According to a new study published in the journal Current Biology, the vampire squid (Vampyroteuthis infernalis) has a reproductive strategy unique among soft-bodied cephalopods.
The vampire squid (Vampyroteuthis infernalis). Image credit: MBARI.
A ‘living fossil,’ the vampire squid inhabits the deep waters of all the world’s ocean basins at depths from 500 to 3,000 m.
The species is a soft-bodied, passive creature, about the size, shape, and color of a football. It has a dark red body, huge blue eyes, and a cloak-like web that stretches between its eight arms.
When threatened, the squid turns inside out, exposing rows of wicked-looking ‘cirri.’
While other squid reproduce all at once late in their lives, vampire squid show evidence of multiple reproductive cycles.
According to a group of marine biologists led by Dr Henk-Jan Hoving of the GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany, female vampire squid spawn their eggs, then return to a resting reproductive state, which is followed by the development of a new batch of eggs.
This reproductive cycle is likely to be repeated more than 20 times. This combination of reproductive traits is different from that of any other extant coleoid cephalopod.
“Their slow mode of life seems insufficient to support one big reproductive event, unlike other coleoid cephalopods. 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,” Dr Hoving said.
He and his colleagues characterized the reproductive status of more than 40 vampire squid females.
They report that one female in the sample, despite being in a reproductive resting phase, had released at least 3,800 eggs yet still retained 6,500 viable oocytes for future spawning.
Assuming an average batch size of 100 eggs, they suggest that this one female had already spawned about 38 times, with eggs in reserve for another 65 or so spawning episodes.
The findings suggest that vampire squid live longer than shallow-water squid species typically do.
The discovery is also a reminder of just how much we have to learn about life in the deep sea.
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Henk-Jan T. Hoving et al. 2015. Vampire squid reproductive strategy is unique among coleoid cephalopods. Current Biology, vol. 25, no. 8, R322–R323; doi: 10.1016/j.cub.2015.02.018
