Lobsters grow by cyclically shedding their outer skeleton. This process means their journey from egg to adult takes a significant amount of time.
The Lobster Life Cycle
Lobsters begin their lives as tiny eggs, often carried by the female under her tail until they hatch. Upon hatching, they enter a larval stage, where they are transparent and free-swimming, drifting in the ocean’s upper layers. This planktonic phase typically lasts between 3 to 10 weeks, during which the larvae undergo several molts, transforming through distinct stages.
Growth occurs through molting, or ecdysis, where they shed their rigid exoskeleton to increase in size. Their hard shell does not expand, so a new, larger shell forms underneath the old one before it is shed. After the final larval molt, the lobster enters a post-larval stage, resembling a miniature adult, and settles to the ocean floor. Each molt results in a significant size increase, with lobsters gaining approximately 15% in length and 40% in weight.
From the post-larval stage, they transition into juvenile lobsters, seeking shelter and continuing to grow through repeated molts. Growth is not continuous; instead, it happens in bursts immediately after each molt when the new, soft shell expands before hardening. Juvenile lobsters can molt frequently, sometimes up to 25 times in their first few years of life.
Factors Influencing Growth Rate
Environmental and biological elements affect how quickly a lobster grows. Water temperature plays a substantial role, as warmer waters generally lead to increased metabolic rates and more frequent molting. In colder environments, lobsters may grow more slowly and molt less often, sometimes going two years between molts.
The availability and quality of food directly impact a lobster’s growth. A plentiful and nutritious diet allows lobsters to accumulate the energy required for molting and shell formation, leading to faster growth. Conversely, scarce food resources can slow down their developmental progress.
Habitat conditions, including suitable shelter and space, contribute to their survival and ability to grow safely. Different lobster species possess varying growth rates, with some growing faster or reaching larger sizes than others. Salinity and water depth are additional factors that can influence molting frequency and overall growth.
Typical Time to Maturity
The time it takes for a lobster, particularly the American lobster, to reach market size or reproductive maturity can vary. On average, American lobsters typically take between 5 to 7 years to grow to a legal harvestable size, which is often around 1 pound (approximately 3 1/4 inches carapace length).
After reaching maturity, molting frequency decreases, with adult males typically shedding their shells once a year and females once every two years. This slower molting pattern in adulthood means that while lobsters continue to grow throughout their lives, the rate of increase slows down.