Hybridization in the wild between Tursiops truncatus (Montagu 1821) and Delphinus delphis (Linnaeus 1758)

A case of intergeneric hybridization in the wild between a female bottlenose dolphin (Tursiops truncatus) and a short-beaked common dolphin (Delphinus delphis), considered members of 'vulnerable' and 'endangered' subpopulations in the Mediterranean, respectively, by the International Union of Conservation of Nature is described in this paper. The birth of the hybrid was registered in the Bay of Algeciras (southern Spain) in August 2016, and the animal has been tracked on frequent trips aboard dolphin-watching platforms. This unique occurrence is the result of an apparent ongoing interaction (10 years) between a female bottlenose dolphin and common dolphins. The calf has a robust body with length similar to Tursiops, while its lateral striping and coloration are typical of Delphinus. It displays the common dolphin's 'criss-cross' pattern. However, the thoracic patch is lighter than in D. delphis and its dorsal area is light grey, with a 'V' shape under the dorsal fin. This paper also provides a comprehensive mini-review of hybridizations of T. truncatus with other species

Monitoring Extreme Impacts of Rugulopteryx okamurae (Dictyotales, Ochrophyta) in El Estrecho Natural Park (Biosphere Reserve). Showing Radical Changes in the Underwater Seascape

The invasive macroalga Rugulopteryx okamurae represents an unprecedented case of bioinvasion by marine macroalgae facing the European coasts. Since the first apparition of the species in the Strait of Gibraltar in 2015, its fast dispersion along the introduced habitats constitutes a real challenge to develop monitoring strategies that ahead of its impacts. The present study uses three different approaches to address impacts on the benthic ecosystems, at the same time offers relevant data for future management actions in El Estrecho Natural Park (PNE). Information obtained by monitoring permanent sentinel stations revealed a significant loss in resident species coverage after the moment of maximum growth in 2017. Thus, despite coverage of R. okamurae did not strongly varied in the latter years, impacts generated remain high in the habitats studied. Estimations of the invasive species coverage by combining cartographic image analysis and in situ data predicted a major occupation (over 85% coverage) between 10 and 30 m, coinciding with the maximum rocky surface areas (m2) mapped on the PNE. Furthermore, a Citizen Science research collaboration evidenced impacts on the benthic seascape through an ad hoc exploration of images that allowed a “before” and “after” comparison of the invasion process in the same geographic locations. This has made it possible to graphically demonstrate severe changes in the underwater seascape and, therefore, the general impact of this new biological invasion. The spatial colonization estimations combined with the impacts reported by both scientific [Sessile Bioindicators in Permanent Quadrats (SBPQ) sentinel stations] and civilian (Citizen Science) monitoring methodologies claim the urgent development of further studies that allow the design of monitoring strategies against R. okamurae expansion across the Mediterranean and Atlantic waters

The Invasive Macroalga Rugulopteryx okamurae: Substrata Plasticity and Spatial Colonization Pressure on Resident Macroalgae

The present study constitutes the first evaluation of the space colonization strategies performed by Rugulopteryx okamurae when co-occurring with the resident macroalgal community in the introduced areas. Since the first apparition of the nonindigenous macroalga in the Strait of Gibraltar, its high propagation capacity together with its colonization ability has enhanced the establishment success of the species in detriment of the resident biota. In this study, we carried out observational surveys during 2017–2020 in order to assess the coverage levels of R. okamurae on different lighting conditions, surface orientations, and substrata types (artificial and natural). Results revealed that, beyond the high percent coverages already reported at illuminated and semi-illuminated natural rocky habitats, R. okamurae is able to settle on a wide variety of artificial substrata. The settlement performance of the species was also investigated and different mechanisms underlying the space colonization were proposed. Thus, R. okamurae was observed interacting with 43 resident macroalgal species at generally illuminated rocky habitats of the northern Strait coasts. Six colonization mechanisms were proposed for spatial growth scenarios. Overall, results pointed out that, in most of the cases where the invasive species co-occur with the resident community, R. okamurae would be favored as regards spatial growth success. Competitive interactions and environmental factors which influence results obtained must be addressed in order to fully predict impacts on resident communities. Moreover, together with previous scientific works, overall data provided in this study highlight the need to urgent implement management measures focused on habitats susceptible to be invaded, as well as studies on the ecology and dispersal vectors of R. okamurae in the Strait of Gibraltar and adjacent areas

