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Renewed esteem for a former marine enemy

  • 16 October 2006

Recently the NSW Department of Primary Industries put out a press release, proudly announcing the development at its Cronulla Fisheries Centre of artificial wombs to assist with breeding larger numbers of grey nurse sharks. Archimedes was fascinated that this $600,000 project was duly reported and discussed in the media with a minimum of public outcry. He can remember the days when grey nurse sharks were cast as villains who preyed on unsuspecting swimmers. As such they were to be shunned, feared and killed. We know better now. The modern image of the shark is of a top predator and endangered species, whose potential disappearance from the marine ecosystem could lead to nasty imbalances further down the food chain. And, as it turns out, grey nurses are supposedly not particularly aggressive.

In nature, things are often not as they seem superficially. If there’s one thing the development of the biological sciences—ecology, biochemistry, genetics—has taught us over the past 50 years, it’s how bewildering complex organisms and their interactions are. At the level of the shark and the snake, we seem to have absorbed that lesson. They are not necessarily evil animals, and are an important, functional part of the environment. We now also know that simple solutions, such as the blanket use of broad spectrum insecticides and antibiotics, can have a negative impact and that introducing exotic creatures, such as rabbits, foxes and cane toads to the Australian environment, is a mistake. But we still have great difficulty coming to terms with biological complexity. We don’t handle it at all well. We seem to hunger and thirst for a simpler world. Take our attitude to diet, for instance. It seems that every second week the advice as to what is good for you and what is bad for you changes. And often the same dietary ingredient is labelled both good and bad at the same time on the basis of different studies. If we stop to think about it, this is not surprising. Most foods and drinks consist not just of one ingredient, but of hundreds of different compounds, many of which can interact in different ways with the hundreds of thousands of different molecules which make up our bodies. So, the stimulant caffeine is only one compound in coffee, which also includes a range of cancer-preventing antioxidants, and many other biologically-active substances besides. Further, whether the balance of ingredients in