Summer for many of us means a gambol at the beach, a quick plunge in cold water and a sunburn to show for it all. But for a lobster, summer means ... sex.

Lobster procreation is not the stuff of romantic movies. There are no passionate glances, no come-hither looks. Lobster love has more to do with the temperature of the water and wafting pheromones than it does with candlelight and champagne.

When it comes to mating, the heavily armed lobster turns out to be more of a softy than his shell would indicate. To find the right mate, he must find and defend a nice burrow for two, a hiding place with a good flow of seawater by the front door. Then he waits for a female to venture into the neighborhood. The female doesn’t drop her name card through the letter slot in the front door. She is definitely not coy. A female interested in a male with a particularly fine burrow will squirt her urine from the ducts by her eyes into the burrow to let the male know she’s there. If she is acceptable, the male will let her into the burrow. If not, he chases her away.

The couple hangs out together in the burrow while the female gets ready to shed her shell. Shedding, which is called ecdysis (from the Greek ekdysis, which means “getting out”), is triggered by water temperature and occurs in all growing lobsters. When coastal waters warm in July and August, it’s time to shed the old carapace and enjoy a new and roomier one. But the process of shedding takes many days, and during that period the lobster is vulnerable. Predators, like seals and large cod, like to eat the soft, weakened creatures. So what does a canny lady lobster do? Move in with a sturdy male who can defend her as she progresses through the shedding process.

First, she must dry out her tissues to make them smaller and easier to retract from the shell. It takes anywhere from a few minutes to a few hours, depending on the lobster’s size, to actually wiggle out of the old shell. Then the female lobster draws seawater into her tissues to plump up and begin to harden her shell. Lobstermen who find lobsters at this stage call them “jellies.”



That’s when the act of mating occurs. The male lobster turns the soft female lobster over, holding her body off the seafloor in his legs. He uses a pair of special swimmeret legs called gonopods to push a packet of sperm (spermatophore) into a receptacle in the female’s body. Transfer complete, the male releases the female, who uses her tail to flip out from under him.

Monogamy is not the name of the game for male lobsters. The female will leave the den a week or so after the mating occurs with a semi-firm shell. The male then will welcome the next pulchritudinous lady to his burrow.

After a few months while her shell, particularly the tail, continues to harden and after eating copious amounts of food, the female will allow the sperm packet to fertilize her eggs. Once fertilized, she extrudes the tiny dark green eggs from oviducts at the base of her legs. The eggs settle on her abdomen, where they remain glued to her for nine to twelve months. A one-pound sexually mature female may have eight thousand tiny eggs attached to her for those months; large females will carry ten times that amount. Mature females generally molt every two years rather than every year, as do the males.

During the warmth of the summer, lobsters have plenty of food and put a lot of their energy into growth. In the winter months, when the water is cold, they move around less and their bodies concentrate on producing sperm and eggs for the summer lovefest. Diane Cowan, a biologist and founder of The Lobster Conservancy based in Friendship, is concerned that the changing environment of the Gulf of Maine could affect that cycle. If the period of truly cold weather that brings seawater temperatures into the low 40s and upper 30s shortens, so too the time when the animals produce eggs and sperm will shorten. Fewer cold months may equal fewer little lobsters in the future.

Yet another consequence of a changing climate to worry about!