In 1988 data on coral reef community composition were collected from two areas, Akumal and Chemuyil, Quintana Roo, Mexico, ranging from 5-35m depth. These areas were revisited in 2005 and data were collected by the same methods and at the same depths as in 1988. Data from 1988 and 2005 were compared to determine if the coral reefs had undergone significant changes, and what specific changes had occurred. Chi-square analysis determined that community composition data collected in 1988 are significantly different from data collected in 2005 at all sites and depths within the categories of corals, gorgonians, sponges, and macroalgae. Mann-Whitney U analyses were performed on abundance data for coral, gorgonians, sponges, macroalgae, crustose coralline algae, erect coralline algae/calcareous algae, filamentous/multi-species turf algae, and non-living substrate. Results from the Mann-Whitney U analysis varied between sites; however significant trends of increasing macroalgae, crustose coralline algae and filamentous/multi-species turf, and declining non-living substrate were observed at almost all sites. H' biodiversity indices J' evenness values and species number (S) were calculated for all sites over the two time periods, with no discernable trends observed. Increases in crustose coralline algae and filamentous/multi-species turf algae suggest that eutrophication and overfishing may be responsible for the trends observed on the reefs at Akumal and Chemuyil. Anecdotal accounts also suggest that eutrophication from septic water flowing through the highly porous karst limestone of the Yucatan Peninsula may be the largest malefactor causing the observed changes. The increase in filamentous/multi-species turf algae exhibited by the data suggests that eutrophication is predominantly responsible for the alternate states of the reefs. Furthermore, evidences indicative of other forms of stress on the reefs, such as bleaching, scraped or broken coral heads, disease, and sedimentation, were rarely observed.

Os recursos pesqueiros estão sendo sobre-explotados mundialmente. A pesca pode conduzir ao efeito de cascata trófica e essa exploração pode ser insustentável. Por isso políticas de manejo são urgentes, mas faltam dados para subsidiar tais políticas e nesse sentido, estudos com pescadores artesanais através de entrevistas têm colaborado com o conhecimento sobre a dinâmica pesqueira. A pesca artesanal brasileira é a principal atividade econômica ou de subsistência e o pescado é a maior fonte de proteínas para populações caboclas ribeirinhas amazônicas e populações de caiçaras que vivem na área litorânea da Mata Atlântica. Esta pesquisa analisou padrões ecológicos espaciais e temporais na pesca artesanal brasileira em dois ecossistemas: a costa sudeste da Mata Atlântica e a Amazônia fluvial, tendo como base de dados entrevistas realizadas com pescadores ao longo de vários projetos de pesquisa. No capítulo 1 analisou-se a produtividade pesqueira no litoral sudeste. Foi testada a variação da biomassa média capturada citada pelos entrevistados em função de fatores temporais (idade do pescador e data em que ocorreu sua última pescaria) e espaciais (região aonde se localiza a comunidade do pescador entrevistado). Foram analisadas entrevistas com 423 pescadores, que indicaram que: a) houve uma diminuição na quantidade de peixes capturados ao longo do tempo; b) a biomassa capturada não foi influenciada pelo fator espacial; c) não houve influência da idade do pescador na biomassa capturada mencionada. O capítulo 2 abordou a costa sudeste da Mata Atlântica e a Amazônia fluvial. Foram analisadas a composição dos peixes, através dos nomes populares citados e seu nível trófico médio. Foram analisadas entrevistas com 658 pescadores da Amazônia fluvial (de 1987 a 2006) e 821 pescadores da costa sudeste da Mata Atlântica (de 1986 a 2009) (n=1479 entrevistados). Não houve variação do nível trófico segundo o tempo, porém o nível trófico variou de acordo com os fatores espaciais (ecossistema e região), sendo que o fator que mais influenciou essa variação foi região. Na costa sudeste da Mata Atlântica há possível substituição das espécies de nível