Contamination, parasitism and condition of Anguilla anguilla in three Italian stocks.
In conjunction with habitat loss and overfishing, pollution and parasitism are believed to be relevant causes of collapse of Anguilla, as these can affect eel swimming ability and the development of gonads and embryos. The present study investigated Persistent Organic Pollutant (POP) concentrations, infection levels of Anguillicoloides crassus, lipid content and gonad abnormalities in eels sampled in 2007-2008 in three Italian water bodies (Caprolace Lake, Lesina Lagoon and Tevere River) that vary in salinity, trophic condition, contamination level and fishing pressure. Our analysis revealed that low-to-moderate levels of contamination and parasitism were not associated with gonad abnormalities in Caprolace Lake and Lesina Lagoon. On the contrary, POP concentrations and abundances of swim bladder nematodes were remarkably high in eels from the heavily urbanized Tevere River and were associated with significant gonad and swim bladder alterations. Contamination and infestation levels were so high to potentially impair spawner successful migration and reproduction. POP concentrations in Tevere eels also exceeded levels considered safe for food consumption. Though marginally contaminated, eels from the oligotrophic Caprolace Lake were in critical health condition: their lipid reserve was so low as to be considered insufficient to sustain the energetic costs of the transoceanic migration. Lesina eel stock was the only one displaying relatively good quality but here spawner abundance is likely limited by overfishing. Our results suggest that multiple stressors may potentially affect eel reproductive success. More definitive studies are needed to assess whether health effects caused by these multiple stressors are additive, compensatory or synergistic.
Department of Theoretical and Applied Sciences (Environmental Section), University of Insubria, Via Dunant 3, 21100, Varese, Italy. silvia.quadroni@uninsubria.it
Silvia
S
Quadroni
Silvana
S
Galassi
Fabrizio
F
Capoccioni
Eleonora
E
Ciccotti
Gilberto
G
Grandi
Giulio A
GA
De Leo
Roberta
R
Bettinetti
D000811:Anguilla / Q000469:parasitology / Q000502:physiology*; D025041:Animal Migration; D000818:Animals; D005260:Female; D005393:Fish Diseases / Q000469:parasitology*; D006066:Gonads / Q000002:abnormalities; D007558:Italy; D008055:Lipids / Q000737:chemistry; D008297:Male; D009348:Nematoda / Q000302:isolation & purification; D009349:Nematode Infections / Q000469:parasitology*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D008055:Lipids; D014874:Water Pollutants, Chemical