Tall Tales: Giant Squid

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Searching for signs of the Giant Squid

One way of tracking down the huge invertebrates is to follow in the wake of larger predators.  Sperm whales, due to their sheer size, are some of the only animals capable of making a meal of a giant squid; scientists sometimes find squid beaks floating around in the contents of their stomachs.  In fact, squid of various sizes form an important part of the sperm whale’s diet and joining up these links in the food chain could be vital to understanding more about the giant squid’s role in marine ecosystems, especially if populations start to decline.  “The effects will be widespread, as cephalopods are consumed by many different types of animal,” says O’Shea.

Severed appendages, and rare catches such as Archie, an 8.6 metre giant squid now on display at the Natural History Museum, have provided researchers with enough data to continue their studies.  So few whole specimens exist, however, that the team responsible for Archie’s installation had to think long and hard about the preservation process they were going to use.  Archie’s body was eventually plunged into formol-saline solution in a nine-metre long acrylic tank, made by the same company who created display cases for Damien Hirst’s famous “dead animal” artwork.

Such incredible finds have at least allowed researchers to build up detailed pictures of the creatures’ body structures and, for example, to identify the differences between giant and colossal squid.  “They’re quite different,” says Allcock. “The thing they have in common is size and that’s about it.” 

But surely a squid is a squid, and a colossal squid is just a larger giant squid?  “That’s basically true,” concedes Allcock, “But you’ll find there are differences in the smaller morphologies – in the shape and arrangement of the clubs on the end of their tentacles and in the funnel-like organ that connects the head and the mantle.”  In fact, it has been suggested that the giant squid is more closely related to small, deep sea species of squid, from a family known as the neoteuthidae, than to the colossal squid.

What’s missing, however, is any in depth description of the giant or colossal squid’s lifestyle.  How do they breed?  How do they hunt?  We can only learn from watching them in the wild.

Are Giant Squid moving from their traditional homes?

In an epic battle early last year, a ship's crew from New Zealand hooked a colossal squid 10 metres long, reported as having “eyes as wide as dinner plates”.  It took two hours to drag the 450kg super heavyweight aboard their fishing boat.  Despite a lack of hard evidence, however, some squid enthusiasts remain convinced that even bigger squid exist.

The problem is that the chances of snapping one of these monsters may be growing slimmer by the day.  “Global warming will inevitably change the diversity and distribution of cephalopods,” says O’Shea. “We may well witness a loss of large-bodied species, the likes of giant and colossal squid.”  Whereas marine species that inhabit tropical environments may thrive in waters warmed by climate change, deep sea species look likely to lose out as temperatures rise.  But as a recent study of Cassell’s old enemies, the red demons, concluded, no single environmental effect can ever been considered in isolation.

In June 2007, Louis Zeidberg and Bruce Robison published a study on the “invasive range expansion” of Humboldt squid in the Pacific near California; fisherman called it simply “an invasion”. The demons were multiplying at an alarming rate, decimating commercial fish stocks in the region.  Although some put the squids’ soaring numbers down to increases in temperature, Zeidberg and Robison pointed out that declines in predatory fish had recent left a gaping hole in the food chain – one that the squid had been swift to fill. “The removal of top predators like tuna and billfish may promote [Humboldt] population growth and range expansion by reducing competition for their shared prey species,” explains Robison.

O’Shea agrees, stressing that global warming is far from being the only thing squid have to worry about.  “There are much more immediate threats, such as fisheries, which have greater and more sinister effects on the welfare of cephalopods and other ocean life.  Global warming right now is probably the lesser of two evils.”  A recent study of marine ecosystems carried out by scientists at Stanford University highlights the many threats humans pose to marine ecosystems.  From shipping to coastal development, everything we do is taking its toll.  Squid will have to adapt to changing habitats if they are to continue to thrive, but with so little to go on, who’s to say how they will cope?

Of course, the real thrill is in experiencing these giants in the flesh, an occurrence that may become less and less common.  And as Jamieson points out, it takes a certain quirk of personality to volunteer for such a mission.  “Anyone who even thinks about getting into a manned submersible is crazy.”  But by observing them in their natural habitat we can learn so much more than by simply studying their dead remains, which is why explorers like Scott Cassell continue to put their lives at risk for the sake of a film.  “Last Tuesday this 7ft long squid allowed me to hold him for five seconds, then wrestled free and bit my forearm and head, drawing blood through my armour,” he says, quickly followed by, “I love my job!”

For more information

The University of Aberdeen - The 'EuroSquid'
http://www.abdn.ac.uk/eurosquid/

Oceanlab
http://www.oceanlab.abdn.ac.uk