Four-year study gives no clue on great white numbers off WA
well this is rather interesting result , cant say I id agree with it though ..seems every week some one is seeing or having an encounter with GW of a WA beach
hezzy
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A four-year investigation of WA’s great white shark population has left Fisheries Department experts with no idea whether numbers are going up or down.
Despite claiming two years ago that there were as many as 5400 great whites off WA, the State Government concedes a lack of data has made it all but impossible to estimate the species’ population. It says it must “keep an open mind” about how to mitigate the risk of attacks.
A Fisheries Department report on great white numbers — to be released today — combined the known lifespan of the shark with patchy yearly catch records off WA since 1938 to develop a series of population trajectories that varied wildly.
While making an open-ended finding, the report “suggested” WA’s population could have increased up to 7 per cent a year since the species was given protected status in 1997.
In another scenario, which assumed lower reproductive rates and high “post-capture mortality”, the population off WA had fallen more than 10 per cent before 1997 and was still in decline. In another — one of about 120 modelled — numbers rebounded by more than 10 per cent in the same period.
report, commissioned in 2012 after a spate of shark attacks in WA, relied heavily on assumptions because of a lack of evidence.
It found the number of great whites caught between WA and South Australia peaked in the mid-1980s at between 300 and 900 a year. It has since fallen to between 50 and 80 a year, including 35 off WA, as commercial fishing across the region has declined.
The report has enabled Fisheries to identify ways to reduce the uncertainty over great white numbers, including improving the way commercial bycatch figures for the shark are recorded.
Fisheries Minister Joe Francis said improved fish stock management and Commonwealth marine park proposals and sea lion exclusion zones meant there would be more prey for great whites and “it is likely they will become more common”.
While the Government did not support a cull or removing them from the protected species list, Mr Francis said it would keep an open mind about options and would always put humans ahead of “absurdly simplistic arguments” such as more people being killed by cars than sharks.
“Frankly, I have been left gobsmacked at those who display so much compassion towards a large species of fish and so little towards their fellow humans,” he writes in an opinion piece in today’sThe West Australian .
OFW 11
evil flourishes when good men do nothing
Deckie
Posts: 1297
Date Joined: 03/04/09
Speculate.
Did you really expect anything but speculation ????
They can only count the ones they see, not the ones that are 100 meters away or the ones that come in after dark or before sunrise.
I agree on the last comment about those who show compassion towards them, but I also think that people should understand it is their natural habitat not ours.
We enter at our own risk with the odds of ever seeing one very low, let alone actually being confronted by one.
Perhaps those "compassionate" folks could show as much interest in the poor older people that get mugged in their own homes by the low life of our society.
Maybe have a big rally for them down the main street & get things changed.
I know this is flogging a dead horse so I won't say anything else........
Cheers & Stay safe
Paul H
Posts: 2104
Date Joined: 18/01/07
"the number of great whites
"the number of great whites caught between WA and South Australia peaked in the mid-1980s at between 300 and 900 a year. It has since fallen to between 50 and 80 a year, including 35 off WA, as commercial fishing across the region has declined."
work of a rocket scientist - regardless of ones views they have also banned recreational fishing for them since the mid 80's so numbers caught was always going to decline - simply they are no longer being targeted
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chris raff
Posts: 3257
Date Joined: 09/02/10
Grab a coffee or maybe a
Grab a coffee or maybe a redbull , here’s the actual report 123 pages if your keen . The investigation team has now been commissioned for a further 4 years to ascertain just how long a piece of string actually is
http://www.fish.wa.gov.au/Documents/research_reports/frr277.pdf
“Intelligence is like a four-wheel drive. It only allows you to get stuck in more remote places.”
carnarvonite
Posts: 8627
Date Joined: 24/07/07
WOFTAM
The whole study is WOFTAM [waste of time and money] How can you count the number of white pointers when they migrate all over the world, if the season is good you are going to get a big snapshot but 6 months later there is probably none around.
With a $10.000 fine for killing one then anyone in their right mind isn't going to report it, I know I wouldn't, so that puts another huge hole in their figures.
meglodon
Posts: 5981
Date Joined: 17/06/10
A very dissapointing result
After a four year study, with no positive results is quite a bit of a disappointment.
resurgence
Posts: 573
Date Joined: 23/04/14
Clearly there is an interest
Clearly there is an interest in knowing. Unfortunately that's the nature of scientific research - you don't know what you will find out until you do it.
Still, it was interesting to me that they reported "no result" when it's possible that some potentially misleading conclusions could have been drawn from inconclusive data.
Depth_Charge
Posts: 24
Date Joined: 10/01/11
I don't care if there are
I don't care if there are 100 or 100,000 out there...I'm still not swimming in the ocean! :)
GGs
Posts: 330
Date Joined: 06/09/14
Im just curious why everyone
Im just curious why everyone is so quick to bag out the research when it has no conclusive results. As resurgence said, thats the nature of the beast with scientific research.
Calling something an "absurdly simplistic arguement" in an opinion piece is a negligent statement by someone in his position i believe, however yes i agree there are many other factors that come into question here (cars on roads v people in water).
There was a report in 2014 that correlated the increase in GWS encounters off the WA coast between 1974 - 2013 with the known 10% annual increase in humpback whale numbers. They also make the 'absurdly simplistic agruement' that encountering a GWS when swimming less than 25m from shore in summer/autumn is estimated to be at least 50x safer than cycling and that off-shore (diving/surfing) has similar risks to cycling. They have to put it into context for the general population somehow.
We still know so little about these sharks and what we do know about GWS migration seems to be based on genetic variation... does this not justify extending the investigation to get a better understanding? Without more data on migration/breeding/feeding patters they're never going to be able to make a calculated decision on how to tackle this issue. Implementing a dedicated tagging progam would surely increase the data they have to work with but unfortunately this all costs money (alot!).