| Summary: | Abstracl During the summe. of 1993 fish were collected from both sides of the embankment between the islands of Saaremaa and Muhu in westcm Estonia. Questioning of local fishermen completed thc picturc of the fish fauna, which now includes at lcast 35 species (comparcd with some 22 spccies recorded in the jate 1960s). Several cyprinid spccies have increased notably during the last decades and so have both Stiaoste.lion lucroperca and Osmerus epe anus. Salmo salar, Coregonus lavaretus, and Leuciscus idus have decreased notablv while Salmo tru(a truta is stlll a common sriecics. Fish diseases fike lymphocystis and ulcers among PLttichthys fiesrJ, "cauliflower disease " and ulc€rs among Anguilla anguilla. and sjgns indicating a poor condition of Clupea harengus v. membras ha\/e been increasingly more frcquently repofled from the whole area during the last yea6. Parasitological studies showcd. with a feq exccplions, no remarkable differcnces from the situation in the other coaslal arcas of the no|rhcrn pan of the Balric Sea. Notablc amounts of chlorinated hydrocarbons, mostiy DDTS and PCBs, were observed in all the fishcs. especiaily in Clupea harengus v. membras. Cl. sfauus balicus. Belanc belone (DDTs and PCBs), and tsor lllcilr (rcBs). Key words: changes in fish faum; fish discases: fish pa.asites; PCB: DDT; V?iike Viiin, Estonia_
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