Species identification of small pelagic fish schools by means of hydroacoustics in the Eastern Mediterranean Sea

  Reliable biomass estimates by means of hydroacoustics largely depend on the correct identification of acoustic targets. Data collected during five summer acoustic surveys (2004-2008) in the North Aegean Sea (Greece) were analyzed to explore effective discrimination of small pelagic fish schools according to the species they belong. Discriminant Function Analyses (DFA) using bathymetric, energetic and morphometric school descriptors as explanatory variables were applied per research cruise as well as to pooled data from all surveys. Results revealed that the schools can be successfully classified into the five species considered (anchovy Engraulis encrasicolus, sardine Sardina pilchardus, round sardinella Sardinella aurita, blue whiting Micromessistius poutassou, and Atlantic mackerel Scomber scombrus). The percentage of correct classifications in terms of number of schools was higher in the analyses of the annual cruises (75.6%-95.36%) than in the analysis of pooled data (≈72%). This is because of (i) the lower number of species, as well as (ii) the reduced intraspecific variability, occurring in each separate cruise. Significant differences were detected among school descriptors for the different species, revealing discrete aspects of schooling behaviour for each species. The benefit of the specific approach is that the classification functions of the DFAs can be used to classify a larger set of schools, which has not been possible to assign to specific species. Overall the approach constitutes an objective, more automated and less time consuming procedure for the analysis of acoustic data and can contribute to the improvement of biomass estimates in the area

A modular approach for remote operation of humanoid robots in search and rescue scenarios

In the present work we have designed and implemented a modular, robust and user-friendly Pilot Interface meant to control humanoid robots in rescue scenarios during dangerous missions. We follow the common approach where the robot is semi-autonomous and it is remotely controlled by a human operator. In our implementation, YARP is used both as a communication channel for low-level hardware components and as an interconnecting framework between control modules. The interface features the capability to receive the status of these modules continuously and request actions when required. In addition, ROS is used to retrieve data from different types of sensors and to display relevant information of the robot status such as joint positions, velocities and torques, force/torque measurements and inertial data. Furthermore the operator is immersed into a 3D reconstruction of the environment and is enabled to manipulate 3D virtual objects. The Pilot Interface allows the operator to control the robot at three different levels. The high-level control deals with human-like actions which involve the whole robot’s actuation and perception. For instance, we successfully teleoperated IIT’s COmpliant huMANoid (COMAN) platform to execute complex navigation tasks through the composition of elementary walking commands (e.g.[walk_forward, 1m]). The mid-level control generates tasks in cartesian space, based on the position and orientation of objects of interest (i.e. valve, door handle) w.r.t. a reference frame on the robot. The low level control operates in joint space and is meant as a last resort tool to perform fine adjustments (e.g. release a trapped limb). Finally, our Pilot Interface is adaptable to different tasks, strategies and pilot’s needs, thanks to a modular architecture of the system which enables to add/remove single front-end components (e.g. GUI widgets) as well as back-end control modules on the fly

Neural Learning of Vector Fields for Encoding Stable Dynamical Systems

Lemme A, Reinhart F, Neumann K, Steil JJ. Neural Learning of Vector Fields for Encoding Stable Dynamical Systems. Neurocomputing. 2014;141:3-14

Strong fisheries management and governance positively impact ecosystem status

Fisheries have had major negative impacts on marine ecosystems, and effective fisheries management and governance are needed to achieve sustainable fisheries, biodiversity conservation goals and thus good ecosystem status. To date, the IndiSeas programme (Indicators for the Seas) has focussed on assessing the ecological impacts of fishing at the ecosystem scale using ecological indicators. Here, we explore fisheries Management Effectiveness' and Governance Quality' and relate this to ecosystem health and status. We developed a dedicated expert survey, focused at the ecosystem level, with a series of questions addressing aspects of management and governance, from an ecosystem-based perspective, using objective and evidence-based criteria. The survey was completed by ecosystem experts (managers and scientists) and results analysed using ranking and multivariate methods. Results were further examined for selected ecosystems, using expert knowledge, to explore the overall findings in greater depth. Higher scores for Management Effectiveness' and Governance Quality' were significantly and positively related to ecosystems with better ecological status. Key factors that point to success in delivering fisheries and conservation objectives were as follows: the use of reference points for management, frequent review of stock assessments, whether Illegal, Unreported and Unregulated (IUU) catches were being accounted for and addressed, and the inclusion of stakeholders. Additionally, we found that the implementation of a long-term management plan, including economic and social dimensions of fisheries in exploited ecosystems, was a key factor in successful, sustainable fisheries management. Our results support the thesis that good ecosystem-based management and governance, sustainable fisheries and healthy ecosystems go together.IOC-UNESCO; EuroMarine; European FP7 MEECE research project; European Network of Excellence Eur-Oceans; FRB EMIBIOS project [212085]info:eu-repo/semantics/publishedVersio

New Fisheries-related data from the Mediterranean Sea (October 2015)

In this third Collective Article, with fisheries-related data from the Mediterranean Sea, we present the historical length distribution of Lophius budegassa in the catch of commercial trawlers in the Greek seas; length-weight and length-length relationships of five flatfish species (Lepidorhombus boscii, L. whiffiagonis, Platichthys flesus, Pegusa lascaris and Solea solea) from different coastal areas of Turkey (Black Sea and Eastern Mediterranean Sea); growth of settled Polyprion americanus and length-weight relationships of this species and of Deltentosteus quadrimaculatus, Capros aper and three commercially important groupers in the Eastern Mediterranean Sea; the age, growth and mortality of Zosterisessor ophiocephalus in the Eastern Adriatic Sea; the length-weight relationship and condition factor of Atherina boyeri in a Central Mediterranean semi-isolated lagoon, and also the length-weight and length-length relationships of three Alburnus species from different inland waters in Turkey