Greetings Fishcrazy
I would like to add a little to the debate if I may.
I note you are a 3rd year Marine Science student, and as such I was at the same stage, in my first degree, in 1970. Now I am definitely NOT implying you are in any way NOT experienced however there is a small issue of "life experience" as you get older - do NOT poo poo it.
Within my profession, Veterinary Science, there are graduates who are quite happy to work for PETA (People for the Ethical Treatment of Animals) and others who are quite happy to join hunting expeditions for Bear and deer.
My implication is that you will find an extremely diverse group within Marine Science and I will almost guarantee you that some in your year would as much "kill a fish" as "shoot a bear". By the time you get to 55yo., you may find that one or two of your compatriots are in very senior roles in the public service. Depending on their philosphy on life now, they will adopt that position and force it on those "under them" in 30 years time.
The classic example of this is the Director of the NSW National Parks and Wildlife - Dr. Tony Fleming - he was awarded his PHd in Forestry. The NPWS is the "project manager" for the Batemans Marine Park. At some point "personal philosophies" on what is "Comprehensive, Adequate and Representative" are what "shape" the BMP in terms of sanctuary zones etc.- perhaps to the detriment of those who live here.
In life we all try and support that which benefits our own agenda. I don't want to be a smartarse but of course anyone in a position of power will try and implement policies which they believe in! I respect life experience, but unfortunately this does not always give rise to wise decisions. I know that I still have alot to learn, and I hope I will continue to do so until the day that I die. I believe it is my place to question those with more 'life experience' than myself, because as history has shown they're not always right (nor do I expect to be!).
Having retired and moved to Narooma in 2002 I became interested in the GNS when the NPA/NCC and Wilderness Society became rampant in their desire to lock up the "aggregation sites" with a radius of 1500m fishing exclusion zone. I will say that I have been a "serious" fishermen since about 1960. I can still remember at South West Rocks where we went every Xmas, seeing hundreds of GNS strung up. I was NEVER allowed to dive, but even schoolkids used to buy a powerhead and go shooting GNS. Of course, at the time, I thought a good idea since it was fully accepted that the GNS and other sharks were "man-eaters".
The shooting of GNS with powerheads in the late '50s thru to the early '70s, is the THE single issue that has bought the GNS to its present state.
I won't debate this point! Fishing (of all forms) and netting have also contributed (significantly or otherwise).
It s impossible to convey the difference in life between when I grew up, and my boys grew up (eldest is 30yo). Suffice to say that society was a far LESS questioning society then. Without shadow of doubt the greatest change has been in the area of communication. I refer to the Internet.
Now as to your feeling ""We really don't know how many GNS there are left, and that will significantly affect any estimates of population viability"" I refer you to ALL of Otways studies. In particular Otway, N. & Burke, A (2004). "Mark-recapture ...." Gives a definitive study as to numbers. However you will hear many anecdotal stories about other 1000's of GNS in the wild, in places "never heard about". I will NOT talk about them (not enough hours in the day), but in the scientific world you can only go on what has been published, or YOU publish, from your own ORIGINAL research, or papers that you cite from reputed, peer-reviewed journals
To save a little time and another half dozen papers by Otway et al between 1999 and 2004, we then move onto Otway's definitive paper. Otway, N., Bradshaw, C. & Harcourt, R. (2004) "Estimating the rate of Quasi extiction of the Australian GNS." Now the reason this is a definitive work is that it is the ONLY paper that has been published in a scientific peer reviewed journal. As you would be aware this is the "gold standard" when it comes to getting your scientific literature published. ALL the other publications are reports to NSW Fisheries, or papers presented at conferences.
I've had a (very!) quick look at the published paper by Otway, Bradshaw and Harcourt. They base their quasi-extinction estimates on population abundances and assumed mortaility rates, and note the the importance of "obtaining precise estimates of abundance". The first paper on marked recapture by Otway and Bourke gives an indication of numbers, but this is only one survey method and their confidence intervals still indicate a reasonably large variation. Good papers, but we still don't know with a high degree of certainty the total population. Dr. Harcourt is one of my lecturers, I will ask for his opinion on this next time I see him. I'm 100% sure that population estimates are presently still an issue.
In an earlier posting on this thread I wrote that the GNS is doomed to extinction. That is my opinion based on the studies of Otway. Whether it happens I will never know, I would say I will have pushed off this mortal coil.
You are right that anthropogenic causes of mortality need to be stopped to prevent the GNS slipping away. Of course by Otways BEST ESTIMATE, this will only slow the process down. However these measures would include:
* Stopping ALL fishing inside the 200m. decline. I repeat ALL fishing.
* Removing ALL Shark netting for 365 days per year. Perhaps, just perhaps, this will slow the decline to when my grandkids are about to die.
Again we need to establish population size this with a high degree of certainty before a decision can be made on apropriate conservation managment (if any). Clearly Otway's suggestions are not going to happen, and if anything they highlight the futility of what is being done at present.
