I assessed fish community data collected by the Oklahoma Conservation Commission from 82 minimally impaired wadeable reference streams in eastern Oklahoma to determine whether existing aquatic ecoregions provide the best framework for spatial classification for the development of biological assessment methods and biocriteria. I used indirect ordination and classification to identify groups of sites that support similar fish communities. Although correspondence was observed between fish assemblages and three montane ecoregions, the classification system must be refined and expanded to include major drainage basins and physical habitat attributes for some areas to adequately partition variance in key measures of biological integrity. Results from canonical correspondence analysis indicated that substrate size and habitat type were the primary physical habitat variables that influenced the fish species composition and community structure.

No description available.

Resumo: Os peixes apresentam uma grande diversidade de espécies, sendo na região Neotropical onde se encontra o maior número de espécies de água doce. Entretanto, esta grande diversidade encontra-se ameaçada devido à degradação dos ecossistemas lóticos, principalmente pela alteração do habitat devido à destruição das florestas e fragmentação da rede hidrográfica. As florestas, principalmente as florestas ripárias, possuem funções ecológicas importantes para a estruturação dos riachos e das comunidades aquáticas. Por muito tempo, as florestas têm sido extensamente destruídas, sendo substituídas principalmente pelos usos agrícolas, ocasionando a destruição dos ecossistemas e da biodiversidade aquática. Além das alterações nas florestas, a presença de represamentos e cruzamentos de estradas gera impactos adicionais para os peixes ao romper a conectividade existente na rede hidrográfica. Os peixes possuem ciclos de vida complexos que dependem da complexidade estrutural do riacho e da conectividade entre trechos montante e jusante da rede. Portanto, a conservação das florestas e a manutenção da conectividade hidrológica são fatores importantes para a conservação das comunidades de peixes. Neste trabalho, avaliou-se a diversidade das comunidades de peixes de riachos em função das alterações na estrutura da paisagem florestal (composição e configuração) e da conectividade da rede hidrográfica em paisagens agrícolas. O estudo foi realizado em microbacias de 1ª a 4ª ordem pertencentes à bacia do rio Corumbataí. Diferenças nos índices de diversidade das comunidades foram testadas a partir da Análise de Variância considerando a estrutura da paisagem florestal em diferentes escalas espaciais (microbacia, rede de drenagem e trecho de coleta) e a conectividade da rede hidrográfica. As relações entre as variáveis da paisagem (estrutura da paisagem... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Fish exhibit great species diversity, and the Neotropical region holds the largest number of freshwater fish species . However, this great diversity is threatened due to lotic ecosystems degradation, mainly through forest destruction and stream network fragmentation. Forests, mainly riparian forests, have important ecological functions for stream and aquatic communities structuring. For a long time, forests have been extensively destroyed and replaced mainly by agricultural uses, causing stream and aquatic biodiversity destruction. Besides the alterations in forests, the presence of dams and road crossings generates additional impacts to fish by disrupting existing connectivity to the stream network. Fish have complex life cycles that depend of the stream structural complexity and the connectivity between upstream and downstream sections of the stream network. Hence, forest conservation and maintenance of hydrological connectivity are important factors for the conservation of fish communities. In this study, we evaluated stream fish community diversity in relation to changes in forest landscape structure (composition and configuration) and the stream network connectivity in agricultural landscapes. The study was conducted in 1st and 4th order catchments belonging to the Corumbatai river basin. Differences in diversity indices were tested by Analyses of Variance considering forest landscape structure at different spatial scales (whole catchment, stream network and stream sampled reach) and stream network connectivity. The relationship between landscape variables (forest landscape structure, riparian forest landscape structure and physical and hydrological hierarchy variables) and aquatic environment variables (channel structure and limnology and fish diversity indices) were evaluated using Redundancy Analysis (RDA) and Multiple Regression Analysis. These relationships were also assessed... (Complete abstract click electronic access below) / Orientador: Silvio Frosini de Barros Ferraz / Coorientador: Pedro Gerhard / Banca: Lílian Casatti / Banca: Maurício Cetra / Mestre

