956 resultados para Pike fishing.
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Dissertação de Mestrado, Estudos Integrados dos Oceanos, 13 de Fevereiro de 2014, Universidade dos Açores.
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Dissertação de Mestrado, Estudos Integrados dos Oceanos, 15 de Janeiro de 2009, Universidade dos Açores.
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Jornadas "Ciência nos Açores – que futuro? Tema Ciências Naturais e Ambiente", Ponta Delgada, 7-8 de Junho de 2013.
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Fishing decreases the biomass of target species via reduction in the numbers and/or size of individuals. In natural systems, the strength of biological interactions, including predator-prey dynamics, are often density or size-dependent. Hence, changes in the numbers or size of key taxa may be expected to influence biological interactions but their effects do not need to be identical. Here we compare the effects of biomass reduction in populations of the exploited limpet Patella candei. Biomass removal was experimentally achieved by either removing individuals (density reduction) or by replacing large by small individuals (size reduction), while controlling for total limpet biomass in a laboratory-based experiment. At the experiment’s termination, biomass reduction led to proportional changes in area grazed. However, there was no difference whether this was achieved via changes in density or in size. Furthermore, no discernible effects of treatments were evident on different components of the algal assemblage. A field survey also revealed that P. candei biomass explained a greater proportion in variation in the area free of algae than density alone. Our results suggest that loss of biomass in populations of P. candei has quantitatively and qualitatively similar effects on algal cover regardless of whether it is caused by an equivalent (biomass) reduction in the numbers or size of individuals.
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Jornadas "Ciência nos Açores – que futuro?", Ponta Delgada, 7-8 de Junho de 2013.
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Jornadas "Ciência nos Açores – que futuro? Tema Ciências Naturais e Ambiente", Ponta Delgada, 7-8 de Junho de 2013.
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Jornadas "Ciência nos Açores – que futuro? Tema Ciências Naturais e Ambiente", Ponta Delgada, 7-8 de Junho de 2013.
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Dissertação de Mestrado, Estudos Integrados dos Oceanos, 26 de Fevereiro de 2014, Universidade dos Açores.
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Dissertação de Mestrado, Estudos Integrados dos Oceanos, 25 de Julho 2013, Universidade dos Açores.
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Tese de Doutoramento, Ciências do Mar (Biologia Marinha)
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Studies on the feeding habits of aquatic organisms are a requirement for the management and sustainable use of marine ecosystems. The aim of the present research was to analyze the habits and trophic similarities of decapods, starfish and fish in order to propose trophic relationships between taxa, using Hennigian methods of phylogenetic systematics. This new grouping hypothesis, based on shared and exclusive food items and food types, corresponds to the broad taxonomic groups used in the analysis. Our results indicate that algae, Mollusca, Polychaeta, Crustacea, Echinodermata and Actinopterygii are the most exploited common resources among the species studied. Starfish were differentiated from other organisms for being stenophagic, and were grouped for feeding on bivalve mollusks. A larger group of fish and crustaceans shares algae and mainly crustaceans as food items. A third group united all eight species of Actinopterygii. This largest subgroup of fish is typically carnivorous, feeding on Anthozoa and a great quantity of Crustacea. Synodus foetens has a special position among fishes, due to its unique feeding on nematodes. A Euclidean distance dendrogram obtained in a previous publication grouped S. foetens with starfish. That result was based on a few non-exclusive shared similarities in feeding modes, as well as on shared absences of items, which are not an adequate grouping factor. Starfish are stenophagic, eating bivalves almost exclusively. Synodus foetens and Isopisthus parvipinnis have restricted food items, and are thus intermediary in relation to starfish, decapods, and other fish, which are euryphagous. The trophic cladogram displays details of food items, whether or not shared by all species. The resulting trophic analysis is consistent with known historical relationships.
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Dissertação de Mestrado em Estudos Integrados dos Oceanos.
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Dissertação de Mestrado em Gestão e Conservação da Natureza.
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A sub adult Caretta caretta was found on the 23rd August, 2014 ca. 16 nautical miles south off S. Miguel Island, Azores (Northeast Atlantic), with a large pelagic trawl hook inside its mouth. The individual was kept in a basin of sea water and sent by boat to Terceira Island following instructions by the Azores Regional Government via the Environmental Authority in order to be examined by the author and, if possible, undergo the necessary hook removal procedures. In this note, we describe the surgical procedures and how the turtle was evaluated both pre- and post-surgery.
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Present study aims to describe records of mauled and con-specific injures in various fish inhabiting different environment and to discuss possible impacts on fish behavior and ontogenesis. The fish specimens were collected from the Black Sea and Azores Islands (NE Atlantic). Individuals of European flounder, Pleuronectes flesus, common stingray, Dasyatis pastinaca and turbot, Scophthalmus maximus with missing dorsal and caudal fins and flesh, were found in the Black Sea. Specimens with severe mauls of the ocean sunfish, Mola mola, almaco jack, Seriola rivoliana and sargo, Diplodus sargus were recorded from the Azores Islands. All of them were caught alive and survived severe mauls caused by predators or by accidents with propellers, fishing nets. The NE Atlantic records, although possibly caused by natural predation, are more probably than not the result of negative interactions with human activity. Numerous records of mauled fish species from both regions show that the problem with adverse effects of fisheries is quite important. Predatory and con-specific injuries obviously are compatible with basic fish vital functions of described cases. The problem with negative anthropogenic interactions seems to be insufficiently investigated and need more attention by responsible managers and decision makers.