Crabs are decapod crustaceans of the infraorder brachyura, which typically have a very short projecting “tail” (abdomen), usually hidden entirely under the thorax. They live in all the world’s oceans, in freshwater, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers. Several other groups of crustaceans with similar appearances – such as king crabs and porcelain crabs are not true crabs but have evolved features similar to true crabs through a process known as carcinization.

 

Callinectes sapidus also called Atlantic blue crab, The Blue crab, and Chesapeake blue crab. It is native to the Western Atlantic Ocean and the Gulf of Mexico. It is a decapod crab that belongs to the family Portunidae. It is quite similar to shrimp, prawns, and lobster. There are about 6700 crab species and 93 crab groups. It is omnivores that live on oceans, freshwater, and land. It has a lifespan from three to four years. It measures up to 23 cm (9.1 inches) wide and 25 cm carapace long. The leg spans measure about 4 meters (13 ft) long. It has a thick and armored shell that is 9 inches across. It is blue to olive green in color with bright blue claws. The taste is soft, delicate, and sweet.

Classification

The infraorder Brachyura contains approximately 7,000 species in 98 families,^[rx][rx] as many as the remainder of the Decapoda.^[rx] The evolution of crabs is characterized by an increasingly robust body and a reduction in the abdomen. Although many other groups have undergone similar processes, carcinization is most advanced in crabs. The telson is no longer functional in crabs, and the uropods are absent, having probably evolved into small devices for holding the reduced abdomen tight against the sternum.

In most decapods, the gonopores (sexual openings) are found on the legs. However, since crabs use the first two pairs of pleopods (abdominal appendages) for sperm transfer, this arrangement has changed. As the male abdomen evolved into a slimmer shape, the gonopores have moved towards the midline, away from the legs, and onto the sternum.^[rx] A similar change occurred, independently, with the female gonophores. The movement of the female gonopore to the sternum defines the clade Eubrachyura, and the later change in the position of the male gonopore defines the Thoracotremata. It is still a subject of debate whether a monophyletic group is formed by those crabs where the female, but not male, gonophores are situated on the sternum.^[rx]

Superfamilies

Numbers of extant and extinct (†) species are given in brackets.^[rx] The superfamily Eocarcinoidea, containing Eocarcinus and Platykotta, was formerly thought to contain the oldest crabs; it is now considered part of the Anomura.^[rx]

• Section †Callichimaeroida
  • †Callichimaeroidea (1†)^rx]
• Section Dromiacea
  • †Dakoticancroidea (6†)
  • Dromioidea (147, 85†)
  • Glaessneropsoidea (45†)
  • Homolodromioidea (24, 107†)
  • Homoloidea (73, 49†)
• Section Raninoida (46, 196†)
• Section Cyclodorippoida (99, 27†)
• Section Eubrachyura
  • Subsection Heterotremata
    • Aethroidea (37, 44†)
    • Bellioidea (7)
    • Bythograeoidea (14)
    • Calappoidea (101, 71†)
    • Cancroidea (57, 81†)
    • Carpilioidea (4, 104†)
    • Cheiragonoidea (3, 13†)
    • Corystoidea (10, 5†)
    • †Componocancroidea (1†)
    • Dairoidea (4, 8†)
    • Dorippoidea (101, 73†)
    • Eriphioidea (67, 14†)
    • Gecarcinucoidea (349)
    • Goneplacoidea (182, 94†)
    • Hexapodoidea (21, 25†)
    • Leucosioidea (488, 113†)
    • Majoidea (980, 89†)
    • Orithyioidea (1)
    • Palicoidea (63, 6†)
    • Parthenopoidea (144, 36†)
    • Pilumnoidea (405, 47†)
    • Portunoidea (455, 200†)
    • Potamoidea (662, 8†)
    • Pseudothelphusoidea (276)
    • Pseudozioidea (22, 6†)
    • Retroplumoidea (10, 27†)
    • Trapezioidea (58, 10†)
    • Trichodactyloidea (50)
    • Xanthoidea (736, 134†)
  • Subsection Thoracotremata
    • Cryptochiroidea (46)
    • Grapsoidea (493, 28†)
    • Ocypodoidea (304, 14†)
    • Pinnotheroidea (304, 13†)

Recent studies have found the following superfamilies and families to not be monophyletic, but rather paraphyletic or polyphyletic:^[38][37]

