Mirelurk

Mirelurk is a commonly used term referring to a range of mutated crustacean and turtle species endemic to the Eastern Seaboard, particularly areas belonging to the Columbia and New England Commonwealths.

A similar term, lakelurk, is used to refer to mutated turtles in the Colorado watershed in the Mojave Wasteland.

Background
Mirelurks have the dubious distinction of being one of the first radioactive mutants to emerge into the world, as a result of widespread radioactive pollution of the environment by United States megacorporations such as Poseidon Energy or General Atomics. Environmental organizations such as Nahant Oceanological Society, dedicated to saving the oceans, attempted a variety of last ditch efforts to raise awareness of the problem and encourage radical action to curtail environmental destruction at the hands of reckless corporations. However, their efforts were in vain. Ignored by authorities, to the point where they refused to even take their phone calls (as was the case with the Boston Port Authority), they attempted to garner attention by reporting the situation to the Galaxy News Network. The media ignored their reports as well, except for running a story about the upcoming shellfish season and how great it was going to be. Of course, it neglected to mention that the average increase in mass on the order of 14% in crabs and 12% in lobsters meant that the available food supply would run out quickly, leading to colony collapse and localized extinction.

Although the Great War put an end to corporate pollution, it was replaced by overwhelming amounts of nuclear fallout instead. In the ensuing melting pot of mutations the modern mirelurks emerged. Attempts to classify the resulting creatures have proven difficult. The crab mirelurk, for example, contains multiple phylum markers from two distinct and unrelated species: The Atlantic horseshoe crab (Limulus polyphemus) and the Atlantic blue crab (Callinectes sapidus). As such, it would be necessary to catalogue it simultaneously as belonging to the Crustacea and the Chelicerate phylums, with simultaneous classification a two distinct classes (Merostomata and Malacostrata). As such, wasteland scholars generally assign it its own classification: Scylla serrata horrendus.

Although mirelurks tend to inhabit polluted rivers, coastal waters and sewers, their meat is considered a delicacy among wastelanders. Mirelurk hunters and herders can count on a steady demand for their meat and make a high profit selling it to wasteland traders. However, the size of the meat market means competition is stiff and suppliers can be targeted by rivals attempting to knock them out of the market (sometimes literally). They also grow remarkably fast, requiring just a few weeks for them to reach maturity. If corraled and domesticated, mirelurks can be a flexible supply of food. The Free States did, in fact, entertain such an option.

Mirelurks can also be a blight on permanent settlements, as is the case with Rivet City. Mirelurks nesting below inhabited decks are a continued nuisance for denizens of the city, despite regular extermination operations by the city's security team. Infestations are made even worse by the fact that mirelurks have adapted to lay their eggs in multiple small nests throughout shallow water (unlike pre-War crustaceans that adhered their eggs to their body), likely because they grow larger relative to the parent and have developed a hard calcified shell; if disturbed, the larval mirelurks within exhibit incredible precocious behavior and are ready to attack if need be. 

Characteristics
In Fallout 3, mirelurks are found in three variants: Mirelurks, mutated forms of Chesapeake Bay blue crabs (Callinectes sapidus); mirelurk hunters, mutated Atlantic Horseshoe crabs (Limulus polyphemus); and in the form of mirelurk kings, mutated snapping turtles. They can deal massive damage, and can absorb a great deal in return thanks to their shells. Generally, they can be found near sources of water, including the Potomac River in groups of two or more individuals of one of the above groupings.

In Fallout New Vegas, a strain of mutated turtles native to Lake Mead and other large water bodies appears; resembling the mirelurk kings of the Capital Wasteland, these humanoid turtles are called lakelurks by the locals.

In Fallout 4 and Fallout 76, mirelurks appear markedly more crab-like in appearance than those in Fallout 3, and their posture is generally crouched down to make their vulnerable faces harder to hit. Their shells also possess a mild reflective quality, as lasers ricochet off them. Mirelurk hunters are mutant lobsters rather than crabs. Mirelurk kings are less bipedal, have more prominent fins and have a long tail. Fallout 4 also adds the mirelurk queen, a gigantic creature slightly taller than a super mutant behemoth.

Mirelurk


 One of the most common variants of the mirelurk, Scylla serrata horrendus is the result of mixing between Chesapeake Bay horseshoe and blue crabs. Regional variations exist: for example, crab mirelurks in the Capital Wasteland tend to be bipedal and slimmer, while those in the Commonwealth and Appalachia (migrating from Chesapeake Bay ) are quadrupedal and rounder.

Their most noticeable feature is the large, chitinous shell that provides excellent resistance to firearms, melee weapons and even energy guns. Soft body parts, such as their faces and sections of their abdomen, are much less resistant. Of course, that only applies to adult mirelurks. The shell's chitin takes time to harden and young mirelurks are quite vulnerable at that stage of their life.

One feature of crab mirelurks is that they instinctively know how to protect themselves with their shell. When faced with prey that can attack them at range, a crab mirelurk will lower its head to cover its body with the chitinous shell, greatly increasing its ability to survive. Other animals tend to avoid mirelurks, perhaps instinctively realizing the danger posed by the shell.

When hunting, mirelurks rely on their extraordinary sense of smell, with their poor eyesight a secondary aid. They catch their prey with their primary large claws. Once immobilized, the prey is then stripped down and consumed with the claws on their abdomen, capable of stripping animals down to the bone within minutes. 

Softshell mirelurk


A weaker version of the mirelurk found in Fallout 4 and Fallout 76.

Mirelurk hatchling


Small, radroach-sized creatures that spawn from the eggs of a mirelurk clutch, or born live from the mirelurk queen. They appear to be baby mirelurks, and are instantly aggressive from birth.

Mirelurk hunter


A lobster-like creature that spits acid in splatter like shots.

Mirelurk king


Creatures that live symbiotically with other mirelurks, but according to Enclave research, appear to be mutated from snapping turtles. They use sonic attacks to kill their prey.

Lakelurk


Mutated turtles native to the large water bodies of the Mojave Desert. They use sonic attacks to kill their prey.

Mirelurk queen


Considerably larger and more dangerous than the other mirelurks. They have very large health pools, to the point they can even take several mini nukes to the torso without dying. One spawns at the Castle in Fallout 4 during the quest Taking Independence.

Nukalurk


Can be found in the Nuka-Cola plant in Fallout 3. They are blue because of taking in the strontium isotope from the Nuka-Cola Quantum. Their meat gives 10 Action Points. Commonly found in amusement park Nuka-World in the Fallout 4 add-on Nuka-World.

Nukalurk queen


The Nukalurk queens can only be found in the Nuka-Cola bottling plant. She is a unique version of the mirelurk queen and has a blue glow due to the strontium isotope from Nuka-Cola Quantum. She has a large health pool, but when the Sole Survivor finally kills her, she drops queen Nukalurk meat which when consumed grants 120 Hit Points and 2 points in Endurance but 30 rads. The Sole Survivor can cook it at a cooking station to make a grilled version that has higher stats.