trófico similar por outras espécies de mesmo valor econômico com o tempo. Na Amazônia fluvial esse padrão de substituição das espécies não foi observado. Conclui-se que a diminuição da biomassa capturada ao longo do tempo somada à substituição de determinadas espécies de peixes capturados na costa da Mata Atlântica, podem indicar que a pesca não está sendo sustentável. Medidas preventivas de manejo pesqueiro devem ser implementadas. / Fisheries resources are being over-exploited worldwide. Excessive fishing can lead to trophic cascades and this exploration may be unsustainable. Therefore, management policies are urgent, but data are lacking to support such policies. In this sense, studies addressing interviews with fishermen have collaborated with the knowledge about the dynamics of fishing. The Brazilian artisanal fishing is the main economic and subsistence activity and the main source of protein for riverine Amazonian Caboclo populations and caiçara populations, who live in the coastal area of the Atlantic Forest. This study examined spatial and temporal ecological patterns in Brazilian artisanal fisheries in two ecosystems: the southeast coast of the Atlantic Forest and the fluvial Amazon; the data was based in interviews with fishermen on the course of several research projects. In Chapter 1 it was analyzed the fishery productivity in the southeastern coast. It was checked the variation in the average biomass of fish captured according to the interviews with fishers, due to temporal factors (fishermen’s age and date of their last fishery) and spatial factors (the region where the community of fishermen interviewed is located). There were analyzed interviews with 423 fishers, indicating that: a) there was a decrease in the biomass of fish caught over time, b) the biomass of fish caught was not influenced by the spatial factor c) there was no influence of age of the fisherman on the biomass of fish caught that was mentioned by them. Chapter 2 addressed the southeast coast of the Atlantic Forest and the Inland freshwater Amazon. It was analyzed the composition of fish caught, through their popular names mentioned by fishers and their mean trophic level. There were analyzed interviews with 658 fishers in the Amazon Basin (from 1987 to 2006) and with 821 fishers in to the southeast coast of the Atlantic Forest (from 1986 to 2009) (n = 1479 fishers). There was no variation in trophic level according to the time since the last fishing trip, and according to the spatial factors (ecosystem and region), and the region was the factor that most influenced the variation in trophic level. On the southeast coast of the Atlantic Forest species with similar trophic levels have been probably replaced by species of similar economic value over time. However, in the freshwater Amazon this pattern of species replacement was not observed. It is concluded that the decrease in biomass captured over time and the replacement of species on the Atlantic coast, may indicate that the fishery has been not sustainable. Preventive fisheries management measures should thus be devised.

Os recursos pesqueiros estão sendo sobre-explotados mundialmente. A pesca pode conduzir ao efeito de cascata trófica e essa exploração pode ser insustentável. Por isso políticas de manejo são urgentes, mas faltam dados para subsidiar tais políticas e nesse sentido, estudos com pescadores artesanais através de entrevistas têm colaborado com o conhecimento sobre a dinâmica pesqueira. A pesca artesanal brasileira é a principal atividade econômica ou de subsistência e o pescado é a maior fonte de proteínas para populações caboclas ribeirinhas amazônicas e populações de caiçaras que vivem na área litorânea da Mata Atlântica. Esta pesquisa analisou padrões ecológicos espaciais e temporais na pesca artesanal brasileira em dois ecossistemas: a costa sudeste da Mata Atlântica e a Amazônia fluvial, tendo como base de dados entrevistas realizadas com pescadores ao longo de vários projetos de pesquisa. No capítulo 1 analisou-se a produtividade pesqueira no litoral sudeste. Foi testada a variação da biomassa média capturada citada pelos entrevistados em função de fatores temporais (idade do pescador e data em que ocorreu sua última pescaria) e espaciais (região aonde se localiza a comunidade do pescador entrevistado). Foram analisadas entrevistas com 423 pescadores, que indicaram que: a) houve uma diminuição na quantidade de peixes capturados ao longo do tempo; b) a biomassa capturada não foi influenciada pelo fator espacial; c) não houve influência da idade do pescador na biomassa capturada mencionada. O capítulo 2 abordou a costa sudeste da Mata Atlântica e a Amazônia fluvial. Foram analisadas a composição dos peixes, através dos nomes populares citados e seu nível trófico médio. Foram analisadas entrevistas com 658 pescadores da Amazônia fluvial (de 1987 a 2006) e 821 pescadores da costa sudeste da Mata Atlântica (de 1986 a 2009) (n=1479 entrevistados). Não houve variação do nível trófico segundo o tempo, porém o nível trófico variou de acordo com os fatores espaciais (ecossistema e região), sendo que o fator que mais influenciou essa variação foi região. Na costa sudeste da Mata Atlântica há possível substituição das espécies de nível trófico similar por outras espécies de mesmo valor econômico com o tempo. Na Amazônia fluvial esse padrão de substituição das espécies não foi observado. Conclui-se que a diminuição da biomassa capturada ao longo do tempo somada à substituição de determinadas espécies de peixes capturados na costa da Mata Atlântica, podem indicar que a pesca não está sendo sustentável. Medidas preventivas de manejo pesqueiro devem ser implementadas. / Fisheries resources are being over-exploited worldwide. Excessive fishing can lead to trophic cascades and this exploration may be unsustainable. Therefore, management policies are urgent, but data are lacking to support such policies. In this sense, studies addressing interviews with fishermen have collaborated with the knowledge about the dynamics of fishing. The Brazilian artisanal fishing is the main economic and subsistence activity and the main source of protein for riverine Amazonian Caboclo populations and caiçara populations, who live in the coastal area of the Atlantic Forest. This study examined spatial and temporal ecological patterns in Brazilian artisanal fisheries in two ecosystems: the southeast coast of the Atlantic Forest and the fluvial Amazon; the data was based in interviews with fishermen on the course of several research projects. In Chapter 1 it was analyzed the fishery productivity in the southeastern coast. It was checked the variation in the average biomass of fish captured according to the interviews with fishers, due to temporal factors (fishermen’s age and date of their last fishery) and spatial factors (the region where the community of fishermen interviewed is located). There were analyzed interviews with 423 fishers, indicating that: a) there was a decrease in the biomass of fish caught over time, b) the biomass of fish caught was not influenced by the spatial factor c) there was no influence of age of the fisherman on the biomass of fish caught that was mentioned by them. Chapter 2 addressed the southeast coast of the Atlantic Forest and the Inland freshwater Amazon. It was analyzed the composition of fish caught, through their popular names mentioned by fishers and their mean trophic level. There were analyzed interviews with 658 fishers in the Amazon Basin (from 1987 to 2006) and with 821 fishers in to the southeast coast of the Atlantic Forest (from 1986 to 2009) (n = 1479 fishers). There was no variation in trophic level according to the time since the last fishing trip, and according to the spatial factors (ecosystem and region), and the region was the factor that most influenced the variation in trophic level. On the southeast coast of the Atlantic Forest species with similar trophic levels have been probably replaced by species of similar economic value over time. However, in the freshwater Amazon this pattern of species replacement was not observed. It is concluded that the decrease in biomass captured over time and the replacement of species on the Atlantic coast, may indicate that the fishery has been not sustainable. Preventive fisheries management measures should thus be devised.

