Stone fishing
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The commercial salvage of boulders and larger stones from bodies of water is referred to as stone fishing or stone cutting (sometimes also: stone diving, if a diving device is used) . It is largely only of historical importance. The raised stones served as building material, especially for piers , roads and foundations .
The industry has always been regionally limited. For one thing, it only had a basis if there were no quarries nearby on land . On the other hand, it was a prerequisite that stones of the appropriate size were stored at an accessible depth in such large quantities that it was worthwhile to mine them. Larger blocks with a weight of a few hundred to 5,000 kg were preferred.
Stone fishing in the Baltic Sea
A center of maritime stone fishing in Europe was the Baltic Sea , where large quantities of stones driven during the Ice Ages are stored. The deposits have been mined near the coast since the beginning of the 19th century . For reasons of coastal protection , however, it was later switched to removing stone fields only at greater depths of 6 to 20 meters. The centers of stone fishing in the Baltic Sea were, for example, the waters off Fehmarn and Eckernförde and the Hohwachter Bay . The industry was also important in Mecklenburg-Western Pomerania and Denmark .
A ship positioned itself over the site to rescue the stones. A helmet diver descended to the bottom of the sea and placed a man-sized pair of pliers, which had been lowered with a loading boom , around a suitable stone . The stone was then hoisted into the hold of the ship.
The diver's work was extremely dangerous because he was under the suspended load during the lifting process. Again and again it happened that a boulder slipped out of the stone pincers and injured or even killed the diver when it fell. Even when gripping the stone with the pliers, it could slip and endanger the diver. In addition, there was a risk that a stone that got prematurely out of the tongs during loading could break through the bottom of the ship and cause it to sink.
Stone fishing was a flourishing industry until the 1960s. But with advanced exploitation of the deposits and noticeably decreasing profit margins, the industry soon fell below the profitability limit . In the mid-1970s, stone fishing in Schleswig-Holstein was completely given up. It is still practiced in Denmark , but is of little economic importance. The stonefishing profession has all but died out in Central Europe.
Environmental impacts of stone fishing using the example of the Baltic Sea
As important biotopes, the stone fields in the Baltic Sea were home to a diverse range of marine flora and fauna . In particular, the stones served as a substrate for algae , which in turn were habitat for other species. The large-scale harvesting of the fields caused long-term disturbances in this ecological equilibrium , since, in addition to the damage directly caused by the salvage process, they only left sandy areas on which the algae do not adhere. Therefore, a few artificial reefs were created to compensate for this damage. In implementing the EU Water Framework Directive , efforts are being made to standardize and coordinate efforts.
The ecological effects were recognized relatively late and in 1976 led to the ban on stone fishing off the coast of Schleswig-Holstein.
Much earlier it became clear that natural breakwaters had been removed with the stone fields directly on the coastline, which meant that the land behind was more exposed to erosion by the surf. For this reason, the shores of the Baltic Sea were largely closed to stone fishing as early as 1873. And their exercise at greater depths soon required an official license . The zones that were important for the safety of the coast were declared protected areas and marked so that they can be recognized from the sea by means of appropriate blocking beacons. Stone fishing off the West Pomeranian coast was generally prohibited by police ordinance as early as 1906.
Stone fishing in rivers
The current forms pebbles in river beds . Harvesting larger chunks was therefore also of interest here earlier. However, divers were usually not used; rather, the wading zone was mostly harvested by hand.
literature
- Gesche M. Bock, Frank Thiermann, Heye Rumohr, Rolf Karez: Extent of stonefishing on Schleswig-Holstein's Baltic coast . In: Annual report of the State Office for Nature and the Environment of Schleswig-Holstein . 2003 ( landsh.de [PDF; accessed on November 21, 2010]).
References and footnotes
- ↑ Special examples: Stones from Fehmarn stonefishers were used for the pier in Kiel, Puttgarden and Copenhagen, for the memorial in Laboe and for the Vogelfluglinie.
- ^ Ordinance of the Schleswig-Holstein police of August 26, 1873
- ^ Ordinance of the Schleswig-Holstein police of June 25, 1890
- ↑ Federal Ministry for the Environment, Nature Conservation and Nuclear Safety - Initial Assessment of the German Baltic Sea (PDF link) ( Memento of the original from October 19, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
See also
- Pliers (engineering) , the removal of stones from the coastal area