Underwater Robots Find Unusual Deep-Sea Squid Tending to Enormous Eggs

The vast and mysterious realm of the deep sea has yielded another intriguing discovery, thanks to the advanced underwater robots of the Monterey Bay Aquarium Research Institute (MBARI). During an expedition to Mexico's Gulf of California, MBARI's remotely operated vehicle, Doc Ricketts, encountered an extraordinary sight: a mother squid nurturing a cluster of giant eggs.

This discovery stands out due to the unusually large eggs, which are twice as large as those typically seen in other deep-sea squids.

Underwater Robots Find an Unusual Deep-Sea Squid with Giant Eggs

Researchers from MBARI, GEOMAR's Helmholtz Center for Ocean Research Kiel, and the University of South Florida analyzed ROV footage and examined specimens of similar squids gathered on previous missions to the Gulf of California.

They concluded that this particular squid potentially belongs to an unidentified species within the Gonatidae family, known for brooding enormous eggs.

The unusually large size of its eggs, around 11.6 millimeters in diameter, captured the researchers' interest. Previous sightings of brooding Gonatus squids reported egg diameters up to six millimeters.

Moreover, the squid in the Gulf of California cared for far fewer eggs than typical for Gonatus squids. Researchers said she carried between 30 and 40 eggs, while other Gonatus squids brood as many as 3,000 eggs.

Squids are crucial in marine ecosystems, serving as both predators and prey. However, much remains to be learned about the squids that inhabit the deep ocean.

According to Henk-Jan Hoving, the lead author of the study, the advanced technology of underwater robots is revealing new details about the lives of these elusive creatures, offering insights into their biology and behavior.

MBARI scientists claim to be pioneers in observing brooding behavior in deep-sea squids. Throughout 37 years of deep-sea exploration, their remotely operated vehicles have captured 17 instances of brooding squids.

These include sightings of the black-eyed squid (Gonatus onyx), other armhook squids (Gonatus species), and the deep-sea squid Bathyteuthis. However, the squid spotted in the Gulf of California exhibited distinct characteristics that intrigued the researchers.

MBARI Senior Scientist Steven Haddock noted that the deep sea, as the planet's largest habitat, remains largely unexplored. The surprising discovery of a squid nurturing giant eggs during the Gulf of California expedition underscored the diverse survival adaptations that deep-sea creatures have evolved.

The Advantage of Small Eggs

The researchers noted that producing various small eggs can be advantageous in environments with food scarcity and high predation, as it increases the chances that some offspring will survive.

Larger eggs might also be more favorable in the stable conditions of the deep sea, allowing for higher parental investment in fewer offspring with better survival prospects.

According to the research team, this approach has also been observed in other deep-sea cephalopods, such as the warty deep-sea octopus (Graneledone species) and the pearl octopus (Muusoctopus robustus).

The team estimated that the eggs of this newly discovered deep-sea squid could take one to four years to mature, surpassing the entire life cycle of most shallow-water squids. The findings of the team were published in the journal Ecology.