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The striped dolphin (Stenella coeruleoalba) is a cosmopolitan cetacean and the most commonly sighted dolphin in the Mediterranean Sea. It usually appears in groups of very different sizes, ranging from less than ten to more than 500 individuals, although it is usually found in groups of between 21 and 50 individuals. In the western Mediterranean, and more specifically in the Gulf of Mazarrón, S. coeruleoalba was the most frequently sighted cetacean during the 1042 whale-watching trips. The goal of this study was to establish the spatial and temporal distribution of striped dolphin sightings along the Gulf of Mazarrón between 2004 and 2014. Spatial patterns were analysed using a Random Forest based Species Distribution Model to estimate the presence of the species. Twentythree variables (three geographic, one temporal, eight geomorphometric and twelve oceanographic) were used as predictors. Out of the 1042 cruises, 872 records of striped dolphins were obtained. Some variations in the grouping patterns of these mammals were observed during the years 2006–2007, with an average shift in the size of the groups to fewer individuals (3−10). This variation is probably related to an epizootic event of morbillivirus occurring during those years, which was responsible for an abnormal rate of strandings of striped dolphins and long-finned pilot whales (Globicephala melas). The Random Forest model allowed to select 6 predictors related to morphometry and sea currents, suggesting the importance of specific habitat in offshore areas between 1000 and 3000 m depth in the continental slope.

An emergent disease has relegated populations of the Mediterranean pen shell, Pinna nobilis L. critically endangered to sanctuaries featuring salinities outside the 36.5 to 39 range. Point pattern analysis was used in three areas of the Alfacs Bay (Ebro Delta) still hosting pen shells to assess the possible undergoing of disease spread by comparing the spatial distribution of live individuals vs. empty shells across spatial scales. We also evaluated the importance of other ecological aspects of conservation relevance such as the size distribution of individuals, and the possible association to seagrass habitats. The population assessment showed no recent mortality and a clear dominance of large adults among empty shells (97.3%) pointing to no disease spread during the study period. At the low spatial scale Nearest Neighbor (NN) analyses evidenced significant clustering (NN Ratios of 0.4–0.8), but in one of the zones NN distances were closer in empty shells than in live individuals, suggesting a former localized outbreak. At the larger spatial scale, MDSCA confirmed clustering patterns up to distances of 115 to 190 m, with higher aggregation of empty shells at the same study zone. The bay also featured low juvenile availability (3.2%), which risks the continuity of the population. No evidence for habitat or conspecific selection could be observed from abundance patterns and variation in NN across study regions. Our research provides a tool for assessing population condition in paralic environments, where salinity conditions tend to slow down disease spread, thus allowing a time gap for undertaking conservation decisions.

Pinna nobilis (Linnaeus, 1758) is the largest bivalve endemic to the Mediterranean. It is distributed in a wide range of coastal environments, including estuaries. Pinna nobilis has recently become a critically endangered species (with almost 100% mortality) along the entire Spanish Mediterranean coast. This may be due to coinfections caused by Haplosporidium pinnae and bacterial pathogens such as Mycobacterium spp. We extensively sampled P. nobilis from Mar Menor lagoon (SE Spain), a site where individuals still survive. Using conventional PCR, we found Haplosporidium spp. in 7.1% of mantle and faecal DNA samples in different individuals of P. nobilis. We identified and quantified Haplosporidium pinnae in P. nobilis using Sanger sequencing and qPCR. Faecal H. pinnae detection is non-invasive, unlike biopsies. Therefore, this non-lethal and non-invasive sampling method could contribute to the welfare of living populations, particularly in eutrophic environments, where they are prone to septicaemia. The use of faecal DNA analysis could be a major advance in epidemiology and recovery assessment studies of P. nobilis.

Pinna nobilis is undergoing one of the most dramatic events suffered by an endangered species. An emerging disease has relegated its populations to coastal lagoons or estuaries with salinities beyond the 36.5–39.7 psu range. The Mar Menor is one of two such locations on the Spanish coastline. Poor environmental conditions and eutrophication and anoxia events, that became critical in 2016, 2019 and 2021, have reduced its population in >99 %. In this work, the spatial distribution of the species within the lagoon and the factors determining its survival along the successive crises of eutrophication are studied using a two-stage (presence/absence estimation and density modelling) Species Distribution Model. A potential area of 200.97 ha and an average density of 1.05 ind.100 m2 is estimated for 2020. The viability of the Mar Menor population depends on management actions designed both for the species and to improve the lagoon environmental state.

