Hagfish are used for food, leather goods, scientific research, and increasingly as inspiration for military and medical technology. Despite their reputation as one of the ocean’s least glamorous creatures, these jawless, eel-shaped fish support a surprisingly diverse range of industries, from Korean barbecue restaurants to U.S. Navy defense labs.
Food in South Korea
The market for hagfish is almost entirely in South Korea, where they are considered a delicacy. Koreans barbecue hagfish fresh and prepare them in stir-fry dishes, often served with spicy sauce at specialty seafood restaurants. The texture is chewy and the flavor mild, somewhat comparable to squid. South Korean demand drives most of the global hagfish harvest, including significant exports from the Pacific coast of North America.
Leather and “Eel Skin” Products
If you’ve ever bought an “eel skin” wallet, phone case, or handbag, there’s a good chance it was actually made from hagfish skin. The material is commonly marketed under the more appealing name because hagfish skin shares many of the same qualities as true eel leather: it’s supple, has a distinctive texture, and takes dye well.
Structurally, hagfish skin is a multilayered composite. A thin outer layer sits above a dense middle layer packed with fibrous tissue, followed by a fatty inner layer. This construction makes the skin relatively thick and strong. Tensile testing shows it’s comparable in strength and stiffness to the skins of other elongated fish species, which helps explain why it holds up as a durable consumer product.
Military Technology Inspired by Slime
Hagfish produce a remarkable defensive slime that swells to 10,000 times its original volume when it contacts seawater. This property caught the attention of the U.S. Navy, which has been developing synthetic versions of hagfish slime for military applications.
A team at the Naval Surface Warfare Center Panama City Division created a program called Maritime Vessel Stopping Occlusion Technologies (MVSOT), designed as a non-lethal way to stop incoming boats. The concept works by deploying material that wraps around a vessel’s propeller blades. The propeller keeps spinning, but the material prevents the blades from pushing water, effectively killing the boat’s thrust. In testing, hagfish-inspired slime proved persistent and effective at clogging propellers and water intake systems. The synthetic version combines properties of hagfish slime and spider silk proteins to achieve swelling, adhesion, and strength that no existing commercial material can match.
Medical and Bioengineering Research
The biological properties of hagfish slime also make it interesting for medical research. The slime contains protein threads that are each about 60 centimeters long but only 1.5 microns wide, roughly 50 times thinner than a human hair. These threads are built from tightly bundled structural fibers arranged in parallel, giving them unusual strength for their size.
Researchers have explored hagfish slime as a natural biomaterial for tissue engineering. Because the slime is soft and biocompatible, it can serve as a three-dimensional scaffold where cells can grow and organize. Early research suggests it could help with wound healing by covering injured skin and supporting the body’s repair process. The protein structure of the slime’s threads, similar to keratin, also makes it a candidate for nerve regeneration, bone repair, and controlled drug delivery systems.
Understanding Vertebrate Evolution
Hagfish hold a unique position in evolutionary biology. As one of only two surviving lineages of jawless fish (the other being lampreys), they offer a window into what the earliest vertebrates looked like hundreds of millions of years ago. Scientists have debated for decades whether hagfish represent a very early branch of the vertebrate family tree or whether their simple body plan is the result of losing complexity over time.
A 2024 study published in Nature sequenced the genome of the brown hagfish at chromosome-level detail and helped resolve this question. The research showed that hagfish underwent extensive genomic changes after splitting from other vertebrates, including chromosomal fusions and the loss of genes essential for organ systems like eyes and bone-resorbing cells. In other words, hagfish didn’t just fail to evolve complexity. They actively lost it. This finding reshaped the scientific understanding of how vertebrate genomes evolved, including the timing of ancient whole-genome duplication events that gave rise to the genetic toolkit shared by all animals with backbones.
Hagfish also practice something called programmed DNA elimination, where they discard portions of their genome in certain cell types during development. This unusual genetic behavior makes them valuable for studying how genomes can be reorganized within a single organism’s lifetime.
Deep-Sea Ecosystem Recycling
On the ocean floor, hagfish function as nature’s cleanup crew. They are aggressive scavengers that burrow into the carcasses of dead whales, fish, and other marine animals that sink from the upper water column. By consuming and breaking down this organic material, hagfish play a critical role in recycling nutrients back into the deep-sea ecosystem. Without scavengers like hagfish, far more biomass would accumulate on the seafloor rather than re-entering the food web. Their feeding activity helps redistribute energy from surface waters to deep-sea communities that have few other nutrient sources.