Os recursos pesqueiros estão sendo sobre-explotados mundialmente. A pesca pode conduzir ao efeito de cascata trófica e essa exploração pode ser insustentável. Por isso políticas de manejo são urgentes, mas faltam dados para subsidiar tais políticas e nesse sentido, estudos com pescadores artesanais através de entrevistas têm colaborado com o conhecimento sobre a dinâmica pesqueira. A pesca artesanal brasileira é a principal atividade econômica ou de subsistência e o pescado é a maior fonte de proteínas para populações caboclas ribeirinhas amazônicas e populações de caiçaras que vivem na área litorânea da Mata Atlântica. Esta pesquisa analisou padrões ecológicos espaciais e temporais na pesca artesanal brasileira em dois ecossistemas: a costa sudeste da Mata Atlântica e a Amazônia fluvial, tendo como base de dados entrevistas realizadas com pescadores ao longo de vários projetos de pesquisa. No capítulo 1 analisou-se a produtividade pesqueira no litoral sudeste. Foi testada a variação da biomassa média capturada citada pelos entrevistados em função de fatores temporais (idade do pescador e data em que ocorreu sua última pescaria) e espaciais (região aonde se localiza a comunidade do pescador entrevistado). Foram analisadas entrevistas com 423 pescadores, que indicaram que: a) houve uma diminuição na quantidade de peixes capturados ao longo do tempo; b) a biomassa capturada não foi influenciada pelo fator espacial; c) não houve influência da idade do pescador na biomassa capturada mencionada. O capítulo 2 abordou a costa sudeste da Mata Atlântica e a Amazônia fluvial. Foram analisadas a composição dos peixes, através dos nomes populares citados e seu nível trófico médio. Foram analisadas entrevistas com 658 pescadores da Amazônia fluvial (de 1987 a 2006) e 821 pescadores da costa sudeste da Mata Atlântica (de 1986 a 2009) (n=1479 entrevistados). Não houve variação do nível trófico segundo o tempo, porém o nível trófico variou de acordo com os fatores espaciais (ecossistema e região), sendo que o fator que mais influenciou essa variação foi região. Na costa sudeste da Mata Atlântica há possível substituição das espécies de nível trófico similar por outras espécies de mesmo valor econômico com o tempo. Na Amazônia fluvial esse padrão de substituição das espécies não foi observado. Conclui-se que a diminuição da biomassa capturada ao longo do tempo somada à substituição de determinadas espécies de peixes capturados na costa da Mata Atlântica, podem indicar que a pesca não está sendo sustentável. Medidas preventivas de manejo pesqueiro devem ser implementadas. / Fisheries resources are being over-exploited worldwide. Excessive fishing can lead to trophic cascades and this exploration may be unsustainable. Therefore, management policies are urgent, but data are lacking to support such policies. In this sense, studies addressing interviews with fishermen have collaborated with the knowledge about the dynamics of fishing. The Brazilian artisanal fishing is the main economic and subsistence activity and the main source of protein for riverine Amazonian Caboclo populations and caiçara populations, who live in the coastal area of the Atlantic Forest. This study examined spatial and temporal ecological patterns in Brazilian artisanal fisheries in two ecosystems: the southeast coast of the Atlantic Forest and the fluvial Amazon; the data was based in interviews with fishermen on the course of several research projects. In Chapter 1 it was analyzed the fishery productivity in the southeastern coast. It was checked the variation in the average biomass of fish captured according to the interviews with fishers, due to temporal factors (fishermen’s age and date of their last fishery) and spatial factors (the region where the community of fishermen interviewed is located). There were analyzed interviews with 423 fishers, indicating that: a) there was a decrease in the biomass of fish caught over time, b) the biomass of fish caught was not influenced by the spatial factor c) there was no influence of age of the fisherman on the biomass of fish caught that was mentioned by them. Chapter 2 addressed the southeast coast of the Atlantic Forest and the Inland freshwater Amazon. It was analyzed the composition of fish caught, through their popular names mentioned by fishers and their mean trophic level. There were analyzed interviews with 658 fishers in the Amazon Basin (from 1987 to 2006) and with 821 fishers in to the southeast coast of the Atlantic Forest (from 1986 to 2009) (n = 1479 fishers). There was no variation in trophic level according to the time since the last fishing trip, and according to the spatial factors (ecosystem and region), and the region was the factor that most influenced the variation in trophic level. On the southeast coast of the Atlantic Forest species with similar trophic levels have been probably replaced by species of similar economic value over time. However, in the freshwater Amazon this pattern of species replacement was not observed. It is concluded that the decrease in biomass captured over time and the replacement of species on the Atlantic coast, may indicate that the fishery has been not sustainable. Preventive fisheries management measures should thus be devised.