SAN DIEGO (FOX 5/KUSI) -- The Deepwater Horizon oil spill that began nearly 15 years ago may have had a larger impact on offshore ecosystems than previously thought, recent research suggests. The oil spill, which happened in April 2010, was broadly considered one of the worst environmental disasters in U.S. history. It began following an explosion on the Deepwater Horizon oil drilling rig owned by Transocean and operated by BP, which killed 11 workers and released about 168 million gallons of oil into the Gulf of Mexico. According to a paper recently published in the scientific journal, Nature Communications Earth and Environment, a team led by researchers at UC San Diego's Scripps Institution of Oceanography found that sperm whale populations have declined by about 31% and beaked whales by about 83% as a result of the spill. SDG&E warns thousands of potential public safety power shutoffs Additionally, dolphin populations may have declined by up to 43% since then, the study said. The Gulf of Mexico is home to at least 18 species of odontocetes, or toothed whales, the paper stated, which primarily rely on sounds for navigation, foraging and communication. Researchers said the presence or lack of sounds detected, as well as densities in population per unit area, were used to indicate the health of the ecosystem in offshore regions. To conduct the study, researchers collected acoustic recordings at five different monitoring stations between May 2010 and March 2020. The sounds were collected using high-frequency acoustic recording packages, also called "HARPs." Hydrophones, devices that detect and record sounds underwater from all directions, were buoyed about 20 meters above the seafloor, the study stated. The locations of the sites were chosen based on their position in relation to the oil rig's footprint. Local bakery forced to hunt for eggs as CA egg prices rise amid supply shortage, demand Estimated populations declined throughout multiple sites during the 10-year period, although a few of them showed increases in dolphin densities. "Long-term declining trends in marine mammal density at the monitored locations were observed over the 10 years following the 2010 DWH oil spill, for seven of the eight identified species categories," researchers said. The largest declines were found in beaked whales, according to the study. They were initially observed at all three of the deepest sites where data was gathered, but had declined by over 70% across all sites during the 10-year period.