Food preferences of larvae of Antarctic silverfish Pleuragramma antarcticum Boulenger, 1902 from Terre Adélie coastal waters during summer 2004

Ichthyoplankton samples were collected from 19 to 31 January 2004 in the Dumont d’Urville Sea (East Antarctic shelf). The Nototheniidae Pleuragramma antarcticum comprised more than 90 % of the sampled larvae. Gut contents of 95 P. antarcticum larvae were examined. Most larvae fed on phytoplankton, especially diatoms, whereas some other specimens had a mixed diet with phyto- and zooplankton prey. A single specimen fed exclusively on copepods. The stomach contents was dominated by three diatoms taxa, such as Thalassiothrix antarctica, Fragilariopsis spp. and Chaetoceros spp. Prey selection was apparently food density dependent, with an inverse relationship between food abundance and selection feeding. Larvae selected positively some diatoms, such as Coscinodiscus spp. and T. antarctica, presenting a low concentration in the water column compared to Fragilariopsis spp., which were strongly negatively selected. During summer, larvae were opportunistic feeders with a broad trophic niche, which allowed them to switch between different food types

Dioxins, furans and co-planar PCBs in juvenile harbour porpoises (Phocoena phocoena) from the Belgian coasts

Dioxins, furans and PCBs are lipophilic anthropogenic contaminants that have found their way into marine food webs and accumulate in top predators such as marine mammals, adding a stress factor to an already vulnerable population. In this study 7 congeners of dioxins (PCDDs), 10 congeners of furans (PCDFs) and 4 congeners of coplanar PCBs (cPCBs) were determined using high resolution gas chromatography and mass spectrometry in the blubber of 19 juvenile harbour porpoises (Phocoena phocoena) stranded along the Belgian North Sea coastline between 1995 and 2001. These results were contrasted with nutritional status (emaciated or not), sex and trophic level (through stable carbon and nitrogen isotope analysis). Mean blubber concentrations of SPCDD/Fs were 12.8 pg/g lw (lipid weight) and mean related toxicity 1.84 pg TEQs/g lw (TEQs = TCDD toxic equivalents). Mean cPCB concentrations were 223,5 pg/g lw and mean related toxicity 4,47 pg TEQs/g lw. The levels detected in these individuals were of the same order as those found in a previous study in the Wadden Sea (Bruhn, 1999). Both sexes show rather similar levels. No significant relationship was observed between stable carbon or nitrogen isotope values and pollutant levels. Concentrations and toxicity show a tendency to be higher in emaciated ndividuals than in nonemaciated ones. This could indicate a possible relationship between the nutritional status of the animals and dioxinlike pollutants (which could participate in weakening the animal). This situation should be further studied on adult individuals in order to obtain a more global view of the possible effects on the population

Marine mammals from Northeast Atlantic: relationship between their trophic status as determined by delta C-13 and delta N-15 measurements and their trace metal concentrations

The relationship between trophic position through delta(13)C and delta(15)N and trace metal concentrations (Zn, Cd, Cu and Hg) was investigated in the tissues of six marine mammal species from the Northeast Atlantic: striped dolphin Stenella coeruleoalba, common dolphin, Delphinus delphis. Atlantic white-sided dolphin Lagenorhynchus acutus, harbour porpoise Phocoena phocoena, white beaked-dolphin Lagenorhynchus albirostris, grey seal Halichoerus grypus stranded on French Channel and Irish coasts. White-beaked dolphins, harbour porpoises, white-sided dolphins, common and striped dolphins display the same relative and decreasing trophic position, as measured by delta(15)N values, along both the Irish and French channel coasts, reflecting conservative trophic habits between these two places. Hepatic and renal Cd concentrations were significantly correlated to muscle delta(13)C and delta(15)N values while Hg, Zn and Cu did not. These results suggest that Cd accumulation is partly linked to the diet while other factors Such as age or body condition might explain Hg, Zn or Cu variability in marine mammals. Combined stable isotope and trace metal analyses appear to be useful tools for the study of marine mammal ecology. (C) 2003 Elsevier Science Ltd. All rights reserved

Ichthyoplankton in the neritic and coastal zone of Antarctica and Subantarctic islands: A review

International audienc

Ichthyoplankton in the neritic and coastal zone of Antarctica and Subantarctic islands: A review

International audienc