摘要:In the Wadden Sea areas of Denmark, Germany and The Netherlands, a total of 162 fish and lamprey species is known. 72 of these species are migrants entering the area occasionally; the total number of resident species in the Wadden Sea area is 90. In the Wadden Sea, in total, 20 species of fish and lamprey species are threatened in at least one subregion. Of these, 19 species are threatened in the entire area and are therefore placed on the trilateral Red List. 2 species of the listed fish and lamprey species are (probably) extinct in the entire Wadden Sea area. The status of 5 species of fish and lamprey species is critical, 5 species are (probably) endangered, the status of 6 is vulnerable and of 1 species susceptible. For about 16 rare species which may also be threatened, data were not sufficient to estimate past and present population sizes. The contributors to the list would like to encourage researchers to intensify work on the ecology and the present population sizes of these rare Wadden Sea species (see Fricke et al., 1995).
关键词:Waste Water;Population Size;Water Management;Water Pollution;Rare Species