Made available in DSpace on 2014-12-17T14:02:02Z (GMT). No. of bitstreams: 1 LilianeLGS.pdf: 3221431 bytes, checksum: 94de7bf42be19a1c9a513aa1e36efe19 (MD5) Previous issue date: 2006-07-10 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The reproductive ecology of fish plays a key role both for rational exploitation methods and for protective measures of natural stocks. The purpose of this study was to analyze the reproductive aspects of the damsel-fish, Stegastes fuscus, during October 2004 to September 2005, in the coastal rocky reefs of B?zios Beach, N?sia Floresta, RN. Fish were captured using hooks and hand nets, during low tide. Reproduction was determined using sexual ratio, mean length of first maturation (L50), absolute fecundity and macroscopic characteristics of gonads. The following parameters were related to gonadosomatic index (GSI): condition factor (CF), hepatosomatic index (HSI), rain fall and temperature. In relation to sex distribution, it was observed that 78% were females and 22% were males. The L50 was 6.2 cm for females and 7.0 for males. Average fecundity was 6832 oocytes. Results showed that S. fuscus had better body condition in the months prior to spawning, particularly during initial and intermediate stages of maturation. Five stages of gonadal maturation were identified through macroscopic analysis: immature, in maturation, mature, spent and resting. The HSI was inversely related to the GSI. This was possibly due to the reproductive cycle of this species which was associated to the dry period of this region. During this period, low rain fall and high temperatures provide an propitious reproductive condition for the study species / A ecologia reprodutiva dos peixes ? fundamental na racionaliza??o dos m?todos de explora??o e na prote??o dos estoques naturais. O presente estudo analisou aspectos relacionados ? reprodu??o do peixe-donzela, Stegastes fuscus, durante o per?odo de outubro de 2004 a setembro de 2005, nos arrecifes rochosos da praia de B?zios, N?sia Floresta, RN. Os peixes foram capturados durante a mar? baixa utilizando anz?is e rede de m?o. A reprodu??o foi verificada mediante a propor??o sexual, o comprimento m?dio da primeira matura??o, a fecundidade absoluta e os caracteres macrosc?picos gonadais. Os seguintes par?metros foram relacionados ao ?ndice gonadossom?tico (IGS): fator de condi??o (FC), ?ndice hepatossom?tico (IHS), pluviosidade e temperatura. Em rela??o ? distribui??o por sexo de S. fuscus, 78% foram f?meas e 22% foram machos. O L50 foi 6,2 cm para as f?meas e 7,0 cm para os machos. A m?dia da fecundidade absoluta foi 6832 ov?citos. S. fuscus apresentou melhores condi??es corporais nos meses que antecederam a desova, principalmente nos est?dios inicial e intermedi?rio de matura??o gonadal. A partir de an?lises macrosc?picas das g?nadas, foram identificados cinco est?dios de matura??o gonadal: imaturo, em matura??o, matura??o, esgotado e repouso. O IHS demonstrou tend?ncia inversa ao IGS. Este fato pode estar relacionado ao ciclo reprodutivo da esp?cie, que foi relacionado ao per?odo de seca na regi?o. Neste per?odo, as menores precipita??es e as temperaturas elevadas conferem condi??es reprodutivas favor?veis para a esp?cie em estudo

