. Effluents of a siderurgic industry, COSIPA, and of a fertilizer plant, ULTRAFÉRTIL/JARDIM SÃO MARCOS, were used. Both are discharged into the estuary of Cubatão river. The test with M. juniae was the most sensitive of the acute methods, for both kinds of effluents, while that with Artemia sp was the least sensitive. Chronic toxicity test with L. variegatus showed to be very useful for the evaluation of sublethal effects. The different effluent samples of both industries had great variability in their toxic effects, along the different sampling periods, as was evidenced by the high coefficient of variation for tests with M. juniae. The effects of salinity on the sensitivity of M. juniae and Artemia sp to chemicals (zinc and DSS) and to the industrial effluents, was evaluated. Salinity did not signifieantly affect the test results, except for the experiment conducted at 15x10-3 with Artemia sp, with the effluent from the siderurgic industry. The possible effect of the use of brine, obtained by freezing or evaporating sea water, was also analyzed. Freezing was the recommended procedure to salinize effluents.

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2017-02-09T13:57:16Z No. of bitstreams: 1 PDF - Climélia da Nóbrega Silva.pdf: 2378682 bytes, checksum: bc27dc4732d9c3146e265bcaaa7cece6 (MD5) / Made available in DSpace on 2017-02-09T13:57:16Z (GMT). No. of bitstreams: 1 PDF - Climélia da Nóbrega Silva.pdf: 2378682 bytes, checksum: bc27dc4732d9c3146e265bcaaa7cece6 (MD5) Previous issue date: 2014-12-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Estuaries are environments that run important ecosystem services, such as nurseries and feeding places for numerous species. However, are subject to various anthropogenic impacts that directly affect their operation. This study aimed to test which taxonomic level is sufficient to evaluate the environmental condition as well as assess the relative efficacy of ecological indicators in estuaries assumed as subject to anthropogenic pressures of different intensities. The research was conducted in the estuaries of the River Paraíba do Norte and Mamanguape River (Northeastern Brazil), in November 2013, totaling 27 sampling sites, parted into four zones according to the values of salinity, sediment composition and depth. The organisms collected were sorted and identified to the lowest possible taxonomic level. This study is divided into two chapters, the first taxonomic depicts sufficiency by addressing the hypothesis that the family level would be more efficient to detect the environmental condition and the second test whether the combined use of the thermodynamically oriented indicators, functional trophic groups wealth rate and diversity index Shannon-Wiener would provide consistent answers in the evaluation of the ecological condition of estuaries. Fill Taxonomic showed that for the purpose of this study, both the family level as gender were enough to detect changes in environmental conditions, for this sample period. Regarding the use of associated ecological indicators to detect changes in ecological conditions of the estuaries, the indicators based on taxa richness, diversity, specific eco- exergy and functional feeding groups did not respond concurrently in the detection of changes in the ecological condition of estuaries with different levels of human impacts. Only eco-exergy index indicated differences in the ecological condition of the assessed ecosystems. Thus, the results obtained from the survey showed the importance of the study on the taxonomic sufficiency and ecological indicators based on benthic communities as a biomonitoring tool, which aims to understand the variations and fluctuations of ecosystems as well as the basis for measures proposed to mitigation of human impacts, conservation and environmental management. / Os estuários são ambientes que prestam serviços ecossistêmicos importantes, como berçários e locais de alimentação para inúmeras espécies. Porém, estão sujeitos a diversos impactos antrópicos que afetam diretamente seu funcionamento. O objetivo do trabalho foi testar qual nível taxonômico é suficiente para avaliar a condição ambiental, assim como verificar a eficácia relativa de indicadores ecológicos em estuários assumidos como sujeitos às pressões antrópicas de diferentes intensidades. A pesquisa foi realizada nos Estuários do Rio Paraíba do Norte e do Rio Mamanguape (Nordeste brasileiro), em novembro de 2013, totalizando 27 pontos de amostragem, divididos em quatro zonas de acordo com os valores de salinidade, composição do sedimento e profundidade. Os organismos coletados foram triados e identificados ao menor nível taxonômico possível. Este estudo está dividido em dois capítulos, o primeiro retrata a suficiência taxonômica, abordando a hipótese de que o nível de família seria mais eficiente em detectar a condição ambiental e o segundo testou se o uso associado dos indicadores termodinamicamente orientados, grupos tróficos funcionais, riqueza de taxa e índice de diversidade de Shannon-Wiener forneceriam respostas concordantes na avaliação da condição ecológica dos estuários. A suficiência taxonômica demonstrou que, para o objetivo desta pesquisa, tanto o nível de família quanto o de gênero foram suficientes em detectar alterações nas condições ambientais, para este período amostral. Em relação à utilização associada de indicadores ecológicos para detectar as mudanças nas condições ecológicas dos estuários, os indicadores baseados na riqueza de taxa, diversidade, eco-exergia específica e grupos tróficos funcionais não responderam de forma concordante na detecção das variações na condição ecológica dos estuários com níveis de impactos antrópicos distintos. Apenas o índice da eco-exergia indicou diferenças na condição ecológica dos ecossistemas avaliados. Assim, os resultados obtidos pela pesquisa evidenciaram a importância do estudo sobre a suficiência taxonômica e indicadores ecológicos baseados nas comunidades bentônicas como um instrumento de biomonitoramento, cujo intuito é entender as variações e flutuações dos ecossistemas, assim como servir de base para propostas de medidas para mitigação dos impactos antrópicos, conservação e gestão ambiental.

