Duckbill eel

Around 45 duckbill eel species are organized by 7 genera belonging to the family of eels which have long, flat snouts that look similar to the bills of ducks and long, pointed tails. Also called witch eels, they live deep in the Indian, Pacific, and Atlantic Oceans.

Kingdom: Animalia

Phylum: Chordata

Class: Actinopterygii

Order: Anguilliformes

Family: Nettastomatidae

Genus: Various (see below)

Species: Various (see below)

Duckbill eels are brown-grey, bottom-dwelling eels that lack pectoral fins. The eels vary in size between species but reach an average of 4 feet (125 centimeters) in length. Duckbill eels eat aquatic invertebrates and small fish using their pointed, large mouths. The eels belong to seven genera—Hoplunnis, Leptocephalus, Facciolella, Nettastoma, Nettenchelys, Saurenchelys, and Venefica.

Of the Hoplunnis genus, the freckled pike-conger (Hoplunnis macrura) and spotted pike-conger (Hoplunnis tenuis) belong to a small family of eels, most of which live in deep waters. These two duckbill eels swim from 180 to 1,390 feet (55 to 420 meters) deep.

The bodies of the freckled pike-conger and spotted pike-conger have long, flattened snouts that resemble slightly the bills of ducks. Inside their large mouths are two to three rows of large, sharp teeth. Their bodies appear long, but in actuality, their bodies are short and taper into long tails. The spotted pike-conger grows to measure 1 1/2 feet (45 centimeters), while the freckled pike-conger may reach 20 inches (50 centimeters). Weights are not available for these two eels. Both eels’ single dorsal (back) fin begins near the head and pectoral fins and runs down the back. The dorsal fin meet the caudal (tail) fin, which loops around the eel’s tail, joins the anal (rear) fin on the underside of the body, and continues partway along the bottom side toward the head.

As their names suggest, these two eels have markings to help identify them. The silver body of the one pike-conger has brown freckles, while the silver body of the other pike-conger has a row of small black dots along each side of its body and several more on top of its head and snout.

The diets of these eels are not certain. Possibly, they eat crustaceans and other small organisms in the water like other species, or they may eat larger prey, since they have two or three rows of sharp, large teeth.

Predators of the pike congers are unknown, but since they are smaller eels than other species, they may fall prey to larger creatures of the deep.

Although the details of season and site are unknown in these species, reproduction is likely similar to that in other eels. Spawning occurs when the female releases many eggs into the water, and the male then fertilizes them. The adults do not care for the eggs or the young once they hatch. The newly hatched eels do not look much like eels, but rather like clear, slender willow leaves. They are called leptocephali. This stage of life is called a larval stage. The time in which the leptocephali of these species live in this stage is not certain, but in others, it is from one to two years. After this time, the leptocephali metamorphose, or change, into the adult form.

How long these two duckbill eels live is unknown.

Bibliography

"Nettastomatidae - Duckbill Eels." PBS, nhpbs.org/wild/Nettastomatidae.asp. Accessed 5 Apr. 2024.

"Species: Hoplunnis Macrura, Freckled Pikeconger, Freckled Pikeconger Eel." Smithsonian Tropical Research Institute, biogeodb.stri.si.edu/caribbean/en/thefishes/species/2900. Accessed 5 Apr. 2024.