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.
Mirelurk hatchlings are a minor threat, more of a nuisance, really.
- Hatchlings are spawned when the player steps on or approaches a mirelurk egg cluster. The effect is random, and sometimes the clutch can be safely collected.
- Nahant Oceanological Society terminals: Research Terminal, Goals: "Here at the Nahant Oceanological Society we strive to save our oceans by researching the longterm effects of radioactive exposure on aquatic life and working with the community to raise public awareness. We believe that companies such as Poseidon and General Atomics have gone unchecked too long and that radical action is neccessary to protect our world from a horrific future."
- Nahant Oceanological Society terminals: Research Terminal, Lobster growth: "This is insane. An increase in average mass by 14% in crabs and 12% in lobsters is not something to be celebrated! If this trend continues, the additional food necessary to sustain the shellfish population could lead to colony collapse! I've tried again to bring our findings about the growth and mutations to the press and those assholes at GNN just took our findings and spun them into a story about how great shellfish season is going to be."
- Enclave Field Research Terminal, Field Entry: "Mirelurk": "Kingdom: Animalia
Class: Merostomata / Malacostraca / ???
After going to enormous lengths to procure DNA samples of hypothesized forebears, we cannot explain why ancestry evidence is present from two vastly different creatures; the Limulus polyphemus (horseshoe crab) and the Callinectes sapidus (blue crab). It's obvious that a mutation occurred, giving this creature bipedal movement and massive growth, but I cannot explain the presence of multiple subphylum markers in DNA/RNA. Given their mystifying origins, I have decided the species deserves its own classification, and have thus dubbed them "Scylla Serrata Horrendus." They can often be found in sewers and caves and should be considered hostile and very dangerous, as their chitnous shell provides excellent resistance to both firearms and hand-held weapons. They are disgusting creatures, and I cannot fathom their popularity as a food source among the citizens of the Wasteland."
- The Lone Wanderer: "They descended from local crabs. I'd call them "Scylla Serrata Horrendus.""
Moira Brown: "That's very scientific of you! Personally, I wasn't sure if they were crabs or if they came from some sort of brine shrimp, perhaps. Some of these observations about their armor and camouflage gave me an idea for reinforced, neutral-colored headgear. Here, consider it thanks for not interfering with them. Oh, speaking of which, take these. So you can continue to avoid them in the future."
(Moira Brown's dialogue)
- Note for Ted: "Ted,
The Mirelurks busted out of the storage area and have been raisin' hell through the whole facility. Price says the bastards get smarter every day. He says I'm paranoid, but I think somebody might be sabotaging things around here. We've taken on so much extra help, I don't know who I can trust around here anymore. Things don't look too good.
I don't think I'll be walking out of here, and I figure you should be the one to get our stash. I managed to get it hidden pretty well in case something like this happened.
I don't want any of these damn fools tripping over it, so I threw a couple of curves in, but it's nothing you can't handle. Start with my terminal -- just log in and follow the instructions. And if for some reason you've forgotten the password, you might want to sit down and have a think with a Nuka-Cola, if you catch my drift.
If this damn meat weren't in such high demand, I'd have pulled out of this racket before the word go. I got too greedy, Ted."
- Merc's orders: "By now, your handler's given you the location of the job and your basic orders. Here are the details.
Traders have been making a killing with Mirelurk meat, and we've been losing business because of it. One of our people got involved with a caravan supplier, and we finally know where it's all been coming from.
The meat's mostly coming from one group holed up along the river smack in the middle of the ruins. There's a huge old facility under some war memorial where they've herded up a nest of Mirelurks and have been breeding and butchering them. They've been in business for months and are sure to be sitting on a pile of caps. Take what you can carry -- we just want them out of the meat market. The rest is up to you.
This isn't the biggest job, but pull it off clean and there's plenty more work for a man with your skills. Get back to your handler as soon as the job is done and we'll be in touch."
- Mirelurk research
- Rivet City terminals. Council Meeting Minutes: "In attendance:
Science Rep. - Dr. Madison Li
Civilian Rep. - Bannon
Security Rep. - Harkness
* Bridge repair continues to be a drain on funds. Permanent bridge considered, but dismissed as too risky, in case of attack.
* "Bridge Tax" for non-residents proposed by Bannon. Vote fails.
* Hydroponics and city health continues well, thanks to the efforts of Dr. Li and her scientific team. However, system breakdowns are commonplace, requiring much maintenance.
* Li proposed recruiting other scientific minds from Tenpenny Tower or Underworld. Vote fails.
* Attempts to clear out the Mirelurk infestation in down-below continue as usual. Harkness and team is able to contain them and occasionally wipe them out, but they continue to nest in the area, posing a theoretical risk if they ever turn aggressive towards higher decks.
* Bannon suggests closing off lower deck fore. Vote fails.
* Funds and ammunition allocation for a Mirelurk cleaning operation proposed by Harkness. Vote passes.
* Dr. Li leaves early to oversee hydroponics testing.
* Meeting adjourned."
- Behavior in Fallout 4.