Coastal wetlands of Georgian Bay have been virtually ignored by ecologists until recently, when these ecosystems were found to have exceptionally high biodiversity compared to other Gr,~at Lakes wetlands. To address this deficiency, we conducted a baseline survey (2002 to 2007) to determine the biotic and abiotic characteristics of 92 wetlands in 18 quatemary watersheds, using a suite of published ecological indices developed specifically for coastal wetlands (Water Quality Index (WQI); adjusted Wetland Macrophyte Index (WMiadj), and the Wetland Fish IndexBasinPAex (WFIBasinPAex)). Although a majority of the watersheds are located in remote eastern and northern parts of the Bay and therefore receive minimal human disturbance, one watershed, Sturgeon River, located in southern Georgian Bay receives relatively high urban, recreational and agricultural disturbance. Mean scores of WQI and WMiadj varied significantly across the watersheds, ranging from 0.48 to 2.15, and from 2.29 to 3.77, respectively. Mean WFIBasinPAex scores, however, were less variable and only ranged from 3.53 to 3.86. Of the 88 macrophyte species identified, the most common were hardstem bulrush. (Schoenoplectus acutus), water celery (Vallisneria americana), richardson's pondweed (Potamogeton richardsonii), slender waternymph (Najasjlexilis) and Canadian waterweed (Elodea canadensis). Six non-native macrophytes, Purple loosestrife (Lythrum wlicaria), narrow-leaf cattail (Typha angustifolia), hybrid cattail (Typha x glauca), Eurasian milfoil (Myriophyllum spicatum), curly pondweed (Potamogeton crispw) and frogbit (Hydrocharus morsus-ranae) were also recorded, the most common ofwhieh was Eurasian milfoil. Sago pondweed (Stuckenia pectinata), a native species that can be invasive, and is tolerant of poor water-quality, was present in about half of the watersheds. Ofthe 51 fish species, pumpkinseed (Lepomis gibbosus) bluntnose minnow (Pfmephales notatus), brown bullhead (Ameiurus nebulosus), rock bass (Ambloplites rupestris), and yellow perch (Percajlavescens) were the most widespread and abundant. Three non-native species, common carp (Cyprinus carpio), alewife (Alosa pesudoharengus), and round goby (Neogobius melanostomus) were present but not dominant. WMI scores were highly correlated with WQI scores, and as expected, wetlands in the most disturbed southern watershed were associated with the lowest WQI and WM[ scores, and had the greatest number of exotic species. However, WMI scores of wetlands in a few exposed sites located at the tip of the Bruce Peninsula were similarly low, even though these sites are not yet impacted by human activities. There was no significant relationship between WFIBasinPAand WQI scores, although the WFIBasin PA did not seem to be affected by exposure. We recommend that the WQI and WMiadj be used in long-term monitoring programs of Georgian Bay to track negative impacts of human disturbance on these valuable ecosystems. / Thesis / Master of Science (MS)

Ichtyofauna with emphasis on fish fry community was studied in cascade reservoir complex of the Vltava River. Fish spatial distribution and species composition was observed along longitudinal axis of Kamýk, Slapy, Štěchovice and Vrané reservoirs using hydroacoustic, trawling and beach seining.

Area of Occupancy (AO) is a frequently used indicator to assess and inform designation of conservation status to wildlife species by the International Union for Conservation of Nature (IUCN). The applicability of the current grid-based AO measurement on freshwater organisms has been questioned due to the restricted dimensionality of freshwater habitats. I investigated the extent to which AO influenced conservation status for freshwater taxa at a national level in Canada. I then used distribution data of 20 imperiled freshwater fish species of southwestern Ontario to (1) demonstrate biases produced by grid-based AO and (2) develop a biologically relevant AO index. My results showed grid-based AOs were sensitive to spatial scale, grid cell positioning, and number of records, and were subject to inconsistent decision making. Use of the biologically relevant AO changed conservation status for four freshwater fish species and may have important implications on the subsequent conservation practices.

