Tuesday 4 September 2007

“Large sea animals of over two meters that remain to be discovered”

Dr Charles Paxton’s interest in marine biology has led him to move into what he calls “the dark side” – statistics and statistical ecology. He currently works at the Maths Department of the University of St Andrews, home of the government sea mammal research unit. At St Andrews, Dr Paxton is developing statistical models and curves on graphs to predict sea animals over two meters long yet to be discovered, which was the subject of his talk at the Centre for Fortean Zoology’s Weird Weekend 2007 conference.
“Professional scientists have lost sense their sense of wonder", laments Dr Paxton whose own survey showed that less than 5 per cent of scientists cite “wonder” as a motivation for their career choice.
Dr Paxton says eyewitness reports are unreliable, and that cryptozoologists are wrong to approach the evidence for “sea monsters” on a case-by-case basis. Mainstream biologists aren’t going to be influenced by individual case reports, it’s the clear signals send by the patterns in statistical data sets that will convince them there could still be undiscovered “sea monsters” out there.
To investigate how bad (or how good) eyewitness reports are, Dr Paxton placed a small, deliberately rubbish monster model in Windermere, a 2.33m tall black ‘F’-shaped black monster made of plastic pipes. People get the size and shape right, but they got its distance from them all wrong. Distance is the least reliable thing in eyewitness testimony over water. ‘Newbies’ on well-resourced marine mammal surveys are introduced to buoys at set distances to train them to estimate distances, as it’s so important for marine surveys.
Children in Dr Paxton’s rubbish sea monster model survey turned out to be lousy witnesses, females significantly underestimate sizes, males significantly over-estimate them. Women do more accurate drawings.
Dr Paxton’s statistical model for “large sea animals of over two meters that remain to be discovered” is based on a graph that plots a curve with the dates of discovery of sea animals over time, to see if that tells us anything about what still is to be found. The graph starts from 1758 and goes up to the present, 1758 being the tenth edition of Carolus Linneaus’ Systema Naturae, the book which established today’s classification system for species. Dr Paxton took the years in which species were formally described by scientists. There were 35 large marine mammals in the tenth edition Linneaus, there are 306 now.

Dr Paxton admitted there were some problems with the first version of his ‘large sea animals of over two meters that remain to be discovered’ curve. The first version predicted minus 1 (-1) animals waiting to be discovered. Dr Paxton’s conclusion was, ‘my model is rubbish.’ An earlier model predicted 47 animals waiting to be discovered. The problem with the first model is that it assumed the ‘search effort for monsters’ has been constant since 1758. There are now more professional marine biologists, more universities and more scientific journals than in 1758. Cheap camera traps have also speeded up the discovery of any remaining animals.
Some people say there were a lot more discoveries going on then, because of whaling. But there are a lot of whale surveys going on now, which means there’s about the same level of activity going on as earlier.
There are other variables. Not all monsters are equally easy to detect. Animals found most recently are the less easy to find ones. We can’t measure ‘detectibility.’ We can factor in the level of the ‘search effort’ through looking at the indexes of scientific journals.
There’s also the population size. Animals that turn out to rare are less likely to be discovered sooner than the more common ones.
Taking all these factors into account, Dr Paxton has now adjusted his statistical model and come up with a revised figure of 306 already known sea animals over two meters, and the curve predicts a total of 321 of these, meaning there are 15 of these creatures yet to be discovered, with a margin of error of plus or minus five.
Dr Paxton has made curves based on the rate of discovery so far for different types of sea creatures over two meters, and come up with three remaining sharks yet to be discovered (with a margin of error factored in of plus or minus two), three yet to be discovered whales (plus or minus three, which may mean there aren’t any whales left to be found,) two bony fish species over two meters out there waiting for us to find them, and one invertebrate. The margin of error in each of these last two categories may mean we’ve found all of these already, although recent film of what might be a 7-foot worm in the Pacific may mean we’ll have to adjust the total for yet to be discovered invertebrates upwards. Dr Paxton’s survey of the indexes of marine biology journals suggests we are still finding new large species at regular intervals. He warned that we should treat all these figures for animals awaiting discovery as underestimates, as there are some variables that just can’t be factored in using statistical models.

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