Submitted by Natalia de Souza Gonçalves (natalia.goncalves@ufpe.br) on 2016-09-19T14:13:17Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) ALBENIZE NEVES DE LIMA_DISSERTAÇÃO DE MESTRADO.pdf: 1473137 bytes, checksum: bf11eb181d30c0640533062cd06c8a46 (MD5) / Made available in DSpace on 2016-09-19T14:13:17Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) ALBENIZE NEVES DE LIMA_DISSERTAÇÃO DE MESTRADO.pdf: 1473137 bytes, checksum: bf11eb181d30c0640533062cd06c8a46 (MD5) Previous issue date: 2016-02-25 / CAPES / O rio Formoso tem 12km de extensão e nasce na porção noroeste do município de mesmo nome, no estado de Pernambuco, Brasil. O estuário do rio Formoso apresenta relevante importância ecológica devido à presença de manguezais, prados de fanerógamas e área recifal. Está inserido em duas Áreas de Proteção Ambiental (APA): a APA de Guadalupe e a APA Costa dos Corais e ao longo do seu percurso recebe efluentes domésticos, resíduos provenientes da agroindústria açucareira e atividade de carcinicultura. Esse trabalho teve como objetivo avaliar a condição ambiental da zona estuarina do rio Formoso (Tamandaré, Pernambuco, Brasil), através da distribuição da biomassa fitoplanctônica e da hidrologia. As amostras de água foram coletadas na superfície durante três meses do período chuvoso (maio/ julho/ agosto/ 2014) e três de estiagem (outubro/ novembro/ dezembro/ 2014), durante a baixa-mar e preamar de um mesmo dia, em maré de sizígia. Foi realizada também uma segunda campanha em novembro/2014 para verificação da distribuição longitudinal e vertical da salinidade. Foi observada uma influência sazonal sobre os parâmetros hidrológicos e biológicos, condicionando durante o período chuvoso menores valores de temperatura, transparência da água, salinidade e da clorofila a e maiores concentrações dos nutrientes, exceto do N-amoniacal. A profundidade apresentou o mínimo de 2,00 m e o máximo de 8,30 m. A temperatura variou de 26,00°C a 29,5 °C, a transparência de 1,00 m a 4,00 m e a salinidade de 20 a 35. Os teores de oxigênio dissolvido oscilaram de 3,36 ml L-1 a 5,84 ml L-1 e seu percentual de saturação de 69,49% a 125,82%. O material particulado em suspensão (MPS) variou de 13,2 mg L-1 a 30,4 mg L-1. Os valores de N-amoniacal variaram de não detectável a 0,02 μmol L-1, de N-nitrito de não detectável a 0,20 μmol L-1, e de N-nitrato de não detectável a 3,47 μmol L-1. Para as concentrações de P-fosfato foram registrados valores de não detectável a 0,80 μmol L-1 e o Si-silicato de 1,56 μmol L-1 a 39,22 μmol L-1. As concentrações de clorofila a oscilaram de 0,67 mg.m- a 12,64 mg m-3. A comunidade fitoplanctônica <20 μm (pico/nanofitoplâncton) apresentou uma maior contribuição, sendo responsável por até 100% da biomassa algal. O estuário caracterizou-se como homogêneo em função da forte intrusão marinha, havendo um gradiente decrescente de jusante para montante do oxigênio dissolvido, salinidade e MPS, ao contrário da clorofila a e do silicato. O ambiente caracterizou-se como mesotrófico e livre, momentaneamente, do processo de eutrofização antrópica em função da melhoria do tratamento dos efluentes domésticos. / The river Formoso is 12km long and it is born in the northwest portion of the municipality of the same name in the state of Pernambuco, Brazil. The estuary of river Formoso presents relevant ecological importance due to its mangroves, meadows of phanerogams and reef area. It is inserted in two environmental protection areas (APA): the APA of Guadalupe and the APA Costa dos Corais. Along its course, the estuary receives household wastewater and waste from the sugar agroindustry and shrimp farming activity. The aim of this work was to evaluate the environmental condition of the estuarine zone of river Formoso (Tamandaré, Pernambuco, Brazil) through the distribution of phytoplankton biomass and hydrology. Surface water samples were collected for three months of the rainy season (May/July/August 2014) and three months of the dry season (October/November/December 2014) at low tide and high tide of the same day in the spring tide. A second campaign was also held in November 2014 to verify the longitudinal and vertical distribution of salinity. The biological and hydrological parameters were influenced by seasonal factors during the rainy season resulting in lower temperatures, water transparency, salinity and chlorophyll a and higher concentrations of nutrients, except ammoniacal-N. The minimum depth was 2.00 m and the maximum depth was 8.30 m. Temperature ranged from 26.00°C to 29.5°C, transparency ranged from 1.00 m to 4.00 m, and salinity ranged from 20 to 35. The dissolved oxygen levels varied between 3.36 ml L-1 and 5.84 ml L-1 and its percentage of saturation ranged from 69.49% to 125.82%. Suspended particulate matter (SPM) varied between 13.2 mg L-1 and 30.4 mg L-1. Ammoniacal-N varied from non-detectable to 0.02 μmol L-1, nitrite-N ranged from non-detectable to 0.20 μmol L-1, and nitrate-N ranged from non-detectable to 3.47 μmol L-1. The recorded phosphate-P concentrations varied from non-detectable to 0.80 μmol L-1 and the concentrations of silicate-Si ranged from 1.56 μmol L-1 and 39.22 μmol L-1. Chlorophyll a concentrations varied between 0.67 mg.m and 12.64 mg m-3. The phytoplankton community <20 μm (pico-/nanophytoplankton) presented a greater contribution with up to 100% of the algal biomass. The estuary was characterised as homogenous due to the strong marine intrusion. There was a descending downstream to upstream gradient of dissolved oxygen, salinity, and SPM and the contrary was observed for chlorophyll a and silicate. The environment was characterised as mesotrophic and momentarily free of the anthropogenic eutrophication process due to improved domestic effluent treatment.