Area of Occupancy (AO) is a frequently used indicator to assess and inform designation of conservation status to wildlife species by the International Union for Conservation of Nature (IUCN). The applicability of the current grid-based AO measurement on freshwater organisms has been questioned due to the restricted dimensionality of freshwater habitats. I investigated the extent to which AO influenced conservation status for freshwater taxa at a national level in Canada. I then used distribution data of 20 imperiled freshwater fish species of southwestern Ontario to (1) demonstrate biases produced by grid-based AO and (2) develop a biologically relevant AO index. My results showed grid-based AOs were sensitive to spatial scale, grid cell positioning, and number of records, and were subject to inconsistent decision making. Use of the biologically relevant AO changed conservation status for four freshwater fish species and may have important implications on the subsequent conservation practices.

This thesis is focused on the fish spatial distribution and its changes mainly during the diel cycle. In the first part, I described the fish spatial distribution in the tropical lake ecosystem of Lake Turkana. The second part deals with the fish spatial distribution in a temperate reservoir on the different spatial scales from in/offshore habitats over the fine-scale to the level of individuals. The linkage of fish distribution patterns with selected environmental variables was also evaluated.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-10-23T18:42:10Z No. of bitstreams: 1 2013 - Taynara Pontes Franco.pdf: 1292257 bytes, checksum: 6adb092b864fac2081ba5afb46e52d2e (MD5) / Made available in DSpace on 2018-10-23T18:42:10Z (GMT). No. of bitstreams: 1 2013 - Taynara Pontes Franco.pdf: 1292257 bytes, checksum: 6adb092b864fac2081ba5afb46e52d2e (MD5) Previous issue date: 2013-02-22 / FAPERJ / Coastal lagoons can have different salinity gradient depending on the geographical position, hydrological balance, type of sea connection and other environmental conditions, which influence structure of fish assemblages that uses these systems. The aim of this study was to assess the use of ichthyofauna and eventual changes in structure of fish assemblages in relation to environmental variables, mainly the salinity, in three choked lagoon systems of the coastal lowlandsof Rio de Janeiro State (Maric?, Saquarema and Araruama). The raised hypothesis wasthat different fish assemblages use lagoons with different salinity gradient and that the species richness is directly associated to salinity with optimum at normal marine water (36), and that changes above or below this value can limit occurrence of species. Beach seines and environmental variables measurements were performed during the winter 2011 and the summer 2012. Three zones determined according to distance from the connection with the sea (Inner zone ? the farthest area from the channel that connect the lagoon to the sea with lesser marine influence; Middle zone ? the central part of the lagoon; and Outer zone - next to the channel thatconnect the lagoon to the sea, with more marine influence) and ten sites evenly distributed in each lagoon were sampled in three replicates, totaling 168 samples. Environmental variables of salinity, temperature, depth, transparency and turbidity were measured in each sampling occasion. Considering all pooled samples, the environmental variables that most contributed to lagoon separation was the salinity (higher in Araruama and lower in Maric?) and temperature between the two sampled periods (winter and summer). A total of 57,083 fishes were collected in 44 species. The more representative families were Gerreidae with six species, Clupeidae and Gobiidae with cinco species and Sciaenidae with four species. Twenty species were common to the three lagoons with more represented species being Atherinella brasiliensis and Anchoa januaria with frequency of occurrence higher than 65%. Despite of differences in environmental gradient, mainly the salinity, only the fish assemblage of Araruama lagoon differed from the other two lagoons, although with high fish sobreposition. The highest richness found in the hyperhaline Araruama lagoon (32 esp?cies) was very close of fish richness in the Saquarema lagoon (30 species), although