No surprise that sharks are attracted to areas where food is plentiful and, likewise, learn to avoid dangerous locales. In this regard they are far smarter than green-thinking alarmists, who denounce netting while remaining pointedly unaware that a rotting shark drives away fellow predators
The legal protection of sharks and ever-increasing restrictions on commercial fishing have resulted in a significant increase in coastal shark populations around Australia. Combined with a growing population and more people in the water this has also led to a significant increase in attacks over recent years. Government now faces conflicting pressures in demands to save the lives of both people and sharks.
Politicians simply cannot take the time to become well informed on the myriad issues they must deal with so they have to rely heavily on the advice of experts. This works well in matters where there is a firmly founded body of knowledge, but less so in areas where knowledge is sketchy, conflicting and uncertain. Unfortunately we now have certified “experts” for every occasion, including topics about which we are in fact quite ignorant. Such “experts” know only what they have been taught in the degree mills, and what they offer is not so much evidence but more opinion and ideology. In environmental matters this situation is both common and compounded by a vigorous suppression of any questioning where a particular perspective has been deemed ethically correct by an academic community which leans overwhelmingly to the political left.
Although employing shark nets off popular swimming beaches has a well-established record in greatly reducing attacks, academic “experts” now deem this to present an unacceptable risk to “endangered” marine life. If their proclaimed expertise included any practical knowledge of sharks and shark fisheries they would know nets are not only effective but pose little risk to overall shark populations. It simply causes them to avoid the netted area.
In World War II night vision was critically important in many military activities, and good night vision depends on a healthy intake of Vitamin A. This is normally supplied from fresh vegetables but these were impossible to provide in many situations. The synthesis of Vitamin A had not been achieved at that time but shark liver oil was known to be a particularly rich natural source. As part of the war effort shark fisheries were initiated in a number of different areas and the fishermen soon learned that taking the liver and discarding the bodies quickly drove other sharks away from an area. Decaying shark flesh appears to be a strong shark repellent.
When shark netting is employed off beaches there is an initial high catch which quickly declines along with sightings in the general area. The overall catch and area affected is tiny relative to the wider population. Most importantly, to be maximally effective the carcasses of any sharks caught should be left in the area, not disposed of elsewhere.
Like most animals, sharks are attracted to areas where they are fed and likewise soon learn to avoid areas where they are in danger. No marine fish or invertebrate has ever been exterminated by fishing and the effect of introducing a few danger zones for them so that we too can enjoy the sea with minimal risk would be only a small price to pay for them or us.
In my personal experience, I have encountered two situations clearly confirming the effectiveness of this form of deterrence. The first was as a child growing up on an island in the Florida Keys. My family had a dock where several fishing boats were based. In the evening, when the boats returned from fishing, catches were cleaned at the dock, with fish heads, backbones and entrails tossed into the water, where half a dozen or more sharks gathered to quickly consume them. This was a normal daily situation for years but at one point I decided to catch one of the sharks to make myself a set of shark jaws like I had seen on the wall in a local bar. After cutting out the jaws I threw the body back in the water. The next day it was still there clearly visible on the bottom in a couple of metres of water. Over the next week as it decayed and was eaten by crabs and small fishes the other sharks stayed away and only started coming back some days after it was gone.
The other instance was in the Solomon Islands, where I spent three years in the mid-1970s. A Japanese company had established a small tuna cannery at Tulagi Island. Tuna offal from the cannery was disposed of daily by dumping it in deep water just off the island where large numbers of predatory fish and sharks quickly devoured it in a feeding frenzy of remarkable intensity. Several species of sharks were involved, predominantly dozens of the largest, fattest grey reef sharks I have seen anywhere. This continued for several years until some of the local villagers discovered the market for shark fins and started to catch them. As they were fishing from small canoes they couldn’t handle big, thrashing fish, nor did they have any use for the whole shark, so they simply cut off the fins and left the bodies to sink. The result was again an immediate and dramatic disappearance of sharks from the area.
Half-baked notions of environmental evangelism being presented as sound science by self-proclaimed “experts” have played a major part in driving a majority of our small primary producers out of their industry. These were the flexible, low-overhead operations which played a key role in providing abundant low cost food and raw materials. The result has been steep price increases in food, housing and energy going from among the most affordable in the world and rising to among the most expensive.
Now we have the highest level of personal debt in the world, half the population signed up as indentured servants to the banks for most of their working lives and much of the remainder in an ongoing battle to pay for rent, food and energy. Regardless, the eco-salvationists are doubling down on demands for still more restrictions.
Genuine expertise is firmly based on evidence, not just proclaimed authority. We should always be mindful that what we need from experts is evidence, not just opinion.
Walter Starck, a regular Quadrant contributor, has been researching coral reefs for more than 50 years. His biography can be found here