Poor Knights Dolphins
The Poor Knights Islands are a small group of unihabited islands about 12 miles off the northern coast of New Zealand. They were designated as New Zealand's second marine reserve in 1981, and managed by the Department of Conservation. Permits are needed to land (usually only granted for scientific research purposes), but there are several tourist operations that conduct scuba dive operations. The Poor Knights is reckoned to be one of the top ten dive locations in the world.
Schools of bottlenosed dolphins(Tursiops truncatus) and common dolphins (Delphinus delphis) can be seen feeding on shoals of fish, which they may well have herded to the surface, in this location. The general surface commotion which ensues, attracts flocks of seabirds - mostly southern black backed and red billed gulls. Herding behaviour has been seen in both species, as well as dusky, spinner, white-beaked and spotted dolphins.
The common dolphin has 180 teeth in its jaw which it uses to hold the fish fast while it is turned round to be swallowed head first. I've often wondered how dolphins manage to eat underwater without taking in vast quantities of sea-water, I found the answer in a book(!) "On the upper surface of the tongue of many species are small perforations, whose purpose is to stimulate the mucuous glands at the base of the tongue as soon as the fish is taken into the mouth. This mucus floods the area at the base of the tongue and the entrance to the gullet, adhering to the walls. As the fish enters the gullet, the mucus clings closely to the skin of the fish as well as the walls of the gullet and it closes behind the disappearing tail, thus preventing any salt water from reaching the stomach." - lovely!
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Reference: Save the Dolphins by Michael Donohgue & Annie Wheeler. Auckland, David Bateman Ltd., 1990. ISBN:1-86953-044-6