In a recent study of vampire squid, researchers were rewarded with a reminder of how little we know about deep sea life.
Most squid wait until late in life to reproduce and then do it all at once. Vampire squid, on the other hand, appear to reproduce a little bit at a time in a way that is more common among fish.
This is in keeping with what is known about vampire squid in that they seem to do everything a little bit at a time. The small squid, which reach a total size of up to 1 foot in length are covered in photophores, light producing organs which flash to disorient potential predators or prey. They live at depths of 1600 to almost 10,000 feet spend the vast majority of their time floating instead of swimming and consuming a diet of zooplankton and detritus which is very low on calories.
Although it has not yet been proven, it is also suspected that the squid live for a much longer time than their counterparts; doing things very slowly but for a very long time.
“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,” says Henk-Jan Hoving in a statement.
Hoving is working for the Cluster of Excellence “Future Ocean” at the GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany and is the lead author of a new paper on the vampire squid published in the journal Current Biology.
Having an his team were examining collections of vampire squid from the 1960s and 70s at the Santa Barbara Museum of Natural History when they noticed something unusual in the female squid.
Many of the animals they examined had clearly spawned but had no ripe or developing eggs. In total they examined 40 specimens and noted that one female in particular had released 3,800 eggs but still had 6,5000 viable oocytes, which indicates that it was ready for future spawning. Because the average batch of squid eggs numbers about 100, this indicated to the researchers that the vampire squid could spawn up to 100 times over the course of their lives, instead of just once.
“We know very little about deep-sea organisms and their life-cycle patterns, in particular in the water column of the deep sea. The patterns we know from coastal and shallow-water organisms may not apply to deep-sea species. We need to enhance our knowledge of deep-sea pelagic organisms and the system they are part [of], since the pelagic deep sea is the largest living space on the planet. A better understanding of this unique marine ecosystem will eventually allow for better development of management and conservation strategies,” says Hoving.
