Lobsters, the large marine crustaceans prized for their meat, do lay eggs, but their reproductive cycle is complex. The female lobster carries her developing eggs externally for an extended period, a biological strategy that provides protection for the next generation. This process requires a precise sequence of mating, fertilization, and incubation that spans nearly two years from start to finish.
Mating and Internal Fertilization
The reproductive journey begins with mating, which usually occurs right after the female has shed her hard outer shell, a process known as molting. During this vulnerable period, the female is soft-shelled and releases pheromones to signal her readiness to mate. A male lobster, often one who has established dominance, will guard her until she sheds her shell.
Mating involves the male transferring sperm packets, called spermatophores, into a specialized receptacle on the underside of the female’s body near her walking legs. Fertilization does not happen immediately; the female stores the live sperm in this internal chamber for up to two years. This ability allows her to delay the fertilization and egg extrusion until environmental conditions, such as water temperature and food availability, are optimal. When she is ready to reproduce, the stored sperm fertilizes the eggs as they are released.
The “Berried” Stage: Carrying and Protecting the Eggs
When a female lobster extrudes her fertilized eggs and attaches them to her body, she enters the “berried” stage. This term comes from the appearance of the eggs, which resemble small, dark berries clustered on the underside of her abdomen. The eggs are released from the oviducts and are fertilized by the stored sperm as they pass the seminal receptacle.
The female uses a sticky substance to cement these eggs securely to her swimmerets, the small appendages located on the underside of her tail. A large female can carry anywhere from 3,000 to over 100,000 eggs, depending on her size. This external carrying period lasts approximately 9 to 12 months, though the duration depends on the surrounding water temperature.
Throughout this incubation, the mother performs continuous care to ensure the eggs develop properly. She actively “fans” the egg mass with her swimmerets, which serves the dual purpose of circulating oxygen-rich water over the eggs and removing debris and sediment. The eggs change color as they develop, starting as dark green and gradually turning black or reddish. This extended period of maternal care contrasts with the strategies of many other marine animals that simply release their eggs into the water.
From Larva to Juvenile Lobster
Once the eggs are fully developed, they begin to hatch from the mother’s abdomen, usually over several nights. The newly hatched lobsters are tiny creatures called larvae, and they are immediately released into the ocean currents. In this initial phase, the larvae are planktonic, drifting near the surface of the water for several weeks.
During this free-swimming period, the larvae undergo a series of molts, typically three to four, to grow and change their form. Each molt brings them closer to the adult form, a process known as metamorphosis. They are vulnerable to predators while floating near the surface, and the mortality rate during this stage is immense. It is estimated that only a tiny fraction will survive to reach harvest size.
After the final larval molt, the creature transforms into the post-larval stage, resembling a miniature adult lobster. The young lobster settles to the ocean floor, seeking shelter in rocky crevices or grassy areas to avoid predation. Juvenile lobsters continue to molt frequently as they grow, a cycle that takes several years to reach maturity.