Coastal marine lagoons are environments highly vulnerable to anthropogenic pressures such as agriculture nutrient loading or runoff from metalliferous mining. Sediment microorganisms, which are key components in the biogeochemical cycles, can help attenuate these impacts by accumulating nutrients and pollutants. The Mar Menor, located in the southeast of Spain, is an example of a coastal lagoon strongly altered by anthropic pressures, but the microbial community inhabiting its sediments remains unknown. Here, we describe the sediment prokaryotic communities along a wide range of environmental conditions in the lagoon, revealing that microbial communities were highly heterogeneous among stations, although a core microbiome was detected. The microbiota was dominated by Delta- and Gammaproteobacteria and members of the Bacteroidia class. Additionally, several uncultured groups such as Asgardarchaeota were detected in relatively high proportions. Sediment texture, the presence of Caulerpa or Cymodocea, depth, and geographic location were among the most important factors structuring microbial assemblages. Furthermore, microbial communities in the stations with the highest concentrations of potentially toxic elements (Fe, Pb, As, Zn, and Cd) were less stable than those in the non-contaminated stations. This finding suggests that bacteria colonizing heavily contaminated stations are specialists sensitive to change.

La presente guía incluye aquellas especies de elasmobranquios que han sido documentadas en los ambientes marinos del litoral de la Región de Murcia. Se han identificado un total de 31 especies de tiburones y rayas. Cada una de ellas está descrita en una ficha que incluye diversos apartados como morfología, hábitat biología y comportamiento, presiones y amenazas, estatus y curiosidades. Además, por primera vez, se presenta un mapa actualizado de la distribución de cada especie en base a los datos obtenidos en todas las fuentes de información disponibles en el momento de la elaboración del documento. El objetivo de esta guía es que se convierta en un recurso divulgativo para ser utilizada como manual de campo por aquellas personas interesadas en ampliar su conocimiento sobre estos animales imprescindibles en el desarrollo de la vida marina y que son grandes desconocidos para gran parte de la ciudadanía. Se trata de la primera guía disponible sobre tiburones y rayas presentes en la Región de Murcia y pretende servir de referencia para otras publicaciones de ámbito regional, estatal e internacional.

Mar Menor is one of the largest coastal lagoons in the Mediterranean basin. Over the years, Mar Menor has suffered a significant environmental degradation due to multiple factors with anthropogenic origin. The transformation from a rain-fed basin to intensive irrigated agriculture has led to an rise in the water inflow and nutrients in the basin, which has provoked severe eutrophication. The increase in nutrients led to changes in the structure and function of the lagoon ecosystems. The epibenthic and suspension feeder organisms have benefited from this imbalance, proliferating and reaching a high population density. The composition and abundance of the species assemblage found in the sub-coastal bottoms of the coastal lagoon after the environmental crisis occurred in 2016, using artificial settlement structures. The variation in community density and affinity between sampling sites in 2017 and 2018, were determined. A total of 31 species belonging to 27 genera and 7 phyla were observed in 11 samples. The best represented class are polychaeta (Phylum Annelida) with 11 identified species. The genus with the greatest species richness was Hydroides with two species: H. dianthus (Verrill, 1873), and H. elegans (Haswell, 1883), both of them considered potentially invasive and opportunistic species followed by the genus Serpula, with two species: S. vermicularis (Linnaeus, 1767), and S. concharum (Langerhans, 1880) and the genus Branchiomma was represented with another exotic invasive species, B. boholense (Grube, 1878), which is only found in collectors in 2018. These results have allowed to increase the knowledge about the effect of eutrophication in the structure of the fouling community in the assemblage succession in the Mar Menor coastal lagoon.

For decades, inputs of nutrients and organic matter into the Mar Menor coastal lagoon have favored the change from an original oligotrophic to a eutrophic state. The lagoon reached a stage of severe eutrophication and “environmental collapse” during the spring of 2016. This paper describes the massive growth of Serpulidae (Annelida, Polychaeta) forming large aggregations and reef structures after the environmental collapse caused by the eutrophic crisis. Four species belonging to the genera Hydroides and Serpula were identified; the identified species are Hydroides elegans, Hydroides dianthus, Serpula concharum, and Serpula vermicularis. The presence of bi-operculate and tri-operculate specimens is also documented in this study.

