Este trabalho tem como objeto de estudo, a relação entre fatores sócio-ambientais e a pesca artesanal nos setores norte (Iguape) e sul (Cananéia) do Complexo Estuarino-Lagunar de Cananéia-Iguape (SP), considerando as mudanças hidroquímicas provocadas pela água que adentra o sistema através Valo Grande, um canal artificial que drena parte água do Rio Ribeira de Iguape para o Mar Pequeno, junto ao município de Iguape. Os parâmetros hidrológicos abordados foram: penetração de luz, temperatura, salinidade, oxigênio dissolvido, pH, MPS e nutrientes dissolvidos obtidos em diferentes profundidades. Os dados relativos à atividade pesqueira e perfil social dos pescadores foram obtidos por meio de entrevista semi-estruturada, com perguntas fechadas e abertas junto às comunidades caiçaras de Cananéia e Iguape. Os resultados ambientais mostraram diferenças hidrológicas importantes entre os dois setores, com baixa salinidade no setor norte, sob maior influência do canal do Valo Grande, enquanto a porção sul preserva as características estuarinas, porém sinais da interferência do setor norte já estão sendo sinalizados no sul, o que pode ser verificado junto a dados pretéritos do corpo hídrico. As espécies alvo de pesca encontradas nos dois setores do sistema também indicaram as alterações ambientais, mostrando características locais e variações sazonais. Foi verificado que os pescadores adaptaram-se às modificações ambientais, alternando as artes de pesca ao longo do ano e, investindo em embarcações, motores e petrechos de pesca, dando continuidade à atividade. Avaliando-se o perfil dos pescadores urbanos, foram verificadas condições sócio-econômicas que permitem viii que a maioria de suas residências seja de alvenaria, dispondo de abastecimento de água e energia provenientes da rede pública, porém a maioria dos entrevistados interromperam seus estudos. Este estudo evidenciou a dificuldade dos pescadores em ter o sustento somente da atividade pesqueira praticada, comprometendo assim, a sobrevivência desta tradição, e desestimulando o desenvolvimento deste setor. Esta situação também leva ao registro de um perfil diferenciado de caiçara, marcado pelo desempenho de outras atividades além da pesca. Assim, foi possível observar que diante de mudanças, extremas ou não, o comportamento humano estará sempre interligado ao ambiental, os quais estão em constante renovação, caracterizando a cultura de gerações. A economia solidária estabelecida por meio de uma cooperativa, ou de ações apoiadas por políticas públicas, constituem alternativas que contribuem à solução de alguns problemas que afetam as comunidades estudadas. Certamente, ações participativas que insiram o pescador nos projetos gestão e preservação ambiental, permitindo uma maior atuação junto às políticas públicas locais, contribuirão à sustentabilidade ambiental, sócio-cultural e econômica. / This work aims to study the relations between socio-environmental factors and the artisanal fishery in the sectors north (Iguape) and south (Cananéia) of the Cananéia-Iguape Estuarine-Lagoon Complex, considering the hydrochemical changes caused by the water that enters within the system through Valo Grande, an artificial channel that drains part of the Ribeira de Iguape River waters to Mar Pequeno, Iguape. The hydrological parameters studied were: penetration of light, temperature, salinity, dissolved oxygen, pH, suspended particulate matter and dissolved nutrients obtained in different depths. The data concerning the fishery activities and social profile of the fishermen were obtained through semi-structured interviews, with closed and open questions made with the communities of Cananéia and Iguape. The environmental results showed important hydrological differences between the two sectors, with low salinity in the northern sector, under greater influence of Valo Grande Channel, while the southern sector still preserves estuarine characteristics. However, signals of the north interference are already being noticed in the south, this can be verified by comparing past data of the water body. The fishery target species found in the two sectors of the system also pointed to environmental changes, showing local characteristics and seasonal variations. It was verified that the fishermen adapted to the environmental changes by changing the fishery type throughout the year and investing in boats, engines and fishery equipment, this way continuing with the activity. Socio-economical conditions that allow most of the residences to be made of masonry, having energy and water supplied by the public services, were verified evaluating the fishermen profile. However most of the fishermen had their formal education interrupted. This study shows the difficulty of the fishermen to have their livelihood only by fishing, therefore compromising the survival of this tradition and discouraging the development of this sector. This situation also leads to register a differentiated fishermen profile, marked by the realization of other activities besides fishery. So, it was possible to observe that faced with changes, extremes or not, the human behavior will always be linked to the environment, they are in constant renovation, x characterizing the culture of generations. The solidarity economy established by a cooperative or by actions supported by public politics constitutes alternatives that contribute to the solution of some problems that affect this community. Certainly, participative actions, that insert the fishermen in management and environmental preservation projects, allowing a greater participation in local public policies, will contribute to the environmental, socio-cultural and economic sustainability.