the latter had a much smaller area, which confirm the hypothesis that the highest richness occur in salinity near to the marine water salinity. Differences in environmental conditions among the three lagoon zones were significantly only in Maric? lagoon, which may be related to its estuarine conditions. Salinity, transparency and turbidity were the most important factors influences fish assemblages depending on the lagoon, with Maric? having a higher influence of transparency on fish assemblages, while the turbidity had higher influence during the Summer in Saquarema and Araruama fish assemblages. Such information are a baseline to future evaluation of the environmental condition of these systems aiming the resources conservation, but other studies need to be incorporate to these analyses, mainly the influences of physical habitat on fish assemblages structure. / Lagunas podem assumir diferentes gradientes de salinidade dependendo de sua localiza??o geogr?fica, balan?o h?drico, conex?o com mar e outras condi??es ambientais, as quais influenciam a estrutura das assembleias de peixes que utilizam esses ambientes. O objetivo deste trabalho foi avaliar o uso da ictiofauna e eventuais varia??es na estrutura das assembleias de peixes em rela??o ?s vari?veis ambientais, principalmente o gradiente de salinidade em tr?s sistemas lagunares sufocados da Baixada Litor?nea do Estado do Rio de Janeiro (Maric?, Saquarema e Araruama). A hip?tese testada foi a de que diferentes assembleias de peixes usam lagunas com diferentes gradientes salinos, e que a riqueza de esp?cies ? diretamente associada a salinidade at? o valor da salinidade normal da ?gua do mar (36), e que varia??es acima ou abaixo destes n?veis poderiam restringir a ocorr?ncia das esp?cies. Arrastos de praia e medi??es de vari?veis ambientais foram realizados durante o Inverno de 2011 e Ver?o de 2012. Tr?s zonas foram determinadas a partir da dist?ncia da conex?o com o mar (Zona Interna ? mais distante do canal de conex?o com o mar e com menor influ?ncia marinha; Zona Central ? parte mais central da laguna, e Zona Externa ? mais pr?xima do canal de conex?o com o mar e com maior influ?ncia marinha) e dez locais de coleta foram amostrados, com tr?s r?plicas cada, distribu?dos entre estas zonas em cada laguna, totalizando 168 amostras. Vari?veis ambientais de salinidade, temperatura, profundidade, transpar?ncia e turbidez foram medidas em cada arrasto realizado. Considerando todo o conjunto de amostras, as vari?veis ambientais que mais contribu?ram para a separa??o das lagunas foram salinidade (maior em Araruama e menor em Maric?) e a temperatura entre os dois per?odos de coleta (Inverno e Ver?o). Foram coletados 57.083 indiv?duos em 44 esp?cies de peixes. As fam?lias de maior representatividade foram Gerreidae com seis esp?cies, Clupeidae e Gobiidae com cinco esp?cies e Sciaenidae com quatro esp?cies. Vinte esp?cies foram comuns ?s tr?s lagunas e as esp?cies de maior representatividade entre elas foram Atherinella brasiliensis e Anchoa januaria com frequ?ncia de ocorr?ncia superiores a 65%. Apesar das diferen?as no gradiente ambiental, principalmente na salinidade, somente a assembleia de peixes de Araruama diferiu das demais, embora com grande sobreposi??o de esp?cies. A maior riqueza foi encontrada na laguna hipersalina de Araruama (32 esp?cies), por?m muito pr?xima da riqueza na laguna de Saquarema (30 esp?cies), embora com esta ?ltima tendo uma ?rea bem menor, o que confirma a hip?tese de maior riqueza em salinidade pr?xima da ?gua do mar. As diferen?as nas condi??es ambientais existentes entre as zonas das lagunas somente foram significativas na laguna de Maric?, o que pode estar relacionado ao seu car?ter estuarino. A salinidade, transpar?ncia e turbidez foram os fatores que mais influenciaram as assembleias de peixes, com diferentes graus de influ?ncia dependendo da laguna, com Maric? tendo maior influ?ncia da transpar?ncia na assembleia de peixes, enquanto a turbidez teve maior influ?ncia no ver?o nas assembleias de peixes em Saquarema e Araruama. Estas informa??es servem de base para futuras avalia??es da condi??o ambiental deste sistema visando a conserva??o destes recursos, por?m outros estudos devem ser incorporados nas an?lises, principalmente as influ?ncias do habitat f?sico na estrutura das assembleias de peixes.

