SERIES: Invertebrate of the Week

Invertebrate of the Week #9 – Bigfin Squid (Magnapinnidae)

On November 7, 2007, a Shell Oil Company ROV team worked to retrieve drilling equipment on the seabed near the Perdido project in the Gulf of Mexico. They were working around a well located around 2,450 meters below the ocean’s surface when their camera panned across the creature in the video below.

Bigfin squid in ROV footage.

Hovering near the oil well, perpendicular to the ground, was a large squid with 10 articulated arms terminating in long, dangly tentacles.  

It looked like one of the aliens from the movie Independence Day,” stated Shell Senior Operations Coordinator Patrick Desrouleaux when he first saw the images.

The video made the rounds through oil-industry email inboxes until it made its way to Michael Vecchione of the National Oceanic and Atmospheric Administration (NOAA) and the  National Museum of Natural History in Washington, D.C. Vecchione is an authority on deep-sea cephalopods and was able to identify the squid as a member of the genus Magnapinna (Family: Magnapinnadae) – a bigfin squid.

In 1998, Vecchione and University of Hawaii biologist Richard Young became the first to formally document bigfin squid and laid the taxonomic foundation for their inclusion in the tree of life. Later, in 2001, the duo got a major break when the ROV Tiburon operated by the Monterey Bay Aquarium Research Institute (MBARI) recorded 10 minutes of crisp video footage of a Magnapinna bigfin squid at a depth of around 3380 meters.

When first encountered, the approximately 4-5 meter long cephalopod was hovering perpendicular to the seafloor with its tentacles dangling along the substrate before it was startled by the vehicle and retreated into the water column. Based on this video, along with observations from four other encounters recorded by deep-sea explorers since 1988, the pair were able to generate the first reports on adult Magnapinna bigfin squid in 2001.

Magnapinna sp. – Long-armed squid – MBARI
SightingDateSubmersibleDepth (m)Comments
1Sep 1988Nautile4735Western Atlantic, off Brazil
2Jul 1992Nautile2950Eastern Atlantic, off Africa
3Jul 1992Nautile3010Eastern Atlantic off Africa
4Nov 1998Shinkai 65002340Indian Ocean
5Jan 2000Commercial ROV2195Gulf of Mexico
6May 2000Nautile2576Indian Ocean
7Oct 2000Alvin1940Gulf of Mexico
8May 2001Tiburon3380Central Pacifc
Summary of submersible big-fin squid encounters adapted from Vecchione, M., Young, R. E., Guerra, Á., Lindsay, D. J., Clague, D. A., Bernhard, J. M., … & Segonzac, M. (2001). Worldwide observations of remarkable deep-sea squids. American Association for the Advancement of Science.

Their work suggests that Magnapinna enjoys a global distribution. Bigfin squid have been observed in the Pacific, Atlantic, and Indian Oceans as well as the Gulf the Mexico at depths between 1,940 – 4,735 meters. They also appear to be relatively large, reaching lengths of 7 meters. They are propelled through the water by two large terminal fins that also allow the bigfin squid to hover perpendicular to the substrate in a vertical position.

The most intriguing physical feature of the squid is the arm morphology. Whereas most deep-sea squids possess eight short arms and two long tentacles, Magnapinna possess ten indistinguishable arms. These appendages extend perpendicular to the body and abruptly bend at 90 degrees in an elbow-like kink. From there, the arms taper into long, thin tentacles.

Bigfin squid have been observed dragging these tentacles across the seabed to retrieve small bits of food and that may be their primary means of feeding. Researchers like Vechionne, however, suspect that the morsel-feeding behavior may only supplement a primary strategy of lying in wait for passing prey to become ensnared in their grasp.

Aside from these casual observations, not much more is known about Magnapinna. Yet, as scientific researchers and commercial explorers both get better at traveling through the depths, it is almost certain that we will have more information on what is apparently a geographically widespread and conspicuous creature.

Update: Observations from Australia in 2020

On November 11, 2020, researchers from Commonwealth Scientific and Industrial Research Organisation and Museums Victoria published a paper outlining the first observations of bigfin squid in Australian waters. The researchers used Remotely Operated Vehicles and a towed camera system at depths between 946–3258 meters to survey the biodiversity and geology of the Great Australian Bight. During their survey, they managed to capture five visual records of bigfin squid.

These observations have more than doubled the visual record count of bigfin squid worldwide and yielded invaluable insights around locomotion, posturing, ecological associations, and general morphology. I highly recommend checking out the paper below if you have time. In the meantime, here is some of the compiled footage captured by the research team:

This post has been updated from an earlier version published in 2014.

References and Further Reading

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