Cryptic and biochemical responses of young cuttlefish Sepia officinalis exposed to environmentally relevant concentrations of fluoxetine

- Effects of fluoxetine on cryptic behaviors and brain chemistry of young cuttlefish.
- Chronic exposure to low doses of fluoxetine (FLX) during the perinatal period.
- Exposure duration-dependent effect of FLX at 1 ng L−1 on uniform camouflage.
- Sand digging behavior of hatchlings impaired at 1 ng L−1, not at 100 ng L−1.
- FLX induced changes in brain dopaminergic activity at one-month old.

Antidepressants released in the environment have the potential to generate neural disrupting effects in non-target organisms, yet their putative effects on behaviors have never been studied in cephalopod molluscs. This study assessed the impact of the antidepressant fluoxetine (FLX) on the efficiency of cryptic behaviors (body patterns on uniform, checkerboard and sandy substrates), locomotor activity, and brain chemistry in young cuttlefish exposed to environmental concentrations (1 and 100 ng L−1 of FLX) during the perinatal period. Behavioral responses of cuttlefish were monitored at hatching and two weeks later, and brain monoamine contents were quantified at one month of age. FLX significantly altered the camouflage efficiencies on uniform and sandy backgrounds only at the lowest concentration, but not at 100 ng L−1. Hatchlings exposed to 1 ng L−1 of FLX exhibited a duration exposure-dependent decrease in the uniform camouflage. They also showed a significant increase of the frequency of sand digging behaviors which might make them highly visible to predators in nature. When tested again two weeks later, cuttlefish seemed to have recovered and no more behavioral alterations were observed showing a transitory effect of the antidepressant. FLX did not affect the levels of serotonin, norepinephrine and their metabolites; however, it seemed to influence dopaminergic activity between the two FLX-exposed groups. The results show for the time that environmentally realistic concentrations of a single SSRI significantly impair the cryptic performances of newly hatched cuttlefish, and may ultimately reduce their chance for survival.