Calm before the storm…

In off the sea early today, 1230, as a westerly buster has arrived. Truth be told, it may not be the worst thing in the world as things have quietened down considerably after the chaos of the early week. A strong westerly wind might just stir things up! During the vicious weather of last week, the gannets would probably have experienced difficulty in feeding, and that may have been why the activity was so hectic for two days after the strong winds had passed. Certainly our data show that gannets feed more after a cold front (= westerly buster) has passed through a stretch of coastline.

We are finding plenty of fish scattered around – it is easy to find a group of common dolphins working a small baitball. Often there are less than about 200 fish in the ball (picture left), and the common dolphins don’t hang around and corral the ball. These little balls are spread thinly over the shelf along this part of the coastline, and the commons merely move from one little ball onto another. When they manage to round up a nice plug of fish, then the gannets get involved and dive onto the ball. Gannet success rate during these plunge dives seems to be quite high, probably over 30 or 40 %, depending upon the density and size of the ball, and its proximity to the sea surface.

The big sighting of the morning, not made by us, alas, was Orcinus orca, or killer whale. It is not known whether these dolphins (yes, they are not whales) eat sardine, but there has been some footage of them eating dolphin, and lets face it, there’s plenty more dolphin in this sea. Sightings of killer whales along this coast, however, are very rare. It was a very lucky find, indeed.

This morning we headed straight out off Poenskop and were rewarded with some good gannet and common dolphin activity. While we were kitting up, we could see the activity slowing down, and as we were about to jump in the water, a Bryde’s whale lunged to the surface and swallowed the baitball. That was the end of the baitball. There were a few dolphins on either side of the lunging Bryde’s whale, and it’s probable that the dolphins snack on fleeing fish, which must be completely disorientated from the feeding lunge. It is still amazing that we are getting so many Bryde’s whales this far north. Fantastic!!

After that we headed south to Ebulauw (about 30 km south of PSJ) looking for cleaner water, and did manage to get in on a decent little baitball with quite a few solid bronze whalers and the other usual predators, but it was in green water, so not much good footage was obtained. In fact, there is very little clean water around anywhere. We are not sure if it is because of the recent massive surf stirring up fine silt sediment deposited by rivers, or whether it is an algal bloom. We’ll have to get onto the ocean colour website to check.

I have still not managed to get on to the rsmarinesa website. It is most frustrating because I’m getting calls asking where the sardines are. We know that a lot of sardine has come up as far as Port St Johns, and has reached the Waterfall Bluff Bight, but that it has been very scattered to the north of Waterfall Bluff. This area is crucial to the success of the sardine run; here the continental shelf is very narrow, only about 9 km wide. If the Agulhas Current (= warm and unsuitable for sardines) flows up against the shoreline, then sardines will not be able to pass through and make it to KZN. Then the sardines will stay south of the Bluff and we’ll be happy in Port St Johns. If conditions allow, for example, if a cool current gets pulled up on to the shelf and passes north through the Bluff area, even if it is below the surface and not observable by satellite imagery, then there is a great chance that this activity will reach KZN. I hope for ya’ll sakes that this happens.

So…when there is nothing going on predator feeding wise, one can always take a moment to watch the many humpback swimming past (pictured left). Over the past few days, we hadn’t seen many humpbacks, but they are back in force again. Humpback whales are known to move in groups where the males travel separately to females with calves. It might be that another pulse has arrived and is travelling in the same area together. We saw groups of 6, 7 and even 8 animals together, breaching and blowing and making the long trek northwards on their breeding migration.

On a sad note, you can see Justin (pictured left) hunched over his Nikon D300 camera which was in house underwater housing, which decided to become a swimming pool. Justin managed to get the camera out, but was gutted because a) he didn’t know if the camera was knackered (this is a seriously nice camera) and b) the underwater component of his epic holiday had just ground to a halt. To be fair, he did not throw his toys off the boat, but was REALLY introspective for the next three hours. Happily, Rod siliconed the hell out of the dome port, and Justin was able to dive with his housing today. That is why he looks so happy in the photo of us travelling up the Mzimvubu estuary. From left to right: Me, Rod Haestier, Vic Peddemors and Justin Gilligan.
Good luck with the waiting,
Sean