Características populacionais de Microphrys bicornutus (Brachyura, Mithracidae) no fital Halimeda opuntia (Chlorophyta, Halimedaceae), em área recifal submetida à visitação humana, em João Pessoa, Paraíba

Abstract

ABSTRACT. Population characteristics of Microphrys bicornutus (Brachyura, Mithracidae) on the phytal Halimeda opuntia (Chlorophyta, Halimedaceae), on reef area submitted to human visitation, in João Pessoa, Paraíba, Brazil. The aim of this study was to characterize and compare the population structure and dynamic of Microphrys bicornutus Latreille, 1825 on the phytal Halimeda opuntia (Halimedaceae) collected on the reef areas of Picãozinho (visited by tourists) and São Gonçalo (control area), in João Pessoa coast (Northeastern of Brazil), under the influence of environmental conditions and visitant numbers. In both study areas the populations analyzed were composed similarly of mature and immature males and females, with predominance of males and immature animals, and similar size frequency and reproductive period. Sex-ratio, size frequency distribution, and size of the biggest specimens differed from those estimated in others latitudes and habitats for this species. Sex ratio estimation has made evident that independently of maturation stage, males tended to predominate significantly and the proportion of females to decrease with sexual maturation. Without exhibiting influence of the alga biomass, and of the salinity and temperature of the water, significant population variations were associated to the increase of juvenile during rainy periods. The low population density and the largest disproportion of the relationship male: female in Picãozinho subarea with larger flow of people, are suggestive that the trampling of the alga might have induced this population variation. KEYWORDS.Population composition, population density, sex ratio, algae trampling, seasonal effect. RESUMO. Este trabalho teve como objetivos caracterizar e comparar a estrutura e a dinâmica populacional de Microphrys bicornutusLatreille, 1825 no fital Halimeda opuntia (Halimedaceae) coletado nas formações recifais de Picãozinho (submetida à visitação turística) e São Gonçalo (área controle), na costa de João Pessoa (Nordeste do Brasil), sob influência de fatores ambientais e do número de visitantes. Nas duas áreas de estudo as populações analisadas estiveram compostas por fêmeas e machos maduros e imaturos com significativa predominância de machos e de animais imaturos, freqüência de tamanho e períodos reprodutivos similares. O tamanho máximo dos exemplares, a freqüência de distribuição de tamanho e a razão sexual diferiram dos resultados obtidos para a espécie em outras latitudes e habitats. Dados de razão sexual evidenciam que independentemente do estágio de maturação, os machos apresentam predominância significativa (RS>1,0), e que a proporção de fêmeas diminui com o amadurecimento sexual. Sem sofrer influência da biomassa da alga, e da salinidade e temperatura da água, variações populacionais significativas foram associadas ao aumento de juvenis durante períodos chuvosos. A baixa densidade populacional e a maior desproporção da relação macho: fêmea em subárea de Picãozinho com maior fluxo de pessoas sugerem que estas variações podem ter sid...

The response of meiofauna to human trampling on coral reefs

“…In this study, Casu et al (2006a) did not find differences among the abundances of taxa collected during the summer at the visited station (Cala Sabina) and the taxa sampled at the control stations (Cala Arena and Cala Sant'Andrea). Similarly, Batista et al (2009), who compared the population structure of Microphrys bicornutus (Brachyura, Mithracidae) in the Halimeda opuntia (Halimedaceae) phytal in two reef areas in northeastern Brazil, Picãozinho (visited by tourists) and São Gonçalo (control area), did not find differences in algal biomass or the crustacean population parameters between the reefs. In contrast to these studies, at the Purbeck Marine Wildlife Reserve within the boundary of the Dorset and East Devon World Heritage Site on the south coast of the UK, Pinn and Rodgers (2005) investigated the influence of visitors on the intertidal biodiversity of macrobenthos at Kimmeridge Bay.…”

Population dynamics and reproductive aspects of the decorator crab Microphrys bicornutus (Crustacea: Brachyura: Majidae) in an extreme shallow Thalassia complex

“…Also, reproductive output (expressed in number of eggs/female) and egg size, provide indicators for population dynamics, considering the production of new offsprings per year (Hernández-Reyes et al , 2001; Lardies & Castilla, 2001; Carmona-Suárez, 2003). Moreover, population structure will indicate how stable (or not) the species is in its habitat (Carmona-Suárez, 1992; Litulo, 2005; Batista et al , 2009).…”

“…The tropical decorator crab Microphrys bicornutus (Latreille, 1825) lives in a great diversity of habitats, and is commonly found in coral reefs (Williams, 1984), but it is also a frequent inhabitant in Thalassia meadows (Heck, 1977; Holmquist et al , 1989; Carmona-Suárez & Conde, 1996; Carmona-Suárez, 2007), as well as in phytals of Halimeda opuntia (Linnaeus) (Batista et al , 2009) . This decorator crab has also been reported living on Rhizophora mangle (L.) roots (Reyes & Campos, 1992; López-Greco et al , 2000), inside sponges (Pearse, 1950), and in nests of the fish Malacanthus plumieri (Bloch, 1787) (Gutiérrez-Salcedo et al , 2007).…”

“…Although there is a large body of literature concerning its geographical occurrence (Lemaitre, 1981; Williams, 1984; Carmona-Suárez & Conde, 1996; Marcano & Bolaños, 2001; Castaño & Campos, 2003), little has been written about its ecology. Hartnoll (1965) mentions some aspects on relative growth and reproduction, while several authors (López-Greco et al , 2000; Carmona-Suárez, 2007; Batista et al , 2009) deal with several population characteristics of this decorator crab in different habitats and geographical regions (mangroves and seagrass in Venezuela, and macroalgae in Brazil). Specifically in Buchuaco—Venezuela, Carmona-Suárez (2007) determined that ovigerous females were present throughout the year, excepting during the first months, where the lowest water temperatures were present.…”

Análise dos estudos de capacidade de carga turística para os recifes de Picãozinho, Seixas (João Pessoa-PB) e Areia Vermelha (Cabedelo-PB)

“…Os recifes de Picãozinho (07°06'15"S, 34°48'45"W), Seixas (07°09'08"S, 34°47'14"W) e o Parque Estadual Marinho de Areia Vermelha (07°00'41,95"S, 034°48'58,02"O) constituem formações recifais que, durante o período da maré baixa, exibem piscinas naturais contendo uma diversidade de organismos marinhos (MELO, 2006;BATISTA et al, 2009;LOURENÇO, 2010 Picãozinho (Figuras 1 e 2) localiza-se a cerca de 1.500 m da costa da praia de Tambaú em João Pessoa, Paraíba, e a realização de atividade turística sem o adequado planejamento ambiental e turístico acontece desde os últimos 15 anos (ILARRI et al, 2008;AMORIM;SASSI, 2009). O translado até a formação recifal dura em torno de 15 minutos com catamarãs bares que comportam em média de 40 a 100 usuários em busca de atividades de mergulho, e de fotografar a beleza natural .…”