Olfactory sensitivity of the marine flatfish Solea senegalensis to conspecific body fluids

9 pages, 7 figures

Chemical communication is better understood in freshwater fish than marine fish. The Senegalese sole (Solea senegalensis) is a marine flatfish wherein one of the problems in aquaculture is the poor reproductive performance of hatchery-bred males. Is chemical communication involved in the reproduction of this species Urine, intestinal fluid and mucus samples were taken from adult fish (wildcaught and hatchery-bred) over the spawning season (March-May), and assessed for olfactory potency using the electro-olfactogram (EOG). The effect of stimulation of the olfactory system with adult female urine on circulating luteinizing hormone (LH) levels was also tested in males. Intestinal fluid and urine were potent olfactory stimuli for both juvenile and adult conspecifics, evoking large-amplitude, concentration-dependent EOG responses, with thresholds of detection at approximately 1:106. However, the amplitude of the response to urine depended on the sex and state of maturity of both the donor and the receiver. Most olfactory activity could be extracted by C18 solid-phase cartridges. Urine from mature females evoked a slight, but significant, increase in circulating LH levels in mature males 30 min after exposure. Furthermore, the olfactory potency of urine differed between wild-caught and hatchery-bred fish; however, contrary to expectations, urine from wild-caught females was less potent than that from hatchery-bred females. Taken together, these results strongly suggest that faeces-and urine-released odorants are involved in reproduction in the Senegalese sole, and establish a basis for further investigation into pheromonal communication in marine teleosts

The study was funded by the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria and the EU through FEDER 2014-2020 ‘Programa Operativo de Crecimiento Inteligente’ projects RTA2011-00050 and RTA2014-00048 coordinated by N.J.D. Partially funded by the Ministerio de Economía y Competitividad (MINECO; grant AGL2013-41196-R to J.C., RTA2013-00023-C02-01 to M.M.). E.F. was supported by a PhD FPI-INIA grant awarded by MINECO, Spain. This study also received Portuguese national funds from the Fundação para a Ciência e a Tecnologia (Foundation for Science and Technology, Portugal) through project UID/Multi/04326/2013

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