Not all female lobsters lay eggs. A complex interplay of biological processes and environmental conditions determines if and when a female lobster will produce eggs.
The Reproductive Cycle of Female Lobsters
The reproductive journey for a female lobster begins with mating, which typically occurs when she is in a soft-shell state, immediately after molting. She releases chemical signals, known as pheromones, to attract a male, often the largest in the vicinity. Once a male is found, he protects her in his den while her new shell hardens.
During mating, the male transfers sperm into a specialized storage organ within the female called the seminal receptacle, or spermatheca. This stored sperm can remain viable for an extended period, potentially up to two years. The female controls when she fertilizes her eggs, which occurs internally as the eggs pass from her ovaries, through the seminal receptacle, and out of her body.
After fertilization, the female extrudes the eggs, attaching them to the pleopods, or swimmerets, on the underside of her tail using a glue-like substance. At this point, she is referred to as “berried.” A 1-pound female can carry around 8,000 eggs, while a larger 9-pound female might carry over 100,000 eggs.
Factors Influencing Egg Production
A female lobster’s ability to lay eggs is not a constant, as various factors can influence this process. She must first reach sexual maturity, which typically occurs between 5 to 8 years of age, or at a specific carapace length.
Overall health and nutrition play a significant role in a female’s reproductive capacity. A lack of sufficient food or an unhealthy condition can inhibit the development of her gonads and prevent egg production. Environmental stressors can also impact her physiological state, potentially delaying or halting egg laying.
The molting cycle is closely linked to reproduction. While egg extrusion usually occurs after a molt, not every molt leads to egg-laying. Adult females may molt once every two years, and the timing of egg extrusion can be influenced by the timing of this shedding process.
Environmental conditions, such as water temperature and food availability, also influence a female lobster’s reproductive success. Temperature affects ovarian development and the overall reproductive cycle, with warmer temperatures potentially stimulating earlier development. Successful mating is a prerequisite for fertilized egg production.
Egg Development and Larval Stages
Once extruded, lobster eggs are carried and protected by the female under her tail. This incubation period can last from 9 to 12 months, with the exact duration influenced by water temperature. The female actively fans her eggs with her swimmerets, providing them with oxygen and keeping them clean.
As the embryos develop, the eggs change color, initially appearing dark green and gradually turning red as the embryo consumes the yolk. Hatching occurs over several nights, with the female releasing batches of larvae by fanning her tail. The newly hatched larvae are tiny, free-swimming planktonic creatures, about the size of a pea, that float near the surface for several weeks.
These larval stages are vulnerable, as the larvae are susceptible to predation and rely on ocean currents for dispersal. They undergo several molts during this period, gradually changing in form. After approximately 4 to 6 weeks, the few larvae that survive will settle to the seabed and continue their development into post-larval and juvenile lobsters, eventually resembling miniature adults.