ESPECIES

Toxoplasma gondii infection in seagull chicks is related to the consumption of freshwater food resources

Enlace mardeaves Larus michahellis,PUBLICACIÓN CIENTÍFICA,REPOSITORIO ,,
Cabezón, O., Cerdà-Cuéllar, M., Morera, V., García-Bocanegra, I., González-Solís, J., Napp, S., Ribas, M.P., Blanch-Lázaro, B., Fernández-Aguilar, X., Antilles, N. & López-Soria, S., 2016. Toxoplasma gondii Infection in Seagull Chicks Is Related to the Consumption of Freshwater Food Resources. PloS one, 11(3), p.e0150249.
Understanding the spread of Toxoplasma gondii (T. gondii) in wild birds, particularly in those with opportunistic feeding behavior, is of interest for elucidating the epidemiological involvement of these birds in the maintenance and dissemination of the parasite. Overall, from 2009 to 2011, we collected sera from 525 seagull chicks (Yellow-legged gull (Larus michahellis) and Audouin’s gull (L. audouinii)) from 6 breeding colonies in Spain and tested them using the modified agglutination test (MAT) for the presence of antibodies against T. gondii. Chick age was estimated from bill length. Main food source of seagull chicks was evaluated using stable isotope analyses from growing scapular feathers. Overall T. gondii seroprevalence was 21.0% (IC95% 17.5–24.4). A generalized linear mixed-effects model indicated that year (2009) and food source (freshwater) were risk factors associated to the individual risk of infection by T. gondii, while age (days) was close to significance. Freshwater food origin was related to the highest seroprevalence levels, followed by marine origin, supporting freshwater and sewages as important routes of dispersion of T. gondii. Year differences could indicate fluctuating rates of exposure of seagull chicks to T. gondii. Age ranged from 4 to 30 days and seropositivity tended to increase with age (P = 0.07), supporting that seropositivity is related to T. gondii infection rather than to maternal transfer of antibodies, which in gulls is known to sharply decrease with chick age. This study is the first to report T. gondii antibodies in Yellow-legged and Audouin’s gulls, thereby extending the range of intermediate hosts for this parasite and underscoring the complexity of its epidemiology.

The importance of hatching date for dominance in young shags

Enlace mardeaves Phalacrocorax aristotelis,PUBLICACIÓN CIENTÍFICA,REPOSITORIO ,

Velando, A., 2000. The importance of hatching date for dominance in young shags. Animal Behaviour, 60(2), pp.181-185.

In birds, conditions and experience in the nest may influence the social rank of juveniles after they become independent. Three main factors may be involved: (1) mass at fledging, larger birds being better able to compete; (2) brood hierarchy, dominance in the brood continuing after the birds leave the nest; and (3) hatching date, birds hatching earlier having more experience and a greater ability to compete. I studied the effect of these factors on the agonistic behaviour of juvenile European shags, Phalacrocorax aristotelis, in crèches. Of all the factors, only hatching date had a significant influence on the dominance rank of juveniles. Birds that hatched earlier had a higher rank. Additionally, males were somewhat more aggressive than females. The importance of an individual’s hatching date for its social rank may have consequences for its future reproductive value.

Acetylcholinesterase activity in seabirds affected by the Prestige oil spill on the Galician coast (NW Spain)

Enlace mardeaves Alca torda,Fratercula arctica,PUBLICACIÓN CIENTÍFICA,REPOSITORIO,Uria aalge ,,,,
Oropesa, A.L., Pérez-López, M., Hernández, D., García, J.P., Fidalgo, L.E., López-Beceiro, A. & Soler, F., 2007. Acetylcholinesterase activity in seabirds affected by the Prestige oil spill on the Galician coast (NW Spain). Science of the total environment, 372(2), pp.532-538.