The Incomati River Estuary is prone to pollutants from anthropogenic activities such as agricultural and industrial activities in the upper catchments. The main aim of the study was to use free-living nematodes as pollution indicators in the Incomati River Estuary. The main objectives were to determine the relationship between nematodes assemblage and environmental variables, and to identify environmental factors that play a role in nematodes community structuring. Lastly, it was to identify free-living nematode genera that can be used as pollution indicators in the Incomati River Estuary. Four sites were selected following the salinity gradient of the Incomati River Estuary. Site E1 with a salinity range of 0-3NST (Oligohaline Zone), E2 with a salinity 3-5NST (Euhaline Zone), E3 with a salinity 6-18NST (Mesohaline Zone), and E4 with 20-27 NST (Polyhaline Zone) were selected and monitored bi-monthly from June 2017 to April 2018. Two sediments samples were collected per site during neap tide using a handheld perplex corer which was 1m long with a 3.6 diameter and 10cm penetration height. Plastic bottles with a height of 13cm and a diameter of 7cm were used to store the sediment samples. One of the two sediment samples was used for free-living nematodes, and the other bottle was used for the analysis of environmental factors. All environmental factors were analysed at Labserve Laboratory, Mbombela Town, Mpumalanga Province. Sediment particle size and organic matter analyses were done following the procedure set by Parker (1983) and Buchanan (1971) respectively. Metal analysis was done following the procedure used by Gyedu-Ababio et al.1999. Nutrients were done using different methods. For nitrates (NO3) analysis, a copper cadmium method by Bate and Heelas, 1975 was used, while a method designed by Strickland and Parson, 1972 was used to analyse orthophosphate. A mixed acid digestion procedure of Oles and Dean 1965 was followed for total phosphate. A method by Lorenzen and Jeffrey, 1980 was used for the analysis of chlorophyll-a. Heterotrophic bacteria analysis were done following a procedure by (Atlas, 1997). Nematodes were extracted using a method by Furstenberg et al.1978, with sucrose as a separating agent. Nematodes were counted following a procedure by Giere, 1993. Nematodes feeding types were investigated using Wieser, 1953 procedure. Different statistical packages including PRIMER version 6 were used to analyse the data. A Bray-Curtis Cluster analysis indicated a similarity between sites E1 (Oligohaline Zone) and E2 (Euhaline Zone), and between site E3 (Mesohaline Zone) and E4 (Polyhaline Zone) which was attributed to similar sediment particle sizes distribution within the sites. There was no significant difference (p>0.05) of sediments particle size between the sites. The highest concentration of metals was found at site E2 which was situated in the Euhaline Zone, whilst the second highest concentration was found at site E1 which was situated in the Oligohaline Zone. A PERMANOVA analysis indicated that there was a significant difference (p<0.05) of Metal concentration between sites sampled. The PCA analyses indicated that there was a positive correlation between Metals and Sediment Particle Size such as Granules. It was observed that sediment particle size and organic matter influenced the distribution of metals in the Estuary. The highest concentration of chlorophyll-a and nitrates (NO3) were found at site E3 which was situated in the Mesohaline Zone, and the second highest was found at site E4 which was situated in the Polyhaline Zone. There was a positive correlation between Heterotrophic bacteria and environmental factors such as zinc, fine sand, very fine sand and mud. This indicated that certain metals and sediment particles size played a role in structuring food source for meiofauna, especially nematodes. The number of free-living nematodes were found to decrease towards site E1. This indicated that salinity influenced the diversity and density of free-living nematodes in the estuary. Site E2 had the lowest diversity and richness followed by site E1. The lower diversity, richness and Maturity Index at site E2 and E1 indicated that these sites were under stress. A Bray-Curtis Cluster analysis indicated that there was a spatio-temporal variation of diversity and density of free-living nematodes in the estuary. All four nematodes feeding types were found in the Estuary and feeding type 1B was the dominant feeding type at the sites, followed by feeding type 2A. The highest number of feeding type 1B (non-selective deposit feeders) was identified at site E2. The life strategy characterisation (colonizer- persisters) indicated that site E2 was dominated by colonizer and intermediate genera (c-p 2 and 3), which indicated that the site was under stress. The study found that genera such as Terschellingia and Theristus were pollution indicators because they were found in higher abundance at a site that was mostly polluted by metals, organic matter, and total phosphate. Further studies in other River Estuaries in South Africa and SADC should be undertaken to add to the findings of the current study. / Environmental Studies / Ph. D. (Environmental Sciences)

No description available.

