Sardine Run Part 3, Cape Gannets
By Lloyd Edwards

The sardine run is still in full swing here in Algoa Bay. Although the fish and predators are still abundant, the weather has not been playing along this last week. It is very unusual that we have such strong easterly winds and fog this time of the year. We have still managed to slip out between the bad weather and continue to have great sightings.

 

This post we feature diving Cape gannets. They are one of my favourite birds, so handsome and perfectly adapted to hunting fish at depth. They can hit the water at speeds of up to 100km/h and have specially adapted “air bags” under the feathers and skin to absorb the shock. They lack nostrils which would give them a nose enema every time they dived! I always thought that they spotted the fish they targeted from above before their dive, but looking at video footage it seems like they choose a place to dive where there are no other predators below. They select a clear patch of water and aim for that. This is probably why there are so few fatalities after a feeding frenzy.

 

Another fact that was brought into contention when looking at a video was that the Common dolphins always find the fish while the gannets follow. We have now observed gannets first locating the school and the Common dolphins then homing in on the spot. Are there any comments from the scientists?

When conditions are rough and the dolphins are relaxing and socializing, they are very difficult to locate in an area as vast as Algoa Bay. It is generally the large flocks of gannets that hover over the dolphins that lead us to the bait balls. Big thanks to them!