Strombus Gigas – Nutritional Value, Health Benefits

Strombus gigas commonly known as queen conch is a large, marine, and gastropod mollusk. Most of the mollusks including the queen conch belong to class Gastropoda and the name was translated from Latin as stomach foot. Other mollusks include clams, oysters, squid, and octopus. The word mollusks are derived from the Latin word mollusks which means soft. Mollusks belong to the phylum of invertebrates with more than 100000 known species.

The Queen conch is a soft-bodied animal having an external and spiral-shaped shell with interior glossy pink or orange. They live in sand, coral reef, and seagrass bed. Generally, it is found in warm and shallow water not deeper than 70 feet (21 meters) throughout the Gulf of Mexico and the Caribbean Sea ranging as far north as Bermuda and as far south as Brazil. It reaches full size in 3-5 years of age and grows to a maximum length of 12 inches long weighing 5 pounds. It is a long-lived species reaching 20 to 30 years old. The estimated lifespan is about 40 years.

Adult has a large, heavy, and solid shell with knob-like spines on the shoulder, a flared thick outer lip featuring a pink-colored aperture. In younger specimens, the flared lip is absent completely. The external anatomy of the soft parts of Lobatus gigas is identical to other snails in the same family. It has two eyestalks with well-developed eyes, a long snout and additional sensory tentacles, a corneous sickle-shaped operculum, and a strong foot.

It serves as home to various types of commensal animals such as porcelain crabs, slipper snails, and cardinalfish. It may include parasites named coccidians. Queen conch is hunted and consumed by several species of large predatory sea snails, also by crustaceans, starfish, and vertebrates such as sea turtles, fish, and humans. Sea snail’s meat is eaten by humans in various dishes. Shell is sold as a memento and used as a decorative object. It has been used historically by indigenous Caribbean people and Native Americans to create various tools.

It is protected under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) agreement in which it is recorded as Strombus gigas. It is due to extreme overfishing as meat is a vital food source for humans. CITES regulation is outlined to halt the export of meat of this species and the commercial export of shells is used as decorative objects.

Biology

Fertilization is internal. The female spawns thousands of eggs in a long tubular egg mass. Spawning occurs during summer. Large egg masses take upto 36 hours to produce and hold from 310000 and 750000 eggs. Egg masses are covered with sand for camouflage and larvae appear after 5 days. During a season, a single female spawns between six to eight times. Larvae are called veligers, float in the open ocean and feeds on phytoplankton, and drift considerable distance from the site where they emerged though the evidence is limited. Later between 18 and 40 days, larvae settle into the sand and metamorphose into adult form.

Adult migrates to deeper water when their size increases and seasonal migrations occur during the summer months. Conch moves by unusual hopping motion where the foot is thrust against the bottom which causes the shell to rise and be thrown forward. They are active mostly during the night and graze on detritus and algae with the use of extendable proboscis. Gastropod produces large spiral shells having spines that are thought for protection. Shell has a wide and fared lip which is rich pink in color. Within the shell, the gastropod’s head has two pairs of tentacles. Larger ones carry eyes whereas smaller pair provides a sense of touch and smell. The large foot is visible at the lip of the shell. In recent years, the large and beautiful shell is prized by tourists.

Shell description

Usually, an adult shell is 15 to 31 cm (6-12 inches) long and the maximum size reported is 13.9 inches (35.2 cm). Shell is very heavy and sold having 9-11 whorls and widely flaring & thickened outer lip. The shell of adult snails has a structure known as the stromboid notch is present on edge of the lip. This notch is not well developed in species as it is in various other species in the same family. The shell feature is nonetheless visible in adult dextral specimens. Spire is higher than in the shell of other strombid snails such as closely associated and even larger goliath conch native to Brazil. The glossy finish around the aperture of the adult shell is primarily colored in pink shades. Usually, the pink glaze is pale and may show the coloration of cream, yellow, or peach but it could be tinged sometimes with deep magenta shading to red. The periostracum is a protein layer in the outermost part of the shell surface which is thin and tan or pale brown in color in this species.

The morphology of the overall shell is not determined solely by animal genes; environmental conditions such as food supply, geographic location, depth, temperature, and biological interactions such as predation exposure can affect it greatly. Juveniles form heavier shells when exposed to predators in comparison that is not exposed to predators. Conch develops thicker and wider shells having fewer but longer spines when living in deeper water. The shell of small juveniles is different in appearance from adults. The shell of the juvenile has a simple and sharp lip which provides hell an iconic and conical outline. Subadult shells possess flared lips i.e. very thin. Until death, flared outer lip of the adult shell increases constantly in thickness with age.