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This study evaluated spatio-temporal distribution of the main species of marine shrimp exploited in the state of Sergipe (Xiphopenaeus kroyeri; Litopenaeus schmitti, and Farfantepenaues subtilis) depending on environmental factors. To do this, the samples were collected monthly from september 2013 to august 2014 in nine seasons according to the local bathymetry, three 15min samples in the depths of 5m, 15m and 30m. The catch of shrimps was performed with the use of a shrimping boat equipped with a doble ring nets. In addition to the biological material at each point were also recorded the following environmental factors: temperature and salinity (surface and bottom), organic matter, sediment texture and rainfall. The shrimps were transported to the laboratory identified the specific level, sexed and measured as the carapace length (CL). Hydrological factors were different when compared over time, the sediment characteristics showed similar results among months. In relation to space, only the bottom salinity and the measure of central tendency (Phi) demonstrated difference. Among the studied species, X. kroyeri was the most abundant, followed by F. subtilis and L. schmitti. There was variation in the temporal distribution of shrimp during the study period, except for F. subtilis. All species demonstrated differences in their spatial distribution, with the highest abundances found in 5m and 15m for X. kroyeri and L. schmitti and 30m to F. subtilis. In reason of the water masses do not show variation in the region, the temporal distribution was best explained in terms of the relations of seasonal cycles of rain or the species life cycle. Regarding space, hydrological factors showed no variation, so the differences in the spatial distribution were better explained due to sediment characteristics with X. kroyeri and L. schmitti associated with finegrained, while F. subtilis was more abundant in regions of coarser grains. Individuals of different reproductive categories showed variations in their abundance. Both individuals with developed gonads and immature individuals were found throughout the year, with the presence of two peaks. Regarding space, individuals with developed gonads were found in greater abundance in the deeper regions, while the immature were more abundant near the shallower areas (5m and 15m), reflecting the life cycle and species occurrence. Regarding the conservation of the species, it can be said that only two species are benefiting the area bounded by IBAMA. / O presente trabalho avaliou distribuição espaço-temporal das principais espécies de camarões marinhos explotados no estado de Sergipe (Xiphopenaeus kroyeri; Litopenaeus schmitti; e Farfantepenaues subtilis) em função dos fatores ambientais. Para tal, foram realizadas coletas mensais de setembro de 2013 à agosto de 2014 em nove estações de acordo com a batimetria local, sendo 3 arrastos de 15min nas profundidades de 5m, 15m e 30m. A captura dos camarões foi realizada com a utilização de um barco camaroeiro equipado com rede de arrasto de portas. Além do material biológico, em cada ponto também foram registrados os seguintes fatores ambientais: temperatura e salinidade (superfície e fundo), matéria orgânica, textura do sedimento e pluviometria. Os indivíduos foram transportados ao laboratório, identificados ao nível específico, sexados e mensurados quanto o comprimento da carapaça (CC). Fatores hidrológicos foram distintos quando comparados em relação ao tempo, já para as características do sedimento os resultados foram semelhantes entre os meses. Em relação ao espaço, apenas a salinidade de fundo e a medida de tendência central (Phi) demonstraram diferença. Dentre as espécies estudadas, X. kroyeri foi a mais abundante, seguida por F. subtilis e L. schmitti. Com exceção de F. subtilis, houve variação na distribuição temporal dos camarões durante o período de estudo. Todas as espécies demonstraram diferenças quanto a sua distribuição espacial, com as maiores abundâncias encontradas nos 5m e 15m, para X. kroyeri e L. schmitti e nos 30m para F. subtilis. Devido as massas de água não demonstrarem variação na região, a distribuição temporal dos indivíduos foi melhor explicada em função das relações dos ciclos sazonais de chuvas ou do ciclo de vida das espécies. Em relação ao espaço, fatores hidrológicos não demonstraram variação, logo as diferenças em relação à distribuição espacial foram melhor explicadas devido às características do sedimento, com X. kroyeri e L. schmitti associados a grãos finos, enquanto F. subtilis foi mais abundante em regiões de grãos mais grossos. Indivíduos das diferentes categorias reprodutivas demonstraram variações quanto sua abundância. Ambos os indivíduos com gônadas desenvolvidas e indivíduos imaturos foram encontrados ao longo de todo o ano, com a presença de dois picos. Em relação ao espaço, indivíduos com gônadas desenvolvidas foram encontrados em maior abundância nas regiões mais profundas, enquanto os imaturos foram mais abundantes próximos as áreas mais rasas (5m e 15m), reflexo do ciclo de vida e da área de ocorrência das espécies. Com relação à conservação das espécies, é possível afirmar que, apenas duas espécies estão sendo beneficiadas pela área delimitada pelo IBAMA.

