Acoustic tracking of nephrops norvegicus by networked moored hydrophones in a deep-sea no-take reserve of the North Western Mediterranean Sea

Abstract

Knowing the displacement capacity and mobility patterns of fished marine resources is pivotal to establish effective conservation management strategies in marine ecosystems. Accurate behavioral information of deep-sea fished ecosystems is necessary, but currently scarce, to establish the sizes and adequate locations of marine protected areas within the framework of large international societal programs (e.g. European Community H2020, as part of the Blue Growth economic strategy). A breakthrough in the autonomous capability of mobile platforms to deliver data on animal behavior beyond traditional fixed platform capabilities (e.g. cabled observatories) is overcoming these limitations. Here, we present useful example of that potential in relation to the implementation of autonomous underwater vehicles (AUVs) and remotely operated vehicles (ROVs) as an aid for acoustic long-baseline localization systems for autonomous tracking of Norway lobster (Nephrops norvegicus), one of the key resources exploited in European waters. We reported the outcomes of that monitoring in combination with seafloor moored acoustic receivers to detect and track the movements of 33 tagged individuals at 400 m depth over more than three months. We identified best procedures to localize both the acoustic receivers and the tagged-lobsters, based on cutting-edge algorithms designed for off-the-self acoustic tags identification. These procedures represent an important step forward for prolonged, in situ monitoring of deep-sea benthic animal behavior at meter spatial scales