• The Thoracotremata superfamily Grapsoidea is polyphyletic
• The Thoracotremata superfamily Ocypodoidea is polyphyletic
• The Heterotremata superfamily Calappoidea is polyphyletic
• The Heterotremata superfamily Eriphioidea is polyphyletic
• The Heterotremata superfamily Goneplacoidea is polyphyletic
• The Heterotremata superfamily Potamoidea is paraphyletic with respect to Gecarcinucoidea, which is resolved by placing Gecarcinucidae within Potamoidea
• The Majoidea families Epialtidae, Mithracidae, and Majidae are polyphyletic with respect to each other
• The Dromioidea family Dromiidae may be paraphyletic with respect to Dynomenidae
• The Homoloidea family Homolidae is paraphyletic with respect to Latreilliidae
• The Xanthoidea family Xanthidae is paraphyletic with respect to Panopeidae

Nutritional value of Crustaceans, Crab, Alaska king, Cooked, Moist heat

Proximity	Amount	% DV
Water	65.92 g	N/D
Energy	82 Kcal	N/D
Energy	345 kJ	N/D
Protein	16.45 g	32.90%
Total Fat (lipid)	1.31 g	3.74%
Ash	1.57 g	N/D

Minerals	Amount	% DV
Calcium, Ca	50 mg	5.00%
Iron, Fe	0.65 mg	8.13%
Magnesium, Mg	54 mg	12.86%
Phosphorus, P	238 mg	34.00%
Potassium, K	223 mg	4.74%
Sodium, Na	911 mg	60.73%
Zinc, Zn	6.48 mg	58.91%
Copper, Cu	1.005 mg	111.67%
Manganese, Mn	0.034 mg	1.48%
Selenium, Se	34 µg	61.82%

Vitamins	Amount	% DV
Water-soluble Vitamins
Vitamin B1 (Thiamin)	0.045 mg	3.75%
Vitamin B2 (Riboflavin)	0.047 mg	3.62%
Vitamin B3 (Niacin)	1.139 mg	7.12%
Vitamin B5 (Pantothenic acid)	0.34 mg	6.80%
Vitamin B6 (Pyridoxine)	0.153 mg	11.77%
Vitamin B9 (Folate)	43 µg	10.75%
Folic Acid	0 µg	N/D
Folate, food	43 µg	N/D
Folate, DEF	43 µg	N/D
Vitamin B-12 (Cobalamine)	9.78 µg	407.50%
Vitamin C (Ascorbic acid)	6.5 mg	7.22%
Fat-soluble Vitamins
Vitamin A, RAE	8 µg	1.14%
Vitamin A, IU	25 IU	N/D
Retinol	8 µg	N/D

Lipids	Amount	% DV
Fatty acids, total saturated	0.113 g	N/D
capric acid 10:00 (decanoic acid)	0.003 g	N/D
Lauric acid (dodecanoic acid) 12:00	0.003 g	N/D
Myristic acid  14:00(Tetradecanoic acid)	0.013 g	N/D
Palmitic acid 16:00 (Hexadecanoic acid)	0.074 g	N/D
Stearic acid 18:00 (Octadecanoic acid)	0.016 g	N/D
Fatty acids, total monounsaturated	0.157 g	N/D
Palmitoleic acid 16:1 (hexadecenoic acid)	0.035 g	N/D
Oleic acid 18:1 (octadecenoic acid)	0.076 g	N/D
Gadoleic acid 20:1 (eicosenoic acid)	0.012 g	N/D
Erucic acid 22:1 (docosenoic acid)	0.032 g	N/D
Fatty acids, total polyunsaturated	0.456 g	N/D
Linoleic acid 18:2 (octadecadienoic acid)	0.017 g	N/D
Linolenic acid 18:3 (Octadecatrienoic acid)	0.012 g	N/D
18:04	0.013 g	N/D
20:4 undifferentiated	0.037 g	N/D
20:5 n-3 (EPA)	0.251 g	N/D
22:5 n-3 (DPA)	0.026 g	N/D
22:6 n-3 (DHA)	0.1 g	N/D
Cholesterol	45 mg	N/D

Amino acids	Amount	% DV
Tryptophan	0.229 g	52.05%
Threonine	0.666 g	37.84%
Isoleucine	0.797 g	47.67%
Leucine	1.306 g	35.34%
Lysine	1.431 g	42.79%
Methionine	0.463 g	N/D
Cystine	0.184 g	N/D
Phenylalanine	0.694 g	N/D
Tyrosine	0.547 g	N/D
Valine	0.774 g	36.65%
Arginine	1.436 g	N/D
Histidine	0.334 g	27.11%
Alanine	0.932 g	N/D
Aspartic acid	1.7 g	N/D
Glutamic acid	2.805 g	N/D
Glycine	0.992 g	N/D
Proline	0.542 g	N/D
Serine	0.648 g	N/D

*Above mentioned Percent Daily Values (%DVs) are based on 2,000 calorie diet intake. Daily values (DVs) may be different depending upon your daily calorie needs. Mentioned values are recommended by the U.S. Department of Agriculture. They are not healthbenefitstimes.com recommendations. Calculations are based on average age of 19 to 50 years and weigh 194 lbs. Source: https://ndb.nal.usda.gov/ 

Health Benefits of Crab

As it is quite popular in seafood, it is loaded with various amounts of health benefits. It promotes heart health, lowers inflammation, enhances immunity, detoxification, and enhances circulation. It is loaded with various amounts of minerals, nutrients, fats which are essential for the functioning of the body. In addition to that, it also contains omega-3 fatty acids and selenium.