Life cycle

Conch is gonochoristic meaning each individual snail is either distinctly male or female. Usually, females are larger in comparison to males in the natural population having both sexes existing in similar proportion. Internal fertilization occurs. In gelatinous strings, females lay eggs that could be as long as 75 feet. It is layered on patches of bare sand and seagrass. Egg strings are long and have a sticky surface that allows them to agglutinate and coil, combining with surrounding sand forming compact masses. The shape is defined by the anterior portion of the outer lip of the female’s shell as they are layered. Each egg masses are fertilized by multiple males. The number of eggs per egg mass varies greatly which depends on environmental conditions such as temperature and food limitation. In each season, females produce an average of 8 to 9 egg masses each containing 180000 to 460000 eggs but numbers could increase depending upon conditions.

During the reproductive season, females spawn multiple times lasting from March to October with peak activity occurring from July to September. After the eggs hatch, two-lobed veliger emerges and spends several days developing in plankton and primarily feeding on phytoplankton. About 16 to 40 days of hatching, metamorphosis occurs. Fully grown protoconch measures 1.2 mm high. Individuals spend the rest of their lives after metamorphosis in the benthic zone remaining buried during their first year of life. It reaches sexual maturity at age of 3-4 years weighing 5 pounds measuring 180 mm shell length. Usually, individuals live up to 7 years in deeper waters. Its lifespan reaches from 20 to 30 years and the maximum lifetime is estimated to reach about 40 years. Due to their thickened shell, its mortality rate is considered to be lower in matured conchs but is substantially higher for juveniles.

Feeding habits

Conch (Lobatus gigas) is regarded as a herbivore and other Strombidae feeds on macroalgae which includes red algae, unicellular algae and seagrass, and also algal detritus. It prefers green macroalga (Batophora oerstedii).

Health Benefits

Traditional uses

• In Chinese herbalism, the Conch shell is used for treating menopause.
• In Ayurvedic medicine, it is known for digestive and antacid properties.
• Blowing conch shell regularly helps to correct the speech of stammering children.
• It is also believed that blowing conch shells regularly clears blockages in the heart and also improves the respiratory system.
• Store water in the conch overnight and in the morning use this water to massage skin. It cures skin problems such as allergies, rashes, white spots,s and skin diseases.
• Store water overnight in the conch and add rosewater to it in the morning. Wash hair using this mixture. It helps to restore the natural color of hair within few days.
• Drink 2 spoons of water stored in the conch overnight for treating indigestion, stomach pain, and laceration in the intestines.
• Gently rub with conch before sleep for five minutes per day to cure dark circles.
• Blowing conch is beneficial for bladder, urinary tract diaphragm, lower abdomen, neck, and chest muscles.
• It also exercises thyroid glands and vocal cords.

Other uses

• Conch shells are sometimes used as decoration, as decorative planters, and in cameo making.
• In classic Maya art, conchs are shown being used in many ways, including as paint and ink holders for elite scribes, as bulges or trumpets, and as hand weapons (held by combatants by inserting their hands in the aperture).
• Conch shells have been used as shell money in several cultures.
• Some American Aboriginals used cylindrical conch columella beads as part of breastplates and another personal adornment.^[rx]
• In India, the Bengali bride-to-be is adorned with conch shells and coral bangles called shakha Paula. It is a traditional wedding ritual for every Bengali bride.^[rx]
• In India and Bangladesh, the conch is blown every day in the evening in Bengali houses as a daily ritual.
• In some Afro-Caribbean and African-American cemeteries, conch shells are placed on graves.^[rx]
• In some Caribbean countries such as Jamaica and the Bahamas, cleaned queen conch shells, or polished fragments, are sold, mainly to tourists, as souvenirs or in jewelry. Responding to a 2003 recommendation from CITES, some countries in the Caribbean have banned the export of queen conch shells. CITES has also asked all countries to ban the import of these shells from countries that are not complying with CITES recommendations for managing the fishery. Queen conch fisheries have been closed in several countries.^[rx] Conch shells or fragments took home by tourists from non-complying countries may be confiscated on return to the tourist’s home country while clearing customs. In the UK, conch shells are the 9th-most seized import.^[rx]
• Conch shells are occasionally used as a building material, either in place of bricks or as bulk for landfills.
• In Grenada, fishermen use the conch shell as a trumpet to announce to the community that fish is available for sale. Conchs are used at carnival times in the Jouvert Jump where Diab Diab (Jab Jab) blows conch shells as part of the festivities. Especially in Guadeloupe, hearing conch shells being blown near ports at dawn and during Carnival times, too, is not uncommon. Many bands are making the conch shell a main instrument.
• In the Bahamas, broken or up-turned conch shells are embedded into the tops of outdoor walls in an effort to maintain home security.
• In Tamil Nadu, India, the conch horn is blown during funerals as an acoustic indication of the funeral and to ward off evil spirits.
• In Key West, Florida, US, a native-born resident is affectionately called a “conch”.
• In Japan, a conch is horagai (or jinkai). It was used as a trumpet in special ceremonies such as a royal cremation during the Edo period.^[rx]
• Conch shells, (pu in Hawaiian) have been historically used as a method of communication, a tradition that is still observed in parts of modern life in Hawai’i.^[rx][rx]

