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Delphinus delphis Linnaeus 1758 is considered an endangered species in the Mediterranean. The species is resident in the Bay of Algeciras - Gibraltar (southern Spain; waters partially shared with Gibraltar, UK). This area is subject to strong anthropogenic pressure, but with an input of renewed waters in its central area. During three consecutive years (March 2017-March 2020), sightings were observed concentrated along the submarine canyon that runs north to south across the bay, forming a "specular S″ with a maximum depth of 460 m. The pods of Dd showed a continuous or semi-continuous spatial distribution along the vertical axis of the submarine canyon, where they feed, mate, breed and rear calves in a well-defined area that constitutes a critical habitat. This area has been cartographically delimited, choosing the area of maximum dolphin frequency as highly vulnerable due to the possibility of collisions with small vessels (15 m) and interactions with sport fishing activities (popping, ballooning, trolling) which constitute the main threat counting the derived impacts from noise pollution. Spatio-temporal mapping has been developed to visualize the overlapping between the dolphin groups and small vessels. Mapping analysis has shown that an international Spanish-British micro-sanctuary urgently needs to be established in order to create a protected area specifically for the common dolphins, and for other species which inhabit/use the waters between Spain and Gibraltar. Coordinates and a delimited surface area have been proposed in this paper.

Mechanisms that control the longitudinal transport of larvae and juveniles in nursery grounds such as estuaries are reported for some species. However, the behaviour and population consequences of these mechanisms are still uncertain. In this study, we tested selective tidal-stream transport from the along-channel (up- and downstream) and cross-channel (from one margin to the other) perspectives for two kinds of fish: estuarine-resident gobies (Pomatoschistus spp.) and marine estuarine-opportunistic anchovies (Engraulis encrasicolus). Three cruises were conducted in the lower Guadalquivir estuary, on the ebb and on the flood of spring tides in summer. Plankton samples were collected across a channel section, at three stations (one in the middle of the channel and two in adjacent shallower areas), near the surface and near the bottom simultaneously. In addition, multiple physico-chemical variables (temperature, turbidity, dissolved oxygen, pH, salinity, chlorophyll-a, along with wind and current direction and velocity) were measured to examine the different correlations used by the studied fish in their strategies. The benthic distribution of gobies indicated that they used flood currents near the bottom of lateral (shallow) areas to ingress into and remain in the estuary, temperature and/or dissolved oxygen being their main possible cues. On the contrary, the anchovies were more abundant near the surface, especially on the ebb tide, showing downstream advection, which was mainly influenced by salinity. However, the largest individual anchovies in the lateral/shallow zones suggested a behavioural ontogeny, which, together with wind induced transport, could contribute to their retention. This comparison also enhanced the knowledge of the habitat distribution of two species common and abundant in estuaries, anchovies and gobies. Universidad del Algarve UID/MAR/00350/2013

During the Anthropocene, species are becoming extinct at unprecedented rates, a trend that will be difficult to reverse, even if we ignore the possibility of a considerable extinction debt. Among the different factors that affect the natural environment, fragmentation of ecosystems by urbanization processes can cause a reduction in species population sizes, thus enhancing their risk of extinction. Nevertheless, some species can maintain stable populations in these urbanized ecosystems. This is the case of the intertidal mollusc Patella ferruginea (Gmelin, 1791), a broadcast spawner, and a sequential protandrous hermaphrodite limpet, whose populations have been historically decimated due to human harvesting. In this study, we analyse the benefits of a new marine conservation tool called ¨Artificial Marine Micro-Reserves¨ (AMMR) in P. ferruginea, one of the most endangered marine invertebrates of the Mediterranean Sea. The results showed that accessibility is the main factor concerning the conservation status of this species, with no-entry areas where populations achieve balanced sex-ratios and high reproductive outputs. The present study was conducted in Ceuta (North Africa, Gibraltar Area), and among its varying results, it shows that in the same body of water inside the port, the proportion of females of P. ferruginea in the area without accessibility (high protection) was 4.68 and 43.54 times higher than in the medium and low accessibility (non-protected areas), respectively. Therefore, the effective protection of these artificial areas has a positive effect on population size structures, as the female's percentage in the population is crucial for fostering the creation of genetic bridges for the recolonization of natural habitats. Furthermore, a potential ‘umbrella effect’ can be derived from the implementation of the proposed AMMR in other protected species, bioindicators, or commercially exploited species detected in artificial structures. In this sense, the creation of artificial marine microreserve networks (AMMRNs) in coastal defense structures is in line with the interdisciplinary approach of Ecosystem-Based Management (EMB), given that this methodology balances ecological, social and governmental principles for achieving humane sustainable development.