Ecotoxicology of estuaries in France and Québec, Canada

Environmental Science and Pollution Research

, Volume 20, Issue 2, pp 723-737

Histopathological lesions and DNA adducts in the liver of European flounder (Platichthys flesus) collected in the Seine estuary versus two reference estuarine systems on the French Atlantic coast

  • Jérôme CachotAffiliated withUniv. Bordeaux, EPOC UMR 5805, LPTC Group Email author 
  • , Yan CherelAffiliated withINRA, UMR 703, Oniris, La Chantrerie
  • , Thibaut LarcherAffiliated withINRA, UMR 703, Oniris, La Chantrerie
  • , Annie Pfohl-LeszkowiczAffiliated withUniv. Toulouse, Laboratoire de Génie Chimique, UMR CNRS/INPT/UPS 5503, INP/ENSA Toulouse
  • , Jean LarocheAffiliated withUniversité de Brest, UMR 6539, LEMAR, Institut Universitaire Européen de la Mer
  • , Louis QuiniouAffiliated withUniversité de Brest, UMR 6539, LEMAR, Institut Universitaire Européen de la Mer
  • , Jocelyne MorinAffiliated withIfremer, Laboratoire Ressources Halieutiques
  • , Julien SchmitzAffiliated withInstitut Français du Pétrole
  • , Thierry BurgeotAffiliated withIfremer Nantes, Département Polluants Chimiques
    • , Didier PottierAffiliated withUniversité de Caen Basse-Normandie, UR ABTE EA 4651, Centre François Baclesse

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Abstract

An epidemiological survey was conducted in the Seine estuary and in two smaller and relatively preserved estuaries on the French Atlantic coast in order to estimate the occurrence of liver lesions in European flounder, Platichthys flesus, and also to seek putative risk factors for the recorded pathologies. Four hundred and seventy-eight fish of both sexes and of different size ranges were sampled in the three studied areas, 338 of which in the Seine estuary. All fish were examined for histopathological liver lesions, while DNA adducts and otoliths were analyzed on a subsample. Five categories of hepatic lesions were recorded with the following prevalence for the Seine estuary: 36.7 % inflammations, 8 % parasites (mainly encysted nematodes), 6.5 % foci of cellular alteration (FCA), 5.3 % foci of necrosis or regeneration (FNR), and 1.5 % tumors. Inflammation occurrence increased according to age, contrary to parasitic infestations and FCA which were more prevalent in young fish, notably those of <1 year old (group 0). Tumors were only observed in females of more than two winters. Females exhibited a higher prevalence of tumors (3.0 %) and FCA (6.5 %) than males (0 and 2.6 %, respectively). Parasitic and infectious lesions and FNR were equally distributed in males and females. The prevalence of FNR was also shown to vary according to sampling season, with significantly more occurrences of liver necrosis in the fish collected in summer than in spring. Spatial differences were observed with a higher occurrence of encysted parasites in flounders from the upper Seine estuary, while inflammations predominated in flounders living downstream. Temporal trends were also noted, with an increased prevalence of parasitic infestations, inflammations, and FCA in the 2002–2003 period in comparison to the 1996–1997 one. The three flounder populations from the Seine estuary (Normandy), Ster estuary (Brittany), and Bay of Veys (Normandy) showed different spectra of hepatic lesions. Flounders from the Bay of Veys had relatively few liver lesions as compared to flounders from the two other estuaries. Flounders from the Ster estuary exhibited the highest prevalence of parasites (37.2 %) and inflammations (51.1 %). Finally, FCA and liver tumors occurred at very similar levels in both flounder populations from the Seine and the Ster estuaries. Group 0 flounders inhabiting the upper Seine estuary were more prone to parasitic and pre-neoplastic hepatic lesions and had higher levels of liver DNA adducts than the older ones living downstream. It was postulated that group 0 European flounders may serve as valuable bioindicators for assessing the quality of estuarine waters and the health status of euryhaline fish populations.

Keywords

Epidemiological study European flounder Seine estuary Liver histopathology Necrosis FCA Tumors Inflammations Parasites DNA adducts Pollution