Precautions                                                                                                 

• People with a hernia, high blood pressure, and glaucoma when blown conch causes extra pressure on the organs. Avoid it.
• Learn to blow conch from an expert because careless blowing damages eye and ear muscles and ruptured the diaphragm.

How to make curried Conch Meat

INGREDIENTS

• 2-3 lbs conch meat
• 1/4 tbsp sea salt
• 2 medium onions (diced)
• 4 heads garlic (diced)
• 2 tbsp pimento seed (whole)
• 1 tbsp parsley (dried)
• 3 stalks scallion (diced)
• 2 ripe scotch bonnet peppers (cut in half)
• 3 sprigs thyme
• 2-3″ piece of ginger
• ¼ cup coconut oil (or other oil)
• 2 to 3 tbsp. curry powder
• 2 tbsp white vinegar or lime juice
• 4 to 6 cups of water
• 1/4 lb chocho, optional (peeled and diced)
• 1/4 lb carrot, optional (peeled and diced)
• 1/4 lb Irish potato, optional (peeled and diced)
• 1/4 lb okra, optional (peeled and diced)

INSTRUCTIONS

1. Break the bottom of the conch shell and remove the conch. Remove the outer skin.
2. Tenderize conch meat by pressure cooking for 45 minutes, or boiling in water for 1 hour 30 minutes to 2 hours over medium-high heat. Test with a fork.
3. Chop tenderized conch into bite-size chunks. Cover and set aside.
4. Heat a large frying pan over medium-low heat. Add the curry powder along with one diced garlic clove and stir constantly for about 10 seconds.
5. Immediately add the oil, then the diced onions, and continue to stir for 10 more seconds.
6. Add the diced scallion, then the rest of the diced garlic. Stir-fry for about 20 seconds.
7. Stir in the conch, then add all the remaining ingredients (water last). Cover and allow simmering for 20 minutes on medium-low heat.
8. Reduce heat to low and continue to simmer, covered, for 10 more minutes.
9. Lastly, serve as is, or alongside rice and mixed vegetables.

How to make conch curry

• 1 lb conch (cleaned and cut into pieces)
• 1/4 teaspoon salt
• 1/4 teaspoon black pepper
• 1 1/2 tablespoon curry powder
• 1 heaping tablespoon Caribbean Green Seasoning
• 1/2 medium onion
• 2 tablespoon veg oil
• 5 cloves garlic
• 1/2 scotch bonnet pepper (adjust to your liking)
• 3 cups water (boiling)
• 2 scallions
• 1 tomato

Method

Firstly, wash and season the conch (cut into 1-inch pieces) with the salt, black pepper, Caribbean Green Seasoning, Scotch Bonnet and a bit of grated ginger (optional – not mentioned in the ingredient list).  Give it a good mix and allow it to marinate for a couple of hours in the fridge.

Heat the oil on a medium flame in a deep saucepan (one with a lid) and go in with the diced garlic and onion – turn the heat to as low as it would go and let it cook for about 3 minutes. Then add the curry powder (heat still on low). In this step, we’re toasting the curry powder to release the flavors of all the spices which make up the curry powder. Cook for about 4 minutes, so you won’t get a raw curry taste when the dish is done cooking. It will go grainy, them clump and go darker and your house will have that lovely aroma of curry! Add a bit more veg oil if you find it’s starting to burn.

It’s now time to raise the heat to high and go in with the seasoned conch and stir well. Place the lid on the pan and bring it to a boil. As it comes to a boil, reduce to a simmer, stir well and let it go for about 10 minutes. It will spring its own natural juices.

continued

Now it’s time to really infuse the conch pieces with the curry, so turn up the heat to high and cook off all that natural juice that you see in the pan (lid off). It may take about 3-5 minutes. Go until you see the oil at the bottom of the pan, then go in with the boiling water and bring it back to a boil. It’s important to use boiling water or again the conch will go tough.

