Report: “Pollutants in mussels (Mytilus edulis) (1994)”
Description
In cooperation with the National Park Administration of Lower Saxony Wadden Sea, Ecosystem Research and the State Fisheries Office, a new, comprehensive mapping of the eulitoral mussel banks took place in spring 1994. The reason was evidence that the decline of the population continued to accelerate after the completion of the last stocktaking (spring 1991). Even the rich incubation in the summer of 1991 did not seem to be able to stop this development. The result confirms the fears: Of the 27 sq km taken by the mussel benches at the time of recording 1989-91, only a good 13 sq km remained in 1994. The total biomass had decreased from 46000 tonnes to below 10000 tonnes live weight. This means a loss of 50 % of the area and almost 80 % of the biomass. On the Borkumer Watt in the Ems estuary, only remains of a good 0.5 sq km were found on the Borkumer Watt in the Ems estuary, and the last, already tiny occurrence in the Weser fatigue had been extinct. In the remaining areas, the decrease was in the order of 40-70 %. Only in jadebusen the area-based decline was relatively small at 14 %. The state of the mussel population is undoubtedly alarming. It is true that in the summer of 1994 there was an exceptionally large-scale incubation of the mussel, starting in spring. It remains to be seen whether he will decisively change the situation or suffer the same fate as the breeding case of 1991. The potential causes of the continued decline are in the previous report (MICHAELIS et al. 1995) has been dealt with in detail. It would not lead to any new insights at the moment to repeat this discussion. It is more useful to wait for a series of ongoing investigations to be completed. From the “Ecosystem Research Lower Saxony Wadden Sea” reports will soon be available on the structure and function of mussel banks and influences of fishing, – feeding pressure of shell-consuming birds on the mussel stock, – reactions of the mussel to eutrophication-related structural changes of the phytoplankton, and – fate of the breeding fall 1994. The results of further investigations initiated by the Lower Saxony Ministry of the Environment dealing with pollutant loads, pollutant effects and parasitic infestations will also be available soon. After combining these findings, a clearer statement about the causes of the decline or at least a more informed weighting of the stock-reducing factors is likely to be expected.
Resources
| Name |
Format |
Description |
Link |
Tags
- niedersächsisches-küstengebiet-niedersächsische-küste
- miesmuschelbestände-miesmuschelbänke-mytilus-edulis-bestandsaufnahme-nlwkn