Every week, when Mark Foster checks his eight lobster traps in Portsmouth Harbor, he sees the black color of epizootic shell disease.
“It’s certainly frequently,” said Foster, who fishes recreationally for lobster to cook at home. He knows that even though the lobsters have the disease, the meat is still safe to eat and that not all of them will die. Still, he wonders if this is just the start of a disease in the Gulf of Maine that killed off a lot of lobsters in Long Island Sound, which is only 300 miles away.
Foster said, “We should know what it is and what causes it.” Foster’s father opened Foster’s Downeast Clambake, a York, Maine seafood institution.
Epizootic shell disease is an infection that can kill lobsters by making their shells soften and turn black with sores. The disease is known to have killed off most of the lobsters in Long Island Sound, where the yearly catch dropped from 3 The Connecticut Department of Energy and Environmental Protection says the amount dropped from 7 million pounds in 1998 to 142,000 pounds in 2011.
The amount of shell disease in Maine is still very low; a recent update on lobster monitoring from the Maine Division of Marine Resources showed that it was found in less than 2% of the population. That was compared by the DMR to Southern New England rates, which were at 20-30%.
Still, scientists are watching the rate as it makes its way into more northern waters. The lead lobster biologist for DMR, Kathleen Reardon, wrote that update. In 2018, she also wrote a paper about how the number of American lobsters from the nearshore Gulf of Maine is growing. The paper made it clear that there are “few reports” of the disease coming from Maine waters. However, it also found that the disease’s average prevalence rose from less than 16% in 2010 to 1. 2% in 2013.
Based on how the disease affects lobsters from southern New England and how it is spreading over time, Reardon wrote that ESD (epizootic shell disease) in the Gulf of Maine needs to be watched more closely.
Seeing your bright red lobster turn black after cooking can be alarming But don’t worry – there are a few possible reasons for this discoloration By understanding what causes it, you can avoid black lobster meat and enjoy perfectly cooked seafood.
What Causes Blackening of Lobster Shells?
There are a few potential causes of black lobster shells after cooking
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Improper Cooking – The most common reason. When lobster is undercooked and the internal temperature does not reach 80°C, an enzyme called phenoloxidase gets activated. This causes deposition of melanin or black pigment in the shell.
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Bruising – Improper handling during processing can cause bruising seen as black spots on raw lobster flesh. Remove these before cooking.
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Undeveloped Eggs – Female lobsters may have black roe or eggs inside. It should turn red when properly cooked. If it stays black, it needs more cooking.
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Old Tank Lobsters – Lobsters kept too long in store tanks can develop black meat from lack of nutrients and eating each other’s antennae. Avoid these.
The key is ensuring your lobster reaches the right internal temperature during cooking. This deactivates the enzyme causing blackening. Quick, high-heat methods like boiling, steaming, or grilling are best.
The Science Behind Lobster Blackening
There are a few scientific reasons why lobster shells turn black when cooked improperly:
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Phenoloxidase Enzyme – This is activated below 80°C. It causes melanin production and blackening. Proper high heat stops this enzyme.
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Astaxanthin Pigment – Lobsters get their red color from this heat-resistant pigment. Undercooking prevents astaxanthin from being exposed and absorbed into the shell.
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Calcium Reactions – Minerals in the shell react during cooking. Inadequate heat prevents full reactions, leaving black pigment.
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Bruise Reactions – Trauma causes hemocyanin reactions with melanin, giving a black/blue color. This persists unless the bruised flesh is removed pre-cooking.
Understanding the science helps you adjust your cooking methods. The goal is quickly bringing the internal lobster temperature up above 80°C before the meat overcooks.
How to Prevent Black Lobsters When Cooking
With a few simple tips, you can prevent black lobster shells and enjoy perfectly cooked seafood:
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Cook lobster quickly under high heat – boiling, steaming, or grilling over an open flame are best.
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Check internal temperature reaches at least 80°C. Insert a meat thermometer into the thickest part of the tail.
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Don’t overcook. Cook just until the internal temperature is met to prevent rubbery texture.
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Avoid using too much salt when boiling or steaming. This can draw out moisture and affect texture.