Made available in DSpace on 2014-08-20T14:38:46Z (GMT). No. of bitstreams: 1 dissertacao_jackes_douglas_manke_dos_santos.pdf: 3999834 bytes, checksum: 5e393348c350bee3d13e827383a72fc0 (MD5) Previous issue date: 2012-02-29 / The Lagoa Mangueira located in southern Brazil is part of a complex river system of the coastal plain of Rio Grande do Sul, in the presence of extensive wetlands, owned by the lagoon system belonging to known as Patos-Mirim. It has inhabited and exploited human populations, and the fishing one of the most important activities. The fishing activity developed in the region has decreased capture rates, as declared by fishermen, causing them to continuous intensification and diversification of their capture techniques. The objective of this study was to characterize the occupation process the Lagoa Mangueira by artisanal fishermen, the composition and quantity of fish caught, and to describe the fishermen behavior against the fish abundance variation. For the identification of fishing communities, field trips were held monthly in the years 2010 and 2011. Semi-structured interviews were conducted on sampling method known as chain of informants. Fish catch data were provided by local fishermen, through their writings, which were tabulated and submitted to descriptive statistics. The first forays into the fishing in Lagoa Mangueira were made in the early 1960s. Currently there are seven fishermen core on the west bank of the lagoon. The entry of new fishermen obey the general criteria for the establishment of traditional communities. The average catch per fisherman in the region is 4766.5 kg / year, and the viola (Loricariichthys anus) is the species with the highest volume of capture and that provides greater economic income of the local fisheries. It demonstrated the importance of participation and inclusion of these agents in the development and implementation of public politics for management and conservation of natural resources in the region, since these populations are in possession of accurate information on the ecosystem. / A Lagoa Mangueira localizada no extremo sul do Brasil faz parte de um complexo sistema hidrográfico da planície costeira do estado Rio Grande do Sul, com a presença de extensas áreas úmidas, pertencente ao sistema lagunar conhecido como Patos-Mirim, o qual é habitado e explorado por populações humanas, sendo a pesca artesanal uma das atividades mais importantes. A atividade pesqueira desenvolvida na região apresenta diminuição dos índices de captura, conforme declaração dos pescadores, fazendo com que estes continuamente intensifiquem e diversifiquem as técnicas de captura. O objetivo do trabalho foi caracterizar o processo de ocupação da Lagoa Mangueira por pescadores artesanais, a composição e a quantidade de peixe capturado, bem como descrever o comportamento destes pescadores frente à variação da abundância do pescado. Para a identificação das comunidades de pescadores, foram realizadas saídas de campo nos anos de 2010 e 2011. A aplicação das entrevistas semi-estruturadas foram realizadas por amostragem, pelo método conhecido como cadeia de informantes. Dados de captura foram fornecidos pelos pescadores locais, através de seus registros, os quais foram tabulados e submetidos à estatística descritiva. As primeiras incursões para pesca na Lagoa Mangueira foram realizadas no início da década de 1960. Atualmente existe 7 núcleos de pescadores na margem oeste da lagoa. A entrada de novos pescadores obedece a critérios gerais do estabelecimento de comunidades tradicionais. A captura média por pescador da região é de 4.766,5 kg/ano, sendo que a viola (Loricariichthys anus) é a espécie com maior volume de captura e que proporciona maior renda econômica da pesca local. Fica evidenciada a importância da participação e inclusão destes agentes na elaboração e implementação de políticas públicas de manejo e conservação dos recursos naturais da região, já que estas populações são detentoras de informações precisas sobre o ecossistema.

