An epidemiological su
rvey was conducted in the Seine estua
ry and in two smalle
r and
relatively p
rese
rved estua
ries on the F
rench Atlantic coast in o
rde
r to estimate the occu
rrence of live
r lesions in Eu
ropean flounde
r,
Platichthys flesus, and also to seek putative
risk facto
rs fo
r the
reco
rded pathologies. Fou
r hund
red and seventy-eight fish of both sexes and of diffe
rent size
ranges we
re sampled in the th
ree studied a
reas, 338 of which in the Seine estua
ry. All fish we
re examined fo
r histopathological live
r lesions, while DNA adducts and otoliths we
re analyzed on a subsample. Five catego
ries of hepatic lesions we
re
reco
rded with the following p
revalence fo
r the Seine estua
ry: 36.7 % inflammations, 8 % pa
rasites (mainly encysted nematodes), 6.5 % foci of cellula
r alte
ration (FCA), 5.3 % foci of nec
rosis o
r regene
ration (FNR), and 1.5 % tumo
rs. Inflammation occu
rrence inc
reased acco
rding to age, cont
ra
ry to pa
rasitic infestations and FCA which we
re mo
re p
revalent in young fish, notably those of <1 yea
r old (g
roup 0). Tumo
rs we
re only obse
rved in females of mo
re than two winte
rs. Females exhibited a highe
r p
revalence of tumo
rs (3.0 %) and FCA (6.5 %) than males (0 and 2.6 %,
respectively). Pa
rasitic and infectious lesions and FNR we
re equally dist
ributed in males and females. The p
revalence of FNR was also shown to va
ry acco
rding to sampling season, with significantly mo
re occu
rrences of live
r nec
rosis in the fish collected in summe
r than in sp
ring. Spatial diffe
rences we
re obse
rved with a highe
r occu
rrence of encysted pa
rasites in flounde
rs f
rom the uppe
r Seine estua
ry, while inflammations p
redominated in flounde
rs living downst
ream. Tempo
ral t
rends we
re also noted, with an inc
reased p
revalence of pa
rasitic infestations, inflammations, and FCA in the 2002–2003 pe
riod in compa
rison to the 1996–1997 one. The th
ree flounde
r populations f
rom the Seine estua
ry (No
rmandy), Ste
r estua
ry (B
rittany), and Bay of Veys (No
rmandy) showed diffe
rent spect
ra of hepatic lesions. Flounde
rs f
rom the Bay of Veys had
relatively few live
r lesions as compa
red to flounde
rs f
rom the two othe
r estua
ries. Flounde
rs f
rom the Ste
r estua
ry exhibited the highest p
revalence of pa
rasites (37.2 %) and inflammations (51.1 %). Finally, FCA and live
r tumo
rs occu
rred at ve
ry simila
r levels in both flounde
r populations f
rom the Seine and the Ste
r estua
ries. G
roup 0 flounde
rs inhabiting the uppe
r Seine estua
ry we
re mo
re p
rone to pa
rasitic and p
re-neoplastic hepatic lesions and had highe
r levels of live
r DNA adducts than the olde
r ones living downst
ream. It was postulated that g
roup 0 Eu
ropean flounde
rs may se
rve as valuable bioindicato
rs fo
r assessing the quality of estua
rine wate
rs and the health status of eu
ryhaline fish populations.
相似文献