1. Healthy bones – Phosphorus is essential for the maintenance of bones and teeth. It has a high content of phosphorus which is vital food. Foods rich in phosphorus such as crabs help to prevent the chances of suffering osteoporosis. (1)

2. Mental health – Crab is loaded with various nutrients such as Vitamin B2, copper, omega 3 fatty acids, and selenium. It is vital for cognition and nervous activities. It strengthens myelin and prevents the nervous system. It also lowers inflammation and plaque. (2)

3. Heart health – The crab’s meat is rich in omega-3 fatty acids. It helps to balance the level of cholesterol and enhance anti-inflammatory properties. It lowers blood pressure, reduces strain on the heart, and prevents the chances of atherosclerosis. It lowers the chances of stroke and heart attack. (3)

4. Lowers inflammation – The nutrients and minerals found in crabs help to lower inflammation. It also contains selenium, copper, omega-3 fatty acids. It should not be consumed by patients with gout, arthritis, gastrointestinal problems. (4)

5. Enhance immunity – Selenium is associated with enhancing immunity and acts as an antioxidant activity to prevent chronic ailments in the body. It helps to eliminate the free radicals that could mutate the cells. Crabmeat has adequate amounts of selenium and riboflavin that raise the antioxidants. (5)

6. Detoxification – The immunity system of the body assists in blood, liver, and kidney detoxification. Crab has phosphorus that enhances the function of kidneys and eliminates toxins and also enhances metabolic efficiency. (6)

7. Assist circulation – Copper is essential for the functions of organs. It is vital for the iron absorption of the gut. Iron is essential for red blood cells production. It enhances circulation and promotes oxygenated blood to the body parts. It speeds up the healing process and cell regrowth during illness and injury. (7)

Others Benefits are

• Prevents Cancer – Crab intake helps to decrease the risk of cancer attack. Studies reveal that crab is suitable for preventing the onset of cancer due to its rich constituent of selenium. The antioxidant selenium in crab inhibits the carcinogenic effects of mercury, arsenic and cadmium that can cause tumour growth and cancer attacks in human beings. In fact the higher the selenium level, the lower the risks of cancer.
• Improves Blood Sugar Metabolism – Due to the high amount of chromium in crab, it is suitable for individuals that have insulin resistance. This is attributed to the fact that the chromium in crab helps to improve the blood sugar metabolism thus reducing the blood glucose levels in the body. The chromium in crab facilitates the action of insulin thus preventing the onset of diabetes.
• Production of Surgical Equipment – Being an excellent source of chitosan and chitin, Subashinghe (1999) attests that crab is suitable for producing surgical equipment such as; surgical thread, gauzes, biomedical beads, medical fabrics, wound dressing, antifungal agents, dialysis membrane and antibacterial materials. This is attributed to the biodegradability potentials of chitosan and chitin thus they can easily wear away during the wound healing process.
• Regulates the Cholesterol Level – The chromium nutrient found in crab helps to increase the HDL (good cholesterol) level in the body. Increasing the good cholesterol in the body helps to minimise the risk of heart attacks, strokes, circulatory and coronary diseases. Moreover, the sterol found in crab helps to inhibit the absorption of possible cholesterol and fat consumed in other food products. The omega 3 fatty acids in crab help to lower the level of triglycerides and bad cholesterol LDL (low-density lipoproteins) that usually block the arterial walls.
• Ideal for Pregnant Women – Nutritionists agree that crab is safe for consumption by pregnant women but this should be in moderation. Being an excellent source of vitamin B and omega 3 acids, crab is highly recommended during pregnancy. Howbeit, pregnant women are encouraged to cook this crustacean very well in other to destroy parasites and bacteria that could possibly affect unborn babies. Pregnant women are also encouraged to consume mainly crabs with the lowest mercury content such as king crab and freshwater crab.
• Facilitates Wound Healing – Crab is an excellent source of chitin and as such suitable for facilitating and accelerating wound healing process. According to Thirunavukkarasu and Shanmugam (2009), the chitosan in crab acts as a wound-healing accelerator as well as helps to protect a wound from bacterial invasion through suppression of bacterial proliferation.
• Supports the Cardiovascular System – Being a rich source of omega-3 fatty acids, crab meat is recommended for supporting the cardiovascular system. It helps to promote the healthy functioning of the heart thus preventing heart-related diseases such as heart failure, heart attacks. The phosphorus in crab aids in the contraction of the heart muscle.
• Boosts the Memory – The high amount of omega-3 fatty acids in crab aid brain development and boosts memory. Crab intake can also help to prevent anxiety and depression.
• Prevents Nutritional Deficiencies – Kala and Chandran (2014) emphasised that crab is a suitable supplement of protein and minerals needed to support and balance human nutrition. Thus consuming edible crabs is essential for preventing nutritional deficiencies.
• Anti-oxidant Properties – Crab is an excellent source of antioxidants such as selenium. This nutrient prevents oxidative damage to the body tissues and cells thereby reducing the risk of cancer attacks.
• Prevents Blood Clotting – The omega-3 fatty acids found in crab are essential for preventing blood clotting.
• Regulates the Blood Pressure – The potassium and omega-3 fatty acids present in crab are essential for regulating the blood pressure level.
• Aids Balanced Weight – Crab is low in carbohydrates, fat and calories thus essential for healthy functioning of the body parts and for maintaining a healthy weight.
• Anti-inflammatory Properties – Crab contains anti-inflammatory properties due to its high constituent of omega-3 fatty acids. It helps to prevent and reduce arthritic pain.

