Andreu Blanco

Biochemical responses of Mytilus galloprovincialis as biomarkers of acute environmental pollution caused by the Don Pedro oil spill (Eivissa Island, Spain)

In the present work, the potential use of several antioxidant and detoxification biomarkers in the digestive gland of wild mussels (Mytilus galloprovincialis) for biomonitoring the marine pollution induced by the Don Pedro oil spill has been investigated. Two locations from the East to South-East of Eivissa (Ibiza) and Formentera islands were selected, one extensively affected by the oil spill and the other one not affected and considered as the control area. Mussels were sampled one, two and six months after the Don Pedro accident. Polycyclic aromatic hydrocarbon (PAH) levels were significantly increased in the soft tissues of mussels in the affected area one month after the disaster, returning to normal values after six months. Markers of oxidative damage in lipids--malondialdehyde, and in proteins--carbonyl derivates, and antioxidant enzyme--catalase, superoxide dismutase and glutathione peroxidase, activities significantly increased as result of the spill oil after one month, returning to basal values at two month sampling time. Glutathione/glutathione disulfide ratio (GSH/GSSG), as a marker of the redox status, was reduced after one and two months indicating a more oxidized situation. Markers of detoxification--glutathione-S-transferase and cytochrome P4501A activities and metallothionein gene expression--were significantly increased by the oil spill one month after the accident, returning to the basal values at two month sampling time. In conclusion, the Don Pedro accident induced a transient situation of PAHs pollution resulting in enhanced antioxidant and detoxification defense systems in the wild mussel M. galloprovincialis returning to normal levels six months from the spill. The selected biomarkers are a useful tool for biomonitoring the response to acute exposure to pollutants in marine mussels.

Muscle and scale isotopic offset of three fish species in the Mediterranean Sea: Dentex dentex, Argyrosomus regius and Xyrichtys novacula

Diet information of organisms was traditionally acquired by the use of lethal techniques (gut content or muscle delta(13)C and delta(15)N isotopic ratios). An increase in the number of isotopic ratio studies and the vulnerability of some species have led to increased use of non-lethal methodologies for conservation purposes. In the present work we have compared the delta(13)C and delta(15)N isotopic signals of muscle and scales of three different fish species in order to test fish-scale sampling as a non-lethal technique in fish trophodynamics. A positive correlation was found between muscle and scales in Argyrosomus regius and Xyrichtys novacula, while Dentex dentex showed no correlation due to the small length range of this species. The isotopic offset (Delta(13)C and Delta(15)N) between muscle and scales was significantly different among species (analysis of variance (ANOVA), p < 0.001) with Tukeys post-hoc HSD indicating a tissue offset difference (p < 0.001) for both stable isotopes in all species, except for Delta(13)C between A. regius and X. novacula and for Delta(15)N between D. dentex and X. novacula (p > 0.05). Mean delta(13)C and delta(15)N values between species showed significant differences (paired t-test, p < 0.01) between muscle and scale with an enrichment for delta(13)C and a depletion for delta(15)N. Spatial differences were found in the Delta(13)C of X. novacula between the studied locations, while no differences were found for Delta(15)N, indicating that non-geographical differences should be considered in the application of scales instead of muscle for (15)N, while for (13)C differences in the geographical isotopic offset should be considered.

Isolation and molecular identification of the scuticociliate Porpostoma notata Moebius, 1888 from moribund reared Hippocampus hippocampus (L.) seahorses, by amplification of the SSU rRNA gene sequences

The Scuticociliatia subclass includes hundreds of species with mostly uncertain phylogenetic relationships and classifications ( Alvarez-Pellitero et al. 2004). On the basis of morphological and morphogenetical data, Lynn (2008) recognized three Scuticociliatia orders: Philasterida, Thigmotrichida and Pleuronematida. They are endemic to worldwide coastal ecosystems where they thrive either as freeliving organisms or parasitic to aquatic animals. In fact, these facultative ciliated protists can occasionally become pathogenic for the hosts, leading to scuticociliatosis in some species of fish, crustaceans and molluscs (Iglesias et al. 2001). The scuticociliates Uronema marinum Dujardin, Miamiensis avidus Thompson & Moewus, and Philasterides dicentrarchi Dragesco have been recognized as causative agents of mass mortalities in some cultured marine fishes such as turbot Scophthalmus maximus (L.) (Iglesias et al. 2001), sea bass Dicentrarchus labrax L. (Dragesco et al. 1995) and olive flounder Paralichthys olivaceus (Temminck & Schlegel) (Kim et al. 2004), among others. In seahorses, ciliates have been reported to cause outbreaks of scuticociliatosis, with high mortality rates in Hippocampus erectus Perry (Cheung, Nigrelli & Ruggieri 1980), Hippocampus trimaculatus Leach (Meng & Yu 1985) and Hippocampus kuda Bleeker (Shin et al. 2011). Indeed, the ciliate P. dicentrarchi has been recognized as the main cause of mortality in captive reared seahorses H. kuda (Shin et al. 2011). P. dicentrarchi infections in syngnathids are usually accompanied by skin ulcerations, abdominal distension and central nervous anomalies. Lethargy, anorexia and rapid death have been also related to P. dicentarchi infections (Umehara, Kosuga & Hirose 2003). Seahorses have a ‘data deficient’ status on the IUCN Red List of Threatened Species (IUCN 2012), and all seahorse species are listed in CITES Appendix II. Due to this situation, seahorse research and rearing have substantially increased in the last decades (Planas et al. 2009). Consequently, a comprehensive identification of associated ectoor endoparasites can help to establish effective preventive treatments in reared seahorses. On this regard, the present work describes the isolation and molecular identification of the scuticociliate Porpostoma notata Moebius, 1888 in moribund Hippocampus hippocampus juveniles reared in captivity, from a batch with mass mortality. A pregnant male of H. hippocampus was captured by scuba diving in Toralla Island (Galicia, NW Spain) in 2011 and conveniently transferred to the facilities at the IIM-CSIC in Vigo. A batch of 784 newborn of 14.5 mm 2 in length and 3 mg 1.7 in weight was released and reared under controlled conditions, as reported by Planas et al. (2009). High survival rates were recorded Correspondence C Ofelio, Instituto de Investigaciones Marinas (IIM-CSIC), Eduardo Cabello 6, 36208 Vigo, Spain (email: claudiaofelio@gmail.com)

Integrated Multitrophic Aquaculture: Filter feeders bivalves as efficient reducers of wastes derived from coastal aquaculture assessed with stable isotope analyses

Aquaculture industry has rapidly increased from 20 million tons in the 1990s to 68.4 million tons in 2008, overcoming the 67.0 million tons of extractive fisheries, with an approximated global value of 84,791 million Euros (FAO, 2010). The Mediterranean Sea is an important producer of intensive open water fish culture, especially important are industries from Spain, France, Italy and Greece, which generated 2,133 million Euros in 2008 (FAO, 2008).