Olfactory sensitivity of the marine flatfishSolea senegalensisto conspecific body fluids

Abstract

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 1:10 6 . 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.

Short- and Medium-Term Exposure to Ocean Acidification Reduces Olfactory Sensitivity in Gilthead Seabream

“…Olfactory sensitivity to amino acids in fish is believed to be mainly involved in food detection (Hara, 1994; Velez et al, 2007). Bile fluid and intestinal fluid are known to be potent olfactory stimuli in fish, possibly involved in chemically-mediated interactions both within and between species (Velez et al, 2009; Huertas et al, 2010; Buchinger et al, 2014; Fatsini et al, 2017; Hubbard et al, 2017). Therefore, we tested the effect of elevated CO 2 /low pH on the olfactory responses of seabream to conspecific bile, intestinal fluid, and a range of amino acids in fish maintained under control conditions (pH nominally 8.2; P CO 2 nominally 350 μatm) and high CO 2 conditions (pH nominally 7.7, P CO 2 nominally 1,000 μatm) for 4–8 weeks.…”

Environmental enrichment in fish aquaculture: A review of fundamental and practical aspects

“…For example, increased ventilation rate, decreased foraging and swimming activity, increased dashing and dorsal fin erection 176 or even morphological changes 179 are within the effects of exposing fish to chemical cues. These effects should not be taken lightly as many of the most farmed fish species have been characterised in terms of chemical sensing, such as salmonids, 180,181 tilapias, 182‐184 carps, 185 European seabass, 186 gilthead seabream 187 or Senegalese sole 188 …”

Neural Activation in the Olfactory Epithelium of the East African Cichlid (Haplochromis chilotes) in Response to Odorant Exposure

“…Urine was collected from mature male cichlid. Although several studies had collected nondiluted urine from fish, they were limited to some larger fish such as masu salmon, rainbow trout, Mozambique tilapia, and Senegalese sole (Yambe et al ., 1999; Sato and Suzuki, 2001; Keller-Costa et al ., 2014; Fatsini et al ., 2017). Here, by referring to a method to collect urine from Masu salmon used in Yambe et al ., 1999, we developed a noninvasive method to collect urine directly from cichlid, whose size is approximately 6–9 cm under swimming conditions (Figure 5B).…”