The return of the harbour porpoise (Phocoena phocoena) in Dutch coastal waters
The return of the harbour porpoise (Phocoena phocoena) in Dutch coastal waters
复制标题
荷兰沿海水域港湾鼠海豚（Phocoena phocoena）的回归
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
Nederlandse Zeevogelgroep
中科院分区：
文献类型：
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作者：
K. Camphuysen;Koninklijk Nederlands;Nederlandse Zeevogelgroep
The harbour porpoise (Phocoena phocoena) became virtually extinct in Dutch coastal waters in the early 1960s. A systematic method to record seabird passage along the coast became established in the early 1970s and was used ever since. These observations allowed a reconstruction of the return of the elusive harbour porpoi- se in Dutch coastal waters. A small, but gradually increasing number of sightings in the mid-1980s to early 1990s was followed by a proportional rate of increase of 41% per annum over the last 15 years. At first, only full-grown animals were seen and the occurrence was virtually restricted to mid-winter. In later years, numbers sharply in- creased in winter, and more and more animals were seen also in summer and autumn, including mother-calf com- binations. Both the historic decline and the recent increase are concurrent with similar trends in strandings and at- sea survey data. Unambiguous explanations for the initial decline have never been given and it is equally difficult to fully understand the come-back. There is evidence, however, that distributional shifts rather than population fluctuations underlie the trends observed. The re-distribution of harbour porpoises in the North Sea may have been triggered by local reductions or shifts in principal prey availability.
