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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Projeto raia de fogo: aspectos populacionais da raia de fogo (Dasyatis marianae Gomes, Rosa & Gadig, 2000) e pesca de elasmobr?nquios no complexo recifal do Parracho de Maracaja?

Costa, Tiego Luiz de Ara?jo 09 July 2011 (has links)
Made available in DSpace on 2014-12-17T14:02:01Z (GMT). No. of bitstreams: 1 TiegoLAC_DISSERT.pdf: 2534713 bytes, checksum: 03b88ab9e5892a0fca8b5b5ff0512692 (MD5) Previous issue date: 2011-07-09 / The species Dasyatis marianae inhabits coastal areas associated with coral reefs, considered endemic to the northeast of Brazil, occurring from the State of Maranh?o to the south of Bahia. Specimens of this species are commonly sighted by divers and fishermen in the area of Maracaja? reefs, a complex reef that is part of the Environmental Protection Area of Coral Reefs (EPACR), which was developed in this study about the ecology and biology of the D. marianae, in order to characterize aspects of population structure in the area of the reef complex of Parracho de Maracaja?. We analyzed 120 specimens caught by artisanal fishing site of the size, weight, sex, stage of maturity and stomach contents. Most subjects were adult males (1.7:1) and was more abundant for rays with lengths between 25 and 29cm of LD, where females reach larger sizes, a feature common to other rays. The largest specimens were captured in the area of seagrass, which is preferred for the species. The distribution of species in the area showed an ontogenetic and sexual segregation, where the youthful occur near the beach, which is a likely area for nursery and growth of the adult females prevail in the seagrass, which apparently has a high prey availability, and Adult males are more distant, a higher proportion occurring in outlying areas, suggesting a habit more exploratory than the females. The evaluation of the reproductive system indicated 3 reproductive cycles per year, one young per pregnancy, and showed that the mature males were smaller than females. The cubs of D. marianae size at birth 12 to 15cm LD. As for diet, the species was characterized as carnivorous crustacean specialist. The performance of visual censuses in different localities allowed to evaluate the density of D. marianae in different environments of the complex. The species occurs in greater numbers in seagrass, environment very important for the conservation of the species. 100 individuals of D. marianae marked in reef complex area enrolled in a recapture rate of 3%. Some behavioral aspects were evaluated, as diurnal pattern of activity, interaction with cleaning and fish Pomacanthus paru followers as Lutjanus analis and Carangoides bartholomaei. Overall, much of the information obtained should be used for management of the species / A esp?cie Dasyatis marianae habita ?reas costeiras associadas a recifes de corais, sendo considerada end?mica para o nordeste do Brasil, ocorrendo desde o Estado do Maranh?o at? o sul da Bahia. Exemplares da esp?cie s?o comumente avistados por mergulhadores e pescadores na ?rea do Parracho de Maracaja?, um complexo recifal que faz parte da ?rea de Prote??o Ambiental dos Recifes de Corais (APARC), onde foi desenvolvido o presente estudo, acerca da ecologia e biologia da D. marianae, com a finalidade de caracterizar aspectos da estrutura populacional na ?rea do complexo recifal do Parracho de Maracaja?. Foram analisados 120 exemplares capturados pela pesca artesanal local quanto ao tamanho, peso, sexo, est?gio de matura??o e conte?do estomacal. A maioria dos indiv?duos foram machos adultos (1,7:1) e a maior abund?ncia foi para raias com tamanhos entre 25 e 29cm de LD, onde as f?meas atingem maiores os tamanhos, caracter?stica comum a outras raias. Os exemplares de maior porte foram capturados na ?rea de faner?gamas, que ? preferencial para a esp?cie. A distribui??o da esp?cie na ?rea apresentou uma segrega??o sexual e ontogen?tica, onde os juvenis ocorrem pr?ximo ? praia, que ? uma prov?vel ?rea de ber??rio e crescimento destes, as f?meas adultas prevalecem nas faner?gamas, que aparentemente tem uma elevada disponibilidade de presas, e os machos adultos se distanciam mais, ocorrendo numa maior propor??o nas ?reas mais afastadas, sugerindo um h?bito mais explorat?rio quando comparado ?s f?meas. A avalia??o do sistema reprodutivo apontou 3 ciclos reprodutivos anuais, um filhote por gesta??o e mostrou que os machos maturam com menor tamanho que as f?meas. Os filhotes de D. marianae nascem com tamanho de 12 a 15cm de LD. Quanto ? dieta, a esp?cie foi caracterizada como carn?vora carcinof?gica especialista. A realiza??o de censos visuais em diferentes localidades permitiu avaliar a densidade de D. marianae nos ambientes distintos do complexo. A esp?cie ocorre em maior n?mero nas faner?gamas, ambiente muito importante para a conserva??o da esp?cie. De 100 indiv?duos de D. marianae marcados na ?rea do complexo recifal registrou-se uma taxa de recaptura de 3%. Alguns aspectos comportamentais foram avaliados, como padr?o de atividade diurna, intera??o de limpeza com Pomacanthus paru e peixes seguidores como Lutjanus analis e Carangoides bartholomaei. De forma geral, muitas das informa??es obtidas dever?o ser usadas para o manejo adequado da esp?cie

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