Italy is on alert from North to South due to the sudden and abnormal appearance of the blue crab.
This marine species originates from the American continent and its “invasion” of the Tyrrhenian and Adriatic Seas is causing significant damage to aquaculture. As if it wasn’t enough, a second species has recently been identified, arriving from the Red Sea and the Indian Ocean.
Why is there so much concern surrounding this so-called “alien” species? What should we do if we spot one in the sea and, most importantly, how can we recognize it?
In this article, we’ll break down everything you need to know about the blue crab and answer some of the most common questions sparked by curiosity about this marine newcomer that’s stirring up quite a bit of attention.
What Is the Blue Crab?
The blue crab is native to the American continent and belongs to the Portunidae family of decapod crustaceans. Its dangerousness derives from its size and its omnivorous diet, particularly hungry for other crustaceans and mollusks.
Crustaceans in the Portunidae family are found worldwide, they mostly live in marine environments, but many species also inhabit brackish or even freshwater areas.
These crabs have a sturdy, laterally flattened body, which is characteristic of decapods. The front part of their body is covered by a hard, protective carapace. Their claws, known as “chelae,” are larger than the other legs. These are used to catch food and defend themselves from predators.
Their rear legs are flattened like paddles, this way, they can swim with ease. Recent studies show that the blue crab is robust, powerful, and has virtually no natural predators: all “ingredients” that easily explain the rapid spread we are currently witnessing in Italian seas.
What does the blue crab look like?
As mentioned earlier, the blue crab has 10 claws: the two on the front are the characteristic claws, while the rear pair resemble flippers that allow it to swim. Its body is elliptical in shape, with two long lateral spines protruding from each side.
What clearly sets it apart from other native crabs is its striking blue color, which is where its name comes from. It also stands out in terms of size when compared to common Italian marine crabs. Its carapace can reach up to 9 inches in width.
Male and female blue crabs can be distinguished by the shape of their abdomen (rounded in females, slender in males) and by the color differences in their claws (the fixed claw of males is blue with red tips. Females have an orange coloration with hints of purple).
The blue color that characterizes the blue crab’s shell has a fascinating explanation: this shade comes from a mixture of pigments inside the shell, including alpha-crustacyanin (which interacts with a red pigment) and astaxanthin (a carotenoid). When we cook the crab, the alpha-crustacyanin breaks down, leaving astaxanthin to dominate. This, in turn, gives the crab that wonderful red-orange color we all recognize when it arrives on the plate at our table.
Where is it found?
Though the first species identified originates from the American continent and the second comes from the Red Sea and the Indian Ocean, climate tropicalization is accelerating the migration of the blue crab into the Tyrrhenian and Adriatic Seas, where it’s finding an ideal habitat for the species to settle and thrive.
Both types of blue crab prefer environments ranging from lagoon areas to the open sea and can develop extremely dense populations.
How does the blue crab behave?
The blue crab’s behavior in the wild is similar to that of other crabs in the same family. Therefore, it is not strictly necessary to label it as an “alien” species, as the media often do. However, what raises concern is its diet, as it feeds voraciously on other crustaceans and mollusks: razor clams, oysters and, most of all, clams. This is causing serious challenges for aquaculture farmers.
It also appears that the blue crab is more aggressive than its relatives: it does not hesitate to use its claws for hunting and defense and has been reported to damage even the most delicate fishing nets.
Still, when encountering humans, it typically exhibits the common crab behavior of fleeing and hiding (unless provoked or disturbed).
Why this is alarming?
According to estimates made in the Veneto region, this year the blue crab invasion is expected to cause an 80% drop in clam production. The risk, as highlighted by President Zaia, is that this could completely disrupt the identity of the area and make it impossible to continue cultivating clams in the lagoon.
