North Coast’s shark issue indicates a much bigger problem

ONE of nature's giants is coming under attack from various quarters here on the North Coast and the NSW Premier's recent suggestion that shark nets could be extended to our beaches needs immediate challenge.

White sharks are motivated by feeding and reproduction and have always been travelling by, or become temporary residents.

However, what has changed is the feeding activity of the larger sharks as the usual larger prey is no longer obtainable.

Humans have utilised the energy of fossil fuels to power super trawlers, while purse seiners and long liners deplete fish stocks and generally upset the natural order of the marine animal kingdom to the point where the food chain has been disrupted, biomass depleted and behavioural adaptation has become necessary.

This perceived shark problem could be an indicator of a much bigger problem.

The food chain is under immense pressure from unsustainable fishing, continuing ocean pollution, mangrove destruction, acidification of seawater and global warming.

Oyster beds, the natural filters of sea water, have largely succumbed to pollution here in Ballina. It appears the historic cluster of human / shark encounters locally is multifactorial and a reflection of what is happening in the ocean beyond.

To simply go out and kill sharks to protect the massive increase in people engaging in recreational activities would be enormously irresponsible.

Rather than contemplating killing members of an already depleted population of white sharks, energy should be diverted to cleaning up our rivers, creeks and bays.

Oyster beds need re-establishing and pressure needs to be applied to stop removing the oceans of fish as if there were no tomorrow.

Ocean outfalls need ongoing review and human sewerage, particularly that containing antibiotic residues, need to be prevented from working its way into the sea.

Furthermore, with reference to the recent NSW Government funded tagging of white sharks along the northern NSW coast, I question the ethics that sanctioned elective implantation of sizeable, acoustic, telemetric tags (foreign bodies) into the abdominal cavity of this species of marine animal.

One hopes that a suitably comprehensive risk analysis of the short-term and long-term outcomes has been undertaken.

It is unlikely, however, that all identifiable risks have been taken into account bearing in mind these animals have had no pre-operative medical exam (apart from measurements) or post-operative surgical management or indeed any follow up.

These sharks should have a life span of some 30 years or more when left alone.

Blood chemistry has indicated these sharks become highly stressed when hooked, and when turned on their backs for invasive surgery to insert the implant.

When rolled on to their backs, the sharks enter a catatonic state of immobility described somewhat misleadingly as a state of mild anaesthesia.

However, the predominant feature is profound motor inhibition and there is little firm evidence that this equates to a meaningful reduction in pain sensation.

This procedure appears to rely heavily on the patient being a healthy specimen, with the ability to resist infection.

However, there may be many compromising factors if, for example, the surgery was performed in water close to a river entrance or ocean outfall.

Some obvious questions need answering:

What short and long term postoperative complications are to be expected?

Do researchers know the mortality or morbidity rate of white sharks and how large is this dataset of knowledge on white sharks following abdominal surgery and after release?

These devices are reported to have a battery life of 10 years so, after this time, no data on the shark's health would be available.

What contingency plan does the tagging team have if a vital anatomical structure is inadvertently cut - for example, a liver lobe or intestine?

From whom did the CSIRO obtain their independent veterinary advice?

It appears at first glance some of the basic principles of surgery and animal welfare are being violated.

Applying external tags to white sharks may not be so enduring due to shedding.

However, complications are much less likely than inserting internal acoustic tags.

Tagging will assist researchers to address the fundamental reasons for what may be changes in large white shark feeding habits, and migration patterns generally.

Notwithstanding this, tension between human and sharks will continue as always along our coastlines.

The white sharks have become yet another species under threat and must be protected at all cost.



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