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

Submitted by Rafael Santana (rafael.silvasantana@ufpe.br) on 2017-07-14T18:46:22Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Dissertação_Walter DM Oliveira_ Oceanografia_UFPE.pdf: 1745886 bytes, checksum: 62870c6bfbb9848afc84e4fb94eff45e (MD5) / Made available in DSpace on 2017-07-14T18:46:22Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Dissertação_Walter DM Oliveira_ Oceanografia_UFPE.pdf: 1745886 bytes, checksum: 62870c6bfbb9848afc84e4fb94eff45e (MD5) Previous issue date: 2016-05-31 / Os recifes costeiros são comumente afetados por ações antrópicas que vão desde o turismo contemplativo a poluição por efluentes domésticos. Essas formações recifais abrigam muitas espécies de peixe que em busca de abrigo para diferentes fazes do ciclo de vida e alimento. Nesses sentido as cristas recifais formam um importante papel para o desenvolvimento desses organismos, sem comumente um local de berçário natural. A cobertura de substrato é um outro fator importante para essas espécies pois pode gerar proteção, alimentação direta a indireta com invertebrados epifíticos. As cristas recifais do litoral sul de Pernambuco são dominadas por cobertura algal. Os recifes locais são importantes como fonte de renda para as comunidades locais e para conservação dos ambientes marinhos costeiros. Foram analisadas as relações entre a ictiofauna e a categorias de algas nas cristas recifais de Porto de Galinhas, Serrambi e São José da Coroa Grande, tendo sido amostrados três piscinas em cada praia. Para isso foram feitas amostragens com transecto de faixa de 20x2 m² em cada piscina, com registros fotográficos da cobertura de substrato, essas fotos foram posteriormente analisadas para estimar o percentual de cada categoria representada na cobertura do substrato da crista recifal. Os dados mostraram que Stegastes fuscus, Abudefduf saxatilis, Sparisoma axillare, Halichoeres poeyi e Ophioblennius trinitatis foram as espécies mais representativas nas cristas recifais analisadas. As algas calcárias articuladas e turf foram as algas mais abundantes nessas formações. As algas folhosas foram pouco abundantes, sendo mais representadas em São José da Coroa Grande. A maioria da abundância de peixes representou a categoria trófica de herbívoros errante e a mais rica foi comedores de invertebrados móveis. St. fuscus e O. trinitatis foram registrados em todas as classes de tamanho, enquanto A. saxatilis, Sp. axillare,e H. poeyi foram observados em fases juvenis. A relação verificada entre a comunidade de peixes, a cobertura de substrato e as características estruturais foi baixa visto que a distribuição de peixes foi homogênea e houve pouca variação nas categorias de algas. / The reef crests form an important habitat for fish of different habits and life stages. Coastal reefs are commonly affected by human activities ranging from the contemplative tourism to the pollution from domestic sewage. The substrate coverage can indicate the distribution of fish species that use this place to establish throughout the life cycle or in transitional phases. The reef crests of the southern coast of Pernambuco are dominated by algal cover. Local reefs are important as source of income for local communities and for conservation of coastal marine environments. The relationship between fish community and categories of algae on the reef crests of Porto de Galinhas, Serrambi and São José da Coroa Grande were analyzed. Three points were sampled at each beach. For the sampling of fish were made four transects of 20x2 m in each pool. At the same time were made photos of substrate coverage, these photos were then analyzed to estimate the percentage of each category. The data showed that Stegastes fuscus, Abudefduf saxatilis, Sparisoma axillare, Halichoeres poeyi and Ophioblennius trinitatis were the most significant species in the reef crests analyzed. The jointed calcareous macroalgae and turf were the most abundant in these formations. The sheet-like algaes were less abundant and more represented in São José da Coroa Grande. Most of the abundance of fish represented the trophic category herbivores and the richest was eaters of mobile invertebrates. St. fuscus and O. trinitatis were recorded in all size classes, while A. saxatilis, Sp. Axillare, and H. poeyi were observed in juvenile stages. The relationship between the fish community and substrate coverage and structural characteristics was low as the fish distribution is homogeneous and there was little variation in types of substrate coverage.

Caribbean reef ecosystems have undergone major ecological changes in the last 30 – 40 years, with the result that ecological systems once dominated by structurally complex Acropora cervicornis and Montastraea annularis corals now consist mainly of flattened carbonate substrates with macroalgal overgrowth. A need for greater understanding of coral reef ecosystems is imperative if we are to attempt to conserve them. The threespot damselfish, Stegastes planifrons, is herbivorous damselfish species ubiquitous to Caribbean reefs, where it has been termed a keystone species. Aggressive in nature, S. planifrons defends territories of around 70 cm in diameter from other roving herbivorous fish and urchins, in apparent effort to maintain the algal resources therein for its own use. The predilection of Stegastes planifrons for basing its territories on the now Critically Endangered staghorn coral, Acropora cervicornis, and the Endangered boulder coral Montastraea annularis is well known, however the likely ecological implications of this fact have not been investigated. Using a combination of experimental and observational methodologies we examine the ecological implications of coral microhabitat choice and use by S. planifrons. We also assess the magnitude of the direct and indirect effects of S. planifrons’ territorial behaviour on macroalgal dynamics both within and outside of territory confines, at the reef-wide level. We find that coral microhabitat is a more important determinant of algal community structure than damselfish presence, and that this can be explained by a previously unrecognised effect of coral microhabitat on the grazing behaviour of roving herbivorous fishes - on which S. planifrons’ territorial behaviour has little effect. In a modification of the space availability hypothesis of Williams et al (2001) we suggest that Acropora cervicornis acts as a grazing fish „exclusion zone‟, and we further hypothesise that the existence of large stands of this coral prior to the Caribbean „phase shift‟ may have acted to concentrate the grazing pressure of excluded roving fish onto the remaining areas of the reef. We further hypothesise that the loss of such „exclusion zones‟ and accompanied effective dilution of grazing pressure may have been on a scale large enough to have been a significant underlying factor in the proliferation of macroalgae seen on modern day Caribbean reefs. In the absence of demonstrable direct or indirect effects on benthic algal communities we question the continued keystone status of S. planifrons, particularly since the status 6 was originally based on interference behaviour involving the important grazing urchin Diadema antillarum, which is now functionally absent from Caribbean reefs. Implications of the context-dependant nature of keystone status are also discussed. We find that the effect of S. planifrons on coral community may be more important than its effects on benthic algal community. In examining the factors involved in habitat coral choice we establish a significant preference for 100% live coral substrate over substrates with a supply of algal food. Territory selection was followed by a high rate of coral biting – a behaviour which has previously been shown to result in coral tissue death and the fast establishment of algal turf communities on which S. planifrons likes to feed (Kaufman 1977). We also demonstrate a novel and significant association between S. planifrons presence and disease incidence its primary habitat coral, the Critically Endangered staghorn coral Acropora cervicornis, and a significant correlation between areas of fish biting and the later onset of disease. Changes to the overall role of damselfish on today's Caribbean reefs are discussed in light of these insights.