A new study by the ICM, the UPC and the UdG shows that the combined use of fixed acoustic reception stations and underwater robots for the study of deep-sea allow a better understanding of their ecology.
Exploration of marine ecosystems requires the development of technologies that allow in-depth research for an unlimited time. Acoustic reception stations fixed to the seabed are a good option, as they offer a great temporary resolution, but they have a high deployment cost and their use is limited to the anchorage area. Therefore, the possibility of combining their use with that of remotely operated or autonomous underwater vehicles, commonly known as ROVs and AUVs, is essential.
This is the main conclusion of a study carried out by researchers from the Institut de Ciències del Mar (ICM), the Universitat Politècnica de Catalunya – BarcelonaTech (UPC) and the Universitat de Girona (UdG) and published now in the journal Science Robotics. From its authors, underwater robots act as the perfect complement to fixed stations since they have great flexibility, they can move fast and are able to cover much larger study areas.
This improvement in operational capacity serves to collect biological and ecological information about the activity patterns of benthic marine organisms, which, in turn, should allow an improvement in the recovery actions of their populations, much of which are nowadays suffering as a result of human exploitation.
"Through the installation of acoustic sensors on 33 Norway lobsters and the use of a network of robotic instruments, we have been able to know, for the first time, the specie’s patterns of movement at a depth of 400 meters", celebrates Joan Navarro and Joan Baptista Company, researchers at the ICM and leaders of the project RESNEP in which has been framed part of the experimental work done to carry out the study.
This includes the realization, between 2019 and 2020, of three oceanographic campaigns in a pilot area of fishing reserve settled in one of the main prawn fishing grounds of Spain: the marine zone situated between Roses and Palamós, on the Costa Brava. In addition, the team carried out previous technological validation tests at the Obsea submarine observatory, which is operated by the UPC and located 4 kilometres from the port of Vilanova i la Geltrú and 20 meters deep.
"This has allowed us to carry out an exhaustive analysis of the methods of positioning acoustic labels and synchronization of the different receivers, which are essential for a correct geolocation of marked individuals", explains Ivan Masmitja, first author of the study and postdoctoral researcher at the UPC.
The study also addresses the inherent problems presented by species monitoring at great depths and proposes solutions such as the use of autonomous vehicles in underwater acoustics applications and algorithms based on the calculation of probabilities by detection area.
"This experimental work presents a very important qualitative leap for the study of this type of species in its own habitat, providing new methods and practices for the proper monitoring of deep-sea marine species", add Jacopo Aguzzi and María Vigo, researcher and PhD student at the ICM, respectively, for whom "this type of study is essential to establish conservation policies and carry out a correct management of natural marine resources".
"The use of AUVs significantly reduces costs in obtaining data from the seabed, not only by reducing the necessary infrastructure but also by the possibility of using more than one in the same campaign", highlights the UdG researcher Marc Carreras, responsible for the AUV Girona 500 used in the project. In this sense, the researcher assures that "this technology will be essential in the future and for this reason, we are developing new capabilities that allow vehicles to be more autonomous and adaptable to applications".
A cross-disciplinary collaboration
Apart from the ICM, the UPC and the UdG, researchers from the Monterey Bay Aquarium Research Institute (MBARI) in California (USA), the Institut Supérieur de l'Électronique et du Numérique (ISEN Yncréa Ouest) in Brest (France) and the Oslo Metropolitan University (OsloMet) in Oslo (Norway) have also participated in the study providing complementary and essential technological and ecological knowledge to meet the challenges expected in the study of seas and oceans.
"Collaboration between institutions is key to carry out these types of studies where the work of both scientists and technologists is needed", highlight the authors. An example of this is the collaboration between the ICM and the SARTI group of the UPC, which, through Tecnoterra, a unit associated with the CSIC, has managed to provide technological solutions to various scientific challenges that needed, in addition to data obtained during oceanographic campaigns, other data gathered in situ.
In this sense, Joaquín del Río, UPC researcher and head of the Obsea observatory used in the project validation process, underlines the importance of validating in a real environment the sensors and technologies used later in deeper waters: “the prior validation of the technologies and devices used in this research is crucial to increase the possibility of success of the campaign”.