Viviparous Blenny, Zoarces vivaparous

The viviparous blenny is also called the viviparous eelpout and lives in the cooler waters of the Northeast Atlantic; also in the Baltic, Barents, North, Irish, and White Seas. Ranging to depths of 130 ft., this species inhabits rocky shorelines, tide pools, and occasionally inlets of the English Channel. The viviparous blenny may also be found out of water under seaweed and rocks because of its ability to breathe air.

The viviparous blenny’s skin varies in color with a slimy texture and the bones have a harmless pigment giving them a green tint. The average size of this species is around 12 inches in length and weighing approximately 12 oz., although some can grow to 20 inches and weigh 18 oz.

The diet of the viviparous blenny consists of crustaceans, insects, plankton, worms, and fish larvae including un-hatched eggs from other species of fish.

Mating occurs in late summer by internal fertilization. With the longest known pregnancy of any fish, lasting 6 months or more, the viviparous blenny will birth fully developed young in the frigid water of winter.

After the egg yolk has been consumed by the embryo, it will latch onto a follicle inside the female, making this species the only one that will suckle the offspring. Each embryo will have a single follicle to feed from getting high protein nutrients which flow through this canal. At birth up to 400 young are released.

Because of the way that the pregnancy is carried out this species has been named “The Mother of Eels.” In Mediterranean countries the meat from the viviparous blenny is used as a soup ingredient.

Kingdom: Animalia

Phylum: Chordata

Class: Actinopterygii

Order: Perciformes

Family: Zoarcidae

Image Caption: Eelpout (Zoarces viviparus) from the Gulf of Gdansk, caught near Hel Marine Station. Credit: Ykvach/Wikipedia (CC BY-SA 3.0)