During the last two hundred years many wetlands and streams in Sweden have been lowered to provide land for agriculture and forestry. Some of the coastal wetlands and streams probably served as spawning sites for certain species of fish in the Baltic Sea, but the present situation is not well known. As standardized methods to monitor fish in running waters are carried out during late summer or autumn, there is a need for methods to sample spring-spawning fish in these streams. The aim of this study was to survey the lower kilometer stretch of Hammerstaån in Stockholm, to investigate the extent to which the stream is used by spring-spawning fish. Furthermore, the study aims to evaluate a new type of survey fishing gill net called strömöversiktsnät (SÖN). This was done by comparing the catch of fish by SÖN with that of fyke nets. The comparison of the types of gear included number of fish caught, on a catch per unit effort (CPUE) basis, number of species and the size distributions. The study included 14 days with one gill net and one fyke net at two sites, in total 28 net-days. The inventory yielded in total seventeen species among which only trout (Salmo trutta), perch (Perca fluvitalis), roach (Rutilus rutilus), burbot (Lota lota), eel (Anguilla anguilla) and pike (Esox lucius) were previously known to occur. Six spawning species, smelt (Osmerus eperlanus), vimba bream (Vimba vimba), perch (Perca fluvitalis), roach (Rutilus rutilus), bream (Abramis brama) and white bream (Blicka bjoerkna) were caught in more than 60 individuals, which was set as a limit for comparisons of size distributions. There was no significant difference in CPUE between SÖN and fyke nets. Also length distribution did not differ between SÖN and fyke nets except for the species perch and white bream were the nets caught significant smaller perch and bigger white bream than the fyke nets. The results show that investigations with SÖN or fyke nets during springtime can be of great importance to increase our knowledge about spring-spawning fish in Swedish streams and the coastal areas of the Baltic Sea.

During the last two hundred years many wetlands and streams in Sweden have been lowered to provide land for agriculture and forestry. Some of the coastal wetlands and streams probably served as spawning sites for certain species of fish in the Baltic Sea, but the present situation is not well known. As standardized methods to monitor fish in running waters are carried out during late summer or autumn, there is a need for methods to sample spring-spawning fish in these streams. The aim of this study was to survey the lower kilometer stretch of Hammerstaån in Stockholm, to investigate the extent to which the stream is used by spring-spawning fish. Furthermore, the study aims to evaluate a new type of survey fishing gill net called strömöversiktsnät (SÖN). This was done by comparing the catch of fish by SÖN with that of fyke nets. The comparison of the types of gear included number of fish caught, on a catch per unit effort (CPUE) basis, number of species and the size distributions. The study included 14 days with one gill net and one fyke net at two sites, in total 28 net-days. The inventory yielded in total seventeen species among which only trout (Salmo trutta), perch (Perca fluvitalis), roach (Rutilus rutilus), burbot (Lota lota), eel (Anguilla anguilla) and pike (Esox lucius) were previously known to occur. Six spawning species, smelt (Osmerus eperlanus), vimba bream (Vimba vimba), perch (Perca fluvitalis), roach (Rutilus rutilus), bream (Abramis brama) and white bream (Blicka bjoerkna) were caught in more than 60 individuals, which was set as a limit for comparisons of size distributions. There was no significant difference in CPUE between SÖN and fyke nets. Also length distribution did not differ between SÖN and fyke nets except for the species perch and white bream were the nets caught significant smaller perch and bigger white bream than the fyke nets. The results show that investigations with SÖN or fyke nets during springtime can be of great importance to increase our knowledge about spring-spawning fish in Swedish streams and the coastal areas of the Baltic Sea.

Estuarine habitats are considered nursery habitats for fishes and invertebrates, but oligohaline environments are critically understudied. Using a seine net and fyke nets, we sampled Back Bay, Mississippi (USA), a low salinity estuary, once a month for a year to explore the temporal use of the marsh and adjacent submerged landscape by nekton species. We also looked at whether there is evidence of habitat preference in the most numerous nekton species. We used a novel habitat usage index (HUI) to compare seine and fyke net catches of our top 10 species, and evaluated catch size in relation to maturation size. Consequently, we noted marked differences in 48 nekton species in terms of habitat preference; observed, for our top 10 species, transient species were primarily immatures, and resident species mostly occurred in marshes with some exceptions; and detected size patterns consistent with the spawning cycle of the species in question.

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós–Graduação em Oceanografia Biológica, Instituto de Oceanografia, 2012. / Submitted by Cristiane Gomides (cristiane_gomides@hotmail.com) on 2013-11-18T16:09:12Z No. of bitstreams: 1 BRNA.pdf: 776201 bytes, checksum: 2dd5a6dcf1118a798cbd5a740899215e (MD5) / Approved for entry into archive by Angelica Miranda (angelicacdm@gmail.com) on 2013-11-18T19:39:01Z (GMT) No. of bitstreams: 1 BRNA.pdf: 776201 bytes, checksum: 2dd5a6dcf1118a798cbd5a740899215e (MD5) / Made available in DSpace on 2013-11-18T19:39:01Z (GMT). No. of bitstreams: 1 BRNA.pdf: 776201 bytes, checksum: 2dd5a6dcf1118a798cbd5a740899215e (MD5) Previous issue date: 2012 / O presente trabalho é dividido em dois capítulos, os quais apresentam estudos realizados em três comunidades de pescadores do estuário da Lagoa dos Patos: a São Miguel, o Bosque e a Torotama. O primeiro capítulo trata da estrutura da frota da pesca artesanal na região e sua evolução ao longo do tempo. Foram entrevistados 20 pescadores de cada comunidade, que responderam perguntas com relação aos seus petrechos de pesca e sua visão com relação a mudanças ocorridas no setor. Observou-se uma tendência à diminuição do tamanho de malha das redes, assim como o aumento da potência dos motores, o que evidencia um aumento de esforço pesqueiro quando comparado a décadas passadas. Os pescadores têm consciência das alterações que a pescaria vem sofrendo. O segundo capítulo aborda um assunto pouco estudado no Brasil, o autoconsumo dos pescadores artesanais, ou seja, a quantidade e o tipo de pescado consumido pelos pescadores e seus familiares daquilo que é capturado por eles próprios. Foram entrevistados periodicamente 10 pescadores de cada comunidade, de setembro de 2010 a dezembro de 2011. Coletaram-se informações pessoais sobre a atividade pesqueira e autoconsumo de pescado. O consumo médio anual por pessoa foi de 38,57 kg. A primavera e o verão foram as estações de maior consumo, sendo a corvina e o camarão-rosa as espécies mais consumidas nessas estações, respectivamente. / This study is divided into two chapters which presents studies done in three fishing communities of Patos Lagoon’s estuary: São Miguel, Bosque and Torotama. The first chapter is about the artisanal fishery’s fleet structure in the region and its evolution in time. Twenty fishermen of each community were interviewed, they answered questions about their vessels and the fishing gears and their vision about the changes that occurred in the sector. It was observed reduction trend in mesh sizes as well an increase of the engine power indicating an increase of fishing effort. Fishermen are aware of the changes the fishery has being undergoing. The second chapter addresses a less investigated issue in Brazil, the artisanal fishery self-consumption, i.e., the amount and type of fish consumed by the fishermen and their family of what is captured by them. Ten fishermen of each community were periodically interviewed, from September 2010 to May 2011. Personal information about the fishing activity and fish selfconsumption was collected. The average annual consumption per person was of 38.57 kg. Higher consumption occurred in spring and summer, the white croaker and the pink shrimp are the most consumed species in these seasons, respectively.