Marine Invertebrates of Bermuda Vampire Squid (Vampyroteuthis infernalis) Evan Corey Ingram and James B. Wood (Ed) Abstract Taxonomy  Habitat  Ecology  Recent Research  Commercial Importance  Bermuda Laws  Personal Interest  References  Links

Abstract


Vampyroteuthis infernalis, the vampire squid, is a unique deep-sea cephalopod that is the only living member of the order Vampyromorphida. It possesses unique morphological characteristics that help it to survive at depths of 300 to 3,000 meters, including retractile filaments and the ability to bioluminesce. Instead of jet-propulsion, V. infernalis uses large paddle-shaped fins located near the apex of its body to move. Due to its bathypelagic nature, V. infernalis is rarely seen, and many aspects of its biology are still a mystery.

Taxonomy


Phylum: Mollusca
  Class: Cephalopoda
    Order: Vampyromorphida
      Family: Vampyroteuthidae


Habitat


Vampyroteuthis infernalis occurs throughout the depths of the world’s tropical and subtropical oceans. It is bathypelagic, living in aphotic waters at depths of 300 to 3,000 meters (Sterrer 1986); however, the majority of V. infernalis specimens are found at depths nearer 1,500 meters (Pickford 1949). Rarely are they seen at less than 1,000 meters (Pickford 1950). V. infernalis lives just below the oxygen minimum where there is little or no light, low oxygen content, and temperatures that do not surpass 6°C (Pickford 1949). In the Atlantic, V. infernalis has been caught nine miles southeast of Nonsuch Island, Bermuda at a depth of 1,000 to 2,000 meters (Pickford 1950).

Ecology


It is easy to see where Vampyroteuthis infernalis, with its jet-black body, cape-like webbing, and large eyes that can appear red under a certain light (Seibel et al. 1998), got the name vampire squid. The mantle of V. infernalis is short but broad and is fused dorsally to the head, which holds two large eyes. No buccal membrane is present (Young 1972), but a pair of paddle-like fins project from the apex of the body (Pickford 1950). Eight arms are present, as well as a pair of retractile sensory filaments. The arms are joined by an extensive web, and each are lined with a single row of suckers that are alternated with cirri (Pickford 1950). Males can reach a mantle length of 50 mm, while the mantles of females are thought to grow to a length of up to 80 mm (Pickford 1950).

The eggs of V. infernalis are opaque and have an average size of 3.33 mm (Pickford 1949), but are thought to reach a size of at least 8 mm (Young and Vecchione 1999). The distribution of the eggs has been found to be similar no matter what the time of year, suggesting V. infernalis has no true breeding season (Pickford 1949). During its development, V. infernalis experiences what has been described as a “double-metamorphosis” (Pickford 1950).The hatchlings drift through the water as meroplankton, surviving on a supply of internal yolk until their form changes to that of the typical larvae (Young and Vecchione 1999). V. infernalis larvae differ from adults in many ways. As larvae, they have smaller eyes, undeveloped filaments, and they possess a single-pair of posterior fins. During development, a pair of anterior fins will grow as the larval fin is eventually absorbed and disappears (Young and Vecchione 1999).

As a juvenile, V. infernalis will make use of mantle contraction to propel itself through the water. But because fin swimming is considerably more effective in the deep sea environment, the large fins of V. infernalis are its primary means of locomotion as an adult (Seibel et al. 1998). This results in decreased energy usage compared to other cephalopods, as well as the lowest metabolic rate measured in a cephalopod (Seibel et al. 1998).

V. infernalis has adapted to swim using its fins because, in the light-limited environment, it does not need to rely on speed to feed or to escape predation. Its dietary habits are relatively unknown, although it has been reported to feed upon prawns, copepods, and cnidarians (Young 1977). V. infernalis beaks have been discovered in the stomachs of pennipeds (seals) and deep diving fishes (Robison et al. 2003), as well as in the stomach contents of northern bottlenose whales (Santos et al. 2001).

There is much debate as to the purpose of the retractile filaments found on V. infernalis. Situated between the first and second pair of arms, they are usually found coiled inside a pouch in the webbing (Young 1967). Their ability to stretch in any direction beyond the length of the arms gives credence to the theory that they are useful in detecting predators and initiating the escape response (Young 1967).

V. infernalis has a remarkable ability to bioluminesce. The surfaces of the head, mantle, fins, and arms are covered in photophores (Young 1972). The fins themselves contain large photophores which can produce a bright, blue light (Robison et al. 2003). A yet unnamed organ, located at the tip of each arm, can also produce light (Robison et al. 2003). In response to a threat, V. infernalis will flash its photophores in distinctive patterns, hoping to confuse or distract whatever has disturbed it. Another response exhibited by V. infernalis is to release a luminous fluid from the tips of its arms (Robison et al. 2003). This fluid will form a cloud around the animal and may facilitate the ability to escape from predators or to attract prey (Robison et al. 2003).

