One of the most unusual creatures found in deep seas, the vampire squid, has never been observed mating in the wild. A new research suggests that this creature has a reproductive strategy which makes it very different from other cephalopods.
Cephalopods, meaning octopuses and squids, usually release eggs only one time in their life: exactly before they die. However scientists noticed that squids have a large number of reproductive cycles. They release eggs in multiple stages. As a result of this the vampire squid lives more than the coastal squid and the octopus.
Henk-Jan Hoving of the GEOMAR Helmholtz Centre for Ocean Research Kiel (Germany) explained that in the mating process the male squid releases a sperm packet. Once the female is ready to release the eggs the sperm packet gets mobilized. Hoving together with his colleagues has analyzed the ovaries of more than 40 specimens of vampire squid. The specimens had been preserved at the Santa Barbara Museum of Natural History in alcohol jars since the 1960-80s.
Vampire squids live in regions poor in oxygen, at around 600-900 (2.000 – 3.000 feet) meters below the sea surface. Hoving explained that their slow mode of life may not be enough to enable them to support a single, big reproductive event, like other coleoid cephalopods do. He remarked:
“Perhaps it is therefore that vampire squid return to a gonadal resting phase after spawning, and presumably start accumulating energy for a new reproductive cycle.”
After analyzing the most developed female in the research it was discovered that she had released at least 3.800 eggs before she died and had around 6.500 viable immature egg cells which could have been used for future spawning. Taking into consideration the fact that the female had about 100 eggs in a clutch this means she had spawned at least 35 times and would have been able to spawn 65 times.
The study showed that vampire squids could live for 8 years, whereas normal squids and octopuses live for one or two years. Hoving said that it is important to know if the vampire squid can live for such a long time since longevity is an important factor when it comes to understanding how an ecosystem works.
This is not the first study which has proved that cephalopods which live in the deep sea may live longer than coastal ones. In a study performed last year scientists have discovered that a deep-sea octopus guarded her eggs for 523 months, which is a record. Most octopuses do not live that much.
Image Source: DeepSeaCreatures