Occurrence of Macrobrachium amazonicum (Heller) (Decapoda, Palaemonidae) in Leopoldo\u27s inlet (Ressaco do Leopoldo), upper Paran\ue1 River, Porto Rico, Paran\ue1, Brazil

Studies on the occurrence, temporal distribution and nychthemeral variation of Macrobrachium amazonicum (Heller, 1862) were undertaken in Leopoldo's Inlet, upper Paraná River, Porto Rico, Paraná, Brazil. Seventeen thousand and sixty specimens (11,786 larvae and 5,274 juveniles) were captured with a conicalcylindrical plankton net of mesh 0.5mm in monthly samples between February 1991 and February 1992. Results show that the greatest densities of larvae (301.83 larvae/10m³) and juveniles (168.8/10m³) of this species were caught in December 1991. Largest captures were made during the night. With regard to abiotic factors water temperature ranged from 20º to 30ºC, pH ranged from 5.66 to 7.37 and electric conductivity ranged from 51.83 to 65.33µS/cm. Relationship between the density of larvae and juveniles and abiotic factors was calculated by the Principal Components Analysis (PCA) which revealed the influence of some limnological variables especially on the distribution of larvae

Crescimento relativo do camar\ue3o canela Macrobrachium amazonicum (Heller) (Crustacea, Decapoda, Palaemonidae) em viveiros

<abstract language="eng">Some morphometric relationships in Macrobrachium amazonicum (Heller, 1862) reared in earthen ponds were studied. A total of 239 individuals were collected, sexed and sorted to juvenile or adult. Total length (Lt), post-orbital length (Lpo), carapace length (Lcp) and queliped length (Lql) were measured. The relationships Lt/Lpo, Lpo/Lcp and Lt/Lcp are the same for juveniles, males and females, indicating unchanged growth pattern during post-larval ontogenetic development. While Lt/Lpo showed isometric growth, Lpo/Lcp and Lt/Lcp showed negative allometry. On the other hand, for the Lql/Lcp relationship, juveniles showed isometric growth, females slight positive allometry and males a strong positive allometry. It suggests that the importance of chelipeds may be different in these groups. Quelipeds play important role on food capture and on agonistic, social and reproductive behavior. Therefore, inter and intraspecific interactions may change during prawn growth, even after morphologica