Humans use cnidarians, the group that includes jellyfish, corals, sea anemones, and hydra, in a surprisingly wide range of ways. Some are ancient, like eating jellyfish and crafting coral jewelry. Others are cutting-edge, like extracting glowing proteins for cancer research or converting coral skeletons into bone graft material for surgery. Here’s a breakdown of the major uses.
Food: Jellyfish as a Protein Source
Chinese cultures have eaten jellyfish since ancient times, typically serving the cooked umbrella (bell) in salads. That tradition has spread to Malaysia, Thailand, and Japan, and today China, Japan, and South Korea remain the largest markets for jellyfish products. Only certain species from the order Rhizostomae are considered edible, including species like cannonball jellyfish, which is about 95% water and 4 to 5% protein with very few calories.
Commercial jellyfish fishing now happens well beyond Asia. One of Georgia’s top three fisheries harvests jellyfish specifically for export to Asian markets. In Australia, researchers have tested marinated, semi-dried jellyfish products made from a local species and found acceptable results in taste panels. As jellyfish populations boom in warming oceans, interest in turning them into food is growing in regions that have never traditionally eaten them.
A Glowing Protein That Transformed Biology
One of the most consequential things humans have ever taken from a cnidarian is Green Fluorescent Protein, or GFP, originally found in the crystal jellyfish. Scientists cloned the gene responsible for this glow and learned to insert it into the DNA of other organisms, essentially creating a biological highlighter. When researchers attach the GFP gene to a specific protein or cell type, those cells glow green under certain light, making invisible biological processes visible in real time.
The applications are enormous. GFP and its engineered variants can illuminate growing cancer tumors, track the development of Alzheimer’s disease in brain tissue, and detect arsenic traces in drinking water. The technique is now standard across microbiology, biotechnology, physiology, and environmental engineering. What started as curiosity about why a jellyfish glows became one of the most widely used tools in modern cell biology, earning its discoverers the 2008 Nobel Prize in Chemistry.
Coral Skeletons in Bone Surgery
Coral skeletons are made of calcium carbonate, which can be chemically converted into hydroxyapatite, the same mineral that makes up human bone. The conversion process preserves the coral’s natural porous structure, which is important because those tiny interconnected pores mimic the architecture of real bone and allow blood vessels and bone cells to grow into the material.
Coral-derived hydroxyapatite acts as a scaffold. It supports the attachment and growth of stem cells and bone-building cells, encouraging the body to replace the implant with its own bone tissue over time. It has been used successfully in craniofacial reconstruction, dental procedures like pre-implant bone augmentation, orthopedic repairs for wrist fractures, and treatment of jaw injuries. Clinical trials have compared coral-derived material against standard synthetic bone substitutes and found it to be a viable alternative, produced through relatively simple and cost-effective chemical methods.
Drug Development From Venom
Sea anemones and other cnidarians produce venom loaded with peptides, small protein fragments that interact with ion channels in nerve and muscle cells. These peptides are valuable to pharmaceutical researchers because they can block or modify very specific channels with high precision.
The most advanced example is a peptide originally isolated from a Caribbean sea anemone. Called dalazatide (derived from the toxin ShK), it selectively blocks a potassium channel involved in autoimmune responses and has reached the pharmaceutical market. Researchers have also identified promising peptides from zoanthid corals that block the same type of potassium channel through a different mechanism, potentially offering new routes to treating neurological and autoimmune diseases. Sea anemone toxins have even shown structural similarities to scorpion toxins, an example of how evolution arrived at the same molecular solution in completely unrelated animals.
Hydra and Aging Research
Hydra, a tiny freshwater cnidarian, is one of the few animals that shows no detectable signs of aging. Certain strains maintain themselves indefinitely by continuously dividing their stem cells, with epithelial cells replacing themselves roughly every three to four days and interstitial stem cells dividing every day and a half. Old cells are simply pushed to the ends of the body and shed, keeping the organism in a permanent state of renewal.
This makes hydra a powerful model organism for studying why most animals age and lose the ability to regenerate. Researchers use hydra to investigate the epigenetic mechanisms behind regeneration, looking for differences between organisms that can rebuild themselves and those that cannot. Understanding how hydra maintains its stem cell populations without decline could eventually inform human approaches to tissue repair and age-related disease.
Coral Reef Tourism
Coral reefs generate enormous economic value through tourism. Roughly 30% of the world’s reefs contribute to the tourism sector, with a combined value estimated at nearly $36 billion per year. That figure represents over 9% of all coastal tourism revenue in reef countries. Snorkeling, diving, glass-bottom boat tours, and the simple appeal of white sand beaches (which are largely made of broken-down coral) drive local economies across the Caribbean, Southeast Asia, Australia, and the Pacific Islands.
Coastal Protection
Coral reefs also serve as natural sea walls. Meta-analyses of wave energy data show that coral reefs reduce incoming wave energy by an average of 97%, a figure that holds consistently from small everyday waves all the way through hurricane-level swells. The reef crest, the shallowest part where waves first break, does the heaviest lifting by dissipating about 86% of wave energy on its own. The shallower reef flat behind it absorbs another 65% of whatever energy remains.
For coastal communities, this means reefs function as infrastructure. They reduce flooding, slow erosion, and buffer storm surges. Losing reef structure to bleaching or physical damage directly increases the wave energy reaching shorelines, raising the cost of engineered alternatives like concrete breakwaters.
Jewelry and Decorative Use
Precious coral has been harvested for personal adornment for more than two thousand years. The original and most famous species, red coral, occurs mainly in the Mediterranean Sea and along the nearby Atlantic coast, with other red coral species found in the central and western Pacific. The value of a piece depends on color and size. White and rose-tinted varieties are the most prized, followed by bright red. Red coral beads today serve three principal markets: fashion jewelry, ethnic and traditional jewelry, and tourist souvenirs. Most harvesting historically concentrated along the coasts of Algeria, Italy, Spain, and Tunisia.
Collagen for Skincare
Jellyfish are being explored as a source of collagen for the cosmetics industry. Jellyfish collagen consists primarily of Types I and II, though some species produce Types III, IV, and V as well. The composition is different enough from mammalian collagen that some researchers have proposed classifying it as a distinct category called “Type 0.”
What makes jellyfish collagen appealing for skincare is that its peptides can be broken down into small molecular weights capable of penetrating the skin. Early research suggests these peptides have moisturizing properties and may help protect against oxidative stress and UV radiation damage. The cosmetics applications are still in relatively early stages compared to food or biomedical uses, but jellyfish collagen offers an alternative to bovine or porcine collagen for consumers who want non-mammalian ingredients.