We are happy
to share the new paper of the BigPark project, published in Frontiers in Marine
Science:
Santamaría J, Tomás F, Cebrian E, Ballesteros E. 2021. Herbivory on the invasive algaCaulerpa cylindracea: The role of omnivorous fishes. Frontiers in Marine
Science 8:702492. DOI: 10.3389/fmars.2021.702492
In this paper
we investigated one of the focal objectives of the project: the potential
controlling effect of herbivory on invasive algae. In particular, we examined
the role of 4 species of omnivorous fishes, Diplodus annularis, Diplodus
sargus, Diplodus vulgaris and Spondyliosoma cantharus, on the alga Caulerpa
cylindracea.
Here is the
abstract:
Herbivory
has long been considered an important component of biotic resistance against
macroalgae invasions in marine habitats. However, most of the studies on
herbivory of invasive algae refer only to consumption by strictly herbivorous
organisms, whereas consumption by omnivorous species has been largely ignored
and rarely quantified. In this study, we assess whether the commonest
omnivorous sparid species in the Mediterranean Sea are consuming the highly
invasive alga, Caulerpa cylindracea, and determine both, its importance in
their diet and their electivity toward it as a source of food. Our results
confirm that three of the four fish species studied regularly consume C.
cylindracea, but in most cases, the importance of C. cylindracea in the diet is
low. Indeed, the low electivity values indicate that all species avoid feeding
on the invasive alga and that it is probably consumed accidentally. However,
despite animals and detritus being the main food for these sparid species,
several individual specimens were found to have consumed high amounts of C.
cylindracea. This suggests a potential role that these fish species, being
really abundant in shallow rocky bottoms, may play in controlling, to some
extent, the abundance of the invader.
Our results
show that, even considering that the fishes are omnivorous, the invasive seaweed
was regularly present in their stomach contents. In particular, in D. annularis
26% of the food content was C. cylindracea, which indicates a potential
controlling role of these abundant fishes. This research complements the ongoing research in BigPark with other strictly herbivorous species, namely the sparid
Sarpa salpa.
