Since 2019, One Ocean Foundation is committed to supporting research activities in the Caprera Canyon, considered the area with the largest submarine canyon system in the northeast of Sardinia, in the central Tyrrhenian Sea.
The Canyon is characterized by a large density of pelagic fauna: the site hosts 7 of the 8 species of cetaceans usually present in the western Mediterranean, some of which are considered particularly rare.
The main goal of this project is to develop scientific evidence to protect the Canyon of Caprera area and promote it to Important Marine Mammal Area (IMMA) on the path towards a Marine Protected Area (MPA). Currently, the Canyon of Caprera is recognized as an Area of Interest (AoI) and a HopeSpot within MissionBlue - a global initiative for the conservation of marine biodiversity established by the renowned oceanographer Dr. Sylvia Earle - thanks to the Foundation's constant commitment to research and monitoring activities since 2019.
To pursue this aim, One Ocean Foundation has chosen to support and coordinate itself with important research bodies and universities, to collect scientific evidence on critical information on ecology and cetacean distribution: the CMRE centre of La Spezia, Insubria University, the CNR and SEAME Sardinia association.
These underwater canyons are considered important hotspots for several species of cetaceans, thanks to underwater currents that favor the transport of nutrients and of numerous preys which are the base of the food chain.
Cetaceans are recognized by the EU Marine Strategy Framework Directive as essential components of ecosystems and highly linked to their health, as, being large predators, they can greatly influence the structure of marine ecosystems. However, there are many problems caused by human activities that have a great impact on cetaceans and, to mitigate the consequences, accurate knowledge of the distribution and abundance of these animals is required.
As of today, the project consists of three main research activities: acoustic monitoring, environmental DNA analysis and visual survey.
One Ocean Foundation collaborates with the University of Insubria to develop genetic detection of cetaceans. This technique is based on the collection of seawater samples and analysis of environmental DNA, intended to describe the temporal distribution of the biodiversity of cetaceans in the Canyon of Caprera area. This is a non-invasive monitoring tool, as the physical presence of the organism is not necessary.
A new scientific publication based on the data collected during the research activities, named “Playing hide and seek with the Mediterranean monk seal” and published on Scientific Reports, revealed that the monk seal (Monachus monachus) not only is regularly present in the Canyon of Caprera area, but positive detections were found in at least 2 of the 3 sampling stations. Overall, eDNA results suggest that these waters might represent an important feeding ground and a “hotspot” for this species in the Mediterranean Sea.
One Ocean Foundation supports SEA-ME Sardinia Onlus, a non-profit organization whose mission is to protect cetaceans in the Mediterranean Sea and that implements visual monitoring activities to gather scientific data on the presence, abundance, distribution and movements of cetaceans in the Canyon of Caprera area. These investigations are carried out through sightings on linear transects, photo identification studies and counts of animals that pass in specific geographical points and represent completely non-invasive observational methods which employ professional and qualified marine mammal observers.
Along with zooplankton and environmental DNA sampling, the technique of bioacoustics is used to monitor the biodiversity of Caprera Canyon. It is now known that to communicate, hunt and orient themselves, cetaceans use sounds, which propagate better in water than light and over long distances. For this reason, the use of bioacoustics makes it possible to hear cetaceans when they cannot be sighted. Bioacoustics is also particularly useful for monitoring cryptic and elusive species that spend a long time underwater and only come up to the surface to breathe, such as the Zyphus.
The main tool used is the hydrophone - similar to a microphone used to listen underwater - which allows the One Ocean Foundation team to listen and record sounds coming from the depths of the sea. For example, they can listen to clicks, high-frequency sounds that are used by odontocetes (i.e sperm whales and dolphins) to hunt. This is echolocation, and thus also of the possible presence of prey. Or even whistles, sounds mainly produced by delphinids and used to communicate with each other.
In the past years, with the collaboration of the CMRE center in La Spezia, One Ocean Foundation has positioned 3 sound recording devices in strategic points of the Canyon of Caprera area to monitor the presence and distribution of deep-diving mammals (i.e. Cuvier's beaked whales). The results of this research allowed us to better understand the use of the habitat by marine mammals as well as to conceive solutions to mitigate the impact of anthropogenic noise on cetacean species.
Marine species spotted at the Canyon of Caprera (@LucaBittau, SEAME)
