Reproductive cycle of Macrobrachium amazonicum females (Crustacea, Palaemonidae)

Abstract

Macrobrachium amazonicum is considered a favorite Brazilian species of freshwater prawn for cultivation as a result of its quick development and because it is easy to maintain in captivity. The aim of this work is to describe the sexual cycle stages and determine maturation age of the female M. amazonicum, which was collected monthly from June, 2002 to May, 2003 in the Jaguaribe River, Itaiçaba, Ceará. A monthly sample of water was also collected to determine the following parameters: temperature, dissolved oxygen, pH and salinity. A monthly sample of females was selected among the individuals caught, to determine the total weight (W T ), carapace length (L C ) and abdomen+telson length (L A+T ) and to register the number of non-ovigerous females (NOF) and ovigerous females (OF). Determining ovarian maturation stages of M. amazonicum was done in a laboratory by observing macroscopic characters such as coloring, size, location and appearance of ovarians examined by transparent carapace. The first maturation age was determined from the relative frequency of the total length (L T ) of young and adult females. The environmental parameters of the Jaguaribe River did not hold any influence in the number of individuals collected. A total of 1,337 prawns were sampled, 513 males (38.4%) and 824 females (61.6%). The proportion between males and females in the studied population was of 1:1.6. Among the collected females, 492 (50.7%) did not carry eggs in their abdomens (NOF) and 332 (40.3%) carried eggs in their abdomens (OF). There was no record of intact females. Non-ovigerous females with mature ovaries were recorded throughout all the months of collection. The female ovaries were classified as immature (IM), rudimentary (RU), intermediary (IN) and mature (M). M. amazonicum females reach their first sexual maturity between 4.5 and 5.5 cm of total length.Keywords: reproduction, reproductive cycle, Macrobrachium amazonicum. Ciclo reprodutivo de fêmeas de Macrobrachium amazonicum (Crustacea, Palaemonidae) ResumoDas espécies de camarão de água doce brasileiras, Macrobrachium amazonicum é a preferida para cultivo, devido ao seu rápido desenvolvimento e fácil manutenção em cativeiro. Este trabalho teve como objetivos caracterizar as fases do ciclo sexual e determinar a idade da primeira maturação de fêmeas de M. amazonicum, coletadas mensalmente, de junho de 2002 a maio de 2003, no Rio Jaguaribe, Itaiçaba, Ceará. Uma amostra de água do local foi coletada mensalmente para determinação dos seguintes parâmetros: temperatura, oxigênio dissolvido, pH e salinidade. Do total de indivíduos capturados mensalmente, uma amostra de fêmeas foi selecionada para determinação do peso total (W T ), do comprimento do cefalotórax (L C ) e do abdômen+telson (L A+T ), e para registro de fêmeas não ovígeras (FNO) e ovígeras (FO). A determinação macroscópica dos estágios de maturação ovariana de M. amazonicum foi realizada pela observação da coloração, do tamanho, da posição e da aparência dos ovários observados por transparência da carapa...

Population structure and relative growth of the Amazon shrimp Macrobrachium amazonicum (Heller, 1862) (Decapoda: Palaemonidae) on two islands in the fluvial-estuarine plain of the Brazilian Amazon

“…Overall sex-ratio of M. amazonicum that did not differ significantly from the expected 1:1 was also verified by Flexa et al (2005), Sampaio et al (2007) and Silva et al (2007). The ovigerous females of M. amazonicum were found throughout the year; indicating continuous reproduction, as also observed by Odinetz-Collart (1991) in the lower Amazon region, Peixoto (2002), Lucena-Frédou et al (2010) and Freire et al (2012).…”

“…This pattern diverges from several studies that reported a peak in reproduction only in the rainiest seasons in different regions of Brazil, as well as in other Amazon regions (Odinetz-Collart, 1991), Northeast (Bragagnoli and Grotta, 1995;Sampaio et al, 2007), Midwest (Porto, 1998) and South (Bialetzki et al, 1997). Several environmental factors contribute to reproduction of estuarine shrimp, such as temperature, sediment, salinity and rainfall (Pinheiro and Hebling, 1998).…”

Populational and reproductive aspects of Southern <i>Macrobrachium acanthurus</i> (Wiegmann, 1836) (Crustacea: Palaemonidae), Brazil

“…Continuous reproduction pattern was also observed by other congener species in the Brazilian territory: Sampaio et al (2007) iheringi. There is certainly a variety of proximate and ultimate factors, e.g., water quality, water temperature, rainfall or water flow, availability of larval food, which may influence the reproductive period.…”

Genetic polymorphism, molecular characterization and relatedness of Macrobrachium species (Palaemonidae) based on RAPD-PCR

“…According to the characteristics shown by these bands, they may be considered good markers able to diagnose Mj and Ma, syntopic species that show taxonomic identification difficulties based only on morphological characteristics, due to the high level of morpho-logical similarity between these two species. Furthermore, according to studies conducted by Taddei et al (2006) and Sampaio et al (2007), there is ample diversity in size among the individuals of the same population and also among different populations, depending on environmental variations, which can hinder their identification even more.…”