What the media often don’t disclose is that this species appears to have been present in Europe (especially in France) since the early 1900s. The difference, today, lies in the demographic boom, which seems to have occurred without a certain cause. However, the main reasons for the increase in blue crab presence in Italy are primarily linked to:
- Rising temperatures
- The disruption of biological niches
It’s not the blue crab’s fault that our climate has become so tropical that it’s pushed the species to migrate and colonize our seas…
If we must find a “guilty party” in all this, the blame should fall on ourselves and our failure to effectively manage the climate crisis.
One crucial aspect to worry about, if the blue crab truly threatens the survival of shellfish, is the important role shellfish play in fighting climate change. That’s why their presence in our seas must be protected with great care.
Pros and cons of the new species
What we realize is that, due to the media-driven fear campaign in recent months, consumers may not be fully aware of the potential economic value that the blue crab could bring to Italy.
The blue crab has actually been a welcomed guest in our country for a long time: we use it (imported) in numerous recipes. Do you know which crab species is the most imported and consumed in Italy? It’s precisely the blue crab, as it is the easiest to find pre-cleaned and shelled. Incredible, isn’t it? The very marine animal we now fear has long been on our plates, and it is sold at premium prices in the best restaurants.
As culinary enthusiasts know, all marine species in this family go through a molting phase, during which they become “soft-shell crabs”.
Soft-shell crab is highly prized and commands a price in Italy ranging from 50 to 70 euros per kilo.
It goes without saying that expanding and increasing the commercialization of crab, especially the blue one, which currently abounds in our seas, could bring enormous economic benefits to both the fishing and gastronomic sectors.
Let’s pause for a moment and think about it: how easy it is to complain when things happen beyond our control when actually, over the years, we ourselves have decided (without ever asking nature for permission) to introduce some marine species into our seas? Many of the artificially introduced species have significantly contributed to the growth of the Italian economy (and continue to do so today).
How to eat the blue crab
Let’s start with the most frequently asked question: Is blue crab edible? Absolutely yes and, contrary to false beliefs and fake news circulating about it, it does not carry any new deadly viruses.
Just like any other crab, the blue one requires a specific procedure for cooking, shelling, and eating.
- First of all, it should be noted that the best crabs to eat are male ones. Once purchased, they need to be rinsed under water and then they can be cooked in boiling water
- They should boil for 5-6 minutes, then be drained and completely cooled
- Once cooled you can remove the claws by twisting them in the opposite direction to their natural orientation
- You’ll need to separate the bottom shell from the top shell to extract the meat you will need for your recipes
- Gills and internal organs must be removed, as you’ll only need the crab meat
- Now that you have the meat you can creatively use it in the dishes you wish to prepare
Whether you choose to use it in salads, soups, risottos, or omelets, crab meat is very tasty, delicate, and prized: it will make every recipe a true delicacy, full of sea flavor and aroma.
Nutritional properties
Crab meat is very interesting from a nutritional point of view. First of all, it is a source of high biological value protein: 18.1 g per 100 g of edible portion. This makes it particularly useful for meeting the body’s essential amino acid requirements.
Regarding fats, the amount is quite limited: only 1.08 g per 100 g of edible portion. However, it is important to note that it contains a certain level of cholesterol. That’s why crab meat should be consumed with caution if you suffer from hypercholesterolemia.
Carbohydrates are only present in trace amounts, making it a low-carb food choice.
From a caloric standpoint, blue crab meat has a low energy content: only 87 kcal per 100 g of edible portion. This makes it an excellent option for low-calorie diets.
It’s also rich in several key vitamins: B1 (0.08 mg/100 g), PP (2.7 mg/100 g), and vitamin A (5 IU), as well as essential minerals such as calcium (84 mg/100 g), phosphorus (229 mg/100 g), potassium (329 mg/100 g), sodium (293 mg/100 g), zinc (3.54 mg/100 g), and selenium (37.4 mg/100 g), all of which help support our nutritional needs.
Now, with that in mind, we’d like to leave a suggestion for those who made it to the end of this article: what if we tried to do the same with the blue crab, transforming it from a feared invader into a powerful ally?
