Mola ramsayi Click to enlarge image
New South Wales Fisheries Officer Glen Staples with a 1.7m long Southern Ocean Sunfish. The fish was found washed up on the rock platform near the southern entry to Sussex Inlet, New South Wales, August 2003. It was approximately 190cm from dorsal to anal fin tips and an estimated weight of 750kg. Tissues from this fish are registered in the Australian Museum Fish Collection (AMS I. 42801). Image: NSW fisheries, Schoalhaven office
© NSW fisheries, Schoalhaven office

Fast Facts

  • Classification
    Species
    alexandrini
    Genus
    Mola
    Family
    Molidae
    Order
    Tetraodontiformes
    Class
    Actinopterygii
    Subphylum
    Vertebrata
    Phylum
    Chordata
    Kingdom
    Animalia
  • Size Range
    The species grows to 3.3 m in length.

Introduction

The Southern Ocean Sunfish is a huge round-bodied fish that is sometimes seen 'basking' on the water surface in southern Australian waters. Until recently it was called Mola ramsayi.



Identification

The Southern Ocean Sunfish is a deep bodied species with high dorsal and anal fins placed posteriorly on the body. It has a small mouth with teeth fused into a parrot-like beak. The skin is leathery with rough denticles. Large fish have a ridge above and behind the eyes.

This fish is brown to grey above often with pale blotches, and paler below. After death it becomes white.

Five species of sunfish are found in Australian waters, the Southern Ocean Sunfish, Ocean Sunfish, Mola mola, Hoodwinker Sunfish, Mola tecta, Slender Sunfish, Ranzania laevis, and the Point-tailed Sunfish, Masturus lanceolatus. Mola alexandrini.has a large bump on the head and chin, Mola mola has a distinctly scalloped clavus and Mola tecta has a rounded clavus with a medial indentation.



Distribution

It occurs in oceanic waters of the South Pacific Ocean.

In Australia it is found in temperate marine waters from northern New South Wales, around the south of the country, including Tasmania, to south-western Western Australia.

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



References

  1. Glover, C.J.M. in Gomon, M.F., Glover, C.J.M. & R.H. Kuiter (Eds). 1994. The Fishes of Australia's South Coast. State Print, Adelaide. Pp. 992.
  2. Hutchins, B. & R. Swainston. 1986. Sea Fishes of Southern Australia. Complete Field Guide for Anglers and Divers. Swainston Publishing. Pp. 180.
  3. Hutchins, B. & M. Thompson. 1983. The Marine and Estuarine Fishes of South-western Australia. Western Australian Museum. Pp. 103.
  4. Last, P.R., E.O.G. Scott & F.H. Talbot. 1983. Fishes of Tasmania. Tasmanian Fisheries Development Authority. Pp. 563.
  5. Sawai, E. et al., 2017. Redescription of the bump-head sunfish Mola alexandrini (Ranzani 1839), senior synonym of Mola ramsayi (Giglioli 1883), with designation of a neotype for Mola mola (Linnaeus 1758) (Tetraodontiformes: Molidae). Ichthyol. Res. - Online DOI 10.1007/s10228-017-0603-6.
  6. Thys, T.M. et al. 2013. First record of the southern ocean sunfish, Mola ramsayi, in the Galapagos Marine Reserve. Marine Biodiversity Records. DOI:10.1017/S175526723000377. Vol 6.