Management strategies to prevent overfishing while achieving optimum yield vary according to the available data and life history of the fished stock. I evaluated two sets of management strategies for Pacific coast rockfish: strategies to set harvest limits for data-poor stocks, and strategies intended to protect the age structure of fished stocks. Setting Harvest Limits for Data-poor Stocks - The collapse of canary rockfish, Sebastes pinniger, in the northeast Pacific began more than two decades before the stock was officially declared overfished. The 2006 reauthorization of the Magnuson-Stevens Fishery Conservation and Management Act requires a scientifically-based harvest limit for all fished stocks, including those with data limited to catch. Two such "data-poor" methods are currently in use for the management of west coast stocks, depletion-corrected average catch (DCAC) and depletion-based stock reduction analysis (DB-SRA). To evaluate the performance of each method when challenged with catch and biological uncertainty, I retrospectively applied the methods to the catch and biological data available at the time of the first and second canary rockfish stock assessments in 1984 and 1990. In 1980 canary rockfish would be classified as "data-poor", and in 1990 as "data-rich". To evaluate the sensitivity of DCAC and DB-SRA to error in the catch data, harvest limits were estimated using both the historic catch data from each assessment, and the reconstructed catch data from the most recent stock assessment. In addition, harvest limits were estimated using simulated catch data sets for the years 1916 to 1983 with increasing variability around the true catch. DCAC and DB-SRA estimated harvest limits were significantly lower than the catch recommended in both the data-poor and data-rich stock assessments, but higher than the "true" overfishing limit. Use of current catch data improved the estimated harvest limit when the stock was data-poor, but not when the stock was data-rich. The simple methods responded to increasing error in the catch time series with decreasing mean estimates of the harvest limit, indicating that these methods are highly precautionary for this species, when the catch time series is the only source of error. Age Structure Management Strategies - In a variable oceanographic environment, a population with many reproductive age classes benefits not only from the increased fecundity of older fish; but also, in some species, an increase in larval fitness. Older females may also spawn at different times or over longer periods than younger females, increasing the probability of larvae encountering favorable environmental conditions. Despite the accumulating evidence for the importance of age structure to long-term population viability in harvested fish populations, long-lived west coast rockfish (Genus Sebastes) are managed with a biomass-based harvest control rule. I compared three strategies for age structure management, and evaluated the strategies relative to the status quo, biomass-based harvest control rules, across three rockfish life histories. I examined the tradeoff between yield and traditional management reference points, as well as performance measures that could serve as management reference points for age structure. Yield was reduced by strategies that maintain "old growth" age structure, but annual variation in the catch and the probability of becoming overfished were also reduced. The longest-lived rockfish benefited the most from strategies that maintained older fish in the population through dome-shaped selectivity. The shorter-lived rockfish benefited from adjustments in the catch limit based on the age composition of the catch one year previous. Achieving "pretty good yield" with management strategies that also decrease the potential for overexploitation is an important goal for stocks that are well-studied and those that are poorly understood; these investigations contribute to a growing literature on alternative approaches to sustainable fisheries management. / Graduation date: 2012

The many technological processes that products go through can make consumers less related to the systems behind them and their origins. The same thing happens to food. This project highlights the implications of a food system within the global scale of today’s mainstream economy and explores the possibilities for a product that originates from a more sustainable food system. Apart from re-designing a processed everyday food product, the aim of this study is to increase awareness of the pressure that the world’s fish stocks are suffering due to overfishing – an issue that is being aggravated by our current food system. For this reason fish fingers (aka fish sticks), which is a well known food product in Sweden, have been chosen as the primary focus in order to make a complex issue more tangible. By re-evaluating what a fish is, analysing current food systems and food products, making sensory explorations and collaborating with chefs, Havsbitar 1.0 and 2.0 (”Sea Bites” 1.0 and 2.0) have been developed. It is a series of fish fingers that has been designed for a desirable future scenario, where a resilient food system has been implemented. The aesthetics of Havsbitar intends to connect it to its ingredients and to the ecosystem it comes from, while maintaining the key characteristics of the fish finger as we know it today. The acceptance of the concept as a food product is an important variable to this project. The concept is placed in the field of Transition Design. Nevertheless, the design of Havsbitar 1.0 is a proposal that is intended to create possibilities for dialogue about an ideal industrialized commercial product. On the other hand, Havsbitar 2.0 follows a more discursive, critical angle towards the fact that fish fingers do not resemble fish, its main ingredient. Havsbitar 2.0 could then be placed in the field of Critical Food Design and Discursive Design.

