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.

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

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

El boliche en Grecia: Perfiles de descargas e identificación de potenciales artes menores

Although boat seines have a significant share in the total fish landings in Greece, there is little information on boat seine fisheries. The present study aims to identify boat seine métiers on a national level and contribute to a better understanding of their operation in Greece. We used boat seine landings data collected from a large number of ports in the Aegean and east Ionian Sea between 2002 and 2006. The landings profiles were grouped with a two-step procedure: the first step involved a factorial analysis of the log-transformed landings profiles, and the second step was a classification of the factorial coordinates (hierarchical agglomerative clustering). Six métiers were identified in the Aegean Sea, and three in the Ionian Sea. The ‘picarel-bogue’ métier was the most important in both seas, accounting for 54% and 88% of the fishing trips of the sample in the Aegean and Ionian Seas respectively. Apart from picarel and bogue, other important target species were red mullet, European squid, common pandora, chub mackerel, and European pilchard. Varying spatial (within the Aegean and Ionian Seas) and seasonal patterns were evident for the identified métiers.Aunque la flota de boliche contribuya en una cantidad significativa en las descargas totales de pescado en Grecia, la información que trata de la pesca con boliche es escasa. El presente estudio pretende identificar el arte (métier) del boliche en un nivel nacional y contribuir a una mejor comprensión de su operación en Grecia. Se han utilizado los datos de las descargas de la pesca con boliche, recogidos entre 2002 y 2006 en un gran número de puertos en la costa del Mar Egeo y Mar Jónico oriental. Los perfiles de las descargas fueron agrupados siguiendo un procedimiento en dos etapas: el primer paso consistió en un análisis factorial de los perfiles de descargas transformados logarítmicamente, y el segundo paso en una clasificación de las coordenadas factoriales (agrupamiento aglomerativo jerárquico). Se identificaron seis artes menores en el Mar Egeo, y tres en el mar Jónico. El arte menor “caramel-boga” ha sido el principal en ambos mares, alcanzándose valores del 54% y del 88% respecto al número total de las jornadas de pesca muestreadas en el Mar Egeo y Mar Jónico respectivamente. Aparte de caramel y boga, otras especies objetivo de importancia fueron los salmonetes, el calamar, la breca, el estorino y la sardina. Los artes menores identificados han mostrado unos patrones espaciales (dentro de ambos Mar Egeo y Mar Ionio) y estacionales

Experimental evaluation of the energy balance in Octopus vulgaris, fed ad libitum on a high-lipid diet

Abstract A complete energy balance equation was estimated for the common octopus Octopus vulgaris at a constant temperature of 20°C, fed ad libitum on anchovy fillet (Engraulis encrasicolus). Energy used for growth and respiration or lost with faeces and excreted ammonia was estimated, along with total energy consumption through food, for six specimens of O. vulgaris (with masses between 114 and 662 g). The energy balance equation was estimated for the specimens at 10-day intervals. During each 10-day interval, food consumed, body mass increase and quantity of faeces voided were measured. The calorific values of octopus flesh, anchovy flesh and faeces were measured by bomb calorimetry. Oxygen consumption and ammonia excretion rates were monitored for each specimen during three 24-h experiments and daily oxygen consumption and ammonia excretion were estimated. It was found that 58% of the energy consumed was used for respiration. The amount of energy invested in somatic and gonadal growth represented 26% of the total energy budget. The energy discarded through faeces was 13% of consumed energy. The estimated assimilation efficiency (AE) values of O. vulgaris feeding on anchovy (80.9-90.7%) were lower than the AE values estimated for other cephalopod species with different diets of lower lipid content such as crabs or mussels. Specific growth rates (SGR) ranged 0.43-0.95 and were similar to those reported for other high-lipid diets (bogue, sardine) and lower than SGR values found for low-lipid, high-protein diets (squid, crab, natural diet). Ammonia excretion peak (6 h after feeding) followed the one of oxygen consumption (1 h after feeding). The values of atomic oxygen-to-nitrogen (O:N) ratio indicated a protein-dominated metabolism for O. vulgaris

How many marine aliens in Europe?

In the framework of the European Alien Species Information Network (EASIN; http://easin.jrc.ec.europa.eu/), an inventory of marine alienspecies in Europe was created by critically reviewing existing information in 34 global, European, regional and national databases. In total, 1369 marine alien species have been reported in the European seas (including 110 cryptogenic and 139 questionable species); this is a substantial increase from the 737 species previously reported in 2009 based on the DAISIE (Delivering Alien Invasive Species Inventories for Europe; http://www.europe-aliens.org) dataset. Most of the reported species were invertebrates (63.3%), followed by chromists (13.7%), vertebrates (11.6%), and plants (10.1%). Mollusca is the most numerous phylum, followed by Arthropoda, Chordata, and Annelida. Thecountries with the highest reported numbers of marine alien species were Israel, Turkey, Italy, France, Egypt and Greece. A reporting bias is evident as efforts for monitoring and reporting alien species vary among countries