Saturday, October 04, 2014

GWS vs GWS - two!

Male GWS from the Neptunes with battle scars. In females, the scars could stem from either brawling or mating. Source.

Here we go again.

This is really highly disappointing.
DNS is usually strictly science-driven, with authors that know exactly what they are talking about. But alas, 5,000 dives or no 5,000 dives, Rocha is a Coral Fish guy, not a Shark behaviorist - and it sure shows, along with the fact that like many of his peers, he appears to be against Shark provisioning without having bothered to engage in even the most basic due diligence.

So there.
The Neptune Islands feature a natural GWS aggregation, meaning that the operators did not in any way cause it. Actually, they relocated to there from their initial site at Dangerous Reef once it became clear that GWS sightings at the Neptunes were more regular, numerous and predictable.
Read this - bravo Andrew and once again, no thanks to Barry Bruce whose unfortunate papers are now continuously being abused by the anti-feeding faction!

When the GWS reach those islands, they  sometimes brawl.
They are from two genetically distinct populations and likely do this in order to establish and re-affirm rank. Those confrontations are usually ritualized but can become combative. This behavior is species specific: the same happens in Guadalupe, another natural GWS aggregation, and e.g. the same is being reported from brawling Sicklefin Lemons at Moorea where provisioning has however created an aggregation that is not natural but instead man-made.
Conversely, although we observe the exact same hierarchical confrontations among our Bulls when they come back in January, in this species, dominance is being asserted by posturing and not brawling and therefore, we observe no intra-specific bites other than extremely rare genuine mistakes.

Back to the GWS.
Those confrontations are likely to happen where- and whenever GWS aggregate, and this specifically whenever new arrivals upset the established order - but it stands to reason that we are much more likely to observe them at those commercial sites and not out there in the wilderness, and hence those images, so far, stem from there. 
Do I need to elaborate?

Case in point, this recent video that is equally from the Neptunes.
See? No competition over food but same bite and same tail slapping etc - and remember Howard's video, equally from the Neptunes, equally featuring tail slapping and equally happening away from any bait?

Yes that would be evidence - and Rocha's conviction?
That this “brutal battle” wouldn’t have happened without human intervention and that the correct description of that video would be “Shark feeding by humans causes sharks to attack each other”; “Endangered species of shark forced into battle by human feeding"?
Nothing but the usual unsubstantiated anti-feeding claptrap!

Like I said, highly disappointing!
Sutor ne supra crepidam!


Sunkita said...

Can you tell me more about tail slapping? I had to watch those videos a couple of times to work out what you meant, to an untrained eye it seems subtle. I have a group of sandbars at the moment and I've observed one animal "slap" another multiple times in the face (rostrum, whatever)and at the time I thought it was incidental contact but your comments made me think maybe it was a direct interaction between the animals. I'm just learning, I'd be really interested in any comments you could add about what you define as a tail slap and when you see that behaviour occur

DaShark said...

Damn, I thought I had added a link to it - remedied now and thanks for pointing it out!

What there is called Splash Fight is agonistic social behavior in competition about food and when determining rank.

But I'm not a GWS person - that's about as much as I know.
When I write these posts, I however first confer with several GWS people, and my suggestion would be that you do the same for further elucidations.