ABSTRACT Classifying and Mapping Diversity in a Species-Poor System: the mangrove meta-community of Laguna Chacahua National Park, Oaxaca, Mexico by Elizabeth Kay Weisgerber Both field transects and imagery grid plots were analyzed with the goal of creating a community classification map for the mangrove forest of Parque Nacional Lagunas de Chacahua. In total, data was collected in 49 sites throughout the park, recording measures such as DBH, basal area, estimated dominance, frequency, cover and relative dominance. Field locations were marked and georeferenced with a GPS and grid plots overlaid on satellite imagery of the park were generated via a random number table. Species' attributes delineating the identifiable features for each dominant species within Chacahua were noted and used to recognize patterns in species assemblages. Fourteen distinct ‘sub-communities’ within the mangrove meta-community were recognized using this data and verified with 165 field photos. Relative dominance values were compared between field and grid data. These data revealed a similar pattern with Rhizophora mangle being most dominant under each method. Avicennia germinans was second in relative dominance, Laguncularia racemosa a close third while Conocarpus erectus was rarely found, most likely due to over-harvesting. Rapid degradation of mangrove forests is occurring on a global scale. Understanding the complex dynamics that occur within the mangrove meta-community is essential to its conservation. Vegetation maps are essential tool in monitoring changes throughout the mangrove but are rarely of sufficient detail for everyday use. Generating highly detailed vegetation maps in a cost-effective and timely manner is an important step for their conservation, particularly in developing countries. This study demonstrates methods and techniques for producing a vegetation map that portrays the level of complexity that exists within the species-poor mangrove environment. This map will be donated to the management team of Parque Nacional Lagunas de Chacahua to better aid in management.

<p dir="ltr">The Leatherback Sea Turtle (<i>Dermochelys coriacea</i>) is a globally vulnerable species suffering from declining populations due to anthropogenic pressures. There are seven recognized Leatherback Sea Turtle regional management units; however, the Southeast Atlantic unit is considered data deficient. Bioko Island, Equatorial Guinea, is a primary nesting rookery for the Southeast Atlantic regional management unit and has some of the world’s highest numbers of nesting Leatherback Sea Turtles. Despite Bioko Island’s importance to the species, little is known about the nesting ecology or post-nesting migratory movement and behaviors of its nesting Leatherback Sea Turtles. Here, I present the findings of two individual research projects on the nesting ecology of Leatherback Sea Turtles on Bioko Island. First, I explored the long-term clutch success rates (i.e., hatching success and emergence success) of <i>in situ</i> Leatherback Sea Turtle nests on Bioko and searched for associated variables. I found significant spatiotemporal variation over nine nesting seasons, likely driven by individual beach characteristics rather than regional climate patterns. Secondly, I described a novel effort to use solar-reliant towable transmitters to track the post-nesting migratory movements and behaviors of Leatherback Sea Turtles nesting on Bioko Island. With the results from each project, I make recommendations to further the current conservation and research initiatives of Leatherback Sea Turtles.</p>

<p dir="ltr">The Northwest Atlantic Ocean, which surrounds the US eastern coastline, is an area rich in marine life. The US eastern coastline is also highly urbanized, resulting in a lot of pollutants (like heavy metals) entering the marine environment. This is of concern for long-lived marine species like sea turtles. Since sea turtles are long-lived and highly migratory, their tissues can often incorporate these pollutants through environmental and dietary exposure. I collected tissue samples from 5 different sea turtle populations in the Northwest Atlantic and analyzed them for concentrations of silver (Ag), aluminum (Al), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), selenium (Se) and zinc (Zn) using an Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The first chapter looks at skin (reflects exposure ~1 year ago) and scute (reflects exposure from 4-6 years ago) samples collected during necropsies of juvenile green (<i>Chelonia mydas</i>) (n=8), Kemp’s ridley (<i>Lepidochelys kempii</i>) (n=30) and loggerhead (<i>Caretta caretta</i>) (n=17) turtles that were found cold-stunned in Cape Cod Bay, Massachusetts. In scute samples, the heavy metal with