Recent Research


Vampyroteuthis infernalis has been the subject of much interest due to the metamorphosis it undergoes during development and its reliance on fin-based propulsion. Seibel et al (1998) proved the hypothesis that, when in an aphotic environment where speed is not a priority, fin propulsion, being more economical than jet propulsion, is more prevalent. The transition from jet propulsion to fin swimming in V. infernalis was shown to be an ontogenetic trait related to an increase in body size (Seibel et al. 1998). Fin swimming was also shown to be useful in burst escape responses, allowing a quick movement to provide the means of escape (Seibel et al. 1998).

Research focusing on V. infernalis’s ability to survive in the oxygen minimum layer suggest that this cephalopod possesses specific physiological adaptations that allow it to meet its metabolic needs aerobically through extraction of oxygen from the surrounding water (Seibel et al. 1999). These studies have shown that gill diffusion capacity is extremely high in relation to its metabolic rate and that the capacity of respiratory proteins in V. infernalis to bind with oxygen is relatively high (Seibel et al. 1999). Combined, these provide V. infernalis with an effective oxygen gradient between the blood and the water (Seibel et al. 1999).

Other current research has focused on the bioluminescent ability of V. infernalis (Robison et al. 2003). Observations of the operation, structure, and purpose of the newly discovered arm-tip light organs and the ability to expel the luminous cloud have been beneficial in linking bioluminescence to anti-predation strategies (Robison et al. 2003).


Commercial Importance


Vampyroteuthis infernalis has no commercial importance.

Bermuda Laws


There is no legislation in Bermuda pertaining to Vampyroteuthis infernalis.

Personal Interest


Cephalopods are still a mystery to science. The constant debate that surrounds these beautiful creatures is justification enough for me to enjoy and to pursue a personal interest in these invertebrates. Every question brings up a new question, a new trail to pursue. When inquiring “Are they intelligent?” the only reply is to deliberate the actual definition of intelligence. If squid were able to lead longer lives, what would they evolve into? What role would they play in our lives? Vampyromorpha infernalis, the vampire squid, is one of the most intriguing species I have yet to encounter in my research. It is a species that has eluded science due to nothing more than its mere inaccessibility. The environment that V. infernalis has evolved in has led it to adapt in ways that science is still struggling to make sense of. New discoveries are still being made; new questions are still being asked. Nothing is known of its breeding habits or social structure, and most of what is known is speculation, not fact. Is bioluminescence merely a clever predation avoidance strategy, or is it a form of communication? I enjoy watching as the constant struggle to find answers to these mysteries expands and evolves.

References

Pickford, G.E. 1949. Distribution of the eggs of Vampyroteuthis infernalis Chun. Journal of Marine Research. 8(1): 73-83.

Pickford, G.E. 1950. The Vampyromorpha (Cephalopoda) of the Bermuda Oceanographic Expeditions. Zoologica. New York. 35(1): 87-95.

Robison, B.H., K.R. Reisenbichler, J.C. Hunt, and S.H.D. Haddock. 2003. Light production by the arm tips of the deep-sea cephalodpod Vampyroteuthis infernalis. Biol. Bull. 205: 102-109.

Santos, M.B., G.J. Pierce, C. Smeenk, M.J. Addink, C.C. Kinze, S. Tougaard, and J. Herman. 2001. Stomach contents of northern bottlenose whales Hyperoodon amullatus stranded in the North Sea. J Mar Biol Ass U.K. 81: 143-150.

Seibel, B.A., E.V. Thuesen, and J.J. Childress. 1998. Flight of the vampire: Ontogenetic gait-transition in Vampyroteuthis infernalis (Cephalopoda: Vampyromorpha). The Journal of Experimental Biology. 201: 2413-2424.

Seibel, B.A., F. Chausson, F.H. Lallier, F. Zal, and J.J. Childress. 1999. Vampire blood: respiratory physiology of the vampire squid (Cephalopoda: Vampyromorpha) in relation to the oxygen minimum layer. Experimental Biology Online. Springer-Verlag. 4: 1-10.

Sterrer, Wolfgang, ed. Marine Fauna and Flora of Bermuda: A Systematic Guide to Identification of Marine Organisms. New York: John Wiley and Sons, 1986.

Young, J.Z. 1977. Brain, behaviour and evolution of cephalopods. Symp. Zool. Soc. Lond. 38: 377-434.

Young, R.E. 1967. Homology of retractile filaments of vampire squid. Science. 156(3782): 1633-1634.

Young, R. E. 1972. The systematics and areal distribution of pelagic cephalopods from the seas off Southern California. Smithson. Contr. Zool. 97: 1-159.

Young, R.E. and M. Vecchione. 1999. Morphological observations on a hatchling and a paralarva of the vampire squid, Vampyroteuthis infernalis Chun (Mollusca: Cephalopoda). Proceedings of the Biological Society of Washington. 112(4): 661-666.

Links

CephBase: Vampire Squid
The Cephalopod Page: Vampire Squid
Sea and Sky: Vampire Squid
Vampire Squid Video