Biological invasions are deemed as one of the
most severe threats to biodiversity and can result in huge
economic impacts on natural resources. Many studies have
assessed structural changes caused by the introduction of
nonindigenous species, but urgent questions remain to be
answered about the complex indirect effects of invasive
pests on marine biodiversity at the species and ecosystem
level. Previous investigations focusing on the biological
invasion by Caulerpa racemosa in the Mediterranean indicated
that the lipophilic algal metabolite caulerpin accumulates
in the tissues of the native edible white sea bream
Diplodus sargus feeding on the exotic alga. The level of
caulerpin in D. sargus has been thus used as an indicator of
the trophic exposure of the fish to the seaweed and related
with adverse effects on the fish health. In the present study,
we show that the C. racemosa-based diet can also alter
muscle fatty acids composition in the white sea bream by
reducing the percentage of polyunsaturated fatty acids of
the n-3 and n-6 series, such as eicosapentaenoic (C20:5), docosahexaenoic (C22:6) and arachidonic acids (C20:4).
This represents both a real threat to the health of fish unable
to biosynthesize these essential fatty acids and an impoverishment
of an important source of essential fatty acids for
human nutrition, which helps to prevent cardiovascular diseases,
diabetes, hepatic steatosis, cancer and neurological
disorders. On the whole, this work sheds light on an unexplored
and critical aspect of biological invasions with implication
on the health of both humans and the environment.