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Inspect raw lobster for bruising and remove any black spots on the flesh before cooking.
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Allow cooked lobster to rest 5-10 minutes before cracking open the shell. Carryover cooking ensures it reaches optimal doneness.
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Store cooked lobster properly refrigerated at 40°F or below and reheat gently to prevent further darkening of meat.
With proper handling, preparation, and cooking, you can enjoy bright red lobster every time. Don’t let a black shell ruin your next seafood feast!
What to Do If Your Lobster Turns Black Anyway
If despite your best efforts, your cooked lobster still has some black parts, don’t panic. Here’s what to do:
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First, check if it’s just undeveloped roe. This will be small black beads in the tail meat of female lobsters. It’s safe to eat after thorough cooking.
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Trim away any black flesh, especially if it’s bruising. The remaining meat is still safe to consume.
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The black intestinal vein running through the tail can also cause dark spots. Remove this before cooking.
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If the blackening is just on the shell, it won’t affect the flavor or safety of the meat. Crack it open and enjoy!
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Make sure the lobster is cooked fully through. Any translucent flesh needs more cooking time.
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If lobster meat has turned black or has a bad odor, it’s best to discard it. Don’t risk eating spoiled seafood.
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When in doubt, remember the old saying: “If it’s black, throw it back!” Stay safe and only eat lobster you are confident is fresh.
While you may need to trim some portions, a little black on your lobster doesn’t mean the whole thing is ruined. With smart preparation, black lobster shells can be avoided in the future.
Frequently Asked Questions About Black Lobsters
Is it safe to eat black lobster meat?
Lobster meat that has turned black or has dark spots should not be eaten. Only consume lobster flesh that is white, opaque, and fully cooked through. Discard any meat that is translucent, mushy, or black, as it may be undercooked or spoiled.
What if the blackening is just on the shell?
A blackened shell does not necessarily indicate spoiled lobster meat. As long as the flesh inside looks white and firm, it should be safe to eat. The discoloration only affects the exterior shell, not the quality of the meat. Proceed to crack it open and enjoy!
Can you prevent black spots in lobsters?
Yes! Ensure lobsters are alive right up until cooking. Cook them quickly under high heat until the internal temperature reaches 80°C. Avoid overcooking. Check for bruises on raw lobster and discard any black spots. Store cooked lobster properly refrigerated.
Should you eat lobster roe that is still black?
No, lobster roe needs to be cooked through until it turns red. If the beads of roe are still black, they are likely undercooked and should be avoided for food safety. Return the lobster to the heat until the roe changes to an opaque red color.
How do you know if a lobster is spoiled?
Signs of spoiled lobster include flesh that is mushy, slimy, or has a strong fishy odor. Translucent meat, black spots, sticky residue, and a foul ammonia-like smell also indicate the lobster has gone bad. When in doubt, remember “if it’s black, throw it back!” and discard it.
By learning proper cooking techniques and handling, you can avoid ending up with blackened lobster shells. With a few simple best practices, you can serve up flavorful, appetizing red lobster every time.
What’s causing shell disease in lobsters?
The disease causes bacteria and fungi to grow on the lobster’s carapace so that the lobster is unable to fight off the infection, according to Michael Horst, a scientist who collaborates with Reardon through his work at the University of Maine’s Darling Marine Center. The bacteria secretes enzymes into the shell that dissolve chitin, one of the major constitutions of the lobster shell, he said.
“It makes a soft spot,” Horst said. He said that the soft spot could eventually give way or form a hole or sore. Some lobsters can get better, but others die.
Pesticides were a big issue for lobstermen in Long Island Sound, where the die-off happened, and they think the disease is linked to them. Horst said warm water is also considered a significant factor.
“Ambient water temperature seems to be a trigger for getting this stuff going,” Horst said. That means summer months see the most shell disease. He said that link might make people think about shell disease and climate change, but it’s too early to say how much is due to global warming.
Horst said the disease poses a marketing issue for lobstermen as well. If a lobster has shell disease, the meat can still be eaten, but Horst said the lobsters will look less appealing if they go to market with a discolored shell.
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