Two volcanic eruptions in the Canary Islands have shown researchers what impacts they have on fish.
It’s long been known water doesn’t buffer the extreme destruction around marine life much when a volcano explodes.
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Even the deep waters were not safe when fish floated up by lava flowing into the sea from Hawaii’s Mauna Loa volcano. The famous ichthyologist David Starr Jordan, the original president of Stanford University, described the island’s first documented volcanic fish kill in 1921.
But recently scientists completed a first-of-its-kind study comparing the fish harmed by two types of volcanos, one submerged and another on land that flowed lava into the sea.
Within the first 20 days of the submarine eruption on the island of El Hierro, many fishes appeared dead floating on the sea surface of the volcano area.
Lava flowed for nearly two miles along the seafloor and bombs of heated pyroclastic material shot out of the ocean floor turning the water acidic and heating it over 30F above normal.
The October 2011 eruption lasted five months marking the longest lasting volcanic event in the Canary Islands after the Timanfaya eruption in 1730-1736.
Oxygen decreased in the water and the extreme environment caused fish lesions and distended eyes and swim bladders. The oversaturated volcanic gasses in the water likely led to bubbles in the fish skin.
The 2021 eruption of the Tajogaite volcano on the island of La Palma sent lava into the coastal water more gradually.
Fish in this area had more time to escape leading to less mortality. However, this eruption produced a huge amount of ashes and volcanic particles which prolonged a smaller fish kill.
Volcanic material also caused lesions and ashfall clogged fish gills resulting in respiratory problems and fowled digestive systems.