Im ersten Teil meiner Arbeit habe ich den Einfluss von Seeentstehung und fischereilicher Bewirtschaftung auf Artenreichtum und Zusammensetzung der Fischgemeinschaften in kleinen Seen untersucht. Dafür habe ich fischereilich ungenutzte Naturseen als Referenz herangezogen und deren Fischgemeinschaft mit der von unbewirtschafteten Baggerseen, sowie fischereilich genutzten Baggerseen und Naturseen verglichen. Im zweiten Teil meiner Arbeit habe ich die Mechanismen der Totholzrekrutierung in Baggerseen untersucht und die Wichtigkeit von Totholz und anderen Litoralstrukturen im Vergleich zu den klassischen Seenvariablen Nährstoffgehalt und Seemorphologie auf die Fischabundanz im Litoral analysiert. Des Weiteren habe ich die Habitat-spezifischen Effekte auf die artspezifische, litorale Fischabundanz und die Effekte von zusätzlich eingebrachten Totholzbündeln auf die Abundanz typischer Fischarten in Baggerseen analysiert. Ich habe herausgefunden, dass fischereiliche Bewirtschaftung die Anzahl der Fischarten in Bagger- und Naturseen erhöht ohne die Zusammensetzung der Fischgemeinschaft im Vergleich zu fischereilich ungenutzten Naturseen signifikant zu verändern. Im Gegensatz dazu unterscheidet sich die Fischgemeinschaft in fischereilich ungenutzten Baggerseen durch das Fehlen von typischen Seefischarten und eine hohe Variabilität in der Zusammensetzung zwischen den Gewässern. Ich konnte zeigen, dass die litorale Totholzmenge in Baggerseen durch die Baumdichte am Ufer in Kombination mit der Windrichtung, durch fischereiliche Bewirtschaftung in Interaktion mit der Uferneigung und das Alter der Gewässer getrieben wird und entsprechend in jungen Baggerseen niedriger ist als in alten Naturseen. Ich fand heraus, dass Litoralstrukturen, wie Totholz, wertvolle Lebensräume darstellen, wichtige Deskriptoren der art-spezifischen, litoralen Fischabundanz sind und die Fischabundanz grundsätzlich mit der Strukturmenge ansteigt. / In the first part of my thesis, I studied the effects of lake genesis and fisheries management on fish species richness and community composition in small lakes. I used fish communities in unmanaged natural lakes as reference and compared them to unmanaged gravel pit lakes as well as managed gravel pit and natural lakes. In the second part, I investigated the recruitment of littoral deadwood in gravel pit lakes and analysed the importance of deadwood and other littoral structures on littoral fish abundance in gravel pit lakes compared to the lake environmental variables such as nutrient level and lake morphology. I further analysed habitat-specific effects on species-specific littoral fish abundance and focussed explicitly on the effects of deadwood bundles implemented in the littoral zone. I found fisheries management to increase the number of fish species in gravel pit and natural lakes, but not leading to different fish community compositions compared to unmanaged natural lakes. By contrast, unmanaged gravel pit lakes were characterized by a lack of typical lake fish species and a high variation in fish community composition among lakes (β-diversity). I detected littoral deadwood densities in gravel pit lakes to be mainly driven by lake age, riparian tree density in interaction with wind direction and littoral slope in angler-managed lakes, with lowest deadwood densities in shallow areas of angler-managed lakes. Furthermore, deadwood densities were lower in young gravel pit lakes compared to old natural lakes. I detected littoral structures, such as littoral deadwood, as appropriate habitats and important descriptors of the species-specific, littoral fish abundance in gravel pit lakes with generally positive effects of structure extension on fish abundance. Littoral habitat characteristics were mostly of similar, or even higher, importance for fish abundance compared to lake environmental factors.