https://www.youtube.com/watch?v=t5Dwl47gYxc

How to Eat

• It is consumed whole along with the shell.
• Crab cake could be prepared by mixing the flour to the crab meat.
• It could be used fresh or canned.

Other Facts

• Males are called jimmies and mature females are known as sooks.
• It has five pairs of legs.
• They are omnivores that eat both plants and animals.
• Japanese Spider Crab has a leg span that measures 12 feet.
• Crab could swim and walk.
• The crab’s pregnancy lasts from one to two weeks and deposits from 1000 to 2000 eggs.
• The mating occurs only once in female blue crabs.

Precautions Not Turkey

• The consumption of sea fish if one is trying to reduce inflammatory diseases such as heart disease.
• Farmed ones contain arsenic that leads to arsenic poisoning.
• Seafood should be cooked safely in order to prevent foodborne illness.
• Pregnant women, young children, older adults, people having lower stomach acid and compromised immune systems (HIV/AIDS, liver disease, cancer, diabetes, gastrointestinal disorders, people taking steroids, chemotherapy, or immune system) are prone to higher risk.
• It might be contaminated with bacteria such as Vibrio parahaemolyticus, Vibrio vulnificus, and other bacteria relate to land use, sewage discharges, runoff, etc. These microorganisms occur naturally in warm coastal waters which could cause even death or serious illness in individuals who are at higher risk.
• Listeria monocytogenes could cause a serious foodborne illness known as listeriosis.
• The virus Hepatitis A could survive in light cooking. So one should consume it after being properly cooked.
• Fish could have toxins that could cause illness such as ciguatoxin and scombrotoxin, or histamine poisoning.
• Sea fish is related to Scombrotoxin (histamine) which develops when fish is not kept cold enough. The symptoms develop quickly and also disappear completely within 24 hours.
• The flesh of tropical marine fishes might cause ciguatera poisoning experiencing gastrointestinal maladies that could last for several days, weakness in arms and legs, and reversal inability to differentiate between cold and hot. The symptoms could persist for weeks.
• Farmed seafood results in to increase in inflammation leading to weight gain, arthritis, and heart diseases.
• The imbalance ratio of Omega-6 and Omega-3 causes heart disease and hypertension.
• Seafood and fish in farms have polychlorinated biphenyls (PCBs), organophosphorus (OPs), organochlorine (OC), trifluralin pesticides, and hexachlorobenzene (HCB) causing diseases or even death.
• The seafood has a high content of mercury, which may lead to mercury toxicity.
• Consume it in moderate amounts. So consume it with caution or Avoid consuming it raw.
• Some people might get allergic reactions. So avoid it.
• It has a high chance of contamination.
• One should limit its intake.
• Consult the doctor by pregnant women and children before consuming it. Children and pregnant women should avoid it because the high content of mercury might cause a negative impact on the development of the nervous system of a fetus.
• Seafood or fish have purines in it which is harmful to people having purine-related problems. Excess purines result in an excess buildup of uric acid that could lead to the formation of kidney stones as well as gout.

References

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