Evidence for involvement of chemical communication in reproduction of the eel Anguilla anguilla

Abstracts of the Annual Main Meeting of the Society for Experimental Biology, A2 Genomics in Aquaculture, 11-15 July 2005, Universitat Autonoma de Barcelona, Barcelona, Spain.-- 1 pageThe European eel (Anguilla anguilla) is characterised by long transoceanic migration to spawning sites during which the fish become sexually mature. A previous study demonstrated that mature eels may induce physiological and behavioural changes in immature conspecifics. This raises the possibility that chemical communication may be involved in this process. The aim of the current study was, therefore, to assess the olfactory sensitivity of eels to conspecific-derived odours and to establish whether these odours differ according to sex and/or state of maturity. Solid-phase water extracts (using C18 cartridges), and bile and mucus samples, were collected from mature and immature fish of both sexes. Olfactory sensitivity to these samples was assessed by recording the electro-olfactogram (EOG) from immature males. Of the water extracts, those from spermiating males and pre-ovulatory females evoked the largest responses. Both bile and mucus proved to be highly potent odorants, evoking EOG responses at dilutions as low as 1:107 and 1:106 respectively. Cross-adaptation studies suggest that bile from males and females is qualitatively different and that mucus from mature and immature fish of both sexes is qualitatively and quantitatively different. Taken together, these results provide strong support for a role for chemical communication in this species, suggesting that a number of different odorants and routes of release may be involved. However, the chemical identities of these compounds and their exact biological roles remain to be elucidatedPeer Reviewe