The oceans are essential for humanity, yet these systems continue to be degraded and suffer from pollution, habitat destruction and overexploitation. The Costa Rican Gulf of Nicoya is a productive gulf that is fished by both large-scale industrial fisheries and small-scale artisanal fishermen. However, the gulf is profoundly overfished and there has been a shift in both the type of species and size of fishes being targeted, which has had devastating economic and ecological effects in the region. To improve their livelihoods, artisanal fishermen have together with governmental agencies instituted partially protected marine protected areas, known as AMPRs which are intended to give artisanal fishermen exclusive fishing rights and to better the health of the ecosystems. However, these AMPRs can vary greatly within and between each other in aspects such as what types of fishing gear is allowed. To investigate how fishing techniques impact the health of the fish stocks and the wellbeing of fishermen within an AMPR, the size of a target fish, Spotted Rose Snapper (Lutjanus guttatus) and the number of undesired fish caught, was compared based on the number of approved fishing methods such as nets, longlines and commercial scuba diving, between different zones. This was conducted by identifying and measuring catch in collaboration with the National University of Costa Rica, who contributed with databases and field assistance, and artisanal dead bait longline fishermen (bottom long line) in the Paquera-Tambor AMPR. The results showed that in areas where fishing gear is more restricted, the mean weight of Spotted Rose Snapper was higher, but the relative proportion bycatch was not different. Furthermore, there was no difference in legal capture or breeding lengths between areas with high and low restriction of fishing gear. This indicates that the effects of overfishing are less predominant in zones where fewer fishing methods are permitted. The restriction of fishing methods could increase biodiversity and size in fish by exploiting less cohorts of populations. The preservation of size in fish species is very important regarding reproductive success, and it is therefore paramount that larger individuals are protected. This could be accomplished by for example, restricting the amount of allowed fishing gear or introducing maximum catch sizes. However, an improvement of the fish stocks, and therefore human wellbeing cannot be achieved in the Gulf of Nicoya without a revision of the strategies of two influential governmental bodies, the Costa Rican coast guard and the Costa Rican Institute of Fisheries and Aquaculture.

Elasmobranchs are among the oldest and most successful predators in the ocean, yet one of the most vulnerable to the direct and indirect effects of fishing. Many populations are rapidly declining around the world, and an increasing number is listed as threatened or endangered. The broader ecosystem consequences of these declines, and whether other marine predators can replace sharks, are open questions. In this thesis, I used a diverse set of data and modeling techniques to analyze long-term changes in elasmobranch populations in the Mediterranean Sea, and the consequences of shark declines on marine ecosystems. Because of its long history of fishing, the Mediterranean offers a unique perspective on the response of marine communities to exploitation over long time scales. Here, I reconstructed the history of elasmobranch exploitation over the past 200 years in pelagic, coastal and demersal communities. Results were combined meta-analytically to derive a general pattern of change for the entire region. Overall, I detected multiple cases of regional species extirpations, a strong correlation between historical intensity of exploitation and the stage of community degradation, and some cases of compensatory species increases. My results suggest that compared to other marine ecosystems worldwide, the Mediterranean Sea might be in an advanced stage of overexploitation. To gain more general conclusions about the patterns and consequences of shark declines in the ocean, I reviewed and reanalyzed documented changes in exploited elasmobranch communities around the world, and synthesized the effects of sharks on their prey and wider communities. This work revealed that sharks are abundant and diverse in little exploited or unexploited marine ecosystems but vulnerable to even light levels of fishing. The decline in large sharks has reduced natural mortality in a range of their prey, contributing to changes in abundance, distribution, and behaviour of marine megafauna that have few other predators. In some cases, this has resulted in cascading changes in prey populations and food-web structure. Overall, my thesis greatly enhanced our knowledge about the critical state of elasmobranchs in the Mediterranean Sea and the consequences of the declines of these important marine predators on marine ecosystems.