RealSurf Surfers' Forum

White Sharks are observed to be pretty comfortable in water temps up to 24°C.

White Shark distribution.

Well there's comfortable and then there's increased risk of attack which aren't the same thing.

Beanpole wrote: ↑

Sun Nov 18, 2018 9:04 am

Well I'm not a marine biologist. I'm just refering to the report conclusions based on the stats.

Where is the report Beans?

The WA report found 'only' a third of attacks occurred in water temps of 20°C or over.

http://www.fish.wa.gov.au/Documents/occ ... fop109.pdf

Thanks, foamy. Have a read, Steve.

Isn't the water temperature in Margaret River below 20deg for about 2/3 of the year?
And whilst there are more users in the summertime, attacks often happen at the uncrowded lineups.

Yes, I read that report already.

Very small data set and very weak P value (statistical significance for water temp).

Those "conclusions" obviously don't hold for east coast attack patterns where sub-tropical distributions of sub-adult/juvenile white sharks and subsequent attacks/encounters have very little relation to water temp.

What about shark breeding patterns?

what about them?

Well my original comment that Nick found dubious was that sharks bred more in spring and became more frisky. East coast water temps are coolest from late winter through Spring.
In related matters. I seem to remember just about every Xmas surfing down the south coast and then finding out there were large schools of sharks in the area.

...

Again this year there is a ‘hump’ in tagged fish numbers roughly coinciding with whale migration season. (Much less tagged this winter/spring due to drumlines NOT being used at Forster/Tuncuury and Coffs/Sawtell. (I’ll post the chart when I get to my laptop later)
But, still it would appear from the tag data, and the pingers, some hang around all summer around mid to north coast.

And for some curious reason they seem to be larger sharks.

Bronze Whalers, Greys and juveniles GW 's are feasting on bait fish and salmon a few metres off North Avoca.

Ok, here is the chart for GWS tags for Far North Coast, Dec 16 to Sep18, data from DPI site.
The 81 tagged at Forster/Coffs during the ”trials”, from Aug 17 to Feb 18, are removed to make it apples vs apples.
Pretty seasonal looking, but as mentioned doesn’t mean some move against the grain or hang around, as shown by the pingers.

Fark. Who’s been surfing at the ‘bra?



https://www.abc.net.au/news/2018-11-19/ ... h/10511412

>><< Shark numbers increase this time of year, eh.
That's one big dead shark.

Saw the boat there this morning, thought it was just routine maintenance.