Illegal immigration in the eastern Aegean Sea: a new source of marine litter

The maritime area dominates the current increasing wave of illegal immigration to Europe. The Greek islands of the eastern Aegean Sea are the main entrance points of immigrants arriving from the coasts of Turkey. Immigration to the Greek islands is mainly conducted with inflatable boats, which are abandoned upon arrival along the coasts together with other items such as life-jackets, inflatable tubes, and clothing. This novel type of marine litter dominates many beaches and becomes increasingly abundant. Two beaches in Lesvos Island were surveyed for marine litter, and immigration-related items were found to account for more than 97% of marine litter by weight. Immigration-related littering adds pressure on marine biodiversity and the local economy, impacting the recreational value of beaches

Editorial: Multi-model inference and model selection in Mexican Fisheries

The information theory approach has been widely applied in Mexican fisheries in the last few years. This Special Issue on “Multi-model inference and model selection in Mexican Fisheries” provides the state of the art on this topic in Mexico. It includes studies investigating size at sexual maturity (of the shark Rhizoprionodon terraenovae, the thread herring Opisthonema libertate, and the rocky oyster Striostrea prismatica), and growth (of the cuatete Occidentarius platypogon, the gulf corvina Cynoscion othonopterus, the silky shark Carcharhinus falciformis, juvenile blue crabs Callinectes arcuatus, and Cortes Geoduck Panopea globosa). This Special Issue is an important collection of best practice examples in fisheries science, promoting the shift from the single-model approach to the more robust and less restricted by strict assumptions approach of multi-model inference.JRC.H.1-Water Resource

Modelo del efecto de la temperatura sobre los patrones de eclosión y asentamiento de organismos meroplanctónicos: el ejemplo del pulpo

The duration of embryonic development and the planktonic stage of meroplanktonic species is highly temperature dependent and thus the seasonal temperature oscillations of temperate regions greatly affect the patterns of hatching and benthic settlement. Based on data from the literature on embryonic development and planktonic duration of Octopus vulgaris (common octopus) in relation to temperature, and on observed temperature patterns, several models of hatching and settlement patterns were created. There was a good fit between observed settlement patterns and model predictions. Based on these models we concluded that in temperate regions: (1) when temperature is increasing (from early spring to mid summer) the hatching and settlement periods tend to shorten, while when the temperature is decreasing (during autumn) the hatching and settlement periods tend to lengthen; (2) hatching and settlement peaks are narrower and more intense than a spring spawning peak but wider and less intense than an autumn spawning peak; (3) at lower latitudes, hatching and settlement patterns tend to follow the spawning pattern more closely, (4) the periodic temperature pattern of temperate areas has the potential to cause a convergence of hatching during spring.La duración del desarrollo embrionario y de la etapa planctónica de especies mereoplantónicas depende mucho de la temperatura, por lo que las variaciones estacionales de este parámetro afectan considerablemente a los patrones de eclosión y al asentamiento bentónico. Basándose en datos bibliográficos sobre la duración del desarrollo embrionario y del periodo planctónico del pulpo común, Octopus vulgaris, en relación con la temperatura y en las pautas de temperatura observadas, se han desarrollado varios modelos predictivos de los patrones de eclosión y asentamiento de los alevines. Se observó la existencia de un buen ajuste entre los modelos y los datos de campo referentes al desove y al asentamiento. Según estos modelos, y para las regiones templadas, se concluye que: 1º) cuando aumenta la temperatura (desde principios de la primavera hasta mediados del verano) los periodos de eclosión y asentamiento tienden a reducir su duración, mientras que cuando la temperatura desciende (en otoño) los periodos de eclosión y asentamiento tienden a alargarse; 2º) los picos de eclosión y asentamiento son más estrechos e intensos que el pico de desove en la primavera, pero más anchos y menos intensos en el otoño; 3º) en latitudes inferiores, los patrones de eclosión y asentamiento tienden a ajustarse mejor a las pautas de desove; y 4º) el patrón periódico de la temperatura en áreas templadas tiene capacidad para provocar una convergencia de la eclosión en la primavera.

Records of alien marine species in the shallow coastal waters of Chios Island (2009)

The shallow coastline of Chios Island was surveyed for the presence of any alien marine benthic species, during August 2009. Fourteen randomly selected sites were surveyed by snorkeling during standardized one-hour transects at depths between 0 and 10 m, and the presence of all identified alien benthic species was recorded. Six alien species were identified: Asparagopsis taxiformis, Caulerpa racemosa var. cylindracea, Stypopodium schimperi, Halophila stipulacea, Percnon gibbesi, and Siganus luridus. The green alga C. racemosa var. cylindracea was found in high densities in all the surveyed sites and was characterized as invasive in the island. The brown alga S. schimperi, the crab P. gibbesi, and the fish S. luridussustain established populations in the area. For three of the recorded marine alien species (S. schimperi, P. gibbesi, and S. luridus),Chios Island seems to be the northernmost margin of their geographical range in the Aegean Sea

