Jaws has nothing on these seals - 01:28 pm
03 Feb 2010
Today was actually pretty awful. We’ve fallen in love with the gannets – totally, and today we had to watch the reality that happens when they leave land. We know that the seals here take full advantage of juvenile gannets getting into the water. There are plenty of signs around.
We wanted to see if we could find some of this predation to film. We didn’t know what we were in store for. We’ve been watching all week for signs of seals hunting, but today has been the first significant day. The wind shifted ever so slightly, bringing a bit of drizzle this morning but was very light this afternoon. Virtually none of the juveniles were going out. These weather conditions were for experienced adults only.
But we set up camera in a likely spot and this indeed was the time. There were seven or eight seals patrolling the edge of the shore, waiting.
They’d use the waves’ momentum to peer up, looking for gannets in the water, and if they saw them, they’d be on them straight away.
We thought the adults might have more of a chance than the flightless juveniles, but without any wind, they were struggling. And it showed.
It’s horrific. One after the other, the birds were taken out by the seals. It’s not fun to watch and the tension runs so high. The moment a gannet hits the water, you’re willing it to get back in the air. You can see the seals coming closer, and the chances diminish.
Apparently last year, the seals took 80% of the fledglings on this island. This will be the main reason there are such big gaps in the nesting colony. It’s a completely unsustainable scenario.
And the seals do not stop. They almost seem to hunt together. Pierre and I were getting bleaker and bleaker. How can you watch a massacre?
Every now and again, the adults would sprint across the water to take off and a few got it right. But even as they skim the waves, the seals leap out at them hoping to grab them as they fly past.
This island breaks you.
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Comments
2 posted at 07:15am on 04 February, 2010 by Admin
Nope. It’s not at all normal. There’s no way the gannet population can survive this level of predation. The seal numbers seem to be doing pretty well - but the lack of sardines and other fish that has been affecting the gannet population in these waters, can only affect the seals as well. They also need food. It’s hard not to get sentimental about this, but in fact, the gannet numbers are steadily going down, and every year we notice bigger areas without nesting gannets.
It looks like the gannets are getting a lot of sardines and anchovies in their diet this year which is great, and should mean that their chicks do well. But there is this small group of seals which can wreck even a good year for the birds really quickly. Even with good fish stocks they’ve figured out an easy meal. The gannets have no chance against them. It is a situation which does need some management.
3 posted at 07:19am on 04 February, 2010 by Admin
Also, the seals have been targeting the juveniles in the past. A big enough problem. Now, they’re just as good at getting the adults if the conditions are right...that may well mean losing a chick on a nest as well…
4 posted at 07:55am on 04 February, 2010 by Raymond Besant
Looks like a double edged sword for you guys. Great to get some interesting behaviour but not that pleasant to witness first hand I imagine. Do you know if there is any truth in the idea the seals are only after the stomach contents and not the Gannets themselves?
5 posted at 01:55am on 08 February, 2010 by Admin
That’s an interesting question. I was discussing this with some of the experts and watching specifically to see if I could figure it out. I have to say I still don’t know. There are certainly a lot of gannets which are mostly eaten, but then again, so many just seem to have the body cavity eaten. It may be a combination where some seals will go for the stomach contents and others will take more advantage of the extra protein. From the carcasses which wash up, it does look to be a bit of both. But then again, after the seals have killed a number of gannets, they will have eaten their fill, but they still keep going - at that point just maiming and disabling the gannets and then leaving them. It’s as if they’re practicing their hunting skills rather than anything else at that point. That’s when it gets really disturbing…
1 posted at 07:03am on 04 February, 2010 by Riaan van den Heever
you said 80% of the fledglings was killed by the seals last year, is this normal?
is it because there are to many seals?