|article: fish’n’tip 0600...help save the grey nurse sharks by rob paxevanos
Dated: 31 August, 2011
|“Under Threat? A Juvenile Grey Nurse Shark eating a kingfish at Montague Island” Pic Courtesy Narooma News.|
Rob’s weekly FISH’N’TIP 0600 written for the week of Wed 31/8/2011
Help Save the Grey Nurse Sharks
This week my Guest Writer is Guy Reeve, an angler who is understandably concerned about the very real threat of the extinction of the Grey Nurse Shark in the not so distant future. Here is Guys article on this topic, hopefully it will raise some awareness and spark some debate on this important topic, I have added some comments in brackets:
“The plight of the Grey Nurse is not as well known as it should be, but any angler concerned about their environment would do well to be aware of it.
Grey Nurse Sharks have declined around the world, and in Australia survive only in two separate populations on the east and west coasts.
With an estimated population on the east coast of Australia of between 500 and 1500 animals (about 10 to 30 per cent of what scientists consider a viable population) the Grey Nurse shark is critically endangered.
Grey Nurse sharks are generally passive and do not attack humans. But we didn’t know this in the 50s, 60s and 70s when their undeserved reputation as killers resulted in them being indiscriminately hunted (spearfishing)
At that time little was known about the species. But by the early 1980s it emerged that numbers had been substantially reduced. Steps were taken to protect them. However, by that time the population was already facing extinction.
The Grey Nurse remains particularly vulnerable to further decline becuase they inhabit inshore areas where both commercial and recreational fishing takes place. They live near reefs, caves and gutters in relatively shallow water, and tend to concentrate in small areas known as aggregation sites.
But most of all, they have a very fragile reproduction process. Reproduction does not begin until females are around 12 years old and they live no longer than 35 years. Mature females produce, on average, one pup a year.
According to the latest research, bait fishing in the vicinity of the 18 identified aggregation sites on the east coast of Australia results in many accidental, but overall very predictable, hookups of sharks. This is thought to be one of the biggest threats to the Grey Nurse.
The impact from un educated anglers who unknowingly fish in Grey Nurse Aggregation sites, has gone a long way to dramatically reducing the population over recent years.
Under current circumstances, extinction is inevitable: experts predict that deaths of two or more female sharks per year from non-natural causes (eg fishing) will result in a reduction of the population. But over the last four years, an average of 11 females are known to have died from non-natural causes each year. Although the science is not perfect, one estimate is that quasi-extinction (a population of less than 50 females) will occur within 10-20 years.
Nevertheless, protection of the Grey Nurse remains a contentious issue in New South Wales. In May 2011, the O’Farrell government revoked existing protection measures at Fish Rock and Green Island, and North and South Solitary Islands. Those measures had resulted from a 2010 review in response to research highlighting the impact of bait fishing close to aggregation sites.
With a further review of protection measures in NSW currently under way, what can we recreational anglers do in the meantime to minimise our impacts on the Grey Nurse which is so obviously critically endangered?
First, given the variations and the complexity in the protection measures at the various aggregation sites, the most important thing is for us be aware of their location, and to keep up to date and comply with any changes in the rules.
Key aggregation sites on the south coast of NSW are at Bass Point, off Shellharbour, the Tollgate Islands off Batemans Bay and Montagu Island off Narooma.
Second, regardless of the protection measures in place, anglers should consider always using circle hooks, which means on the extremely rare chance you hook one of these sharks outside it’s aggregation site, it will be mouth hooked and can be released.
Third, spread the word among your mates, I am sure no one out there wants to see this species become extinct.
Thanks Guy, obviously a very important issue this one. While it appears many species, even sharks (eg Great White Sharks) can and are bouncing back in numbers, the Grey nurse has a reproduction biology that is very fragile and vulnerable. Had this have been known earlier, I doubt numbers would’ve been allowed to get so low.
However I also understand there are scientists, anglers, and other people out there who might argue against the above points Guy has highlighted.
For example I have even heard that some divers know of large populations of them in areas not covered in the latest research. I doubt this is true, but I would love it to be proved otherwise.
Some anglers believe the Grey Nurse Shark are being used as a scape goat to shut down certain areas and that it wasn’t anglers fault numbers have got this low (A small number of spear fishos of days gone by, who didn’t realise the impacts at the time, are known to have purposely killed large amounts of Grey Nurse Sharks.)
I welcome responses provided they have research, substance and evidence behind them-you will need to know your stuff.
So just what parts of the above are true or false? This is not stirring the Pot, people are genuinely concerned about the issue. I will publish the best response in the next week or two. This might be your chance to help.
See you on the water
Fishnet Pro Angler
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