Species Focus: Snake Eel (Ophisurus serpens)

By Paul Caiger.

The snake eel or serpent eel is a curious-looking fish found worldwide; intermittently seen on the end of fishing hooks or washed ashore after a storm. Those fishermen that have hauled one up from the depths are immediately struck by the power of the fight, but perhaps more so the gawky snout and gnarly protruding teeth. In days long gone by, seeing one of these would have conjured up thoughts of mythical nautical beasts, the kind that adorned early explorer’s maps and charts.

Snake eels are very long, slender and scale-less, with an average-sized individual reaching 1.5m, yet only around 50mm in diameter. Larger individuals have been found up to three-metres long, making this one of the largest species of all eels. The long slender jaws that are characteristic of this fish bear a striking resemblance to Gonzo. A single row of sharp, prominent teeth are present on the jaws and roof of the mouth, which could undoubtedly inflict a decent wound if handled without care, perhaps more applicable to fishermen than divers. In saying that, these eels are shy and more benign than their moray and conger cousins.

Snake eels can be found inhabiting sand and muddy areas, and are usually seen buried with only the head exposed. Only very rarely have there been reported sightings of snake eels crawling over the sand like a snake, though presumably this is more common at night. Instead of a flat tail for swimming they have a stiff, pointed tail used like an awl for burrowing into the sand. They are found on the continental shelf to 300m in depth, however, it is usually the older individuals found this far out, and juveniles are usually found in shallow harbours and estuaries. This means that the ones that most divers see, or at least their protruding heads, are at the smaller end of the spectrum.

The posterior nostrils that pierce the upper lip and open into the mouth and the large dark pores on the head-region indicate acute sensory abilities. This provides the snake eel with the capacity to ‘taste’ (smelling under water) chemical cues given off by potential prey, and the ability to sense water movement of close-passing animals. Together, this makes these burrowing snake eels a formidable predator and also points to nocturnal habits.

 Fast Facts

  1. A very large eel, can reach up to three metres in length.
  2. One of over 300 species of snake eels.
  3. Circumglobal, but in New Zealand, generally found in the north.
  4. Possess a bony, pointed tail used for burrowing into the sand.
  5. Ambush predators, they feed on crustaceans and small fishes.
  6. Acute sensory abilities, including excellent ‘taste’.
  7. Nocturnally active.