Divers who, as “cultivators,” transplant and/or breed corals in the depths of the Portofino and Gallinara MPAs?
Put like that, it almost sounds like science fiction, but on closer inspection, what has been achieved at Gallinara closely resembles the story of The Man Who Planted Trees , Jean Giono's 1953 novella about a shepherd who, with unwavering commitment, single-handedly reforested an arid valley at the foot of the Alps, near Provence, planting acorns one at a time in a hole dug with his stick. Of course, if we stop at the simile and ignore the fact that—as everyone knows—corals and gorgonians are not trees, but animals... In any case, after the report in recent months that documented the "damage" scuba diving causes to coral colonies in the Portofino MPA, here is a positive activity that also encourages a more conscious approach by divers to the marine environment.
However, there is indeed a serious, scientific project, coordinated by the Polytechnic University of Marche, to study and replant corals and gorgonians in these sites. It has been ongoing for a couple of years and is producing the first tangible results.
Charles Cerrano, a professor at the Polytechnic University of Marche, and a passionate diver, has in fact created a team of specially trained volunteer divers to "transplant" specimens of gorgonians and recreate a population at Gallinara, documented in past decades but then lost.
Another project—also coordinated by Cerrano—concerns coral reproduction at Colombara, both in caves and on cliffs, in both deep-sea (about seventy meters) and shallower (about forty meters) populations. This study aims to better understand the reproductive mechanisms of red coral, also with the aim of promoting the recovery of colonies compromised by both harvesting in recent decades (banned after the MPAs were established about twenty years ago), fishing, and climate factors (warming).
But let's see what the two projects consist of, starting with the Gallinara one, while we will reserve a next "episode" for the red coral.
Gorgonian growers
At Gallinara, a gorgonian nursery at a depth of 35 meters
The first project—extremely interesting, and the one we discuss in this first episode—concerns the reconstruction of a population of gorgonians in Gallinara. This is where the role of volunteer divers, who actively participated in the "transplant" operations, was crucial.
“There are many clues that demonstrate how in the past gorgonians and red coral (which, as is known, belong to the same order, ed.) were present", explains Cerrano. “From the fishermen who found them entangled in their nets, to the brochures that in the 60s advertised the tour of the island by boat and in which there was a photograph of the seabed with the Savalia savaglia, the false black coral, which is a parasite of gorgonians; to some scientific works from those years".
Today, however, the gorgonians have disappeared from Gallinara, «and this would seem to demonstrate that if some species that populate the seabeds of islands disappear, they are unlikely to return in a timeframe reasonable for man ...", says Cerrano.
Gorgonians are a crucial element of the marine ecosystem, because "They produce a forest effect that is very important for protecting biodiversity, as it creates complexity and shelter, reduces hydrodynamics, and creates greater stability by mitigating environmental variations. The presence of dense populations of gorgonians creates a "shadow effect" for numerous organisms that develop in a semi-dark environment and therefore either take refuge in these habitats or must move to much deeper areas."
But what caused this depletion of the gorgonian population?
According to Cerrano, fishing played a key role, with fishing lines that, day after day and year after year, get caught in branches and tear them apart, causing the animals to die over time.
"The larval dispersal of these species is very limited; therefore, once the seabed becomes desertified, recovery is highly unlikely if there are no nearby populations that can produce and disperse new larvae.", explains Cerrano.
The “Merces Project” – which studies the interactions between human activities and the marine environment – has therefore found in Gallinara an ideal case study for the possible reintroduction of gorgonians into the coralligenous habitat.
"Eunicella singularis – explains Cerrano – It was chosen because it is very widespread on the seabed around Gallinara and lives in symbiosis with zooxanthellae algae which provide nourishment to the animal even in case of food shortages..
Over one hundred specimens of Eunicella singularis have been transplanted.
Researchers have thus identified a site at Gallinara deemed suitable for becoming a true nursery for small gorgonians at a depth of approximately 35 meters. Staff from the "InfoRmare ASD" association, the "Sesto Continente Diving Center" of Alassio, and the "Profondo Blu" school of Cuneo supported the researchers in the transplantation activities, positioning over one hundred specimens: "Now it's a matter of seeing if they survive and reproduce. For now, about two years later, the coral is still there and doing well..
The specimens were taken from the Diano Marina plain, where Eunicella singularis It is widespread, with targeted pruning designed to avoid harming the animals. They were then replanted at Gallinara.
To do this, the rock surface is cleaned of algae and then a specific resin (a two-component glue) is applied to it, anchoring the gorgonian branch. This resin hardens within a few hours, ensuring a long-lasting hold.
So can we hope to one day see a forest of gorgonian corals on the seabed around Gallinara?
The study is very important from an experimental point of view, explains Cerrano, as it has allowed us to «Develop an effective grafting technique that increases their chances of survival. We'll also be able to see if they reproduce and develop into larvae. Unfortunately, we've also observed the colonies shrinking in size; we don't know whether this is due to the fishermen's lines or other factors. However, the abrasion effect persists, and we're studying it to understand the extent of the damage. Therefore, while at this point in the research we can say that experimental results are in, we believe that a true recovery will be difficult to achieve if the reasons that led to their extinction in the past persist..
In short, either a marine protected area with fishing regulations is established, or a widespread recovery of the gorgonian population will be impossible, thus risking a progressive impoverishment of the area's biodiversity.
