Fish & Water - Sounds Wild
Mermaid's Purse

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Mermaid's Purse

A beach comber has found an odd leather pouch at the high tide line on an Alaska beach. It fits nicely in her palm, like a fat coin purse made of tough dried seaweed. It rattles - something is inside. It's a mermaid's purse, and although it's not really from a mermaid, it did come from the bottom of the ocean. It's an egg case, containing dried skate eggs, from a skate - a manta ray-like fish related to sharks.

Sometimes called flat sharks, skates have cartilaginous skeletons and wing-like fins. They are bottom-dwellers and eat crabs, clams, worms, and fish. They are slow-growing, long-lived animals, found in oceans throughout the world. There are 16 species in Alaska waters, including two found only in Alaska, the leopard skate and the Aleutian skate. Skates are similar to rays like mantas but differ from rays because they lay eggs instead of bearing live young - and they don't sting.

Skates congregate by the thousands in June and July to lay their eggs in ocean bottom nurseries. These nursery sites are usually located at the heads of undersea canyons, in water 500 to 1,200 feet deep, where temperatures are constant throughout the year. By identifying the genetic makeup of the embryos found in nurseries in the Bering Sea, biologists learned that skates return to the same nurseries. A skate may lay just 25 eggs, every other year, and eggs can take as long as four years to gestate on the sea floor before hatching. Sometimes currents carry those egg cases off the sea floor and away to distant beaches.