Sunday, January 31, 2016

GWS hunting Strategies - Paper!

Marine Dynamics, serial enabler of good research! Source.

Very nice!

Check this out!
No need to write a synopsis as it is open source and also, because there are really nice ones here and here. Great to see that this is once again brilliant research that has been facilitated by Marine Dynamics, a proud member of Global Shark Diving!

And the take-away message of it all?
What once again strikes me, is how behavior is being mediated by the environment (= climate, geography, habitat but also occurrence and/or migration of prey etc) but also by factors like gender, age and of course, individuality - and this all within one and the same species! 
And yes I'm very much repeating myself!

Incidentally, that's what we very much experience here.
We basically conduct two types of feeding, i.e. by hand and from a suspended wheelie bin - and over the years, we have observed that each feeding modality has created its own Shark tribe, with only extremely few individuals switching from one source to the other. In fact, when we briefly discontinued hand feeding after the passing of Rusi, some of the hand feeders appear to have wandered away, only to slowly start coming back once regular hand feeding was resumed.
Maybe individual Sharks learn a preferred strategy early on and then continue favoring it as long as it works, which would also explain why some of the cage dive operators report that the same individual GWS appear to attack the teaser baits always in the same way.

But of course all is relative.
These are trends and not absolutes, meaning that in all likelihood, behavior happens along a continuum and very likely also evolves as prey wisen up and circumstances changes. Plus, Sharks with wide trophic niches are also likely to dispose of an equally wide array of predation strategies.

But I'm digressing as always.
Great paper, and well done to everybody involved!


Shark Diver said...

I love your comment that "these are trends, not absolutes" I always say the only thing that is predictable about the behavior of white sharks is that they are unpredictable.

When you think about it, for millions of years white sharks have successfully hunted mammals, which are arguably smarter than they are. If they were predictable, those mammals would have figured out long ago how to avoid them.

DaShark said...

Like all predator-prey relationships, it's likely to be the usual arms race where the prey learns to avoid a strategy and the predator has to come up with something new!

Yannis said...

There is also evidence that some of the shark behavior is tailored towards juvenile mammals-which are naive and inexperienced. So indirectly the juveniles might impact the adults. While seals can certainly improve their chances (e.g. enter through kelp forests, swim along the bottom) there is no getting around that they have to get in and out of the water at predictable locations.

DaShark said...

= Sharks don't only weed out the sick, dead & dying but also the dumb and reckless - as it should be!