Abstract We evaluated the relationship between southern brown shrimp Penaeus subtilis (Pérez Farfante, 1967) yield and environmental parameters on the Amazon continental shelf. We analysed monthly fishing effort data (number of days spent at sea) and yield (kg of tails) collected between 1978 and 2009. A causal relationship had been expected between Amazon River discharge during the main period of shrimp occurrence in estuarine waters (considering post larval settlement and juvenile recruitment in second semester of each year) and adult abundance (represented by fishery yield in the first semester of the following year). We detected significant correlations between monthly river discharge and yield with a negative lag of four months, and between river discharge during the dry season (June to November) and yield in the following year. In general, low and high discharges during a given year were associated with high and low fishery yields, respectively, during the following year.

Abstract The family Pseudorhombilidae Alcock, 1900 is widely distributed in the tropical western Atlantic, occurring from shallow waters to the continental slope, inhabiting sandy, gravelly, or muddy substrates. Despite the broad distribution of this family in the Americas, the species Pseudorhombila octodentata Rathbun, 1906 and Pseudorhombila quadridentata (Latreille, 1828) have been observed only in a few localities, with disjunct records, and Robertsella meridionalis Tavares and Gouvêa, 2013 has been recorded only in one type locality (Santa Catarina, Brazil). The present work reports new occurrences of P. octodentata from the state of Sergipe and P. quadridentata from the state of Amapá, and the second occurrence of R. meridionalis from the state of Rio Grande do Norte, Brazil. These new records are an important contribution to the understanding of distributional patterns of pseudorhombilid crab species in Brazil and to the increase in biodiversity data of crustaceans from the North and Northeast regions of Brazil.

Eiconaxius carinatus (Bouvier 1925) caracteriza-se, principalmente, por apresentar carenas laterais do rostro lisas, mero da quela maior com carena dorsal lisa, palma da quela maior exibindo carena dorsal bem nítida e dedos da quela menor de comprimento inferior ao da palma. Um exemplar foi coletado ao largo do Estado do Maranhão (00º 08' N e 44º 32' W) a 247 m de profundidade. A área de ocorrência anteriormente conhecida abrangia a Flórida e Antilhas (Santa Cruz e São Vicente), entre 161 e 339 m. Este trabalho registra pela primeira vez a família para o Brasil.

Eiconaxius carinatus (Bouvier 1925) is characterized, mostly, by smooth rostral lateral carinae, merus of major chela with smooth dorsal carina, palm of major chela with dorsal carina evident and length of fingers of minor chela less than the palm length. One specimen was collected off the state of Maranhão (00º 08' N and 44º32'W) in a depth of 247 m; this species was known previously from Florida and West Indies (Saint Croix and Saint Vincent), in depths between 161 and 339 m. This record is the first record of this family for Brazil.