Volatile organic substances (VOS) were extracted from the coelomic fluid of gravid specimens of the lugworm Arenicola marina through the use of using a closed loop stripping technique and analysed via coupled gas chromatography-mass spectroscopy. VOS detectable in coelomic fluid of mature specimens include aldehydes, n-alkanes, methyl-alkanes, terpenes and ketones. The bouquet of compounds is very similar to nereid volatiles that have been recently described as having sex pheromonal activity. One of the major constituents is the ketone 5-methyl-3-heptanone, the sex pheromone of Platynereis dumerilii and Nereis succinea. Behavioural bioassays with gravld specimens produced no evidence that this substance has any pheromonal function in A. marina. Samples taken at monthly intervals showed an increase in the content of VOS in the coelomic fluid of both sexes during maturation with 1 major peak, 2-ethyl-hexanol, representing up to 50% of the total amount of VOS in spawning male lugworms. Behavioural assays with ripe females established the existence of a chemical cue inducing the burrow ~rngation behaviour during which sea water is pumped through the burrows. This behaviour ensures transport of spermatozoa from the water column into the tube inhabited by the female and increases fertilization success by minimising the dilution effects of the incoming tide. The VOS extract obtained from male spawning water had biological activity in eliciting the 'pumping' behaviour in females, with 16 of 24 worms irrigating continuously upon exposure, whilst controls showed no increase of activity, with 'pumping' occurring at 30 to 40 min intervals.

ABSTRACT. In the Teles Pires River watershed, one of the most common techniques currently used by fishermen to catch fish is to provide a food supplement commonly known as "cevas". The purpose of this study was to compare the chemical composition of fillets from Brycon falcatus that were caught in both the presence and absence of cevas. The fish were sampled monthly and captured in the following conditions: the Tapaiúna River without cevas, the Teles Pires River with one ceva/100 m, the Celeste River with one ceva/500 m, the Verde River with one ceva/1000 m and the Cristalino River (control area). Subsequent to capture, the fish were euthanized and preserved on ice to determine their water, ash, crude protein and fat contents. Fillets of fish from the control area exhibited a lower level of crude protein (17.81%) compared with that of fish from the other rivers, which did not differ amongst one other. The fillets of fish from the river with the greatest density of cevas (1/100 m) exhibited a higher fat content (3.63%) than that of fish from the control area (1.51%). Thus, the cevas changed the chemical composition of B. falcatus fillets.Keywords: Amazon basin, fresh soybean, feeding, lipids, matrinxã, protein.Efeito do suplemento alimentar (cevas) na composição química do peixe selvagem Brycon falcatus Müller & Troschel, 1844 na bacia do rio Teles Pires RESUMO. Atualmente, na bacia do rio Teles Pires, uma das técnicas mais utilizadas pelos pescadores para captura de peixes é a oferta de suplemento alimentar, popularmente conhecida como ceva. Objetivou-se comparar a composição química do filé de Brycon falcatus de locais com oferta de suplemento alimentar (cevas) e sem cevas. As coletas dos peixes foram mensais e as capturas foram em rio Tapaiúna sem cevas, rio Teles Pires com uma ceva/100 m, rio Celeste com uma ceva/500 m, rio Verde com uma ceva/1.000 m e rio Cristalino em Unidade de Conservação (controle). Após as capturas, os peixes foram eutanasiados e acondicionados em gelo, para determinação dos teores de umidade, cinzas, proteína bruta e gordura. Os filés dos peixes oriundos da área controle apresentaram o menor teor de proteína bruta (17,81%) que dos outros rios, que não diferiam entre si. Os filés dos peixes do rio com maior densidade de cevas (1/100 m) apresentaram maior teor de gordura (3,63%) que do rio em Unidade de Conservação (1,51%), mas não diferiram dos outros rios. As cevas de soja in natura alteraram a composição química dos filés de Brycon falcatus.Palavras-chave: bacia Amazônica, soja in natura, alimentação, gordura, matrinxã, proteína.