Se trata de una experiencia de innovación educativa interuniversitaria dirigida al alumnado del segundo curso del Grado de Ciencias del Mar de la Universidad de Alicante. Esta actividad, no sólo promueve la interacción entre dos Universidades (Alicante-Vigo), favoreciendo las relaciones interuniversitarias, tanto entre el profesorado como alumnado de ambas universidades, sino también fomenta el intercambio de experiencias y conocimientos en innovación docente entre ambas instituciones. Se trata de una acción en la que se aplica una metodología basada en el aprendizaje activo (Learning by doing) y cooperativo. La puesta en marcha de esta actividad permitirá la adquisición por parte del alumnado de competencias específicas complementarias a las adquiridas en las asignaturas implicadas en la actividad transversal. Esta actividad se ha desarrollado sin ningún impedimento durante 8 cursos académicos consecutivos, lo que muestra el interés por parte del profesorado y del alumnado de mantener la actividad. Sin embargo, durante este último curso académico, debido al confinamiento, no ha sido posible desarrollar la actividad en sí, pero si se ha mostrado la voluntad del alumnado en participar, siendo casi el 100% de los alumnos de segundo curso del Grado, los inscritos en el programa ContiUA.

Populations of the Mediterranean fan mussel Pinna nobilis have progressively decreased over the last decades as a result of anthropogenic activities. The rate of decline has strongly increased since 2016, when a mass mortality event triggered by the parasite Haplosporidium pinnae occurred, and evidence exists that Mycobacterium species may also have played a major role in the event. Indeed, the epidemic has spread throughout the Mediterranean, although coastal lagoons seem to offer a degree of ‘resistance’ against the parasite. In the early 1980s, P. nobilis appeared in the Mar Menor lagoon and rapidly became an important component of the benthos. However, colonization of the lagoon by the fan mussel was cut short in 2016 when a massive mortality event occurred, possibly as a consequence of the environmental collapse that occurred in the lagoon, parallel to the mortality that the species suffered in the Mediterranean that same year. In this study, we estimated the spatial distribution of P. nobilis in the Mar Menor for 3 periods: 2003-2004, 2013 and 2016. The first 2 periods use published data, and the last period uses data collected in a new campaign. The probability of occurrence for the 3 periods was estimated using random forest and random forest regression-kriging models. The main environmental variables that determined the dispersion and colonization of the bivalve in the lagoon before 2016 are also identified.

A devastating mass mortality event (MME) very likely caused by the protozoan Haplosporidium pinnae first detected in 2016 in the Western Mediterranean Sea, is pushing the endemic bivalve Pinna nobilis to near extinction. Populations recovery, if possible, will rely on larval dispersal from unaffected sites and potential recolonization through recruitment of resistant juveniles. To assess the impact of the MME on the species’ larval recruitment, an unprecedented network of larval collector stations was implemented over several thousands of kilometers along the Western Mediterranean coasts during the 3 years after the onset of the MME. The findings of this network showed a generalized disruption in recruitment with dramatic consequences for the recovery of the species. However, there were exceptions to this pattern and recruits were recorded in a few sites where the resident population had been decimated. This hints to the importance of unaffected populations as larval exporting sources and the role of oceanographic currents in larval transport in the area, representing a beacon of hope in the current extremely worrying scenario for this emblematic species.

Anthropogenic drivers and global warming are altering the occurrence of infectious marine diseases, some of which produce mass mortalities with considerable ecosystemic and economic costs. The Mediterranean Sea is considered a laboratory to examine global processes, and the fan mussel Pinna nobilis a sentinel species within it. Since September 2016, fan mussels suffer a die-off, very likely provoked by the protozoan Haplosporidium pinnae. Population dynamic surveys, rescue programmes, larvae collector installation and protection of infected adults from predators, have increased knowledge about the factors conditioning the spread of the die-off; previous model simulations indicate that water temperature and salinity seem to be related to the manifestation of the disease, which at the end are strongly influenced by climate change and anthropogenic actions. The absence of natural recruitment implies that fan mussel populations are not recovering, but the survival of populations living in paralic environments provides an opportunity to study the disease and its conditioning factors. The fan mussel disease outbreak provides a case example for how climate change may mediate host-protozoan dynamics and poses several questions: are we witnessing the potential extinction of a sentinel species? Can we avoid it by applying active measures? If so, which measures will be more effective? How many other more overlooked species might experience a massive and unnoticed die-off before it is too late to implement any preservation action? This is especially relevant because the loss of keystone species can drive to community effects that influence marine ecosystem processes.

