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Previous issue date: 2006-04-26 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Mangrove areas and bays are ecosystems that play an important ecological role by
suppling vias to energy importation and exportation (migrations, predation, fisheries,
etc.). The present work aims to identify variations in juveniles fish assemblages in
beaches and mangrove areas to test the hypothesis that structural differences which
characterize these two systems results in differences in fish assemblages. Fish samples
in sandy beaches of two bays and a mangrove area in southwestern Rio de Janeiro State
were taken by bi-montlhy sampling performed during the day in the bays and by
monthly sampling during the day and the night in the mangrove, from August 2002 to
July 2003. Standartized trawls were carried out perpendicular to the coastline at depth
lower than 1.5 m, in an extension of approximately 30 meters. Sampling were
performed by using a beach seine (10 m x 2,5 m, mesh 7 mm). Environmental variables
of depth, transparency (except during the night), temperature, salinity, dissolved oxygen
and conductivity, besides composed sediment samples were taken at each site. Sample
unit were the total number of fishes caught by a trawl, with three replicates in each site.
Most of fishes were young-of-the-year and immature juveniles. Ninety eight species
were recorded by the pooled sampling programme, including 5 sites in the mangrove
and 14 beaches in the bays, being 7 in the Sepetiba bay and 7 in Ilha Grande bay. A
total of 46,444 individuals were caught, amounting to 66,206.76 grams, and comprising
38 families and 13 orders. The families Carangidae, Engraulidae, Gobiidae, Gerreidae,
Sciaenidae, Mugilidae, Paralichthyidae and Tetraodontidae showed, in decreasing order,
the most richeness in the Sepetiba bay, while the most diverse families in Ilha Grande
Bay were Carangidae, Engraulidae, Gerreidae, Haemulidae and Sciaenidae. In the
Guaratiba mangrove the most diverse families were Carangidade, Serranidae, Gobiidae,
Sciaenidae, Tetraodontidae, Engraulidae, Gerreidae, Mugilidae and Paralichthyidae.
Eleven species showed the frequency of occurrence higher than 10 % in the both bays:
Atherinella brasiliensis, Oligoplites saurus, Eucinostomus argenteus, Trachinotus
carolinus, Strongylura timucu, Anchoa tricolor, Trachinotus falcatus, Mugil liza,
Hyporhamphus unifasciatus, Anchoa januaria and Diapterus rhombeus. In the
Guaratiba mangrove 14 species showed frequency of occurrence higher than 10%:
Atherinella brasiliensis, Eucinostomus argenteus, Gobionellus boleosoma,
Eucinostomus melanopterus, Mugil liza, Sphoeroides testudineus, Diapterus rhombeus,
Harengula clupeola, Anchoa januaria, Mugil curema, Synodus foetens, Citharichthys
arenaceus and C. spilopterus. From a total of 98 recorded species, 87 (360 samples)
were from the mangrove area and 72 (252 samples) from the two bays, being 62 (126
samples) from Sepetiba bay and 42 (126 samples) from Ilha Grande bay. 27 species
occurred in both systems (mangrove and bays), and 31 were commom to the two bays.
The highest specific richness in the mangrove corroborate the expectation that the most
structured system influence in richness compared with the less structured sandy
beaches.The higher richness in the Sepetiba bay, compared with Ilha Grande bay, which
showed similar top abundant species, coincided with differences in hydrographic
variables (higher temperature, condutivity, dissolved oxygen and transparency in Ilha
Grande bay) and sediment nutrient (higher % of organic matter, Carbon, Nitrogen and
Potassium In the Sepetiba bay) with the sediment texture not differing between the two
bays. Overall, assemblages did no differ between sites in the bays, confirming the hypothesis of bay dependence and the refutation of habitat dependence, although it was
only partially confirmed for the Sepetiba bay. This same hypothesis of system
dependence instead the area dependence was confirmed for the mangrove. / ?reas de mangues e ba?as s?o ecossistemas que apresentam um importante papel
ecol?gico, por fornecer vias para importa??o e exporta??o de energia (migra??es,
preda??o, pesca, etc). O presente trabalho teve como objetivo identificar varia??es nas