Les récifs coralliens hébergent la plus grande biodiversité sur Terre et fournissent la nourriture, le revenu économique, la protection côtière et les valeurs culturelles pour des millions de personnes. L'accessibilité des écosystèmes via les réseaux routiers est un déterminant majeur de leurs conditions, les écosystèmes les plus accessibles étant les plus menacées. Longtemps, l’estimation de l'accessibilité par l’Homme s’est limitée à l'utilisation de la distance linéaire qui ignore l’irrégularité des côtes maritimes et les réseaux routiers, facteurs influençant le temps nécessaire pour atteindre les lieux de pêche. Cette thèse présente un double enjeu : (i) développer des indices d'accessibilité intégrant l’hétérogénéité du milieu marin pour quantifier les impacts humains sur les récifs ; (ii) évaluer l'importance de ces nouveaux indices, en interaction avec les mesures de protection, pour expliquer les variations de la biomasse de poissons. Dans un premier temps, j’ai caractérisé la proximité des hommes aux récifs, en tenant compte des surfaces rencontrées (routes, chemin, eau) qui influencent le temps de trajet jusqu’aux récifs. Le temps de trajet a permis de calculer un indice de gravité, défini comme la population humaine divisée par le temps de trajet au carré, pour évaluer le niveau de pression humaine de n'importe quel récif au monde. J'ai trouvé que le temps de trajet et la gravité sont des déterminants majeurs de la biomasse de poissons à l’échelle globale. Dans un second temps, trois applications utilisant ces nouveaux indices ont permis de montrer que (i) la gravité permet de révéler l’efficacité des actions de conservation : les réserves placées là où les impacts humains sont modérés à forts fournissent des gains de conservation élevés pour la biomasse de poissons, mais elles sont peu susceptibles de protéger les prédateurs supérieurs, qui sont uniquement présent dans les réserves soumises à de faibles impacts humains ; (ii) en utilisant un cas d'étude réalisé dans le Nord-Ouest de Madagascar, j'ai illustré comment la proximité du marché peut affecter les communautés de pêcheurs et, finalement, engendrer des changements dans l'exploitation des ressources marines ; (iii) j’ai développé une nouvelle approche, le Community-Wide Scan (CWS), pour identifier les espèces de poissons qui contribuent de manière significative à la biomasse et à la couverture corallienne des récifs de l’Indopacifique, celles-ci pouvant constituer des espèces cibles à protéger. Dans le contexte de changements globaux et de perte de biodiversité, la mesure d’accessibilité constitue un outil puissant et permet de relancer le défi de gestion durable et efficace des socio-écosystèmes coralliens. / Coral reefs have the greatest biodiversity of any ecosystem on the planet and support ecosystem goods and services to million people who depend directly on them for food, economic income, coastal protection and cultural values. Ecosystem accessibility, through road networks, is the main driver of their conditions, with the most accessible ecosystems being most at risk of resource depletion. To date, measuring accessibility to humans was strictly limited to examining the linear distance which ignores ragged coastlines and road networks that can affect the time required to reach fishing grounds. This thesis presents a double challenge: (i) developing new metrics of accessibility that account for seascape heterogeneity to better assess human impacts on coral reefs; (ii) evaluating the importance of coral reef accessibility, in interactions with their management, to explain variations of fish biomass. First, I developed novel metrics of reef proximity to human populations and markets based on the friction distance which is related to transport surfaces (paved road, dirt road, water) influencing the effective reach of human settlements. Travel time was used to build the gravity index, defined as human population divided by the squared travel time, to assess the level of human pressure on any reef of the world. I found that both travel time and gravity are strong predictors of fish biomass globally. Second, three applications using these new metrics highlighted that (i) gravity identified critical ecological trade-offs in conservation since reserves placed with moderate-to-high impacts may provide substantial conservation gains for fish biomass while reserve locations with low human impacts were more likely to support higher-order predation, (ii) using a study case in Northwest Madagascar, I illustrated how market proximity can affect fishermen communities and, ultimately, trigger changes in marine resources exploitation, and (iii) I implemented a new Community-Wide Scan (CWS) approach to identify fish species that significantly contribute to the biomass and coral cover on Indo-Pacific reefs and which provided tractable conservation targets. Within the context of global changes and biodiversity loss, the thesis challenges the sustainable and efficient management of coral reef socio-ecological systems with accessibility being the cornerstone.