Esta guía tiene como objetivo poner en valor el patrimonio natural, costero y sumergido del sureste de la Región de Murcia. A través de la propuesta de cinco itinerarios auto guiados se brinda al lector la posibilidad de disfrutar de la riqueza de 3 enclaves terrestres y 2 dos acuáticos, accesibles para todas las edades y condiciones físicas. En cada uno de los recorridos se ponen de manifiesto los valores naturales, históricos y sociales del Puerto de Mazarrón, Isla Plana y La Azohía, dando a conocer las figuras de protección que confluyen en la zona, con especial atención en la Reserva Marina de Interés Pesquero de Cabo Tiñoso. Incluye mapas, ilustraciones de diferentes especies y un apartado dedicado a las buenas prácticas ambientales que se deben tener en cuenta durante las visitas con el fin de realizar un uso responsable de los espacios naturales durante las actividades de interacción con el medio. Se pone a disposición del usuario esta guía interactiva con información complementaria disponible a través de enlaces externos que conducen al descubrimiento detallado de los contenidos.

La red de innovación docente centrada en la actividad de carácter transversal y multidisciplinar interuniversitaria realizada en el grado de Ciencias del Mar de la Universidad de Alicante, posee como objetivo principal su desarrollo y seguimiento. En esta actividad están implicadas dos Universidades en las que se imparte el Grado de Ciencias del Mar; la Universidad de Alicante (UA) y la Universidad de Vigo (UV). La finalidad de este proyecto es la de promover prácticas docentes transversales en un entorno biogeográfico distinto, que permita al alumnado conocer un ambiente marino diferente al de referencia (Mediterráneo). Esta actividad promueve, a su vez, la interacción entre estudiantes y profesorado de distintas universidades. Es preciso destacar que esta actividad se lleva realizando a lo largo de 8 cursos académicos y ha tenido muy buena acogida, tanto por parte del profesorado como del alumnado. Dicha acción docente incluye objetivos como la adquisición de conocimientos complementarios entre ambas universidades (conocimientos que permitan al alumnado comparar diferentes ambientes marinos, biodiversidad litoral costera y marina, geomorfología y sedimentología costera marina) y destrezas para la aplicación de técnicas de muestreo, así como la adquisición de las competencias específicas, necesarias para el trabajo cooperativo.

La adquisición de las competencias propuestas no siempre es percibida adecuadamente por los alumnos. Se analizan las competencias propuestas en las asignaturas, la valoración de éstas y la percepción de adquisición de esas competencias, la aplicación de diferentes estrategias de aprendizaje para evaluar el nivel de autopercepción de las competencias adquiridas y la definición de indicadores que ayuden a diagnosticar el nivel de autopercepción. Las competencias propuestas en las asignaturas son muy generales y se apartan de los contenidos y objetivos específicos de las asignaturas. Los alumnos dan importancia alta o muy alta a la mayoría de las competencias propuestas. Dan una adquisición alta a aquellas que más directamente se han desarrollado durante el curso, y valoraciones bajas a aquellas competencias generalistas y vagas. Los métodos basados en proyectos son los que generen una autopercepción de aprendizaje mejor y más ajustada a lo que realmente ha aprendido el alumnado. Indicadores que permitan una evaluación eficaz y que generen una autopercepción del aprendizaje más ajustada a la realidad son la asistencia a clases presenciales de manera continua, el conocimiento pleno de qué competencias se deben adquirir y la lectura de la guía docente al principio del curso.

A mass mortality event is devastating the populations of the endemic bivalve Pinna nobilis in the Mediterranean Sea from early autumn 2016. A newly described Haplosporidian endoparasite (Haplosporidium pinnae) is the most probable cause of this ecological catastrophe placing one of the largest bivalves of the world on the brink of extinction. As a pivotal step towards Pinna nobilis conservation, this contribution combines scientists and citizens’ data to address the fast- and vast-dispersion and prevalence outbreaks of the pathogen. Therefore, the potential role of currents on parasite expansion was addressed by means of drift simulations of virtual particles in a high-resolution regional currents model. A generalized additive model was implemented to test if environmental factors could modulate the infection of Pinna nobilis populations. The results strongly suggest that the parasite has probably dispersed regionally by surface currents, and that the disease expression seems to be closely related to temperatures above 13.5 °C and to a salinity range between 36.5–39.7 psu. The most likely spread of the disease along the Mediterranean basin associated with scattered survival spots and very few survivors (potentially resistant individuals), point to a challenging scenario for conservation of the emblematic Pinna nobilis, which will require fast and strategic management measures and should make use of the essential role citizen science projects can play.