the highest concentration for green turtles was iron, zinc for loggerhead turtles, and arsenic for Kemp’s ridley turtles. In skin samples, the heavy metal with the highest concentration for green turtles was iron, arsenic for loggerhead turtles, and aluminum for Kemp’s ridley turtles. Overall, I found scute samples to have higher heavy metal concentrations than skin samples. The second chapter looks at scute samples collected from loggerhead turtles of different life stages. These samples were collected during necropsies of cold-stunned loggerhead turtles from Cape Cod Bay, Massachusetts (CCB; n=17), as well as from live loggerhead turtles in the Mid-Atlantic Bight (MAB; n=37) and off the coast of North Carolina (NC; n=9). We also collected commonly known loggerhead turtle prey items including whelk (<i>Buccinum undatum</i>) (n=12), Atlantic scallop (<i>Placopecten magellanicus)</i> (n=10) and Jonah crab (<i>Cancer borealis</i>) (n=5) from the Mid-Atlantic Bight region to study the occurrence of biomagnification through trophic pathways. NC loggerhead turtles had higher heavy metal concentrations than other locations except for cadmium and zinc, where CCB loggerhead turtles were higher. I found that all heavy metals except silver, cadmium, and lead appear to be biomagnified (TTF>1) in loggerhead turtles. These two chapters provided baseline information on heavy metal concentrations in sea turtles in east coast US.</p>

The Pimpama estuarine plain in subtropical southeast Queensland is comprised of Quaternary sediments infilling older bedrock. These multilayered unconsolidated sediments have various depositional origins, and are highly heterogeneous. The plain is low-lying and the surface drainage is controlled by flood mitigation measures including tidal gates and channelised streams. The control of surface drainage potentially affects the shallow water table. This modification of hydrology has implications for future viability of agriculture and also the environmental health of waterways. Increased landscape modification and water management is likely in the coming years. The combination of sediment heterogeneity, low hydraulic gradients, and artificial drainage modification result in the plain being hydrogeologically complex. In order to understand hydrologic processes in this setting, a multi-disciplinary research programme was conducted which included a drilling program, overland electromagnetic induction and other geophysical surveys (downhole gamma log, electromagnetic induction and magnetic susceptibility) to initially establish the geologic framework. These surveys were followed by hydrogeochemical testing which includes for major and minor ions and also stable isotopes, and mineralogical analysis of drillhole material. Underlying basement rock occurs at up to 60 m depth. Unconsolidated gravel and sand deposits occur within incised paleo-valleys and are overlain by predominantly low-permeability fluvial sandy clays and estuarine and lagoonal muds. Fine-grained delta sands occur in the top 15 m of the sub-surface. Within the unconsolidated sediments, hydrodynamic trends clearly discriminated between upper unconfined and lower semi-confined aquifer systems. A comparison of surface water and shallow groundwater levels indicate limited interaction of groundwater and surface water. Hydrogeochemical analysis effectively distinguished between groundwater bodies, and also distinguished saline groundwater from seawater. Trends in major ion chemistry in the semi-confined system (particularly Na/Cl and Ca/Cl ratios) showed ion exchange accompanying saline intrusion. However, due to factors such as mineral dissolution, major ion chemistry does not clearly identify solute flux trends in the shallow aquifer system. Water stable isotope analysis (δ18O and δ2H) indicated the provenance of fresh and saline groundwater and also the relative importance of the principal hydrologic processes, i.e. evaporation and water uptake by plants. Groundwater exhibited a wide range in salinity, from very fresh to hypersaline. The formation of hypersaline groundwater was attributed largely to uptake of water by mangrove forests. Since mangrove forests were more extensive at the time of the Holocene maximum sea level (approximately 6,000 years ago) than at present, some of this groundwater may represent relict salinity from this earlier time. The relationship of relict salinity to low permeability sediments, particularly at intermediate depths, and their depositional history was examined. Vertical salinity gradients and hydrogeochemistry within these sediments varied according to position within the plain, suggesting deposition under various hydrological and sea level regimes. A preliminary investigation using analysis of stable sulfate