Haul-by-haul steam trawler catch and effort data for 1918�23, 1937�43 and 1952�57, which covers a large portion of the history of steam trawling in the Australian South East Fishery, were examined in detail for the first time. There were 64,371 haul records in total. The catch-rate for all retained catch combined shows a strong decline overall, with a brief recovery during World War II, probably due to increased retention of previously discarded species. The fishing fleet moved to more distant fishing grounds and deeper waters as the catch-rate declined. The catch-rates of the main commercial species followed a similar pattern in a number of regions within the fishery. The catchrate of the primary target species � tiger flathead (Neoplatycephalus richardsoni) � dropped considerably from the early, very high, catch-rates. Chinaman leatherjacket (Nelusetta ayraudi) and latchet (Pterygotrigla polyommata) � species that were apparently abundant in the early years of the fishery � virtually disappeared from catches in later years. The appearance of greater catches of jackass morwong (Nemadactylus macropterus), redfish (Centroberyx affinis), and shark/skate during the war and afterwards was probably due to increased retention of catches of these species. The disappearance of certain species from the catch may be due to high fishing pressure alone, or to a combination of fishing pressure, changes in the shelf habitat possibly caused by the trawl gear, and environmental fluctuations. Catch-rates in weight per haul per species were standardised to annual indices of abundance using a log-linear model. Standardised annual index trends for flathead, latchet and leatherjacket indicate a strong to severe decline over the period covered by the data. All species showed seasonal patterns, but the peak season varied depending on the species. The distribution of standardised catch-rate by area also differed greatly by species, and no single area showed consistent differences across all species. Day trawls caught more flathead, redfish and latchet, while night trawls caught more morwong and leatherjacket. Moon phase had less influence on catch-rates than the other factors examined. Correlation of annual index trends with a number of annual mean environmental factors was examined and no strong correlations were found. Annual catches of the major commercial trawl species on the SE Australian shelf were estimated from recorded total trawl catches, catch species composition from subsamples and estimates of the rate of discarding. These annual catches, standardised indices of abundance and biological population parameters were used in single-species stock reduction models to estimate absolute biomass trends. Biological population parameters and the biomass estimates were used to calculate management reference point fishing mortality rates F0.1, Fspr30 and Fmsy. Results showed that simple plausible population models can be constructed that account for catches over the long period of time from 1915 to 1961. Simple mass-balance ecosystem models were built for the demersal community of the SE Australian shelf for 1915 and 1961 using the Ecopath software. Model inputs were consistent with a more comprehensive SE marine ecosystem model in development by CSIRO. The models demonstrate that biomass estimates produced by the single species stock reduction models can be consistently integrated into simple plausible massbalance ecosystem models. Modern stock assessments for the main commercial species in this fishery today mostly used data collected since about 1985. Abundance indices and total catch estimates from this study have been used in the most recent assessments for tiger flathead and morwong, allowing construction of the exploitation history for these species spanning almost 100 years. Use of the historical information has increased confidence in the estimates of the modern stock assessments � particularly management reference points, and has allowed us to quantify changes in fish abundance that have simply been documented anecdotally in the past.

Thesis (Ph.D.)--Mississippi State University. Department of Wildlife and Fisheries. / Title from title screen. Includes bibliographical references.

