Cameras Hunting a Lost Shipwreck Discover Mysterious Geometric Patterns on Antarctic Seafloor

During an intensive 2019 survey of the Weddell Sea, researchers utilizing the remotely operated vehicle Lassie came up empty-handed in their search for the lost wreck of Ernest Shackleton’s Endurance. However, the 27 hours of high-definition seafloor footage captured a different kind of discovery: a sprawling, intricate network of over 1,000 active fish nests. The findings, recently detailed in Frontiers in Marine Science, shed new light on the reproductive behavior of the yellowfin notie (Lindbergichthys nudifrons).

Geometric Precision Beneath the Ice

The survey revealed 1,036 active nesting sites across five distinct locations, organized into 277 groups. These depressions, situated at depths between 290 and 411 meters, exhibited six complex geometric configurations, ranging from tight clusters and crescents to linear and U-shaped arrangements. While researchers noted that clusters were the most common—accounting for 42 percent of the active nests—they also observed isolated, singular nests that tended to be larger in diameter. This, experts suggest, may indicate that older, more dominant fish are capable of defending their territory without the need for communal protection.

The maintenance of these sites was evident in the sediment. A recent phytoplankton bloom had coated much of the seafloor in a layer of debris, yet the active nests remained conspicuously clear. The yellowfin notie, which can grow up to 19.5 centimeters in length, appears to diligently groom its nursery, protecting eggs through an incubation period that can stretch beyond 100 days.

Strategic Defense Against Predators

The researchers suspect that these geometric patterns are driven by the need for collective security. By applying the “selfish herd” principle, individual fish may reduce their susceptibility to predators by nestling within the center of a larger group, using neighbors as a buffer against threats. Potential predators identified in the area included brittle stars, which were frequently found perched on the rims of the depressions, and the ribbon worm Parborlasia corrugatus. The authors hypothesize that the dense clustering of these nests may help obfuscate the chemical scent profiles of the egg batches, making them harder for olfactory-driven predators to locate.

Implications for Antarctic Conservation

The timing of these observations was made possible by the 2017 calving of the massive A68 iceberg from the Larsen C Ice Shelf. The event exposed previously inaccessible swaths of the seafloor, allowing scientists to study habitats that had been shrouded by ice for varying lengths of time—some for decades, others for potentially geological timescales. Despite these differences in exposure, the yellowfin notie established nests across all surveyed sites, suggesting the species is highly adaptable to varying environmental conditions.

This data arrives at a critical juncture for regional conservation policy. The Commission for the Conservation of Antarctic Marine Living Resources has been debating the establishment of a Weddell Sea Marine Protected Area, a move that requires empirical evidence of sensitive breeding habitats. Because these nesting aggregations meet the criteria for a “Vulnerable Marine Ecosystem,” the authors argue that their findings provide a robust foundation for designating these areas as protected zones, shielding them from the potential impacts of bottom-contact fishing.

While the study represents a significant leap in our understanding of deep-sea Antarctic life, the team acknowledges the challenges of species-level identification from underwater video alone. Though the yellowfin notie was the only species observed tending the nests, further genetic verification may be required to confirm whether other related species are also contributing to these intricate, architecturally complex nursery grounds.