Encyclopaedia of Cryptozoology
Deepstar 4000 fish

Line drawing of the Deepstar 4000 fish by Setofin and Truth is Scarier.

Classification Osteichthyes
Proposed scientific names
Other names Deepstar monster
Sea reported Pacific Ocean
First reported 1968[1]
Prominent investigators Gardner Soule
Matt Bille

The Deepstar 4000 fish was a cryptid giant deep sea fish seen once, off southern California in the Pacific Ocean, by the crew of the Deepstar 4000↗ submersible during a 1966 dive.[2] It was estimated to have measured 30–40 ft (9–12 m) in length, equal to some of the largest known living fish.[3][4]



This fish was allegedly observed by pilot Joe Thompson (1930 – 2003) and marine biologist Gene LaFond (1909 – 2002), during a June 1966 research dive in the San Diego Trough. They had taken the Deepstar 4000 down to around 4,000 ft (1,219 m) to lay hydrographical instruments on the seafloor, and when Thompson happened to look through the window, he found himself staring into the eye of a giant fish which had swam briefly into view. It moved past quickly, bringing up silt from the seabed, before disappearing.[5][6]

Thompson and LaFond initially kept quiet, assuming they would not be believed, but eventually described the fish to submersible expert Edward Shenton,[5] journalist Louis Schafer,[6] and cryptozoologist and marine writer Gardner Soule,[1] to whom Thompson also described a much smaller giant grenadier. Furthermore, according to Soule, the live reactions of the two men were recorded on the submersible's audio log.[1]


Thompson and LaFond did not describe the fish in detail, and were most startled by its allegedly enormous size. It was far larger than the 18 ft (5 m) Deepstar 4000, and was judged to be some 30–40 ft (9–12 m) in length, similar in size to some whale sharks (Rhincodon typus). As well as the submersible itself, the pair were able to judge the fish's length using the hydrological instruments which had been recently placed on the seafloor at set intervals.[5] It possessed "huge pectoral fins," a rounded grouper-like tail fin which seemed to be 4–5 ft (1.2–1.5 m) in height[5] and "serrated,"[6] and eyes "as big as dinner plates."[5] The skin was dark and mottled,[5] and Thompson was certain that it was also scaled.[6]


The Deepstar 4000 fish has sometimes been identified as a Pacific sleeper shark (Somniosus pacificus), a relative of the pictured Greenland shark (Somniosus microcephalus) (CC BY-SA 4.0).

Although the Deepstar 4000 was not able to photograph the giant fish, underwater cameras operated by oceanographer John D. Isaacs (1913 – 1980) in the same area soon produced a photograph of a large "marine monster". Ichthyologist Carl Hubbs (1894 – 1979) identified this as a Pacific sleeper shark (Somniosus pacificus), which were then confused with the better-known Greenland shark (Somniosus microcephalus), which is larger, but is restricted to the Arctic and North Atlantic. Isaacs, who was the Scripps Research Institute's resident "sea serpent expert,"[7] did not initally favour Hubbs' identification,[8] but several more photographs of sleeper sharks were later taken, and ultimately, given the number of times they appeared on camera, it was assumed that they must have been very common around the San Diego Trough.[4][9] It was Isaacs' "marine monster" photograph which initially induced Thompson and LaFond to come forward with their own sighting.[1]

Hubbs later suggested that the Deepstar 4000 fish could have been a very large specimen of this shark, although no sleeper shark is known to grow to the size estimated by Thompson.[2] Isaacs later reported photographing a 30 ft (9 m) sleeper shark near Hawaii,[8] but the average recorded size is some 12–14 ft (3–4 m) long. Other very large sleeper sharks have been reported, including a specimen filmed off Japan which has been falsely represented as a megalodon on the internet in the years after its recording. Richard Ellis also points out that sleeper sharks have comparatively small eyes, which would not warrant Thompson's "dinner plate" comparison.[3] Neither Thompson nor LaFond accepted the sleeper shark as what they had seen.[1] Matt Bille feels that the animal was more likely an undescribed species, and observes that, if it was a bony fish rather than a shark, as appears to be the case, it would be by far the largest and heaviest on record.[2]

Notes and references[]

  1. 1.0 1.1 1.2 1.3 1.4 Soule, Gardner (1968) Undersea Frontiers: Exploring by Deep-Diving Submarines
  2. 2.0 2.1 2.2 Bille, Matthew A. (2006) Shadows of Existence: Discoveries and Speculations in Zoology, Hancock House, ISBN 9780888396129
  3. 3.0 3.1 Ellis, Richard (1998) Deep Atlantic: Life, Death, and Exploration in the Abyss
  4. 4.0 4.1 Soule, Gardner (1970) The Greatest Depths: Probing the Seas to 20,000 Feet and Below
  5. 5.0 5.1 5.2 5.3 5.4 5.5 Shenton, Edward Heriot "Where Have All the Submersibles Gone?," Oceans, Vol. 3, No. 6 (1970)
  6. 6.0 6.1 6.2 6.3 Schafer, Louis S. "The Deepstar 4000," The Compass: A Magazine of the Sea, Vol. 56, No. 1 (1986) – Online
  7. Heuvelmans, Bernard (1968) In the Wake of the Sea-Serpents, Hart-Davis, ISBN 9780246643124
  8. 8.0 8.1 Behrman, Daniel (1969) The New World of the Oceans: Men and Oceanography
  9. Soule, Gardner (1981) Mystery Monsters of the Deep