Presented work is directed to summarize the results of ochtyomonitoring of five stream in Bohemian Forest in autumn 2010. The processing status is evaluated fish communities, especially their species composition, diversity, dominance, evenness and other parameters. They have been evaluated also physico-chemical properties of the sites such as air and water temperature, conductivity and turbidity. Last but not least were evaluated the characteristics of flows and in particular morphological characteristics, types of the bottom substrate and its contours etc. The evaluation of all obtained data showed that fish communities surveyed Bohemian flows are balanced, they are not burdened with invasive species and rand indicators correlated with the state of flow, geographic location and natural conditions. It was caught nine fish species in the total number of 963 individuals. Abundance was at all locations in the range 201,6 to 409,7 individuals per kilometer of flow, showed the diversity of communities from 0,372093 to 2,166085 (Shannon and Wiener index) and from 0,301804 to 0,866948 (Simpson index), then evenness of plant 0,372093 to 0,783906. The most dominant species was the brown trout, the second most frequent species was bullhead.

Monitoring of 0+ juvenile fish communities was realized in years 2012 and 2013 in 39 localities in 25 selected Moravian rivers. It was realized in collaboration with Povodí Moravy SOE research workers. The aim of this diploma thesis was to conduct a survey of 0+ juvenile fish communities and evaluate basic attributes of these ichthyocenosis (species richness, biodiversity, equitability, abundance and domiance). Secondary aim was the evalutation od hydromorphological conditions and water quality based on data provided by Povodí Moravy SOE. This monitoring was realized using the mobile FEG 1500 electrofishing device. The electrofishing crew moved upstream using continuous fishing strategy. Each locality was selected by highly experienced research workers of Povodí Moravy SOE. Caught fish were determined immediately and carefully retruned to the stream. In total there was present 28 0+ juvenile fish species. The most frequent was chub (Leuciscus cephalus, 23 localities), gudgeon (Gobio gobio, 19 localities) and roach (Rutilus rutilus, 19 localities). In 13 localities occured the fish fry of barbel (Barbus barbus) wich is positive surprise due to its sensitivity to water pollution. In contrast the massive presence of round goby (Neogobius melanostomus) in some localities was an unpleasant finding. 4 localities were without fish fry. This survey has observed increasing trend of biodiversity depending on improving of hydromorphological status while the abundance showed almost no diference. Saprobic index of 0+ juvenilie fish community increased with deteriorating of water quality which could mean that the fish fry is relatively reliable indicator of water quality. The results of this diploma thesis could be used in documenting of Moravian streams and in comparisson with another monitorings in these localities.

