Nature

Skate egg case and an undeveloped egg (top). (Switgard Duesterloh photo)

One of my favorite places to be at a low tide is the wide sandy beach that stretches from the mouth of Buskin River down to the old military roads behind Boy Scout Lake. I love the view, the seals that often stick their heads out of the waves to spy on me, and the way the dark basalt and light pumice sands create patterns and pictures on the beach. As the tide withdraws, grains of sand are set into motion, washed towards the sea. The lighter pumice sand travels faster and is transported to the top while the darker and denser basalt sand deposits further down. With each outgoing tide nature’s artists work and reshape these beautiful designs in the sand.

On one of my recent walks along the beach I found a special object. It is a little bigger than my hand, rectangular in shape with horns extending from each corner, and made of a tough keratin material. On first sight it is brown, but brown does not really do justice to the coppery-golden shimmering appearance. No wonder these things are referred to as mermaids purses; which mermaid wouldn’t want such a pretty purse? What I had found is the egg case of a skate; in this case a Big Skate. The Big Skate lives in the North Pacific and is the largest skate species reaching up to six feet.

The egg case was broken on one side, which allowed me a look inside. Inside this mermaids purse were two eggs (see the egg in the front of the picture). I believe there may have been more before the egg case was damaged. The Big Skate is one of only two species known to have more than one egg per case, usually there are 3 or 4, but there can be up to seven. On another hike to another beach I found another egg case. This egg case is a little smaller and lacks the ridges of the Big Skates egg case, but it has an even more stunning golden hue to it. So far my internet quest to find the owner (or maker) of this lost mermaids purse has not been sucessful.

When I researched information about skates in Alaska I came across an interesting NOAA website, which explained that there were several areas in the Bering Sea which have been designated as areas of special concern because they are known skate nursery grounds. In these areas, drag nets often surface with entangled skate egg cases. While this is very destructive to the skate population, it is also highly undesirable to the fishermen, because cleaning the nets off the egg cases costs valuable time. The North Pacific Fisheries Management Board considered skates an important indicator for ecosystem diversity.

Two species of skate have been fished commercially in the Gulf of Alaska. However, skates have very long development times (some skate embryos take three years to develop) and low reproduction rates prohibiting large scale exploitation.

In Kodiak, most sport fishermen release skates when they get hooked during a fishing expedition. However, earlier this spring I witnessed a great sea lion having a feast in the harbor three feet away from the main ramp to the harbor masters office. What the sea lion was eating was obviously a skate. Perhaps the sea lion just happened to catch a skate right there in the harbor, but it is more likely that the skate had been tossed overboard, possibly missing its fins.

Several years ago on a fishing trip near Kodiak one of the anglers on board caught a big skate. I took several pictures of the fish and its eyes before we released it back into the sea and watched it sail into the darkness. I will never forget those mesmerizing golden patterned eyes. What amazing wonders of the ocean depths have those eyes seen? Has that skate lived to deposit on the ocean bottom mermaids purses with eggs inside?

Pictures by Switgard Duesterloh. Skate egg case and an undeveloped egg (top)

Stellar Sea Lion feeding on a skate (below)

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