Sperm whales Physeter macrocephalus show a steady population decline, yet despite their threatened status, there remains a dearth of knowledge in the Mediterranean Sea. The current study reports the preliminary results of sperm whales' acoustic patterns within the Gulf of Taranto and the Northwestern Levantine Sea. "Regular" clicks were recorded in both regions indicating the presence of foraging grounds. "Codas" were also present in the Northwestern Levantine. The presence of codas and social units emphasises the importance of the North-western Levantine as potential nursery grounds. Further, interclick intervals were slightly smaller for the Taranto Gulf while recordings from the North-western Levantine Sea showed similarities with the Mediterranean Sea. Lastly, sperm whales were larger in size in the Taranto Gulf compared to the Northwestern Levantine Sea. The current results depended on data collected on a single date, therefore further research must be implemented to understand the acoustic patterns of sperm whales.

In this paper the idea to develop an underwater drone optimized for shallow water, inland ports and small inlets is shown. The vehicle should be simple and robust: a mathematical part is included on the vertical balance to be able to size weights and payload volumes.

Acoustic, radio frequency (RF) and optical waves systems are the technologies that are used to carry out underwater wireless communications. In scientific, military and industrial sectors, the development of robust and efficient submarine wireless communication links is of enormous interest. To achieve secure short-range wireless communications, the Underwater Optical Wireless Communication (UOWC), which uses the 450-550 nm spectral range of the electromagnetic spectrum, is a good technology. Recently, UOWC applications have been proposed for environmental monitoring, offshore exploration, and military operations. There are many review articles published on this topic. However, research in this field evolves rapidly as does existing literature. The article deals with current and potentially available UWOC technologies in the near future. It is aimed at those who want to undertake studies in this field. Obviously, this paper does not attempt to cover every single aspect of UWOC.

The study of cetaceans is of vital importance to infer biological information useful to drive sustainable action plans aimed at preserving the marine environment and its biodiversity. In a recent study, we developed a novel algorithm for the detection of dorsal fins in the context of a fully automated pipeline for the photo-identification of Risso's dolphins. A lightweight convolutional neural network (CNN) architecture was proposed to recognize fins among cropped images, filtering the inputs for the photo-identification algorithm. In this paper, we compare the performances of that custom CNN to another extremely efficient architecture: Shufflenet. Training an efficient classifier is a key effort to speed up the first part of the photo-identification pipeline, enabling the feasibility of large scale ecological studies. The experiment confirms that both architectures provide a robust feature extraction capability for the problem in hand, even with a significantly smaller number of parameters with respect to other popular state-of-the-art CNNs.

The present work is a part of a larger project relative to design of an instrumented spar buoy within the multi purpose "Lab on Sea" unit equipped with an energy harvesting system for use in marine applications. Such a system wil l be based on deformable bands integral to the unit to convert the wave motion energy into electricity through piezo patch transducers. In this paper, a "fixed point" spar buoy scale model suitable for tests in a controlled ripples type wave motion channel was designed, built and tested. The purpose of this model is to verify that it remains fixed maximizing, then, the displacement of the bands under wave motion. To evaluate its response, the buoy scale model was equipped with a measuring devic e consisting of a MEMS accelerometer and a gyroscope. Results of acquisitions from on board sensors revealed a very low susceptibility of the buoy scale model to the wave motion imposed.