A strange deep-sea squid, captured more than 1,800 feet below sea level by an underwater drone, is now believed to be a new species after nearly a decade of analysis.
Marine biologists first took note of the mother squid, which is now officially described as part of the family Gonatidae – in the Gulf of California off the coast of Baja, where they caught it with eggs twice the size of any ever seen.
Normally, deep-sea squid produce thousands of tiny eggs, as many as 3,000 all at once, but the new ones kind was spotted holding and protecting only about 30 to 40 much larger eggs instead.
The researchers suspect that a lack of predators in the deep sea, or possibly a more stable food supply, allowed this squid to develop reproductive habits that focused more resources on fewer eggs, rather than the shotgun approach to lots of small eggs.
A strange deep-sea squid recorded by an underwater drone more than 550 meters below sea level is now believed to be a new species after almost a decade of analysis. Above is a clip from that 2015 video of the deep-sea squid, described as a possible new species in the family Gonatidae
Normally, deep-sea squids produce up to 3,000 much smaller eggs, in what experts call a ‘bet-hedging’ strategy these creatures have developed to increase their species’ chances of survival. The new squid (above) was spotted with only about 30 to 40 much larger eggs
The strange encounter in 2015 sparked a nine-year investigation by scientists in the US and Germany, who described the ‘gigantic size of the eggs’ as ‘unprecedented’.
“Our unexpected encounter with a squid hatching giant eggs,” senior scientist Steven Haddock of California’s Monterey Bay Aquarium Research Institute (MBARI) told reporters, “captured the attention of everyone in the ship’s control room.”
All previous deep sea squids herein Gonatidae or Gonatus family have been recorded as reproducing via eggs no larger than about a quarter inch (six millimeters).
The scientists called this more traditional squid approach to many small eggs a “bet-hedging” strategy that the creatures developed to increase their species’ chances of survival in parts of the ocean where predators eat baby squid and their eggs.
But the 2015 mother squid hatched eggs nearly twice her size, wrapped in her protective tentacles. half an inch (11.6 millimeters) in diameter.
The unexplained difference set scientists looking for a good evolutionary reason why deep-sea squids might reproduce this way.
“Our unexpected encounter with a squid hatching giant eggs,” a scientist from California’s Monterey Bay Aquarium Research Institute told reporters, “captured the attention of everyone in the ship’s control room.” Above, a close-up of the eggs, which are about half an inch in diameter
All previous deep sea squids herein Gonatidae or Gonatus family have been recorded as reproducing via eggs no larger than about a quarter inch (six millimeters). Above the squid Bathyteuthis berryi documented with a more typical brood of smaller squid eggs
“This remarkable observation highlights the diversity of ways in which animals adapt to the unique challenges of life in the deep,” said MBARI’s Haddock, who served as lead scientist on the expedition that first captured the squid on video.
Data from other marine biologists’ research into the gestation period of squid eggs has only added to the mystery.
Based on frigid ocean temperatures and the sizes of other deep-sea squids with well-documented “egg development rates,” the researchers estimate that the eggs of these new Gonatidae Squid can take up to four years to develop.
“Breeding demands a lot from a mother squid,” Hoving said in a statement MBARI. “She won’t eat while carrying her eggs and eventually dies after her eggs hatch.”
Above, a mother squid with black eyes (Gonatus onyx) hatch a much larger set of the more typical and much smaller squid eggs
“But her sacrifice increases the chances that her descendants will survive,” noted Hoving, who now heads the deep-sea biology working group at GEOMAR – Helmholtz Center for Ocean Research Kiel in Germany.
‘It’s just one of many remarkable adaptations that may help cephalopods (the technical term for squid and octopus species) survive in the deep sea.’
Years of a mother squid caring for her eggs, with this level of sacrifice and determination, would make this species an incredible outlier compared to other squids.
“If the breeding period is indeed longer than a year,” the research team wrote in their new study, published in the journal Ecology‘it lasts longer than the entire life cycle of most shallow-water and coastal cephalopods (both squid and octopus)’
At this point, the researchers suspect that this squid has evolved to produce fewer and larger eggs because its isolated, deep-sea ecosystem is light on baby squid predators.
“Breeding takes a lot out of a mother squid,” the lead author of the new study said in a statement. ‘She won’t eat while carrying her eggs and eventually dies after her eggs hatch’
Two species of deep-sea octopus, the warty deep-sea octopus (Graneledon sp.) and the pearl octopus (Mouse octopus robustus), also lay larger eggs than normal eggs.
The fact that this is a trend in deep-sea regions, the team noted, could indicate that “more stable and predictable conditions” in the deep allow these creatures to metaphorically put all their eggs in one basket.
“Giant eggs may be more cost-effective,” the team wrote in a statement, “allowing higher investment in fewer offspring that have a better chance of survival.”
The new study – a collaboration between MBARI in California, GEOMAR in Germany and the University of Florida – hopes to collect more specimens to more forcefully confirm that this squid is definitively a new species.
Despite the crucial role that deep-sea squids play in the broader ocean food chain, and even in the commercial fishing industry, very little about these creatures is currently well understood by marine science.
Deep-sea squid eat small fish and invertebrates and then become food for commercially important fish such as tuna, swordfish and sailfish. But their life cycle and variety are still major open questions, the researchers said.
“Advanced underwater robots are helping us better understand the lives of deepwater squids and revealing fascinating new information about their biology and behavior,” said Hoving.
“But we still have a lot to learn about the squids that live in the deep,” he added.
“The deep sea is the largest living space on Earth,” MBARI’s Haddock added, “and there is still much to discover.”