Dear MARMAMers, in the German part of the Baltic Sea 120 large explosives (torpedo heads and sea mines of World War II) have been found a few years ago. In October 2006, authorities started to detonate these. No safety regulations for marine mammals have been considered by the ministry of the environment. After protests of 3 NGOs, ministries agreed on using deterrent sound in order to scare harbour porpoises away. Individuals of the rare eastern Baltic population (probably less than 600 animals left) may migrate through or even stay in the area during winter. We doubt that the proposed deterrent is sufficient to scare marine mammals out of the danger zone. 33 explosives have been destroyed so far. Up to 90 explosions are expected during the rest of this winter. These explosions have also implications for further detonations during the construction of the Russian/German Baltic Sea gas pipeline. Therefore we demand a safety protocol for marine mammals. We are unsure about the exact dimensions of the safety zone. We proposed a safe level at the marine mammal ear of 160 dB re 1µPa similar to safety regulations of the NATO Undersea Research Center with respect to sonar. Can anybody of you simulate sound radiation from an explosion of 350 kg TNT at the bottom of 10 m water depth in Kiel Bight (sandy bottom, water temperature 9 degrees Celsius, salinity 12 PSU, mixed water body, gentle slope, distance from coast 2.5 km)? For the authorities it would pe possible to get such a calculation from the German Navy, but they would not do such a calculation for an NGO. And authorities refuse to have a simulation done. We are aware that there is no simple calculation using formulas from Richardsons "Marine Mammals and Noise" because much of the energy will be lost through the surface. And we have no idea how to determine what energy radiates horizontally. Who can help? All the best, Sven Dipl. Biol. Sven Koschinski Kühlandweg 12 D-24326 Nehmten Tel. ++49- (0) 4526 - 38 17 16 priv. ++49- (0) 4526 - 38 08 08 marine-zoology@t-online.de