In November 2002, the tanker Prestige broke in two and sank at the bottom of the ocean spilling about 70,000 t of fuel oil, which reached the coast of Galicia. It was considered the largest spill in maritime history, greatly affecting marine and related avian species. The spilled fuel oil contained high concentrations of polycyclic aromatic hydrocarbons (PAHs). Many species were affected and were found dead, although ongoing research is still being carried out on the sublethal effects. In this sense, little is known about the action of PAHs on Cholinesterase activity in seabirds. Consequently, the purpose of this study was to provide more information on the neurotoxicity of fuel oil on the seabirds most affected by the Prestige accident: common guillemot, Atlantic puffin and razorbill. On the other hand, data on normal values of acetylcholinesterase (AChE) activity were obtained to supply non-exposed values in seabirds. The oil spill produced a clear inhibitory effect on brain AChE activity in common guillemot (16%, p ≤ 0.01) and razorbill (22%, p ≤ 0.01), but not in Atlantic puffin (4%). Physiological levels of brain AChE, expressed in nmol acetylcholine hydrolysed min− 1 mg− 1 protein were similar in non-exposed common guillemot (388.6 ± 95.0) and Atlantic puffin (474.0 ± 60.7), however, razorbill values were higher (644.6 ± 66.9).

Heavy metal and arsenic content in seabirds affected by the Prestige oil spill on the Galician coast (NW Spain)

Enlace mardeaves Alca torda,Fratercula arctica,PUBLICACIÓN CIENTÍFICA,REPOSITORIO,Uria aalge ,,,
Pérez-López, M., Cid, F., Oropesa, A.L., Fidalgo, L.E., Beceiro, A.L. & Soler, F., 2006. Heavy metal and arsenic content in seabirds affected by the Prestige oil spill on the Galician coast (NW Spain). Science of the total environment, 359(1), pp.209-220.

Seabirds are top consumers in marine foodchains which offer opportunities to detect and assess the toxicological effects of different inorganic elements on the marine ecosystem. In order to provide baseline data concerning trace element levels in seabird species from NW Spain, zinc, copper, arsenic, chromium, lead, cadmium and mercury concentrations were analyzed in liver of three different seabird species (common guillemot, Atlantic puffin and razorbill) affected by the Prestige oil spill in September 2002 on the Galician coast. In general, with the exception of mercury, levels of all the analyzed elements were similar or lower in comparison with those reported for the same species in other Atlantic areas, and did not exceed levels indicative of increased environmental exposure.

Population modelling of European shags (Phalacrocorax aristotelis) at their southern limit: conservation implications

Enlace mardeaves Phalacrocorax aristotelis,PUBLICACIÓN CIENTÍFICA,REPOSITORIO ,,,

Velando, A. and Freire, J., 2002. Population modelling of European shags (Phalacrocorax aristotelis) at their southern limit: conservation implications. Biological Conservation, 107(1), pp.59-69.

The European shag (Phalacrocorax aristotelis) population at Cíes Islands (the most important breeding area in its southern limit) increased rapidly from 1986 to 1992, and afterwards the population suffered a slight decline. This study analyzed population data obtained from ringing recoveries and reproductive monitoring between 1993 and 1997. The reproductive success was highly variable and associated with adverse weather events. Adult survival rate was very low compared with other colonies, probably due to high accidental capture in gill-nets. In recent years, the fishing effort with gill-nets increased in the study area. Sensitivity analysis of parameters showed that the population is more affected by changes in adult survival than in reproductive success. When dynamic simulations were run with an increase in shag mortality of 5% above the present level, population extinction occurred in all simulations. In contrast, when a reduction of mortality of 5% was introduced in the simulations, the population increased in all cases. The main lines of action to study and protect this population should be: (1) ringing schemes to obtain better estimates of survival variability; (2) studies on the interaction of feeding areas and fishing vessels; (3) regulations on gill-netting; and (4) the incorporation of population models as an adaptive management tool to synthesize assessment work and management scenarios.

Weak large‐scale population genetic structure in a philopatric seabird, the European Shag Phalacrocorax aristotelis

Enlace mardeaves Phalacrocorax aristotelis,PUBLICACIÓN CIENTÍFICA,REPOSITORIO ,,
Barlow, E.J., Daunt, F., Wanless, S., Alvarez, D., Reid, J.M. and Cavers, S., 2011. Weak large‐scale population genetic structure in a philopatric seabird, the European Shag Phalacrocorax aristotelis. Ibis, 153(4), pp.768-778.
Quantifying population genetic structure is fundamental to testing hypotheses regarding gene flow, population divergence and dynamics across large spatial scales. In species with highly mobile life-history stages, where it is unclear whether such movements translate into effective dispersal among discrete philopatric breeding populations, this approach can be particularly effective. We used seven nuclear microsatellite loci and mitochondrial DNA (ND2) markers to quantify population genetic structure and variation across 20 populations (447 individuals) of one such species, the European Shag, spanning a large geographical range. Despite high breeding philopatry, rare cross-sea movements and recognized subspecies, population genetic structure was weak across both microsatellites and mitochondrial markers. Furthermore, although isolation-by-distance was detected, microsatellite variation provided no evidence that open sea formed a complete barrier to effective dispersal. These data suggest that occasional long-distance, cross-sea movements translate into gene flow across a large spatial scale. Historical factors may also have shaped contemporary genetic structure: cluster analyses of microsatellite data identified three groups, comprising colonies at southern, mid- and northern latitudes, and similar structure was observed at mitochondrial loci. Only one private mitochondrial haplotype was found among subspecies, suggesting that this current taxonomic subdivision may not be mirrored by genetic isolation.