As to the issiue you raised about shark hook deaths in GNS. Hooks have definitelly been found in GNS, some even causing peritonitis when they puncture the gut wall. However - and this iis more for the Dept of Fisheries scientists who read these threads (and I know you do Mr. G!!!) - the HARDEST thing of any post mortem examination is to determine the cause of death. I have personally performed about 1000 post mortems over 30 years practice, and I still remember what the Professor at Syd Uni said many years ago - "Well here we have a dead horse he has definitely stopped breathing .... the rest is conjecture".
Too often I have seen ludicrous assumptions made by Fisheries scientists - perhaps they are more for the public arena??
A small test - next time you are cleaning a fish, imagine trying to give a definitive reason why it died. Even more interesting - leave it in the sun for a few days, and try and do the same, perhaps now you may get my drift about post-mortems.
I see your point here. I'm sure its very difficult to determine the exact cause of death. When I catch a fish, I may not know exactly how it died, but I do know that it died because I caught it! It may be difficult to determine the exact cause of death but if a shark is full of fish hooks it would be fair to assume they played at least some role...unless of course there are dead sharks being found with no sign of fishing related injury.
* Otways studies point to an inevitable quasi extiction state
* Otways solution is absolutely, 100%, NOT PRACTICAL.
Agree....but further work needed to determine accurately total population size.
* The $600k being used to fund the development of a artificial uterus for the GNS is a disgraceful waste of money. WHY .... because in Wildlife population dynamics it absolutely flies in the face of "good science". Issues I have a problem with start with good old fashioned Darwinian theories of evolution (Survival of the fittest etc.). I am sure that you would say that they could "re-clone" the thylacine, which MAY be possible(read mega dollars) - however the offspring would inevitably be lacking in hybrid vigor and genetic diversity, such that its survival in the wild. would be impossible - in a zoo, different story.
A very senior Fisheries scientiost has told me that he believes "this is an example of Fisheries scientists making a c**t of themselves" - which I find strangely amusing
I couldn't agree with you more!
* An extra point is that the GNS is Carcharias taurus. As has been mentioned before C. taurus is abundant in other parts of the worl - although it is on the IUCN red book as vulnerable, the East Coast Australian population, as of March 2006, was still classified as C. taurus. Obviously if there was a sub-species, say C. taurus east coastus, we could TRULY say we were losing something "unique" Sometimes the rhetoric from the NCC and the NPA can reach an uncritical audience.
* Don't even get into the argument that we are losing a "top end predator". The GNS has been at these levels since 1970
Argee...no loss of anything unique would occur. Whether it makes a significant contribution to the ecosystem now doesn't matter, it was a part of the system some stage and we have changed that. The system is not being used sustainably (as I'm sure we would all like to see) if the reduction of biodiversity/abundance is occuring. Whether this is our fault or the previous generation's is irrelevant. Again I'm not offering any solutions to this problem, and clearly it is more complex than just the GNS. And no I don't advocate spending wads of cash on a 'lost cause'.
FINALLY Fishcrazy
* I want you to do a search of the literature and find me one, just one, example of an animal whose "inevitable quasi extinction" has been reversed. Money is NO object. NOT forgetting I said "Quasi extinction", not reversed from endangered ie the Panda bear.
I'll take your word on the fact that this has not occured before. I'll just point out again the need for an accurate population assessment upon which Otway's studies will have much more meaning.
* The other term I want you to read up on is another term that appears lost on the geneticists within the Department of Fisheries, or even the National Parks and Wildlife Service, and that is the term "sport". It has significanvce when talking about "genetic engineering".
* I want you to study the "Precautionary principle", as espoused at the Rio Convention in 1992, Principle 15 I think, and tell me HOW this can be equated to the GNS in its present population status,
PS Good luck with your studies ... you may find genetics over the next 30 years a most worthwhile "major"
I'm running out of time now, but I have had a quick look at the precautionary principle:
Decisions made in the face of uncertainty, typical in biodiversity and conservation. Decisions are made having taken into account all knowledge (scientific and otherwise) and are subject to constant review as our knowledge base expands.
"Principle 15 codified for the first time at the global level the precautionary approach, which indicates that lack of scientific certainty is no reason to postpone action to avoid potentially serious or irreversible harm to the environment. Central to principle 15 is the element of anticipation, reflecting a requirement that effective environmental measures need to be based upon actions which take a long-term approach and which might anticipate changes on the basis of scientific knowledge."
Given this, it seems the use of the precautionary principle is justified in the event of uncertainty, though this is debatable in the case of the GNS given its disappearence form the east coast cannot exactly be categorized as serious or irreversable harm to the environment.
Billfisher, I hear you re: the divers effect. I only know of 1 study on this (though more are planned), the results indicated no long term impact on aggregations. Further work definately needed though!!!!
I agree re: the 1.5km exclusion zone.
