Tag Archives: squid

Live fast and die young: same-sex sexual behaviour in a deep-sea squid

Little is known about the reproductive habits of deep-living squids. Using remotely operated vehicles in the deep waters of the Monterey Submarine Canyon, scientists from the Monterey Bay Aquarium Research Institute and University of Rhode Island have found evidence of mating on similar body locations in males and females of the rarely seen mesopelagic squid Octopoteuthis deletron.

In a study published today in Biology Letters, male squid were found to routinely and indiscriminately mate with both males and females.

Most squid species are short-lived and promiscuous, with a single, brief reproductive period. In the deep, dark habitat where O. deletron lives, potential mates are few and far between. The researchers suggest that same-sex mating behaviour by O. deletron is part of a reproductive strategy that maximizes success by inducing males to indiscriminately and swiftly inseminate every same species squid that they encounter.

Direct observations of mating behaviour of deep-sea squid are restricted to a single observation of a possible mating event. Using remotely operated vehicles (ROVs) for exploration and research, has shed new light on our knowledge of deep-sea squid behaviour.

Males of the genus Octopoteuthis deposit spermatophores, complex structures containing millions of sperm, on the female. Here they discharge sperm-containing sacs called spermatangia that implant into the female’s tissue. Empty spermatangia remain attached to a female’s body and provide evidence of recent mating.

Same sex mating behaviour in marine invertebrates is very poorly known, although it has been reported before in cephalopods.

Mating in O. deletron, as in many other squids, is probably rapid, as spermatophores are quickly passed between partners and spermatangia release follows soon thereafter. Mature males and maturing mated females of O. deletron are of the same size, solitary and have only minor morphological differences. The combination of a solitary life, poor sex differentiation, the difficulty of locating a squid of the same species and the rapidity of the sexual encounter probably results in the observed high frequency of spermatangia-bearing males in this species. Apparently, the costs involved in losing sperm to another male are smaller than the costs of developing sex discrimination and courtship, or of not mating at all. This behaviour further exemplifies the ‘live fast and die young’ life strategy of many cephalopods

Further Reading:
Hendrik J. T. Hoving, Stephanie L. Bush, and Bruce H. Robison
A shot in the dark: same-sex sexual behaviour in a deep-sea squid
Biol Lett 2011 : rsbl.2011.0680v1-rsbl20110680.

New Species of Squid Found

Scientists have discovered a new, large, species of squid in the Indian Ocean, says the International Union for Conservation of Nature.

The new species is 70 cm long, long and slender with a light-producing organ acting as a lure to attract prey.

The squid was found during a seamounts cruise in the southern Indian Ocean. Seamounts are typically steep-sided extinct volcanoes that, officially, are at least 1000 m high. The peaks of these undersea mountains are usually from a few hundred to a few thousand meters below the sea surface. So far, more than 70 types of squid have been identified from the seamounts cruise, representing over a fifth of all squid species around the world.

Seamounts are very rich in sealife. Large ocean predators, like sharks and whales, go there to feed during their migrations. The populations of fish which live around the seamounts, though, are targetted by fishermen. Dr. Alex Rogers from the Zoological Society in London says

“Without a doubt, fishing has been the major threat to seamount ecosystems for probably the last 30 or 40 years…because many of these seamounts were a long way from land regulation of these fisheries has been very poor if no completely missing.”

He added that the fish targetted are incredibly long-lived, up to 150 years. They reach maturity late and so are very vulnerable to over-fishing.

Further reading:
IUCN Seamounts – Seamounts Conservation and Management Project

Colossal Squid Caught at Surface of Ocean

A colossal squid has been caught in Antarctic waters, the
first example of retrieved virtually intact from the
surface of the ocean. “Now we know that it is moving
right through the water column, right up to the very
surface and it grows to a spectacular size.” Commented New Zealand squid expert and senior research fellow at Auckland University of Technology, Dr Steve O’Shea.

There have only ever been six specimens of this squid recovered: five have come from the stomachs of sperm whales and the sixth was caught in a trawl net at a depth of 2,000 to 2,200 metres.

This squid has one of the largest beaks known of any squid and also has unique swivelling hooks on the clubs at the ends of its tentacles.

“It really has to be one of the most frightening predators out there. It’s without parallel in the oceans,”

More info: http://news.bbc.co.uk/1/hi/sci/tech/2910849.stm

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