Alien species related information systems and information management

The conservation of biodiversity and ecosystem services is severely challenged by biological invasions. The rapid globalisation and increasing trends of trade, travel, and transport in recent decades have caused increasing rates of new introductions through various pathways in both aquatic and terrestrial biomes. The Convention on Biological Diversity (CBD) calls the Contracting Parties “to prevent the introduction of, control or eradicate those alien species which threaten ecosystems, habitats or species”. To achieve this target there is a need for accurate, detailed, and timely information on alien species, such as species distribution, pathways of introduction, impacts, and effective management measures. The CBD calls for the “compilation and dissemination of information on alien species that threaten ecosystems, habitats, or species, to be used in the context of any prevention, introduction and mitigation activities”. Such information is necessary to implement policies for the efficient prevention, early detection, rapid response, and management of biological invasions and also to evaluate management measures. However, often data are limited for certain species or ecosystems, making evaluations of impact or an understanding of management options difficult. In recognition of this, a large number of information systems and online databases have been created that document biological invasions on a national, supranational, or global scale, but also act to raise awareness and improve surveillance of biological invasions

Mapping the impact of alien species on marine ecosystems: the Mediterranean Sea case study

Aim. To develop a standardized, quantitative method for mapping cumulative impacts of invasive alien species on marine ecosystems. Location. The methodology is applied in the Mediterranean Sea but is widely applicable. Methods. A conservative additive model was developed to account for the Cumulative IMPacts of invasive ALien species (CIMPAL) on marine ecosystems. According to this model, cumulative impact scores are estimated on the basis of the distributions of invasive species and ecosystems, and both the reported magnitude of ecological impacts and the strength of such evidence. In the Mediterranean Sea case study, the magnitude of impact was estimated for every combination of 60 invasive species and 13 habitats, for every 10 9 10 km cell of the basin. Invasive species were ranked based on their contribution to the cumulative impact score across the Mediterranean. Results. The CIMPAL index showed strong spatial heterogeneity. Spatial patterns varied depending on the pathway of initial introduction of the invasive species in the Mediterranean Sea. Species introduced by shipping gave the highest impact scores and impacted a much larger area than those introduced by aquaculture and the Suez Canal. Overall, invasive macroalgae had the highest impact among all taxonomic groups. These results represent the current best estimate of the spatial variation in impacts of invasive alien species on ecosystems, in the Mediterranean Sea. Main Conclusions. A framework for mapping cumulative impacts of invasive alien species was developed. The application of this framework in the Mediterranean Sea provided a baseline that can be built upon with future improved information. Such analysis allows the identification of hotspots of highly impacted areas, and prioritization of sites, pathways and species for management actions

Crecimiento relativo del cangrejo semiterrestre Pachygrapsus marmoratus: un enfoque a partir de la teoría de la información

The patterns of allometric growth of the grapsid crab Pachygrapsus marmoratus were investigated with an information-theoretic approach. This approach is beneficial, more robust, and may reveal more information than the classical approaches (e.g. hypothesis testing). No differentiation in allometric growth was detected between right and left chelar propods in either sex. Significant sexual differentiation in the allometric growth of chelar propods, abdominal somites and telson was found. It was shown that the allometry of chelar propodus width may be used to identify puberty in males, as there is a marked breakpoint at a carapace width of ~16.0 mm. For females, puberty was identified by the breakpoint in the allometry of the third and fourth abdominal somites at a carapace width of ~16.5 mm. In many cases (e.g. in chelar propods of males, or in most abdominal somites and the telson in females) the classic allometric equation log Y = log a + b log X has no essential support and non-linear allometric models between the log-transformed morphometric characters have to be used.Los patrones de crecimiento alométrico del cangrejo gráspido Pachygrapsus marmoratus, fueron investigados mediante un enfoque a partir de la teoría de la información. Esta aproximación es más robusta, completa, y puede revelar más información que los estudios clásicos (como la comprobación de hipótesis). No se detectó diferenciación en el crecimiento alométrico en los quelípedos derecho e izquierdo en ambos sexos. Sí se halló una diferenciación sexual importante entre el crecimiento alométrico de quelípedos, segmentos abdominales y telson. Se demostró que la alometría del ancho de los quelípedos puede utilizarse para identificar la pubertad en los machos, ya que hay un marcado punto de rotura en una anchura de caparazón de ~16.0 mm. En las hembras, la pubertad se identifica por el punto de rotura en la alometría de los segmentos abdominales tercero y cuarto con un ancho de caparazón de ~16.5 mm. En muchos casos (por ejemplo en los quelípedos de los machos o en la mayoría de los segmentos y el telson en las hembras) la ecuación alométrica clásica log Y = log a + b log X no tiene esencialmente ninguna base y deben utilizarse modelos alométricos no lineales entre los caracteres morfométricos trasformados logarítmicamente