isotopes (δ34S and δ18OSO4) was made. This study shows substantial potential for the application of this technique for quantification of solute flux and sulfur chemical transformations within settings such as this coastal plain. To establish shallow groundwater flow processes, a MODFLOW-based numerical model was used to inversely estimate aquifer parameters under various recharge scenarios. The model was designed to examine the relative importance of evapotranspiration and discharge to surface waters. However, largely due to the complexity of the drainage network and non-uniform surface water flows, the quantification of surface water- groundwater interaction by consideration of hydrodynamics is problematic. Therefore, the chemistry of groundwater and surface water was compared. While the estimated contribution of rainfall to groundwater level fluctuations was significant (46%), high evapotranspiration rates reduced net recharge and it was concluded that baseflow to drains and creeks during dry periods was insignificant, and groundwater velocities in the shallow aquifer are low. The study illustrates the value of both hydrodynamic and hydrogeochemical analyses in estuarine settings where relict salinity and groundwater-aquifer interactions impact significantly on water quality. Saline groundwater is chemically distinct from theoretical mixtures of seawater and freshwater. The study also demonstrates the value of particular chemical parameters, e.g. Na/Cl and SO4/Cl ratios and stable water isotopes, for identifying hydrologic processes in this setting.

[Truncated abstract] The expansion of human populations in coastal land margins has resulted in major modifcations to estuarine ecosystems. The use of numerical models as predictive tools for assessing remediation strategies is increasing. However, parameterisation of physical processes, developed mainly through field investigations, is necessary for these models to be reliable and effective management tools. The physical processes in micro–tidal diurnal tidal systems are relatively unknown and the current study examines field measurements obtained from the upper Swan River estuary (Western Australia), a diurnal, partially mixed system during the summer when the freshwater discharge is negligible. The aims of the study were to characterise, temporally and spatially, the dominant physical processes and associated sediment resuspension. Variability at three dominant time-scales were examined: 1) sub–tidal oscillations (∼5 to 10 days) resulting from local and remote forcing; 2) tidal (∼ 24 hours) due to astronomical forcing; and 3) intra-tidal (∼2 to 3 hours) resulting from the interaction between tidal constituents. Circulation in estuaries is widely accepted in the literature to be dominated, in varying proportions, by tidal range, freshwater discharge and gravitational circulation. In the upper Swan River estuary sub–tidal oscillations were responsible for the largest upstream displacement of the salt wedge in the absence of freshwater discharge. Moreover, these sub–tidal fluctuations in water level modified the ‘classic’ estuarine circulation. The dynamics of diurnal tides are largely controlled by the tropic month, which oscillates at a slightly different period to the lunar month, resulting in the spring–neap tidal cycle to be sometimes different from syzygy. The phase lag between the diurnal (O1 + K1) and semi-diurnal (M2 + S2) constituents, at the seasonal time scale cause the maximum tidal range to be near the solstice. Over a 24–hour tidal cycle this phase lag is manifested as an intra–tidal oscillation that occurs on the flood tide. Turbidity events that last ∼1 to 2 hours occur during the intra–tidal oscillation, but are not related to maximum shear stress predicted from the mean flow characteristics. The increases in turbidity during the intra–tidal oscillation is, however, correlated with the near–bed Reynolds fluxes. During the intra–tidal oscillation advection opposes the estuarine circulation in the near–bed region, promoting vertical shear that results in destratifcation of the water column. The turbulent mixing generated at the interface and in the near–bed region coincide with resuspension events. Similar turbidity data have often been disregarded and documented as being ‘spikes’ based on the premise that the mean flow was below a critical level to resuspend sediment. Resuspension events were not simply related to mean processes and may be controlled by turbulent instabilities generated when tidal currents reverse during an intra-tidal oscillation

