Seismic Impact on Fish; the State of Tuna & How Namibia’s Marine Spatial Plan Fits In

Migratory tuna are sensitive to low frequency sound and in Namibia albacore tuna catches have dropped off drastically. It is believed that the reason for this is the increase in the number of seismic surveys in southern Namibian waters. How will Namibia’s marine spatial plan fit in?

There has been much debate about the impacts of seismic sound on mammals such as whales, and fish. Oil and gas exploration airguns discharge predominantly low-frequency sound, but it is still considered a broad-band source in that it contains elements in a wide range of frequencies. While sound transmission loss reduces the received levels rapidly over the first few kilometres, it is loud enough to remain distinctly audible, even at distances of tens to hundreds of kilometres.