During mining activities historically developed at Sierra Minera (Cartagena-La Unión, Spain), high amounts of trace elements were discharged to the Mar Menor coastal lagoon mainly through El Beal Wadi. The objective of this study is to establish the role played by the Cymodocea nodosa in the coastal marine dynamics of trace elements at the mouth of the wadi. To this end, the content of nine trace elements (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in different marine environmental compartments (i.e. marine and coastal sediments, C. nodosa tissues collected from live seagrass and C. nodosa beach cast litter) at two different locations were determined by inductively coupled plasma atomic emission spectrometry. The results showed that the seagrass C. nodosa could mobilise part of the elements present in marine sediments and water, thereby causing their re-accumulation in the coastal sediments through the C. nodosa beach cast litter.

Marine management in Europe has progressed in implementing a European legal framework. The directives stand out among the legal instruments of such framework; their main objective is to conserve biodiversity in the marine environment in order to maintain a good ecological status. For the application of the directives, it is necessary to improve knowledge of the reef habitat by identifying its ecological value as a first step to define its conservation and ecological status. This study has identified the state of conservation in the rocky coastal habitat of the Region of Murcia (SE Spain) by using the presence of benthic focal species for each type of landscape as an indicator. To identify the landscape units, a hierarchical classification of rocky habitats was carried out. The existence of comparable units makes it possible to search for indicators of ecological status and compare the units within each category. After the definition of landscape units, the specific reference level for rock habitat, adapted to each of the “landscape types,” was defined, allowing its ecological value to be determined; the focus on focal species can help in defining conservation objectives. Of the rocky landscape units analysed, 94% have a high ecological value. In conclusion, with the methodology proposed in this paper, it is possible to easily define the specific reference level for rock habitat and determine its status in relation to it. This way it is possible to provide rapid information on the environmental status of rocky landscape units.

Con la finalidad de promover la coordinación y el trabajo en equipo del profesorado del Departamento de Ciencias del Mar y Biología Aplicada, se comenzó una red vertical de investigación para la mejora de la calidad docente. El objetivo de esta red es la búsqueda de una metodología transversal que permita la coordinación entre asignaturas complementarias a través de prácticas docentes. Mediante criterios de evaluación coordinados se pretende realizar el seguimiento de las técnicas de aprendizaje orientadas a la adquisición del método científico como base en la formación de los nuevos investigadores. En el proceso de evaluación se aplicaban diferentes acciones pedagógicas según el curso evaluado, ya que el grado de madurez del alumno es un punto decisivo en la aplicación del método científico. En base a los resultados previos obtenidos, se detecta un vació que hace necesario incorporar una nueva evaluación que permita confirmar la consolidación del conocimiento del alumnado representado el trabajo integrador del conocimiento adquirido durante sus estudios, el Trabajo Fin de Grado (TFG). En esta asignatura los alumnos y alumnas deben aplicar las destrezas adquiridas a lo largo del Grado, siendo el paso previo a su incorporación como egresados de Ciencias del Mar y Biología.

En la presente memoria se detallan las actividades realizadas en el marco de la red de innovación docente cuyo objetivo principal es el diseño y desarrollo de una actividad transversal interuniversitaria (Universidad de Alicante y Universidad de Vigo), en el grado de Ciencias del Mar de la Universidad de Alicante. A través de esta actividad se propone la participación de los estudiantes en otro contexto universitario (Universidad de Vigo), interactuando con profesorado y estudiantes de otra universidad. Los objetivos incluyen actividades de adquisición de conocimientos complementarios (comparación entre ambientes atlánticos y mediterráneos, biodiversidad litoral costera y marina, geomorfología y sedimentología costera marina) y aptitudes para la capacitación de técnicas de muestreo. La presente memoria recoge aspectos de coordinación, diseño de las prácticas a desarrollar así como de sus materiales docentes, metodologías de evaluación del alumnado, así como la evaluación de la propia acción educativa desarrollada.

