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).
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.
Munilla, Ignacio, José Manuel Arcos, Daniel Oro, David Álvarez, Patricia M. Leyenda & Alberto Velando. “Mass mortality of seabirds in the aftermath of the Prestige oil spill.” Ecosphere 2, no. 7 (2011): 1-14.
In the winter of 2002–03 the Prestige tanker spilled 60,000 tons of oil over the northern half of the Iberian Coastal Large Marine Ecosystem (northern Portugal to France). Most (c. 85%) of the 22,981 oiled seabirds reported were alcids (i.e., auks): Common Murres (Uria aalge), Razorbills (Alca torda) and Atlantic Puffins (Fratercula arctica). Here we estimated the mortality of alcids in Galicia (northwestern Spain), the area that received most of the Prestige oil and where half of the oiled seabirds were collected. We performed three experiments that included: (1) a test of several drift block models in open sea, to select the one that best fitted the drift of alcid carcasses; (2) the release of 450 drift blocks at 9 offshore points to assess the recovery rate of oiled alcids and its spatial variation; (3) the assessment of beach survey effort and the detectability of drift blocks. Mean mortality estimates and their bootstrapped confidence intervals were obtained through an estimation model that established: (1) a temporal limit of 23 days to block drifting; (2) spatial differences in the recovery rates of blocks depending on how far away from the coast they were released; (3) a correction factor accounting for detectability, and (4) the distribution pattern of the three alcid species involved according to three distance classes, based on ship surveys. The Prestige oil spill, in terms of acute seabird mortality, was one of the worst oil spills ever reported worldwide. Compared to other major oil spills the estimated mortality for the Prestige oil spill was higher than expected from the number of carcasses retrieved. We recommend that drift block assessments of seabird mortality should be included in contingency response plans to oil pollution emergencies; therefore, a supply of drift-blocks designed to mimic the drifting behavior of the marine bird species of interests should be at hand.