Made available in DSpace on 2014-12-17T14:02:04Z (GMT). No. of bitstreams: 1 MichelleMR.pdf: 448282 bytes, checksum: a72147e483ab07cc3c64242fa0a8d888 (MD5) Previous issue date: 2007-03-21 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Artificial lakes must differ from natural lakes in important structural and functional aspects that need to be understood so that these ecosystems can be properly managed. The aim of this work was to test the hypothesis that the artificial lakes (impoundments) in the semi-arid region of the Rio Grande do Norte State are more eutrophic and turbid and have different trophic structure when compared to the natural coastal lakes that occur in the humid eastern coast of the State. To test this hypothesis, 10 natural lakes and 8 artificial lakes with about 100 ha were sampled between September and November 2005 for the determination of some limnological variables and the abundance of the main fish species, which were grouped in three trophic guilds: facultative piscivores, facultative planktivores and omnivores. The results show that the artificial lakes had significantly higher concentrations of total nitrogen, total phosphorus, chlorophyll a , total and volatile suspended solids than the natural lakes. Results also show that the values of pH, total alkalinity, electric conductivity, turbidity as well as the coefficient of vertical attenuation of light were significantly higher in the artificial lakes than in the natural lakes. In the artificial lakes, the abundance of facultative planktivores was significantly higher, while the abundance of facultative piscivores significantly lower than in the natural lakes. There was no significant difference in the abundance of omnivorous fish between the two types of lakes. These results suggest that the increase in turbidity together with the other changes in the water quality of the artificial lakes, modifies the trophic structure of the fish communities reducing the importance of piscivores and the length of the food chains / Lagos artificiais devem diferir de lagos naturais em importantes aspectos estruturais e funcionais que precisam ser compreendidos para que possamos manejar adequadamente esses ecossistemas. Este trabalho foi realizado com o objetivo de testar a hip?tese de que os lagos artificiais (a?udes) na regi?o semi-?rida s?o ambientes mais eutrofizados e t?rbidos que possuem uma estrutura tr?fica distinta dos lagos costeiros naturais que ocorrem no litoral leste ?mido do Estado do Rio Grande do Norte. Para testar esta hip?tese, 10 lagos naturais e 8 lagos artificiais com cerca de 100 ha foram amostrados entre setembro e novembro de 2005 para determina??o de algumas vari?veis limnol?gicas e da abund?ncia das principais esp?cies de peixes, as quais foram agrupadas em tr?s guildas tr?ficas: pisc?voros facultativos, planct?voros facultativos e on?voros. Os resultados mostram que os lagos artificiais apresentaram concentra??es significativamente maiores de nitrog?nio e f?sforo total, clorofila a e s?lidos totais e vol?teis em suspens?o do que os lagos naturais. Os resultados tamb?m mostram que o pH, a alcalinidade total, a condutividade el?trica, a turbidez da ?gua e coeficiente de atenua??o vertical da luz nos lagos artificiais foram significativamente maiores do que nos lagos naturais. Nos lagos artificiais, a abund?ncia de peixes planct?voros facultativos tamb?m foi significativamente maior, enquanto que a abund?ncia de peixes pisc?voros facultativos foi significativamente menor do que nos lagos naturais. N?o houve diferen?as significativas na abund?ncia de peixes on?voros entre os dois tipos de lagos estudados. Esses resultados sugerem que a maior turbidez da ?gua aliada a outras mudan?as na qualidade da ?gua dos lagos artificiais eutrofizados afetam a estrutura tr?fica das comunidades de peixes reduzindo a import?ncia dos peixes pisc?voros e conseq?entemente o comprimento das cadeias alimentares

Marine Protected Areas (MPAs), the Ecosystem Approach to Fisheries management (EAF) and Integrated Coastal Management (ICM) have been identified as possible alternatives to traditional linefish management measures, which have largely failed. Monitoring and assessment of fish communities on a long-term basis is necessary, and will provide a means to evaluate the effectiveness of such management measures. Therefore, standardised protocols and optimal sampling methods for long-term monitoring (LTM) and assessment of coastal fish communities are essential. This study aimed to identify suitable methods and develop a protocol for assessment of inshore reef fish communities. A suitable location for evaluation of proposed methods was identified in the warm temperate biogeographical region of South Africa, encompassing the well-established Tsitsikamma Coastal National Park MPA and an adjacent exploited area. Chrysoblephus laticeps (roman) was identified as an indicator species for the study, as it has been well-studied and is well represented in the area. Underwater visual census (UVC) and controlled fishing were identified as suitable methods. UVC transects were found to be superior to point counts, in terms of sampling efficiency, variability, bias and required sample size. An effort of two angler hours per fishing station was shown to provide low catch variability, while at the same time a representative catch and low overall cost and required time. The methods were incorporated in a proposed sampling protocol, and evaluated. The methods were able to detect known differences between protected and exploited communities. It is recommended that LTM within protected areas, for detection of natural change, be focused on community-level indicators, while LTM in exploited areas, aimed at detection of anthropogenic change, be focused on species-level indicators. The proposed protocol with standardised methods will allow for comparisons across a network of LTM sites and provide the opportunity for a broad-scale assessment of the effects of environmental variables on reef fish stocks. The protocol developed in this study has application in other biogeographical regions in South Africa, and other parts of the world. Shift in the focus of much marine research, in South Africa and elsewhere, to LTM, highlights the relevance and timeous nature of this study.