Terrified Fish
If you look to the right of the Humpback Whale you can see terrified fish jumping out of the water. When a predator is nearby, the small fish instinctively gather in a dense shoal. This shoal is constantly moving as the vulnerable fish on the outside squeeze inside the "bait ball", thus exposing new fish on the outside that do exactly the same. The result is a tight, swirling ball of small fish that the whale can simply gulp into its enormous mouth. As the whale approaches the bait ball, fish will try to escape at the surface, so sometimes the sea will appear to effervesce with fish. I think this bait ball must have been quite large as the whale has gulped down part of it, but there are still lots of terrified fish in the water to the right. This was photographed off Port MacNeill on the north east coast of Vancouver Island.
Terrified Fish
If you look to the right of the Humpback Whale you can see terrified fish jumping out of the water. When a predator is nearby, the small fish instinctively gather in a dense shoal. This shoal is constantly moving as the vulnerable fish on the outside squeeze inside the "bait ball", thus exposing new fish on the outside that do exactly the same. The result is a tight, swirling ball of small fish that the whale can simply gulp into its enormous mouth. As the whale approaches the bait ball, fish will try to escape at the surface, so sometimes the sea will appear to effervesce with fish. I think this bait ball must have been quite large as the whale has gulped down part of it, but there are still lots of terrified fish in the water to the right. This was photographed off Port MacNeill on the north east coast of Vancouver Island.