assembl?ias de peixes jovens em sistemas de praias e de mangue, visando testar
hip?tese de que as diferen?as estruturais que caracterizam os dois ambientes ocasionam
diferen?as nas assembl?ias de peixes. Amostragens de peixes em praias arenosas de
duas ba?as e em uma ?rea de mangue no sudoeste do estado do Rio de Janeiro foram
realizadas atrav?s de coletas bimestrais diurnas nas ba?as, e mensais diurnas e noturnas
no manguezal, durante o per?odo de agosto de 2002 a julho de 2003. Os arrastos de
praia foram padronizados, sendo realizados perpendicular ? linha de costa, a uma
profundidade inferior a 1,5 metros, com extens?o de aproximadamente 30 metros. As
coletas foram realizadas com aux?lio de uma rede do tipo picar? (10 m x 2,5 m, malha
de 7 mm). Em cada amostragem, foram feitos medi??es da profundidade, transpar?ncia
(exceto no per?odo noturno), temperatura, salinidade, oxig?nio dissolvido e
condutividade, al?m da coleta de sedimento em cada ponto amostral. A maioria dos
indiv?duos capturados foram juvenis do ano e jovens imaturos. Noventa e oito esp?cies
de peixes foram capturadas ao longo de todo programa amostral, incluindo os cinco
locais de coleta do manguezal de Guaratiba e as 14 praias arenosas, sendo 7 da ba?a de
Sepetiba e e 7 da ba?a de Ilha Grande. Ao todo, foram capturados 46.444 indiv?duos,
pesando 66.206,76 gramas, e compreendendo 38 fam?lias e 13 ordens. As fam?lias
Carangidae, Engraulidae, Gobiidae, Gerreidae, Sciaenidae, Mugilidae, Paralichthyidae e
Tetraodontidae apresentaram, nesta ordem, as maiores riquezas na ba?a de Sepetiba,
enquanto que na ba?a da Ilha Grande foram Carangidae, Engraulidae, Gerreidae,
Haemulidae e Sciaenidae. No manguezal de Guaratiba as fam?lias com maior riqueza
foram Carangidade, Serranidae, Gobiidae, Sciaenidae, Tetraodontidae, Engraulidae,
Gerreidae, Mugilidae e Paralichthyidae. Onze esp?cies apresentaram freq??ncia de
ocorr?ncia superior a 10 % nas duas ba?as: Atherinella brasiliensis, Oligoplites saurus,
Eucinostomus argenteus, Trachinotus carolinus, Strongylura timucu, Anchoa tricolor,
Trachinotus falcatus, Mugil liza, Hyporhamphus unifasciatus, Anchoa januaria e
Diapterus rhombeus. No manguezal de Guaratiba 14 esp?cies apresentaram freq??ncia
de ocorr?ncia superior a 10%: Atherinella brasiliensis, Eucinostomus argenteus,
Gobionellus boleosoma, Eucinostomus melanopterus, Mugil liza, Sphoeroides
testudineus, Diapterus rhombeus, Harengula clupeola, Anchoa januaria, Mugil curema,
Synodus foetens, Citharichthys arenaceus e C. spilopterus. Das 98 esp?cies registradas,
87 (360 amostas) foram do Mangue e 72 (252 amostras) das duas ba?as, sendo 62 (126
amostras) na Ba?a de Sepetiba e 42 (126 amostras) da ba?a da Ilha Grande, com 27
esp?cies ocorrendo em ambos os ambientes (Mangue e ba?as) e 31 foram comuns ?s
duas ba?as. A maior riqueza especifica no manguezal corrobora a expectativa da
influ?ncia da maior estrutura??o deste ambiente em rela??o ?s praias arenosas. As
maiores riquezas da ba?a de Sepetiba, comparada com a ba?a da Ilha Grande, que
apresentaram as mesmas esp?cies mais numerosas, coincidiram com diferen?as nas
vari?veis hidrogr?ficas (maiores temperatura, condutividade, oxig?nio dissolvido e
transpar?ncia na ba?a da Ilha Grande) e em nutriente do sedimento (maiores % de mat?ria org?nica, Carbono, Nitrog?nio e Pot?ssio na ba?a de Sepetiba) com a textura do
sedimento n?o diferindo entre as duas ba?as. Em geral as assembl?ias n?o diferiram
dentre os locais das ba?as, confirmando a hip?tese de depend?ncia da ba?a e a refuta??o
da depend?ncia do habitat, embora isto tenha sido somente parcialmente confirmado
para a ba?a de Sepetiba. Esta mesma hip?tese de depend?ncia do sistema ao inv?s de
depend?ncia do habitat tamb?m foi confirmada para a ?rea de mangue.
| Identifer | oai:union.ndltd.org:IBICT/oai:localhost:tede/598 |
| Date | 26 April 2006 |
| Creators | Costa, Marcus Rodrigues da |
| Contributors | Ara?jo, Francisco Gerson |
| Publisher | Universidade Federal Rural do Rio de Janeiro, Programa de P?s-Gradua??o em Biologia Animal, UFRRJ, Brasil, Recursos Pesqueiros Marinhos |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UFRRJ, instname:Universidade Federal Rural do Rio de Janeiro, instacron:UFRRJ |
| Rights | info:eu-repo/semantics/openAccess |
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