Many people believe lobsters are biologically immortal, capable of living indefinitely and never truly succumbing to old age. This popular notion suggests they only die due to external factors. However, this widely held belief is a misconception. While lobsters possess unique biological characteristics that contribute to their impressive longevity, they are not exempt from the natural process of death.
Unraveling the Myth of Lobster Immortality
The widespread myth of lobster immortality stems from two primary biological features: indeterminate growth and the enzyme telomerase. Unlike many animals, including humans, lobsters exhibit indeterminate growth, meaning they continue to grow in size throughout their entire lives, rather than reaching a fixed adult size. This continuous growth contributes to the perception that they never age in a conventional sense.
Another factor contributing to the myth is the presence of an enzyme called telomerase in many of their cells. In most organisms, including humans, DNA strands are capped by protective sequences called telomeres, which shorten with each cell division. This shortening is linked to cellular aging, or senescence. Lobsters, however, produce significant amounts of telomerase throughout their lives, which helps to restore and maintain the length of these telomeres. This cellular maintenance allows lobster cells to divide more times without the typical deterioration seen in other species, preventing the cellular aging that characterizes senescence.
The Reality of Lobster Longevity
Despite their unique cellular advantages, lobsters are not biologically immortal and do eventually die. While they do not experience the cellular senescence that leads to organ failure in the same way as many other animals, they still face increasing challenges as they age and grow larger. This concept is sometimes referred to as “functional senescence,” where older lobsters encounter practical limitations that ultimately lead to their demise.
As lobsters grow, their physical demands increase substantially. The process of molting, or shedding their exoskeleton to grow a new, larger one, becomes increasingly energy-intensive and risky with age and size. Additionally, maintaining a larger body requires more metabolic energy and a greater intake of food and oxygen, which can become difficult to sustain. These escalating challenges mean that even with their ability to repair cells, older, larger lobsters are more susceptible to various forms of mortality.
Common Causes of Lobster Mortality
Lobsters succumb to a range of natural and external factors.
Molting Failure
A primary natural cause of death is molting failure, particularly for older and larger individuals. The exertion required to shed their old, rigid shell can be too much, leading to exhaustion and death, with estimates suggesting 10-15% of lobsters die this way annually. After molting, their new shell is soft and vulnerable for up to two weeks, making them susceptible to injury or predation until it hardens.
Diseases and Parasites
Lobsters are also vulnerable to various diseases and parasites. Shell disease, caused by bacterial infections, erodes their exoskeleton, creating lesions that weaken the shell and expose them to secondary infections. Other diseases can directly impact their health and be lethal, especially in cold water temperatures. Weakened immune systems, often due to environmental stressors like warming waters, can increase their susceptibility to these pathogens.
Predation and Human Activity
Predation is another significant cause of mortality throughout a lobster’s life. Despite their tough exoskeletons, lobsters are prey for a variety of marine animals, including large fish like cod and haddock, seals, eels, and even other lobsters. Smaller, juvenile lobsters are particularly vulnerable, but even large lobsters can fall prey to powerful predators. Human activity, primarily fishing, represents a major cause of lobster mortality, with commercial and recreational harvesting significantly impacting populations.
Environmental Stressors
Environmental stressors also play a role in lobster mortality. Changes in water temperature can significantly impact their physiological functions, including growth, reproduction, and immune response. Prolonged exposure to warmer waters can lead to stress, increased disease susceptibility, and mass die-offs. Low oxygen levels (hypoxia) and pollution can also be fatal or severely impact lobster health and survival.