One that did not get away

四月 18, 2003

The discovery of a colossal squid in the Antarctic was a dream come true for marine biologist Kat Bolstad

There was a moment of stunned silence as we saw the first image of the colossal squid specimen, Mesonychoteuthis hamiltoni , last month. It was nearly intact and was by far the biggest squid either Steve O'Shea or I had ever laid eyes on. We couldn't wait to see it for ourselves, and the days between the fishermen's initial report from the Antarctic, where the squid had been found attacking fish, and its arrival in Wellington just crawled by.

I recalled my first opportunity to examine a giant squid, Architeuthis dux , early in my acquaintance with Steve. I could hardly believe that the stuff of legends, a creature of every marine biology student's dreams, was at hand. To Steve, the post-mortem morphology of this elusive species presented little mystery.

"Be honest," he said, "You were expecting something bigger." I assured him I couldn't possibly be disappointed. But he had a knowing glint in his eye.

"You know, there is a bigger squid out there," he remarked casually.

And here it was, a prophecy fulfilled - its mantle 30cm longer than the largest Architeuthis , fins spilling over both sides of the metre-wide table, the damaged eyes suggesting original dimensions larger than a human head. Despite its arrival in three pieces, this was the most intact specimen found of a species known to science for nearly 80 years.

With growing wonder we examined the arms, intact to the tips and bearing a stunning array of toothed suckers and hooks; the powerful beak; the smooth muscular fins; and the swivelling hooks on the tentacle clubs. We noted with dismay that the stomach had been lost in transit, preventing us from gleaning any knowledge of the animal's diet, save its known predation of Patagonian toothfish. After partially removing the beak, we marvelled at the anomalously narrow esophagus - that an animal of 5.4m should sustain itself on food carved into pieces smaller than the width of a thumb.

But further internal examination has been forestalled by the month-long preservation process. Details such as the location, size and shape of the statoliths - two tiny bones found within the cartilaginous "skull", or cephalon - will help us determine the animal's mode and manner of locomotion. But this will have to wait until the tissues are stable. The possibility of losing these structures during preservation is a real but necessary risk. Confirmation of the squid's sex and age will also have to wait, though based on the size of its beak and the tiny eggs visible through the wall of its ovary, we surmise it to be a female not yet fully mature.

Meanwhile, we have collected all available information on the other six known specimens, five of which had been recovered from the stomachs of sperm whales. Mesonychoteuthis was originally described based on two half specimens. The largest previously known specimen in good condition had a mantle 1.05m in length, less than half the size of our one. It, too, was a female. This raises myriad questions. Some species of squid are sexually dimorphic, with characteristics differing markedly between males and females. If the female has hooks this size, might the male have even larger ones? How do they reproduce? Does this species follow a trend found in many other squid, with the mature male significantly smaller than the mature female, orI could he be even bigger?

Settling the specimen into its 5 per cent formalin bath was no small feat.

We buffered the solution immediately with 10kg of baking soda, doing our best to distribute it evenly without allowing it to precipitate onto the squid's tissues. The first 24 hours were critical in monitoring the solution's pH; if it became too acidic we would lose the sucker rings and hooks. We took the precaution of removing some rings and hooks before the fixing process, but were relieved to find those on the specimen in perfect condition the following day.

And now we wait. With just a tantalisingly brief glimpse into the colossal squid's biology, we can only begin to speculate on what we may find in a thorough examination. And when will we see this astounding creature alive in its natural habitat? Architeuthis dux has evaded live observation for hundreds of years. Will Mesonychoteuthis prove as elusive?

Finds such as this whet the appetite for more exploration. They remind us of the vast untapped knowledge awaiting discovery. If we are finding relatively unknown animals such as the colossal squid in 2003, what will tomorrow bring?

Kat Bolstad is a research associate working with Steve O'Shea, senior research fellow, at Auckland University of Technology, New Zealand. Their project is funded by Discovery Channel.

请先注册再继续

为何要注册?

  • 注册是免费的,而且十分便捷
  • 注册成功后,您每月可免费阅读3篇文章
  • 订阅我们的邮件
注册
Please 登录 or 注册 to read this article.