RESUMO

The complete larval development of Amphithrax hemphilli was described, illustrated, and compared with that of the previously described larvae of the genus Mithrax sensu lato. Specimens of A. hemphilli were sampled from the northeastern Brazilian coast. The larval development of A. hemphilli consisted of two zoeal stages and one megalopa. Amphithrax hemphilli shows morphological features in all stages of larval development that differ from those observed in other species of Amphithrax, Mithrax, and Maguimithrax. In the first larval stage, A. hemphilli was the only species with two aesthetascs on the antennule and the coxal endite of the maxillule with five setae. In the second larval stage, A. hemphilli was distinguished from the other species of the genus Mithrax sensu lato by the presence of five setae on the basial endite of the maxilla and 26 setae in the scaphognathite of the maxilla. Finally, the megalopa stage of A. hemphilli is characterized by the number of aesthetascs on the three-segmented exopod of the antennule, the setation of both the endopod of the third maxilliped, and pleonites 1-6. Based on the results obtained in the present study, we verified that the more advanced the larval stage, the more distinct characteristics are observed among species of the genus Mithrax sensu lato, facilitating the identification of species through later larval stages.

Assuntos

RESUMO

Considering the importance of establishing different approaches to the early detection of invasive species, the present study aimed to describe and illustrate the morphology of the early larval stages of the shrimp Lysmata lipkei, an invasive species in the Western Atlantic. Additionally, we did a morphological comparison and a review of the other Lysmata species from the Western Atlantic Ocean with a known larvae description. The larvae used in this study were obtained by the maintenance, under laboratory conditions, of ovigerous hermaphrodites of L. lipkei, collected in the wild. Then, larvae were dissected under a stereo microscope and illustrated using a microscope equipped with a camera lucida. The first three larval stages (zoeae) of L. lipkei were illustrated, described, and compared to other species of Lysmata previously described of the Western Atlantic. Some features of the larval morphology of L. lipkei are very similar when compared to other Lysmata species with previous larval descriptions, such as a rostrum long and simple, the eyes stalked with a long peduncle from the second zoeae, one pterygostomian spine and several denticles along the anterior ventral margin of the carapace, similarities in the segmentation of the maxillipeds, and the presence of dorsolateral spines on the posterior margin of the 5th pleomere, among other features. Also, unique features were observed for L. lipkei, such as differences in the setation of some structures, including the antennule, antenna, maxillule, and maxillipeds. Using the morphological descriptions, we expect to identify species from the plankton, especially invaders, that might be present in the Western Atlantic, as well as assist in several areas in which the larval morphology is relevant.

Assuntos

RESUMO

This study evaluated if the temporal and spatial reproduction and recruitment of the main species of marine shrimps exploited in the state of Sergipe (Xiphopenaeus kroyeri, Farfantepenaeus subtilis, and Litopenaeus schmitti) are being protected, in relation to the closed season based on the normative instruction MMA n° 14, of October 14th 2004. The samples were collected monthly from September 2013 to August 2014 at the continental shelf of Sergipe, in nine transects, distributed in the depths of 5, 15, and 30 m using a shrimping boat equipped with double ring nets. After sampling, we identified shrimps to the species level; subsampled, sexed them, measured carapace length, and observed the gonads. Recruitment and reproduction in the three species occur continuously, albeit with intensity peaks. Regarding space, reproductive individuals and recruits were more abundant at 30 m in the case of F. subtilis, while for X. kroyeri and L. schmitti, higher abundances were found at 5 and 15 m. The current normative instruction partially protects the reproductive and juveniles categories of these species, mainly F. subtilis. Thus, we suggest closed seasons at breeding and recruitment seasons of F. subtilis, since the area set by IBAMA already protects other species throughout the year.(AU)

Este estudo avaliou se a reprodução e o recrutamento temporal e espacial das principais espécies de camarões marinhos explotados no Estado de Sergipe (Xiphopenaeus kroyeri, Farfantepenaeus subtilis e Litopenaeus schmitti) estão sendo protegidos, em comparação com normativa MMA nº 14, de 14 de outubro de 2004. As coletas foram realizadas de setembro/2013 a agosto/2014 na plataforma continental de Sergipe, em nove transectos, distribuídos nas profundidades de 5, 15 e 30m, utilizando um barco camaroeiro equipado com rede de arrasto de portas. Após as coletas os indivíduos foram identificados ao nível específico, subamostrados, sexados, mensurados quanto ao comprimento da carapaça e classificados quanto à morfologia gonadal. O recrutamento e a reprodução das três espécies ocorreram continuamente ao longo do ano, apresentando picos de intensidade. Indivíduos reprodutivos e juvenis foram mais abundantes nos 30m para F. subtilis, enquanto para X. kroyeri e L. schmitti foram mais abundantes nos 5m e 15m. A atual instrução normativa protege parcialmente as categorias reprodutivas e juvenis dessas espécies, principalmente F. subtilis. Portanto, sugere-se a adequação dos períodos de defeso para as épocas de reprodução e recrutamento de F. subtilis, uma vez que a área estipulada pelo IBAMA já protege as demais espécies ao longo do ano.(AU)

Assuntos

RESUMO

This study evaluated if the temporal and spatial reproduction and recruitment of the main species of marine shrimps exploited in the state of Sergipe (Xiphopenaeus kroyeri, Farfantepenaeus subtilis, and Litopenaeus schmitti) are being protected, in relation to the closed season based on the normative instruction MMA n° 14, of October 14th 2004. The samples were collected monthly from September 2013 to August 2014 at the continental shelf of Sergipe, in nine transects, distributed in the depths of 5, 15, and 30 m using a shrimping boat equipped with double ring nets. After sampling, we identified shrimps to the species level; subsampled, sexed them, measured carapace length, and observed the gonads. Recruitment and reproduction in the three species occur continuously, albeit with intensity peaks. Regarding space, reproductive individuals and recruits were more abundant at 30 m in the case of F. subtilis, while for X. kroyeri and L. schmitti, higher abundances were found at 5 and 15 m. The current normative instruction partially protects the reproductive and juveniles categories of these species, mainly F. subtilis. Thus, we suggest closed seasons at breeding and recruitment seasons of F. subtilis, since the area set by IBAMA already protects other species throughout the year.

Este estudo avaliou se a reprodução e o recrutamento temporal e espacial das principais espécies de camarões marinhos explotados no Estado de Sergipe (Xiphopenaeus kroyeri, Farfantepenaeus subtilis e Litopenaeus schmitti) estão sendo protegidos, em comparação com normativa MMA nº 14, de 14 de outubro de 2004. As coletas foram realizadas de setembro/2013 a agosto/2014 na plataforma continental de Sergipe, em nove transectos, distribuídos nas profundidades de 5, 15 e 30m, utilizando um barco camaroeiro equipado com rede de arrasto de portas. Após as coletas os indivíduos foram identificados ao nível específico, subamostrados, sexados, mensurados quanto ao comprimento da carapaça e classificados quanto à morfologia gonadal. O recrutamento e a reprodução das três espécies ocorreram continuamente ao longo do ano, apresentando picos de intensidade. Indivíduos reprodutivos e juvenis foram mais abundantes nos 30m para F. subtilis, enquanto para X. kroyeri e L. schmitti foram mais abundantes nos 5m e 15m. A atual instrução normativa protege parcialmente as categorias reprodutivas e juvenis dessas espécies, principalmente F. subtilis. Portanto, sugere-se a adequação dos períodos de defeso para as épocas de reprodução e recrutamento de F. subtilis, uma vez que a área estipulada pelo IBAMA já protege as demais espécies ao longo do ano.

Assuntos