Reproductive features of the swimming crab Callinectes danae(Crustacea, Portunoidea) on the subtropical coast of Brazil: a sampling outside the estuary

Abstract

The life cycle of the crab Callinectes danae is estuarine-dependent, and studies on aspects of their biology should also cover marine areas. The present study investigated the sexual maturity, as well as habitat preference by adults in different gonadal stages, and the crabs' reproductive periodicity outside the estuary. Three bays on the subtropical southeastern coast of Brazil were sampled monthly for two years. For each bay, six transects were established, four of them parallel to the beach line (5, 10, 15 and 20 m depth), as well as one transect in an exposed area, and another sheltered from the action of waves. The results showed that the pattern of spatio-temporal distribution of adults C. danae was similar in three bays, although the highest abundance was found in Ubatumirim. Females with developed gonads/ovigerous females were found in greater abundance than females with rudimentary/developing gonads, mainly in deeper transects. Although the areas sampled have different environmental characteristics, the reproductive pattern of the species did not change, showing continuous reproduction throughout, with more abundance of reproductive females on spring and summer. Males reached maturity at larger sizes than females in all three bays.Keywords: blue crab, change in habitat use, reproductive activity, sexual maturity.Características reprodutivas do siri Callinectes danae (Crustacea, Portunoidea) na região subtropical da costa do Brasil: uma amostragem fora do estuário ResumoO siri Callinectes danae é estuarino dependente em seu ciclo de vida, sendo que os estudos que levantam informações sobre os aspectos da sua biologia devem também abranger regiões marinhas. Assim, o presente estudo teve como objetivo investigar a maturidade sexual, bem como a preferência ocupacional por adultos em diferentes estágios gonadais e sua periodicidade reprodutiva fora da região estuarina. Para tanto, três enseadas da porção subtropical do litoral sudeste brasileiro foram amostradas mensalmente, durante dois anos. Para cada enseada, seis transectos foram estabelecidos, quatro deles paralelos à linha de praia (5, 10, 15 e 20m de profundidade), um transecto exposto e outro abrigado à ação de ondas. Os resultados mostraram que o padrão de distribuição espaço-temporal de adultos de C. danae foi similar nas três enseadas, embora uma maior abundância tenha sido encontrada em Ubatumirim. Fêmeas ovígeras e com gônadas desenvolvidas foram encontradas em maior abundância que fêmeas com gônadas rudimentares e em desenvolvimento, principalmente nos transectos mais profundos. Apesar das regiões amostradas possuírem características ambientais diferenciadas, o padrão reprodutivo da espécie não sofreu alterações, apresentando reprodução contínua, com maior abundância de fêmeas reprodutivas na primavera e verão. Machos atingiram maturidade em tamanhos maiores que as fêmeas nas três enseadas.Palavras-chave: siri azul, alterações na ocupação do hábitat, atividade reprodutiva, maturidade sexual.

Sexual maturity of Callinectes danae and C. ornatus from Paraguaçu river estuary, Bahia state, Brazil

“…The early sexual maturity of females is a constant in both species, since similar studies have also observed this pattern in both sexes (see Table 2 for review). This sexual dimorphism (particularly related to morphometric maturity) is part of the reproductive strategy of portunids, in which pre-and post-copulatory guards are typical and larger adult males take more advantage in protecting females, guaranteeing the paternity of the offspring (Hartnoll, 1969;Sastry, 1983;Pinheiro and Fransozo, 1998;Mantelatto and Fransozo, 1999;Baptista et al, 2003;Andrade et al, 2015). Thus, after the puberty molt, males direct greater amount of metabolic energy to somatic growth, while females invest their energy in reproductive processes, leading to early sexual maturity and longer fertile life, increasing the reproductive output of the population (Hartnoll, 1985;Avila and Branco, 1996;Baptista-Metri et al, 2005;Fernandes et al, 2006;Keunecke et al, 2008).…”

“…Keunecke et al (2012) also found percentages of immature C. danae (16.2%) and C. ornatus (85.6%) females captured by trawling pink shrimp. Populations of overfished portunids can have their asymptotic size reduced and, consequently, the size of maturity can also decrease, reducing the fertility and reproductive output of the population (Keunecke et al, 2012;Andrade et al, 2015). Based on this assumption, the mesh of traps used in the swimming crab fishing at São Francisco do Paraguaçu and other fishing areas of the Todos os Santos Bay should be adjusted to prevent immature animals from being captured.…”

Do the day/night periods and tidal cycles modulate the abundance and distribution of Callinectes danae Smith, 1869 (Brachyura, Portunidae) in an estuary-bay complex from southeastern Brazil?

“…Adults and ovigerous females of C. danae migrate to deeper areas with favorable salinity and current conditions that provide the needed embryonic and larval development and dispersion, similarly observed in C. ornatus (see Mantelatto, 2000). Furthermore, the characteristics of each ecosystem determine how the species migrates between different habitats within its range (Keunecke et al, 2009;Andrade et al, 2015).…”

REPRODUCTIVE ASPECTS OF THE PRAWN <i>Macrobrachium amazonicum</i> IN A CONTINENTAL POPULATION LIVING DOWNSTREAM OF A HYDROELECTRIC DAM

“…The knowledge of a species' reproductive biology is extremely important for the understanding of its life cycle. It also helps planning a more sustainable use of resources so that they can be a source of income for local communities without harming the populations (Andrade et al, 2015). In this way, aiming to support the economic and social development as well as the environmental protection of the region ("Triângulo Mineiro"), we investigated the reproductive cycle of M. amazonicum, focusing on the spatio-temporal abundance of breeding females.…”