New footage taken by an underwater robot has shown for the first time that some squid provide parental care for their eggs, rather than depositing their clutch and leaving them to their own devices.
Scientists at the University of Rhode Island used a remotely operated vehicle, or ROV, fitted with a camera to allow them to study squid in the deep waters of California's Monterey Canyon and filmed five Gonatus onyx squid swimming around while carrying thousands of eggs in their arms.
The footage shows the squid transporting a tubular pouch containing 2000-3000 eggs in its arms and is believed to be the first known example of parental care in a squid species.
The footage shot using the ROV operated by the team of scientists shows the squid carrying eggs in its arms. Footage: Rhode Island University
Dr Brad Seibel, Assistant Professor of Biological Sciences at the University of Rhode Island worked with scientists at the Monterey Bay Aquarium Research Institute in 2000 and 2002 and the team's findings have just been reported in the journal Nature.
Seibel says that the squid repeatedly extend their arms, in what he believes is an intentional attempt to circulate water over the eggs to keep them well-aerated in the low-dissolved oxygen levels found in these very deep oxygen-starved waters.
The eggs mature and break away after several months, hatch out and then become free-swimming.
Picture: Rhode Island University.
Not only is this the only known example of parental care in a squid, it's also provided new evidence to show that the arms and mantle musculature of squid do not always deteriorate following reproduction, which would render G. onyx incapable of caring for its clutch.
However, Seibel says that the muscles may still deteriorate to some degree as the brooding squid become poorer swimmers, making them an easier snack for predators, such as whales.
Gonatus onyx is one of the most common squid species in the Pacific and Atlantic Oceans, but little is known about it, because it lives and reproduces in very deep water.
The squid is a member of the family Gonatidae, and the genus includes around a dozen species most of which reach around 40cm/16" in length and are most common in the West Pacific.