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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

Din?mica populacional e alimentar de Stegastes fuscus, (Osteichthyes:pomacentridae) em arrecifes da praia de B?zius, no Rio Grande do Norte

Canan, Bhaskara 14 December 2007 (has links)
Made available in DSpace on 2014-12-17T15:36:31Z (GMT). No. of bitstreams: 1 BhaskaraC.pdf: 2061435 bytes, checksum: 1ff82521fda22176fb2e79fff7117ece (MD5) Previous issue date: 2007-12-14 / The damselfish, Stegastes fuscus Cuvier, 1830 (Osteichthyes: Perciformes: Pomacentridae), is abundant in the coastal reefs of B?zios Beach, Rio Grande do Norte, Brazil and they play an important role in the reef community ecology. The present study investigated the feeding strategy of this species considering the food habits and morfo-histology of the digestive tract. Influence of the environmental correlates such as temperature, rainfall and luminosity in the tidal rock pools were studied. The fish were captured on a monthly basis from September 2004 to August 2005, during which period 842 individuals of S. fuscus were captured, 125 males, 437 females and 280 individuals without sex identification. The sex ratio observed was 1 M : 3,5 F. The total body length of males varied from 3.6 to 11.3 cm, with a mean of 7.77 cm; that of females varied from 2.9 to 11.4 cm, with a mean of 7.85 cm, and that of sex grouped individuals varied from 2.9 to 11.4 cm, with a mean of 7.83. However, there was no difference between males and females in total body length. This species presented a positive alometric growth and the equations obtained for the relation between body mass and total body length were: Wt =0,0174Lt 3,1123 for males; Wt =0,0137Lt 3,2294 for females and Wt = 0,0148Lt 3.1928 for sex grouped individuals. The relation between total body length and standard length was L t = 1 ,3223Ls + 0,1527 for sex grouped individual s. February to August was associated to a long period of gonadal resting. The fish spawned during January and in September -October. The frequency of fish with empty stomachs occurred during August to December, whereas frequency of fish with food contents i n stomachs occurred during January to July. This species is considered as a preferential herbivore based on the volume of macroalgae in its diet composition. The morfo -histological aspects of S. fuscus confirm herbivory. Among the environmental factors con sidered only rainfall showed a correlation with the feeding habits of this species / O peixe-donzela, Stegastes fuscus Cuvier, 1830 (Osteichthyes: Perciformes: Pomacentridae), ? abundante nos arrecifes costeiros da praia de B?zios, Rio Grande do Norte e desempenha um important e papel ecol?gico em comunidades recifais. O presente estudo investigou a din?mica populacional e alimentar desta esp?cie levando em considera??o o regime alimentar e a morfo -histologia do trato digest?rio. Avaliou - se a influ?ncia das vari?veis ambientais, tais como, temperatura, pluviosidade e luminosidade em po?as de mar?. Foram realizadas coletas mensais no per?odo de setembro de 2004 a agosto de 2005, durante as quais foram capturados 842 indiv?duos de S. fuscus, sendo 125 machos, 437 f?meas al?m de 280 indiv?duos com sexo n?o identificado. A propor??o sexual observada foi de 1 M : 3,5 F. Em rela??o ao comprimento total os valores para machos machos variaram de 3,6 a 11,3 cm, com m?dia de 7,77 cm; para as f?meas de 2,9 a 11,4 cm, com m?dia de 7,85 cm e p ara os sexos agrupados de 2,9 a 11,4 cm, com m?dia de 7,83 cm, n?o havendo diferen?as entre os sexos quanto ao comprimento total. A esp?cie estudada apresentou um crescimento do tipo alom?trico positivo e as equa??es obtidas para a rela??o entre peso total e comprimento total foram: Wt = 0,0174Lt 3,1123 para machos; Wt =0,0137Lt 3,2294 para f?meas e Wt = 0,0148Lt 3,1928 para os sexos agrupados. A rela??o entre o comprimento total e o comprimento padr?o foi L t = 1,3223Ls + 0,1527 para os sexos agrupados. Nesses peixes foi observado um per?odo de repouso gonadal que se prolongou de fevereiro a agosto com a desova sendo realizada em janeiro e em setembro e outubro. Em rela??o ao regime alimentar, as maiores freq??ncias de est?magos sem alimento ocorreram entre os meses de agosto a dezembro enquanto que as maiores freq??ncias de est?magos com alimento ocorreram nos meses de janeiro a julho. Em fun??o do volume de macroalgas em sua composi??o de dieta, a esp?cie Stegastes fuscus ? considerada como preferencialmente herb?vora e os aspectos morfo-histol?gicos confirmam essa prefer?ncia. Dentre os fatores abi?ticos considerados por ocasi?o do estudo utilizando Stegastes fuscus, apenas a pluviosidade influenciou significativamente no regime alimentar desta esp?cie

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