Oarfish, Regalecus glesne
It was initially assumed that the damage towards the tail of the fish resulted from an encounter with a boat propeller. This was not the case. Photo © D. Miller. Image: Duke Miller
Duke Miller

Fast Facts

  • Classification
    Species
    glesne
    Genus
    Regalecus
    Family
    Regalecidae
    Order
    Lampridiformes
    Class
    Actinopterygii
    Subphylum
    Vertebrata
    Phylum
    Chordata
    Kingdom
    Animalia
  • Size Range
    The Oarfish is reported to be the longest of all fishes. It has a ribbon-like body that has been reliably documented to grow to 8 m in length, however specimens up to 17 m in length have been reported.

Introduction

In days past, it was believed that a swimming oarfish would 'row' with its pelvic fins in a circular motion, hence the common name. Unfortunately folk tales aren't always true. The strange pelvic fins are now believed to be used for taste perception not locomotion.

Identification

It is metallic silver with blotches and wavy markings on the body, and pink or red fins.

This species has a concave head profile and a highly protrusible mouth (a characteristic of the order Lampridiformes). It has a dorsal fin that runs the entire length of the body, but lacks an anal fin. There are tiny spines projecting laterally off each caudal and pelvic fin ray.

Although several species of oarfishes have been described, there is now believed to be only one species.

Giant oarfish Regalecus glesne in the Gulf of Mexico (M. C. Benfield et al) from Breaking Science News on Vimeo.

Habitat

It is thought to live at depths between 20 m and 200 m.

Distribution

The Oarfish is found worldwide in all tropical and temperate marine waters.

The map below shows the Australian distribution of the species based on public sightings and specimens in Australian Museums. Source: Atlas of Living Australia.



Feeding and diet

All verified cases of stomach contents consisted of krill (euphausiid shrimps). Reports that the species feeds on invertebrates and fishes are yet to be validated.

Economic impacts

People most often see Oarfish washed up on beaches. Encounters with live Oarfish are rare. They are sometimes seen on the surface, and this may contribute to tales of sea serpents.

References

  • Glover, C.J.M. in Gomon, M.F, J.C.M. Glover & R.H. Kuiter (Eds). 1994. The Fishes of Australia's South Coast. State Print, Adelaide. Pp. 992.
  • Olney, J.E., Paxton, J.R. & W.N. Eschmeyer (Eds). 1994. Encyclopedia of Fishes. Sydney: New South Wales University Press; San Diego: Academic Press [1995]. Pp. 240.
  • Roberts, T., 2012. Systematics, Biology, and Distribution of the Species of the Oceanic Oarfish Genus Regalecus (Teleostei, Lampridiformes, Regalecidae) Pp. 268.