Careful With Those Horseshoe Crabs

Horseshoe crabs that washed up on Sunday

The horseshoe crab spawn is starting already, we saw a pair wash up on Sunday. We flipped them over, they “connected” again and went back into the surf. You will start to see more and more in the surf especially on the bay beaches. If you flip them over do not grab the “tail” that is the telson and it is used to help them steer, if you break it off it can cause a lot of harm. Grab the crab by the side of the shell those little leg pincers do not hurt. Just flip them over they will find their way back to the water on their own.
Horseshoe crabs are known as living fossils, they have been around for 450 million years, so there is still hope for some of you. Their spawn season usually coincides with the migration of the red knots. Horseshoe crab eggs are an important food source for these and other shore birds. When the crabs leave their eggs on the beaches yo can see them in the surf, long lines of tiny multicolored balls the size of pinheads by the billions.

horseshoe crab, spawn, red knots
Horseshoe crabs that washed up on Sunday. The female is upside down.

This time of year into the summer you will catch or snag horseshoe crabs. Especially if you are using bait. For some reason they really like fishbites too. If you hook one, carefully remove the hook with pliers. If the hook is wedged in really bad, cut the hook. The cheaper gear will rust out in no time.
We helped a guy last year and by the time he got done trying to tear out the hook, the crab was filling up with blue blood.

Horseshoe crab blood collecting in the dome shell
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Horseshoe crab blood is used in the medical field and harvested from the crabs. It is a crazy looking process, many are hoping to end soon with synthetic alternatives. The blood is used to detect bacterial contamination in anything that goes into our bodies, drugs, IV’s, you name it. A protein in the blood called Limulus Amebocyte Lysate (LAL) is what pharmaceutical and medical device manufacturers use to test their products for the presence of endotoxins, and bacteria. Without this ability to test these products it would cripple the medical industry. There are alternatives being created, but for the most part the actual blood of the horseshoe crab is the nest source.

horseshoe crabs, harvesting, port mahon, delaware, kent county
Harvesting Horseshoe crabs at Port Mahon, Delaware

Horseshoe crabs are harvested every year in Delaware for this blood and once they are “bled” they are released back into the water, but many do not survive the process. Horseshoe crabs are also used for bait for eels in the commercial fishing community.
Bulkheads and breakwaters along shorelines have caused areas traditionally used by horseshoe crabs to spawn to no longer be accessible. Port Mahon is a great example of a blocked shoreline, and is one of the most popular places to harvest horseshoe crabs during that season.

Fish on!
Rich King

Horseshoe crabs’ eggs hatching at the DuPont Nature Center

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