Multilocus population analysis of Gavia immer (Aves: Gaviidae) mtDNA reveals low genetic diversity and lack of differentiation across the species breeding range

Enlace mardeaves Gavia immer,PUBLICACIÓN CIENTÍFICA,REPOSITORIO ,,,

Bartolomé, C., Maside, X., Camphuysen, K.C., Heubeck, M. & Bao, R., 2011. Multilocus population analysis of Gavia immer (Aves: Gaviidae) mtDNA reveals low genetic diversity and lack of differentiation across the species breeding range. Organisms Diversity & Evolution, 11(4), pp.307-316.

We analyzed the patterns of nucleotide sequence variation at three mitochondrial DNA loci, the noncoding mitochondrial control region and two genes (cytochrome b and cytochrome oxidase I) of Gavia immer in the largest collection of wintering individuals from Southern Europe to date. The sample consisted of 33 birds, oiled during the 2002/2003 Prestige tanker spill and washed ashore on the Galician coast (NW Iberian Peninsula). The aims of the study were to investigate the levels of standing genetic variation in the species, and to identify the geographic origin of these wintering birds. To do this, all available sequences of these loci, mostly from North American specimens collected from both the Atlantic and Pacific coasts, were retrieved from GenBank and included in the analysis. Overall, only 14 genetic variants were detected in the nearly 2 Kb surveyed, which reflects very low levels of nucleotide site diversity in this species. Interestingly, all variants were found at very low frequencies, and there was no indication of any clear subdivision in the G. immer population. This genetic profile is consistent with G. immer being a single panmictic population of small effective population size as compared with other seabirds. These circumstances preclude identification of the breeding regions of these wintering birds relying solely on genetic data. In the light of these results, possible causes, and the genetic and ecological consequences, of this demographic scenario are discussed.

The yellow-legged gull, Larus michahellis, an occasional predator of Timon lepidus in the Atlantic Islands National Park (Galicia, NW Spain)

Enlace mardeaves Larus michahellis,PUBLICACIÓN CIENTÍFICA,REPOSITORIO ,,

Piorno, V., Fernández-Bouzas, J.A. & Velo-Antón, G. The yellow-legged gull, Larus michahellis, an occasional predator of Timon lepidus in the Atlantic Islands National Park (Galicia, NW Spain). Bol. Asoc. Herpetol. Esp. 27(1). (2016).

El lagarto ocelado (Timon lepidus) mantiene poblaciones de gran interés en varias islas, tanto por su estatus de conservación como por las particulares interacciones ecológicas que en ellas se desarrollan. En el caso del Parque Nacional de las Islas Atlánticas de Galicia, esta especie convive con una importante colonia de cría de gaviota patiamarilla (Larus michahellis). Desde el año 2009 hasta 2015 hemos detectado en este Parque Nacional siete casos de consumo de T. lepidus por L. michahellis. Se trata de una conducta nunca antes documentada y de reciente aparición, que podría estar relacionada con los efectos que el cierre de vertederos y la reducción de los descartes pesqueros están teniendo en esta especie de gaviota. El carácter ocasional de esta depredación no hace esperar efectos apreciables en estas poblaciones insulares de lagarto ocelado.

Las colonias de aves marinas de la costa Occidental de Galicia. Características, censo y evolución de sus poblaciones

Enlace mardeaves Larus fuscus,Larus michahellis,Phalacrocorax aristotelis,PUBLICACIÓN CIENTÍFICA,REPOSITORIO,Rissa tridactyla,Uria aalge ,,,

Bárcena, F. & Souza, J.A. Las colonias de aves marinas de la costa Occidental de Galicia. Características, censo y evolución de sus poblaciones. Ecología 1. (1987). ISSN 0214-0896