En la presente memoria se detallan las actividades realizadas en el marco de la red de innovación docente de la Universidad de Alicante del mismo título. Fruto de la colaboración docente entre el profesorado de la Universidad de Alicante y de la Universidad de Vigo, desde el año 2012 se viene realizando en el grado de Ciencias del Mar de la Universidad de Alicante, una actividad interuniversitaria en el dominio marino Atlántico. La actividad, diseñada para el alumnado de segundo curso consta de tres días de campo en el que se analizan de forma multidisciplinar cuestiones relacionadas con la ecología, zoología, botánica sedimentología y geomorfología marina del entorno de la ría de Vigo. En la presente memoria, se describe los detalles de la última campaña, así como los detalles y el material de apoyo de dos de las prácticas realizadas (levantamiento de perfiles binómicos y caracterización sedimentológica de sistemas de isla-barrera lagoon).

El alumnado del Grado de Ciencias del Mar de la Universidad de Alicante, ha de adquirir competencias relacionadas con el método científico. Dichas competencias son adquiridas y afianzadas a lo largo de los diferentes cursos del grado mediante trabajos de investigación dirigidos en asignaturas afines y/o complementarias. El proceso comienza en la asignatura del primer curso “Iniciación a las Ciencias del Mar”, como una de las competencias principales de esta asignatura, y continua en las asignaturas de cursos superiores: “Biología Marina” (segundo curso) y “Ordenación y Conservación de los Recursos Vivos Marinos” (cuarto curso). El objetivo general del presente trabajo es el seguimiento y consolidación de la metodología empleada en las diferentes actividades de carácter práctico de dichas asignaturas para la formación del alumnado de Ciencias del Mar como futuros investigadores. La valoración de la adquisición de las competencias de interés se realiza mediante el uso de herramientas de evaluación estandarizadas (rúbricas) elaboradas por el equipo docente implicado de forma consensuada. Los resultados obtenidos al aplicarlas muestran que las competencias adquiridas por el alumnado en primero y afianzadas en segundo, son implementadas en cuarto curso y probablemente en su Trabajo Fin de Grado.

El impacto producido sobre organismos sésiles como consecuencia del incremento de actividades acuáticas está cada vez más estudiado. Aunque el daño generado de forma puntual por un buceador no es grave, el efecto acumulativo de la actividad a lo largo plazo puede provocar alteraciones severas. Las gorgonias son organismos suspensivoros con un papel significativo en los procesos de transferencia de energía entre las comunidades planctónicas y bentónicas. En las zonas más frecuentadas, la mortalidad de las gorgonias puede verse triplicada por los daños y arrancamientos producidos. En la Reserva Marina de Interés Pesquera (RMIP) de Tabarca, las poblaciones se distribuyen de forma irregular entre los 3- 40 m. Las especies comunes de la reserva son: Eunicella singularis, E. cavolini, E. verrucosa y Leptogorgia sarmentosa. El presente estudio fue llevado a cabo durante los meses de Marzo-Junio de 2015 en zonas someras de Tabarca. De los 17 individuos localizados, un 70.59% pertenecían a la especie Leptogorgia sarmentosa, mientras que Eunicella singularis contribuía con el 29.41% . La mayor parte de las colonias se presentaban dispuestos hacia la orientación NE-NNE o su complementario del cuadrante 3, coincidiendo con la corriente principal de a la isla. Este trabajo ha permitido obtener información sobre las poblaciones de gorgonias en un entorno protegido pero frecuentado por buceadores., The impact on sessile organisms is increasingly studied as a result of water activities, considering although the impact produced by a diver is not serious, the cumulative effect of divers passing by reservation throughout the year can cause several changes. Gorgonians are suspension feeders with a significant role in the processes of energy transfer between planktonic and benthic communities. In the busiest areas, natural mortality of gorgonians can be tripled for damages caused avulsion. In the marine reserve of Tabarca, populations are distributed unevenly between 3 -40 m. The common species of the reserve are: Eunicella singularis, E. cavolini, E. verrucosa and Leptogorgia sarmentosa. This study was conducted during the months of March to June 2015 in the MR of Tabarca. About the 17 individuals located, 70.59% belonged to the species Leptogorgia sarmentosa, while 29.41% belonged to the species Eunicella singularis. The spatial distribution of organisms is quite heterogeneous, being located between 3 m and in no case exceeding 12 m. Although no statistically significant differences between populations of both species in the two sampling points chosen, it can be seen as both species have a slightly larger dimensions in La Nao. On the other hand we have seen that there is no relation between the inclination to present the substrate opposite the tilt of growth. However, in terms of orientation, most individuals had disposed toward the NE-NNE orientation or otherwise, in the supplementary quadrant. In conclusion, this study has yielded information on the populations of gorgonians in an environment like the Marine Reserve of Tabarca.