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This Week’s Creature Feature ... Horseshoe Crabs Mate by Moonlight

June 1’s full moon begins the season

Love is in the air — and on Bay beaches — as love-struck horseshoe crabs begin their annual mating ritual.
    These ancient marine arthropods — despite their name, they are not crustaceans — respond to the pull of the moon and spring tides to procreate. Their spawning peaks during evening tides over three to four days centered on the full new moon dates.
    At peak spawn, the tide lines of prime beaches may be covered in spawning horseshoe crabs. An annual spawning survey tracks the population. Carried out mainly by volunteers, the 2010 survey tallied some 23,000 crabs, the highest number ever counted.
    Horseshoe crabs are harmless, though they may look a bit menacing. Despite their relationship to the scorpion, horseshoe crabs have no tail stingers; the tail, or telson, is the rudder, helping steer through the water and right themselves if stranded upside down.
    They won’t hurt you. And you can help them. Turn over stranded crabs and edge them to the waterline. Pick them up by the sides of the body, not the tail.
    During the spawn, scientists tag crabs. If you find a tagged one, call the toll-free number on the tag and report its whereabouts. Sightings of tagged crabs help scientists understand patterns of movement and spawning.
    Maryland Department of Natural Resources also needs your help in identifying shoreline used as spawning habitat. If you see horseshoe crabs spawning on the shore, document the location (GPS coordinates if possible) and pass your find along to Marek Topolski: 410-260-8263; mtopolski@dnr.state.md.us.