Humboldt Squid
  • The Humboldt Squid can be up to 6 feet long and is a voracious predator.
  • In October 2003, a dozen of the bluish-red squid were found stranded in Pebble Beach; others have been seen along much of the Sanctuary coastline since then.
  • Because the Humboldt Squid spends most of its time in over 600 feet of water, researchers know relatively little about its life cycle and behavior.
  • They have the ability to rapidly change their skin color, which is thought to be a form of communication.

Pebble Beach residents were greeted with a surprise one morning in October of 2003: approximately 12 "jumbo" squid had washed ashore (Figure 1). The squid were over 5 feet long, weighed as much as 10 pounds, and had a distinctive red-purple coloring and huge eyes, shocking locals who had never seen anything like them. Many of the creatures were still alive when people found them; despite rescue efforts, all of the squid died.

The dozen Humboldt Squid (Dosidicus gigas), as they are technically called, found in Pebble Beach were indeed rare, but sightings of stranded Humboldts have become increasingly common as far north as Mendocino in the last several decades. First recorded in Monterey Bay in 1935 (CA Fish Bulletin #49), sightings were infrequent until the 1997-98 El Niño event, when Humboldt Squid were reported in greater numbers near the Monterey Canyon. Dr. William Gilly of Stanford University, an expert on the Humboldt Squid, believes that shifts in prey availability prompted the squid to inhabit the canyon.

While the cause of death for the Pebble Beach squid is unknown, evidence points to neurological damage. Some researchers think that they die from eating fish and krill which feed on algal blooms. The blooms produce harmful acids that get concentrated up the food chain, potentially harming the squid's nervous system.

The Humboldt Squid can reach 6 feet in length and is a fierce predator, with strong arms and tentacles, keen vision, and an extremely sharp beak (Figures 2 and 3). See video footage of Humboldt Squid hunting below. Researchers have observed coordinated hunting behavior among the squid, yet they are also known to be cannibalistic (hence the nickname "red devil"). While their skin is generally reddish-purple, they can rapidly change color by opening and closing chromatophores, or pigment-filled sacs, in their skin. This behavior is controlled by the brain and is thought to be a form of communication, though no one knows exactly what the color changes mean.

The vast majority of the squid's life is spent between 660 and 2300 feet below the sea surface, well beneath depths that can be reached by SCUBA divers. It has therefore been difficult for researchers to learn about the life cycle of these organisms. Fortunately, Humboldt Squid often feed near the surface at night; researchers like Dr. Gilly have studied them during these times. His group has also tagged several of the animals in the Sea of Cortez, demonstrating that the squid migrate seasonally as much as 100 miles (Figure 2). Tagging experiments also indicate that the squid can tolerate an incredible range of depth, temperature, and dissolved oxygen conditions. As a result of this exceptional habitat range, it is most likely that Humboldt Squid migration is primarily motivated by availability of food, rather than fluctuations in oceanic conditions. Yet, the distribution of the squid may be secondarily controlled by oceanic parameters, because these often dictate the location of the squids' prey.

Humboldt Squid have recently been filmed from remotely operated vehicles near Cordell Bank. Click on the video link below to watch some of this footage.

Dr. Gilly believes that the Humboldt Squid are a prolific species for their size; he estimated that as many as 10 million may be living in a 25 square-mile area off Mexico. This implies that their population is enormous, given that they range latitudinally from California to Chile and longitudinally from Mexico halfway to Hawaii. They are an important part of the ocean food web, preying upon small fish and krill and being preyed upon by sperm whales and large fish, such as marlin and swordfish. In addition, they are vital to the fishing industry of Mexico, which sells tons of Humboldt Squid to markets in Japan. Understanding the life cycle and distribution patterns of the Humboldt Squid is vital to managing the fishery.

Figure 1: Humboldt squid that had washed ashore in Pebble Beach were stacked with ice on a picnic table to preserve them. The squid have huge eyes to help them hunt in deep, dark waters. Photo: The Carmel Pine Cone, October 10, 2003.
fresh caught squid
Figure 2: A member of the Sea of Cortez Expedition holding a freshly caught Humboldt Squid. Photo: Sea of Cortez Expedition and Education Project.
Figure 3: Humboldt squid swimming. Photo: Rick Starr.
Video clip of humboldt squid hunting fish at Cordell Bank. Video provided by Cordell Bank National Marine Sanctuary. Launch video (8.8 Mb WMV file)

Links to More Information

Stanford faculty website for Dr. William Gilly:

Dr. Gilly and others encounter the Humboldt Squid while exploring the Sea of Cortez:

An article in The Carmel Pine Cone highlighting the stranding event:

Humboldt Squid covered by National Geographic:

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