The spotted grunter (Pomadasys commersonnii) is an important, estuarine-dependent, fishery species in southern Africa. Since estuaries are essential habitats in the life history of this species, the quantification of area use patterns and movements is important for fisheries management. In this study, acoustic telemetry was used to investigate movements, use of habitat and home range dynamics of spotted grunter in the small intermittently open East Kleinemonde Estuary on the Eastern Cape coast of South Africa. Nine spotted grunter (range: 326-489mm TL) were surgically equipped with uniquely coded acoustic transmitters. Positional fixes were obtained by manual tracking tagged individuals on six days and six nights during five tracking sessions from March to November 2004. In addition, five stationary data-logging receivers, moored at specific locations from the mouth to the top of the estuary provided additional long-term monitoring. Kernel home ranges (95% UD) varied in size (26 296-165 321m²) but were all located in a common high use area situated between 300-1 300m from the estuary mouth, which coincided with the highest abundance of prey items. There was no significant variation in home range size [C² (N = 9, df = 4) = 4.18; p = 0.38] between the temporally segregated tracking sessions (over nine months). The persistence of these home range estimates were confirmed by the long-term data-logging receivers. There was no significant diel variation in home range size [F(4, 64) = 0.05, p = 0.99] or core area size [F(4, 64) = 1.40, p = 0.25]. Fish length showed negative, although not significant, relationships between home range size (p = 0.225); number of home range areas (p = 0.065); core area size (p = 0.512) and home range length (p = 0.320). Use of habitat and home range dynamics of spotted grunter in the East Kleinemonde Estuary were consistent over the nine month study period, and they appeared to be influenced more by biotic than abiotic factors. However, when the mouth opened at the end of the study, most tagged fish vacated their home ranges and emigrated to sea.

The fish community structure of two contrasting estuaries, one with a well developed mangrove forest (Mngazana) and the other without mangroves (Mngazi) was compared. Both the Mngazi and Mngazana estuary fish communities were dominated by marine species, reflecting the importance of these systems as nursery areas for marine fishes. The Mngazi Estuary contained 18% more estuarine fishes in terms of catch per unit effort (CPUE) than the Mngazana Estuary. The reduced tidal influence due to the narrow mouth opening is a possible reason for the heightened CPUE of estuarine species in the Mngazi estuary. The recorded higher diversity of fish species in the Mngazana Estuary when compared with the Mngazi Estuary was attributed to the greater influence of the marine environment due to the wide permanently open mouth, as well as the presence of a variety of habitats in this system. In both estuaries tropical and temperate species were captured, confirming the transitional nature of their biogeographic location which is situated close to the boundary between the subtropical and warm temperate regions of the Southern African coastline. Contrary to previous studies, which recorded seasonal changes in the proportions of tropical and temperate species, the proportions of tropical species remained unchanged at approximately 70% during the January and June sampling occasions. Global warming as a possible reason for the increased dominance of tropical species is discussed. Although several studies in southern Africa have investigated estuarine food web structure, none have compared mangrove and non-mangrove estuaries. In this study, the primary sources of carbon utilised by the fish fauna in the Mngazi and Mngazana estuaries was investigated. The carbon isotopic values of fishes in both estuaries displayed a continuum rather than a tight clustering around particular energy sources. Most detritus feeders of the family Mugilidae (mullets) from both estuaries were relatively more enriched than other fish taxa. The isotopic values of the mullet species suggest a diet derived from relatively enriched carbon sources such as benthic microalgae, the eelgrass Zostera capensis and associated epiphytes. Based on the isotopic values, piscivorous fishes from both estuaries could not be linked to specific prey fish taxa, but clearly the mullet species were not their main food source. The invertebrate feeders that were found in both estuaries showed greater isotopic variations in the Mngazana Estuary than in the Mngazi Estuary, probably reflecting the higher diversity of habitats (carbon sources) and invertebrate prey species in the Mngazana system. Generally the isotopic signatures of fishes from the Mngazi Estuary were more enriched than those from the Mngazana Estuary, thus indicating the possible effect of δ¹³C depleted mangrove derived carbon in the latter system.