Abstract Alpheus christofferseni Anker, Hurt and Knowlton, 2007 was described based on four specimens from Atol das Rocas, northeastern Brazil, and one specimen from Bocas del Toro, the Caribbean coast of Panama. Here, we report the collection of two specimens from Pernambuco, Brazil (~ 8°41’S), thus increasing the knowledge on species distribution along the Brazilian coast by approximately five latitudinal degrees south of its type locality (Atol das Rocas, Rio Grande do Norte, ~ 3°51'S). We also report a substantial increase in the known bathymetric distribution from shallow intertidal to approximately 51 m. Notes on morphological variation are provided based on the new material, and the first sequence of the 16S ribosomal subunit gene for the Brazilian coast is provided and compared with congeners.

Abstract We investigated the abundance and spatial distribution of Callinectes danae Smith, 1869 during the day/night periods and tidal cycles in a coastal area of Brazil. Sex ratio, size class distribution, and mean sizes of males and females were also analyzed. The sampling occurred between February and March 2011 in the estuary-bay complex of São Vicente. Collections occurred in six sampling stations during both daytime and nighttime. A total of 1997 specimens were collected in the bay and 963 specimens in the estuary. The abundance of males and females differed between the bay and estuary, with males more abundant in the estuary and adult females in the bay. Crabs in all demographic categories were more abundant at night. The species distribution was intrinsically related to the interaction between environmental factors. In addition to the higher capture during nocturnal collections, a positive correlation was found between the abundance of reproductive females and salinity, while juveniles were more abundant in shallower stations and at lower salinities. Our results contribute to a better understanding of the influence of day/night periods and tidal cycles on the abundance and distribution of the swimming crab C. danae.

Abstract The spatio-temporal distribution of juveniles of the pink shrimps Farfantepenaeus brasiliensis (Latreille, 1817) and Farfantepenaeus paulensis (Pérez-Farfante, 1967) in the Ubatuba region (SP) was investigated. Sampling was performed in the bays of Ubatumirim (UBM), Ubatuba (UBA) and Mar Virado (MV). A total of 2,018 F. brasiliensis and F. paulensis were collected. The largest catch of juveniles of both species occurred in UBA (N = 867), followed by UBM (N = 729) and MV (N= 422). The bottom sediment in MV had the highest silt and clay content, which explains the negative correlation of the substrate with the abundance of both species. Temperature was positively correlated with the abundance of both species. Juveniles were highly abundant in shallower areas in the summer of 1998. The high rainfall in this El Niño period may have lowered the salinity in estuarine waters and led the shrimps to move to coastal areas in search of higher salinities such as in bays. With this unusually early reduction in salinity, individuals migrated to the bay before the closed season began and thus became more exposed to fishing. We confirmed that monitoring environmental variations, especially in El Niño years, is essential for understanding the distribution patterns of juveniles of both species.

ResumoFoi investigada a dinâmica populacional de Acetes americanus, enfocando a razão sexual, crescimento dos indivíduos, longevidade, recrutamento e a relação da abundância com dos fatores ambientais na região de Macaé, a qual é fortemente influenciada pela ressurgência costeira. Foram realizadas coletas de julho de 2010 a junho de 2011, em dois pontos (5 m e 15 m), utilizando uma rede otter trawl. Cerca de 19.500 indivíduos foram capturados com predominância de fêmeas (77,15%) e essas foram maiores que os machos indicando dimorfismo sexual. Houve inversão do paradigma latitudinal, onde os camarões apresentaram maiores tamanhos e longevidade quando comparados a outras regiões de maiores latitudes e isso provavelmente se deve às baixas temperaturas e alta produtividade primária. Apesar de não apresentar correlação estatística entre a abundância e os fatores ambientais, a espécie foi mais abundante em temperaturas próximas aos 20,0º C e nos meses com alta concentração de clorofila-a. Devido às características peculiares da região, os espécimens de A. americanus apresentarem diferenças em relação a tamanho e longevidade quando comparados aos indivíduos amostrados em outros estudos realizados na plataforma continental do sudeste brasileiro.

AbstractThe population dynamics of Acetes americanus was investigated, focusing on the sex ratio, individual growth, longevity, recruitment and relationship between abundance and environmental factors in the region of Macaé, strongly influenced by coastal upwelling. Otter trawl net samplings were performed from July 2010 to June 2011 at two points (5 m and 15 m). Nearly 19,500 specimens, predominantly females (77.15%), were captured. Their sizes, larger than that of males, indicated sexual dimorphism. Shrimps at lower latitudes present larger sizes and longer longevity than those from higher latitudes. This difference is probably due to low temperatures and high primary productivity. Though no statistical correlation was found between abundance and environmental factors, the species was more abundant in temperatures closer to 20.0º C and in months with high chlorophyll-a levels. Due to the peculiar characteristics of this region, A. americanusshowed greater differences in size and longevity than individuals sampled in other studies undertaken in the continental shelf of Southeast Brazil.

Registramos a incidência de parasitismo por vermes Mermithidae em larvas de Chironomus gr. decorus (Diptera: Chironomidae), no Rio dos Peixes, Dois Córregos, região centro-oeste do Estado de São Paulo, Brasil. Neste estudo, de um total de 791 larvas amostradas, 205 (25,9%) estavam infectadas por mermitídeos, indicando que larvas de Chironomidae são comumente parasitadas por vermes mermitídeos.

We report the incidence of Mermithidae (Nematoda) parasitism in Chironomus gr. decorus larvae (Diptera: Chironomidae) at Rio dos Peixes, Dois Córregos, central west region of São Paulo State, Brazil. In this study, of a total of 791 larvae, 205 (25.9%) were infected by mermithid worms, indicating that Chironomidae larvae are commonly parasitized by Mermithidae worms.