Relative growth and sexual maturity of the freshwater shrimp Palaemon pandaliformis (Crustacea, Palaemonidae) in northeastern of Brazil (Canavieiras, Bahia)

Abstract

ABSTRACT. This study comprises the description of relative growth and sexual maturity of a population of Palaemon pandaliformis Stimpson, 1871 in Salsa River (Northeastern Brazil). Samples were collected monthly between September 2009 and August 2010. Females were larger, heavier, and showed a greater allometric coefficient (b) than male specimens. Only carapace length vs. pleura length in females presented a significant difference in the relative growth pattern, indicating a puberty moult. This relationship is strictly correlated to reproduction and its success rate in female shrimps. Estimated carapace length in 50% of mature females (CL 50 ) was 4.53 mm. It was not possible to compare obtained CL 50 results due to a lack of studies on this species. Comparison was based on the size of the smallest captured ovigerous female (3.81 CL mm), which is within the scope of recorded size for estuaries located in higher latitudes. This study reveals the lack of research on this genre in freshwater environments on a national and global scale. KEYWORDS.Caridea, allometric growth, morphometric relationships. RESUMO.Crescimento relativo e maturidade sexual de Palaemon pandaliformis (Crustacea, Palaemonidae) no Nordeste do Brasil (Canavieiras, Bahia). Foram descritos o crescimento relativo e a maturidade sexual de uma população de Palaemon pandaliformis Stimpson, 1871 do rio Salsa (Nordeste do Brasil). As coletas foram realizadas mensalmente entre setembro de 2009 e agosto de 2010. As fêmeas foram maiores, mais pesadas e exibiram um coeficiente alométrico (b) maior que os machos. Apenas a relação comprimento de carapaça vs. comprimento de pleura nas fêmeas, apresentou uma diferença significativa no padrão de crescimento relativo, evidenciando a muda da puberdade. Esta relação é estritamente correlacionada aos eventos reprodutivos e ao sucesso deste em fêmeas de carídeos. O comprimento da carapaça em que 50% das fêmeas estão maduras (CL 50 ) foi estimado em 4,53 mm. Não foi possível comparar os resultados de CL 50 obtidos devido à falta de estudos enfocando a espécie. A comparação foi feita através do tamanho da menor fêmea ovígera capturada (3,81 CL mm), o qual está dentro da amplitude de tamanho registrada para estuários localizados em latitudes mais elevadas. Este trabalho aponta a falta de estudos para este gênero em ambientes dulceaquícolas, uma vez que estes são raros, mesmo em escala nacional e global. PALAVRAS-CHAVE.Caridea, crescimento alométrico, relações morfométricas.

Growth and reproductive biology of the amphidromous shrimp Palaemon pandaliformis (Decapoda: Caridea) in a Neotropical river from northeastern Brazil

“…Sex was determined by examining the endopodite shape of the first pair of pleopods and by inspecting the appendix masculina (presence or absence) on the endopodite of the second pair of pleopods (Bauer 2004). Individuals with carapace length smaller than the smallest identified male were counted as not sexable (Paschoal et al 2013b). These individuals were not used in the analysis.…”

“…recruits, as established by Paschoal et al 2013b). Recruitment patterns were determined by observing modal peaks of juveniles during the studied period (i.e.…”

“…Females of P. pandaliformis tend to invest more energy on growth of the brood pouch than on other parts of the body (Paschoal et al 2013b). The abdomen and their segments suffer morphological alterations that facilitate protection during deposition, incubation and spawning (Bauer 2004).…”

“…Until this moment, only two studies were conducted in freshwater environments, namely paschoal et al (2013a), who observed the association of this shrimp with macrophytes, their habitat preferences, and their uses by males and females; and Paschoal et al (2013b), who estimated the sexual maturity and assessed the relative growth variability between sexes, thus showing that females were larger and heavier than males.…”

Phytophilous caridean shrimps (Atyidae and Palaemonidae) in Salsa river (Canavieiras, Bahia, Brazil)

“…It is considered one of the main tributaries of Pardo river, with a basin that covers an area of 30,360 km². This region is subject to dumping of domestic untreated effluents, artisanal and commercial fishing, ecological tourism and water sports (Paschoal et al, 2013).…”