In the depths of the ocean, when a whale dies, its carcass sinks to the seafloor, creating a unique and rich ecosystem known as a whale fall. Recently, scientists have discovered an extraordinary number of these whale falls off the coast of Los Angeles—over 60 skeletons, a number that surpasses the total found worldwide since 1977. This remarkable density of whale falls has turned the region into a hotspot for marine biologists and ecologists eager to study these deep-sea oases. A recent video (2019) from the Exploration Vessel (E/V) Nautilus captured the excitement as scientists came upon a whale fall on the Davidson Seamount off California.

(The Davidson Seamount, which we have written about before, is a hotbed of biological activity, a deep sea oasis of life, providing habitat for millions of creatures, including the famous gathering of brooding ocotpus (Muusoctopus robustus) known as the Octopus Garden, seen in video here.)

Whale falls provide a dramatic example of how death can foster life. When a whale carcass settles on the ocean floor, it becomes a feast for a variety of marine creatures. Initially, scavengers like hagfish, sharks, and crabs strip the soft tissues. Over time, the remaining bones support a succession of organisms, including bone-eating worms called Osedax, which bore into the bones and extract lipids. These processes can sustain life for decades, creating a complex and dynamic micro-ecosystem.

The discovery off Los Angeles is attributed to several factors. Detailed surveys of the area have been conducted, coupled with the region’s oxygen-poor waters, which slow decomposition and preserve the skeletons longer. Additionally, the lack of heavy sedimentation ensures that the whale bones remain exposed and easier to find. However, the proximity to busy shipping lanes raises concerns about the potential role of ship strikes in the high number of whale deaths.

Eric Terrill and Sophia Merrifield, oceanographers from the Scripps Institution of Oceanography at UCSD, led surveys in 2021 and 2023 to assess waste spread across 135 square miles of seafloor in the San Pedro Basin. This area, twice the size of Washington, D.C., and located about 15 miles offshore, was used as an industrial dumping ground in the early to mid-1900s. Many of the objects discovered during the survey were barrels containing the banned pesticide DDT and its toxic byproducts.

Researchers consider it unlikely that the toxic waste and discarded weapons in the area are causing whale deaths. Instead, the high volume of ship traffic is a probable factor, as this area might see more whales killed by ship strikes compared to other regions. The Los Angeles and Long Beach ports, the two busiest in the United States, are located just northeast of the study site, with shipping lanes spreading throughout the area. Additionally, thousands of gray whales migrate through these waters each year, and blue whales regularly feed here, John Calambokidis, a marine biologist with Cascadia Research Collective, a nonprofit in Washington State, told The Atlantic.

Whale falls are crucial not only for the biodiversity they support but also for their role in carbon sequestration. When a whale dies and sinks, it transfers a significant amount of carbon to the deep sea, where it can be stored for centuries. This process helps mitigate the effects of climate change by reducing the amount of carbon dioxide in the atmosphere. The impact is not huge, but scientists say it is significant.

The size of whales plays a significant role in the extent of these ecosystems. Blue whales, the largest animals on Earth, are now seen regularly off the coast. The population of blue whales off the coast of California (as well as Oregon, Washington and Alaska) is known as the Eastern North Pacific blue whale population. This group is one of the largest populations of blue whales globally and migrates between feeding grounds off the coast of California and breeding grounds in the tropical waters of the Pacific Ocean. Their massive bodies provide an abundant food source, supporting a greater diversity and number of species at whale fall sites.

(It should be noted that many articles and Web sites regularly claim that blue whales often reach 100 feet or more. That is false. It is unlikely any blue whale over 80 feet has plied California waters in modern history. John Calambokidis told California Curated that the persistent use of the 100-foot figure can be misleading, especially when the number is used as a reference to all blue whales.)

As many who spend time along the shore know, the waters off California are home to a variety of whale species, including blue whales, humpback whales, gray whales, and fin whales. Blue whale populations, although still endangered, have shown signs of recovery due to conservation efforts. Humpback whales, known for their acrobatic breaches and complex songs, undertake one of the longest migrations of any mammal, traveling between feeding grounds in the Arctic and breeding grounds in Mexico. Fin whales, the second-largest whale species, are also present in these waters, though their populations are also still recovering from historic whaling.

The newfound whale falls off Los Angeles offer a unique opportunity to study these deep-sea ecosystems in greater detail. Researchers are particularly interested in understanding the succession of species that colonize these sites and the overall impact on deep-sea biodiversity. Furthermore, studying whale falls can provide insights into the health of whale populations and the broader marine environment.

The discovery of whale falls in the deep sea reveals the remarkable interdependence of life in our oceans. These massive carcasses, sinking silently to the ocean floor, become rich oases that sustain a diverse array of creatures—from giant scavengers to microscopic bone-eating worms. This cycle of life and death highlights the ocean’s intricate balance, where even in the darkest depths, every organism contributes to a larger, interconnected web. Gaining a deeper understanding of these hidden processes is vital, not just for the sake of marine conservation, but for preserving the overall health and resilience of our planet’s ecosystems.