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Population dynamics, ecology and fisheries of aquatic beings

Grant number: 01/13299-7
Support Opportunities:Research Projects - Thematic Grants
Duration: May 01, 2003 - April 30, 2007
Field of knowledge:Biological Sciences - Ecology - Ecosystems Ecology
Principal Investigator:Miguel Petrelli Junior
Grantee:Miguel Petrelli Junior
Host Institution: Instituto de Biociências (IB). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil


Population Dynamics and Fisheries Project 1 -"Population dynamics and fishing of the shark hammer Sphyrna lewini (Griffith and Smith, 1834), caught in the territorial sea and exclusive economical zone off the southeast-south of Brazil. The shark hammer, Sphyrna lewini (Elasmobranchii, Sphymidae), one of the more valuable cosmopolitan species in the international market of fins, has been captured in the southeast-south of Brazil by the seine fleets and of surface longline. Due to its crescent importance in the landings, this project seeks to characterize the seine and longline using capture data and the available effort, as well as to know the population dynamics of the species, through growth studies and age determination by lengths frequency analyses and reading of rings in vertebrae of S. lewini, that will allow us to establish management and conservation plans for this potentially endangered species.Project 2 - Population dynamics of demersal rays of the genus Rioraja and Atlantoraja (Elasmobranchii, Rajidae) of southeast and south coast of Brazil. The family Rajidae is composed by bentonic demersal individuals, being found in almost all of the seas of the world, temperate and tropical. They are very common in the catches by bottom trawling and seines in the southeast and south coast of Brazil. The genus Rioraja and Atlantoraja are always larger proportions in the landings of the commercial fleet, inside of the category "emplastro". This work has as objective to test and to evaluate several methodologies for age rings readings in vertebrae, studying the growth and ageing of Rioraja and Atlantoraja (R. agassizi, A. cyclophora, A. castelnaui and A. platana), as well as to estimate their growth parameters, reproduction and mortality, evaluating the population structure of those species. Project 3 - Reproduction, feeding and growth of the freshwater rays (Elasmobranchii: Potamotrygonidae) in Rio Paraná-Tocantins. In Brazil occurs the largest number of species of freshwater rays of the world. There are evidences that many others are still to be able discovered, mainly in the Amazon Basin. The use of species of the family Potamotrygonidae in aquariofilia has been intensified lately, being necessary more knowledge on the biology of those species, aiming their management and conservation. The objective of present study is to identify and redescribe the species of that family which occurs in the Rios Paraná and Arraias, Center-west Brazil, besides knowing the reproduction, feeding and growth in the wild and captivity, in order to obtain more information on the population dynamics of those rays. Project 4 - Biology and fisheries of the cutlassfish Trichiurus lepturus (Trichiuridae, Teleostei) ofthe southeast-south coast of Brazil. The cutlassfish, Trichiurus lepturus (Teleostei, Trichiuridae), is one of the species among the coastal fishing resources of the Southeast-south Brazil, that it is assuming an increasing importance with several fishing gears, in spite that there is not being a fishery directly to this species. The cutlassfish is a cosmopolitan species, being distributed at West Atlantic from Massachusetts (USA) until the north of Argentina. Due to its importance as a potential fishing resource, and the inexistence of complete studies on its biology, the present study has for objectives: to determine the population structure through length-frequency analysis of the landed fish; to study the reproductive cycle of the species; to estimate the growth parameters of the species; to estimate taxes of natural, fishing and total mortality; to determine the CPUE of the fishing for the species; to apply methods of virtual population analysis of cohorts (VP A) and predictive models for assessing its stocks. Part 2. Ecology or communities Project 5 -"Bases for the ecologically sustainable management of the fish community of Barra Bonita dam (SP), Brazil. The Barra Bonita dam represents an ecosystem under high environmental stress. Variations in the abundance or diversity of the fish community are representative of the quality of this habitat. Therefore, the fish constitute important scientific target, not only for the understanding of the dynamics of the ecosystem, as well as for the definition of criteria ecologically sustainable. So we intend to analyze the system evidencing the relationships among the morphologic characteristics of the dam, the hydraulic procedure and the physiochemical quality of the water of the reservoir together with the biological cycles of the fish fauna; to characterize the fish community in terms of species richness, diversity and abundance; to evaluate the degree of biotic integrity and of stress of this community, adapting the index of biotic integrity (IBI), besides verifying the effects caused by the local man induced disturbance in order to define ecologically sustainable criteria of management, guaranteeing the maintenance of the resources and its safeguard for the future generations. Part 3. Fisheries Project 6 - The fishing activities of the caiçara community at Picinguaba (Ubatuba, SãoPaulo). The coastal small scale fisheries are of great importance providing food and income for the local populations. The dynamics of the fishing resources exploitation is important for fish stock management and the determination of the number of active boats the first step to understand the operation of a fishery. The fishermen community of Picinguaba (Ubatuba) is traditional and conservative of the seaside habits inhabitants, presenting the largest representativeness of fishermen in the 70's. This work has for objective to diagnose the operational characteristics of the community of Picinguaba fishing fleet, in agreement with their physical characteristics, fish species target and fishing area, as well as to assess the relationship between these characteristics and the income of each fishing trip, allowing to define the more appropriate unit of fishing effort for the more important fishing gears of the area. We also intend to understand the fishing strategies developed by the community through the social conviviality and interviews. Project 7 - Hook selectivity of the commercial fish in the Pantanal of Mato Grosso do Sul, Brazil. In order to promote the appropriate management of the fishing resources, as more information on fish resource exploitation are available, easier will be to take the right decisions, the knowledge of the selectivity of the hooks employed by the professional fishermen (the only gear allowed by law) will indicate the most appropriate sizes in order to avoid juvenile catches. The present study has for objectives the determination of the selectivity of different sizes of fishhooks of most important commercial species: pacu, pintado, cachara, dourado and piraputanga of the Pantanal of Mato Grosso do Sul, being defined the appropriate size just the one which selects only adult individuals. (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
KOTAS, J. E.; MASTROCHIRICO, V; PETRERE JUNIOR, M.. Age and growth of the Scalloped Hammerhead shark, Sphyrna lewini (Griffith and Smith, 1834), from the southern Brazilian coast. Brazilian Journal of Biology, v. 71, n. 3, p. 755-761, . (01/13299-7)

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