Presencia permanente del delfín común en la bahía de Algeciras. Hacia un plan de gestión, vigilancia y conservación de la especie

La especie Delphinus delphis Linnaeus 1758 está considerada en “peligro crítico de extinción” en Andalucía. En la bahía de Algeciras se localiza de forma permanente, donde se alimenta y reproduce. Durante el periodo de estudio se registraron partos, neonatos y crías en los grupos, observándose que el máximo número estimado de neonatos coincide con los picos de temperatura. Se han identificado las amenazas y evaluado la incidencia del acercamiento de embarcaciones a las manadas. Se aportan datos de distribución de la especie y una cartografía de las zonas con mayor frecuencia de avistamientos y, por tanto, de probabilidad de afección antropogénica. Se propone un plan de gestión y vigilancia ambiental, la delimitación de una zona de protección, así como un protocolo de aproximación a la especie en el temario de titulaciones náuticas.Delphinus delphis Linnaeus 1758 is considered “critically endangered species” in Andalusia finding groups permanently in the bay of Algeciras. During the study period dolphins births, newborns and calves were detected within the groups, showing a positive correlation between estimated number of newborns and Sea Surface Temperature. Threats have been identified and the incidences of vessels approaching the dolphin groups have been evaluated. Distribution of the species and frequency maps of the sightings are provided, and, therefore, the probability of anthropogenic impact. A proposal is made for an environmental management and monitoring plan, the delimitation of a cetacean protection zone, as well as including the cetacean protocol for approaching cetacean at all levels of navigation licenses training programs

Mechanisms for longitudinal transport on early life stages in benthic-pelagic fishes within a tide-dominated estuary

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/00350/201

Rugulopteryx okamurae (E.Y. Dawson) I.K. hwang, W. J. Lee & H.S. Kim (Dictyotales, ochrophyta), alga exótica “explosiva” en el estrecho de Gibraltar. Observaciones preliminares de su distribución e impacto

Durante los últimos dos años, el alga exótica Rugulopteryx okamurae se ha expandido de forma muy agresiva sobre fondos rocosos iluminados del submareal en zonas del estrecho de Gibraltar, produciendo graves impactos sobre las comunidades bentónicas preestablecidas, la acumulación de miles de toneladas de algas de arribazón y problemas de enganches en redes de pescadores. En el presente estudio se describe la morfología y ciclo de vida de esta especie con el fin de facilitar su identificación in-situ, así como características ecológicas –tales como su euritermia o la alta concentración de compuestos alelopáticos en sus tejidos- que podrían explicar su comportamiento expansivo. Actualmente, la distribución de esta especie se encuentra restringida al enclave geográfico del Estrecho, lo cual no ha parecido limitar su comportamiento invasor y superioridad competitiva frente a la biota local. Adicionalmente, la acumulación y descomposición de biomasa en el intermareal y zonas someras podría estar causando impactos indirectos sobre los ecosistemas costeros. Aunque de momento Rugulopteryx okamurae no es considerada formalmente como especie invasora, los resultados provisionales expuestos en este trabajo la postulan como tal.Exotic species Rugulopteryx okamurae has expanded massively on subtidal illuminated marine hard-bottoms within the strait of Gibraltar in the past two years, producing serious impacts over the benthic communities previously established, accumulation of hundreds of tons of seaweed in nearby beaches and wrack zones and hooks on fishing nets. In this study, morphology and lifecycle of this species is described in order to facilitate in-situ identification. Also, ecological characteristics as its euthermia and allelopathy - which may be highly responsible of its invasive behaviour within the Strait and high competitiveness over other native and invasive species - and epibiosis are described. Actually, this species distribution is restricted to the limits of the Strait, which has not limited its invasive behaviour within this area, due to its competitive superiority against local biota. In addition, the accumulation and decomposition of detached biomass nearshore may be causing indirect impacts on coastal ecosystems. Despite Rugulopteryx okamurae is not yet considered as an invasive species, provisional results formally postulate it as such