While retracing the route of polar explorer Sir Ernest Shackleton and his sunken ship, the Endurance, scientists stumbled upon an unexpected ecological find in the Weddell Sea. During an expedition in 2019, researchers utilized a remotely operated vehicle (ROV) to explore the seafloor in Antarctica”s Western Weddell Sea, uncovering over 1,000 circular nests of fish, meticulously arranged in geometric patterns.
This intriguing discovery highlights the unique ecosystems thriving in the planet”s harshest environments, reinforcing the argument for designating the Weddell Sea as a Marine Protected Area. The nests, which are indentations in the sandy seafloor, belong to a species of rockcod known as the yellowfin notie. They were found in a region previously covered by a 656-foot-thick ice shelf. The nests exhibit various arrangements, ranging from solitary positions to clusters and curves, suggesting a complex social structure among the fish.
Researchers noted that the yellowfin notie demonstrate a remarkable level of cleanliness in their nesting behavior. While the surrounding seafloor was littered with plankton debris, each individual nest remained pristine. The fish community appears to balance cooperation and self-interest, as documented in a recent study published in the journal Frontiers in Marine Science. Each nest was likely guarded by a parent fish, and the strategic arrangement of the nests serves as a defensive mechanism.
The clustering of nests aligns with the “selfish herd” theory, which posits that individuals in the center of a group enjoy greater safety than those on the periphery. The researchers speculate that isolated nests may house larger, more robust fish capable of better defending their territory.
The discovery of these fish neighborhoods coincided with efforts to locate Shackleton”s long-lost ship during the Weddell Sea Expedition 2019. The expedition aimed to investigate regions near the Larsen Ice Shelf and find the wreck of the Endurance, which was trapped and ultimately destroyed by pack ice in 1915. Although the challenges posed by the harsh conditions of the Antarctic prevented the team from locating the ship during their 2019 mission, they successfully explored previously unreachable areas of the seabed.
The Larsen Ice Shelf, located in West Antarctica, is a critical formation that influences ice flow and sea level rise. In 2017, a significant portion of this ice shelf, known as Larsen C, calved into one of the world”s largest icebergs, the A68 iceberg, which measured 2,240 square miles at its peak. The expedition team used ROVs and autonomous underwater vehicles (AUVs) to study these newly accessible regions, leading to the important discovery of the fish nests.
Given that these findings reveal a unique and vulnerable habitat vital to biodiversity, they carry important implications for conservation efforts in the region. The study adds to a growing body of research advocating for the formal designation of the Weddell Sea as a Marine Protected Area, highlighting that life persists even in the planet”s most extreme environments.
