Found most frequently in the south east Pacific Ocean, these remarkable creatures also live in the north Atlantic, which makes the well-preserved deep seas around the Azores an excellent place to look for them. Although we have only a short time to explore, and the giant squid is notoriously elusive, in our hearts we can't help believing that our drop-camera, the newly resurrected Phoenix, might capture at least a glimpse as it scans the seamount at depths of up to 800 metres. Of course our heads tell us not to hold out too much hope.

Giant squid are the second largest invertebrates on earth, exceeded in size only by their recently discovered close relative, the colossal squid (an estimated 14 metres long), and are one of the biggest predators. The largest giant squid are female and grow to 13 metres, although only just over two metres of this is the body (or mantle). The rest is tentacles! Males are slightly smaller at 10 metres.

But if they are so big, why don't we know much more about them? Well, given that they swim so deep, how do we know anything at all? In truth, their life and habits have remained largely a mystery. The available information is fragmentory, based on dead or dying animals that have been washed ashore or captured in trawl nets. We do know that they possess the second largest eyes of any living creature (second only to - you've guessed it, it's collosal cousin), live at depths of between 200 and 4,000 metres, and belong to the same family as the octopus and cuttlefish.

Although many expeditions have set out in search of these ocean giants, only one has successfully captured images of them in the wild. In 2004 Japanese scientists snapped more than 500 extraordinary images of oneof the massive cephalopods at a depth of 800 metres, before it broke free after snagging itself on a hook.They also recovered one of its two longest tentacles, which was severed during its struggle. They used sperm whales, which love to feed on giant squid, as guides to help them in their hunt. Since we have the capability to film at this depth, and are in prime sperm whale and squid territory, there is just a chance of a close encounter - unlikely yes, but our attitude must be 'never say never'.

As commercial fishing operations empty our coastal waters of fish and head out to bottom-trawl the high-seas to fish at ever greater depths, they are literally removing entire populations of deep water fish such as orange roughy and occasionally catching and killing giant squid as 'bycatch' This kind of fishing is comparable to mining and may be disrupting the entire ecosystem - for instance depriving sperm whales of their prefered prey species.

In order to ensure that healthy populations survive in our oceans we need to protect the wider marine environment as a whole. That’s why we urgently need marine reserves, areas similar to national parks on land, which are off limits to all forms of exploitation - to give the seas time to recover. Otherwise the treasures of our oceans - the amazing giant squid among them - could all too soon be a thing of the past.

- Alejandro