Industrial agricultural runoff and untreated sewer water may be to blame
According to a Twitter announcement released Nov. 2 by the The El Salvador Ministry of Environment and Natural Resources, between 300 and 400 sea turtles were discovered off the coast of El Salvador in Jiquilisco Bay dead or dying this past month. Additionally, members of the country’s Eastern Pacific Hawksbill Initiative claim an additional 300 dead turtles have been found 30 miles west in Isla Tasajara. This additional report is currently unconfirmed by the environmental ministry. This is the largest sea turtle mortality event recorded in El Salvador, though not an uncommon experience. In 2013, 200 turtles were found dead, and in 2006 approximately 120 turtles were found dead in the area.
Previously, the majority of the blame was placed on shrimp trawling. In the North Pacific Ocean, where El Salvador borders, as many as 97% of the biomass caught by shrimp trawlers is thrown away, including sea turtles. However, a month-long moratorium for shrimping has been in effect in El Salvador since October 17th rendering shrimp trawling an unlikely cause. For this event, scientists speculate that red tide is likely the cause of the mass die-off, according to National Geographic.
While red tide is a natural part of ocean ecosystems, the harmful tide is exacerbated by industrial agricultural runoff or untreated sewer water. Red tide occurs when colonies of algal blooms grow out of control, and can become toxic to both marine life and humans. If the red tide continues, some species of sea turtles, such as hawksbills and leatherbacks which are already endangered, are increasingly vulnerable.