Once it comes to a boil (we need patience now) reduce the heat to a gentle simmer, have the lid slightly ajar, and let that go for about 1.5 to 2 hours. Remember to stir every 10 minutes or so.

After you’ve achieved the sort of tenderness you like, taste for salt, and then turn up the heat to thicken the gravy. In most cases, you’d find that traditionally curry conch is cooked dry (no gravy). The last 5 minutes of cooking is when you’d go in with the chopped tomato and scallions to give the dish a bit of color. You can even add a bit of chopped shado Beni or cilantro if you like.

Important: In the Caribbean, we wash all meats and seafood with lime or lemon juice before seasoning/cooking, but in this case DO NOT do so. Instead, rub with a bit of plain flour and water, drain and rinse. The acid from the lime or lemon juice will cause the conch meat to go really tough and no matter how much you cook it, it will not go tender. Also, if doing this recipe according to a gluten-free diet, pay attention to the curry powder you use as some manufacturers add flour to the mix and it will not meet your gluten-free dietary needs.

The safety profile for using conch

• People who are allergic to seafood should take advice from their doctor before consuming it.

Conch Fun Facts       

• Sometimes shells are used as decoration such as in cameo making or as decorative planters.
• In Classic Maya art, conchs are used as ink and paint holders, trumpets, bugles, and hand weapons.
• Various cultures use Conch shells as shell money.
• In African-American and Afro-Caribbean cemeteries, shells of conch are placed on graves.
• Occasionally, conch shells are used as building material whether as a bulk for landfill or in place of bricks.
• In Tamil Nadu, the conch is blown to ward off evil spirits during funerals.\
• The “queen” conch is a large edible sea snail, a type of marine mollusk.
• Conchs are also native to the coasts of the Caribbean, the Florida Keys, the Bahamas, and Bermuda.
• Conchs are herbivores – they eat algae and other tiny marine plants.
• The conch’s main predators include loggerhead turtles, nurse sharks, other snail species, blue crabs, eagle rays, spiny lobsters, and other crustaceans.

Did you know?

• Male and female conchs copulate to reproduce. Mating aggregations can have hundreds or even thousands of individuals.
• Female conchs lay hundreds of thousands of tiny eggs in a sandy egg mass. The larvae emerge after 5 days and may drift on ocean currents for up to a month before settling in suitable habitat on the seafloor.
• During the first year of life, conchs live under the sand during the day and come out to feed on the surface of the sand at night.
• It may take a queen conch at least 5 years to reach maturity. At this stage in life, they have a very hard flared lip and can reproduce.
• The queen conch lives an average of 7 years but is known to live as long as 20 – 30 years.
• Conchs produce natural pearls that come in a range of hues, including white, brown, orange, and pink.
• As conchs age, their shell becomes thicker.
• Conch is listed under Appendix II in the Convention on International Trade in Endangered Species (CITES) which includes species that are not necessarily threatened with extinction but may become so if the trade is not tightly controlled.
• It is illegal to take queen conchs in the state of Florida. Commercial and recreational fishing was banned in the 1980s after conch populations became severely overfished.
• 80% of the legal internationally traded conch is consumed in the United States. The smuggling of conch meat into the U.S. is a significant challenge to conch management in The Bahamas.
• Lastly, queen conch is vulnerable to overfishing because they are relatively slow to grow, late to mature, aggregate to mate, and are easily harvested in shallow waters.

How to Eat         

• Conch meat is consumed minced, marinated, raw, and copped in various dishes such as chowder, salads, soups, fritters, pates, stew, and local recipes.
• It could be added to burgers and gumbos.
• In Jamaica, it is added to stews, soups, and curries.
• In Grenada, the Dominican Republic, and Haiti, it is consumed in spicy soup and curries.
• In Puerto Rico, the conch is marinated in lime juice, vinegar, olive oil, onions, green peppers, and garlic.
• Use it to fill empanadas.
• Delicately fried meat is used in chowders.

Precautions

• People allergic to seafood should avoid it.
• It causes allergic symptoms such as hives, itching, difficulty breathing, swelling, dizziness and abdominal pain.
• If experienced other symptoms then immediately seek for medical attention.
• It should be consumed with some safety concerns.
• Refrigerate seafood until it is ready to use.

References

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