Eastern Red Scorpionfish, Scorpaena jacksoniensis Steindachner 1866

Introduction

The Eastern Red Scorpionfish is very common in shallow coastal waters around Sydney. The fish is commonly seen by divers as it lies motionless on the bottom, usually moving only when disturbed.

For many years, this species was called Scorpaena cardinalis. The 2011 paper by Motomura et al (see below), showed that the correct name for the species is S. jacksoniensis and that S. cardinalis occurs in New Zealand waters and around the offshore islands of the Tasman Sea.

Identification

Many scorpionfishes have cryptic colouration. This is is an advantage for predatory fishes like the Red Rockcod that often lie motionless on the bottom. Although the Eastern Red Scorpionfish is often bright red, its colouration is highly variable, ranging from light grey to bright red with blotches. The chest usually has small dark spots.There are skin flaps on the head, lateral line and other parts of the body. These help to disguise the shape of the fish.

Two species of Scorpaena occur in New South Wales waters, the Eastern Red Scorpionfish and the Southern Red Scorpionfish (S. papillosa). They can be separated by a number of characters. The Eastern Red Scorpionfish is usually bright red. Although its body coloration is quite variable, the Southern Red Scorpionfish is never bright red. It is usually darker, often brown or black, sometimes reddish-brown. The Eastern Red Scorpionfish is a large fish that grows to over 40 cm in standard length, whereas the Southern Red Scorpionfish grows to less than 20 cm. The number of dorsal fin rays differs (9 in S. jacksoniensis and 10-11 in S. papillosa).

Habitat

Scorpionfishes can be found in marine, estuarine and even fresh waters. Some species, such as the Idiotfishes (subfamily Sebastalobinae) are found on the deep ocean floor down to 2200 m. Others, like those in the subfamily Setarchinae, swim in the oceanic midwaters. Most species, however, live in coral or rocky reefs.

The Eastern Red Scorpionfish is often found with sponges and in rocky areas covered with algae.

Distribution

The Eastern Red Scorpionfish is found in temperate waters of eastern Australia, ranging from southern Queensland to eastern Victoria.

The species has never been found outside the Australian mainland (pers. comm. H. Motomura). The similar-looking Scorpaena cardinalis (previously known as S. cookii) occurs at Lord Howe Island (and New Zealand).

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

The Eastern Red Scorpionfish is a predatory fish with a big mouth. It often lies motionless on the bottom waiting for passing prey of small fishes and invertebrates. The species swallows its prey whole, so within reason, the bigger the mouth, the larger the prey item that can be consumed.

Other behaviours and adaptations

Scorpionfishes at all characterised by a bony strut (the suborbital stay) running below the eye. In genera such as Helecolenus this is not much more than a smooth ridge, whereas in others, the Eastern Red Scorpionfish included, the suborbital stay is produced into a raised row of spines. The function is unclear, but may help to protect the eyes.

Danger to humans

The twelve dorsal spines of the Eastern Red Scorpionfish are toxic. A sting from this fish can be excruciatingly painful, and last for half a day. The poison is denatured by heat so immersing the affected area in very hot water is the best first aid before consulting a doctor.

References

1. Eschmeyer, W.N. in Paxton, J.R. & W.N. Eschmeyer (Eds). 1994. Encyclopedia of Fishes. Sydney: New South Wales University Press; San Diego: Academic Press [1995]. Pp. 240.
2. Kuiter, R.H. 1993. Coastal Fishes of South-Eastern Australia. Crawford House Press. Pp. 437.
3. Kuiter, R.H. 1996. Guide to Sea Fishes of Australia. New Holland. Pp. 433.
4. Edmonds, C. 1978. Dangerous Marine Animals of the Indo-Pacific Region, (Diving Centre Monograph on identification first aid and medical treatment). 2nd reprint. Wedneil Publications. Pp. 235.
5. Motomura, H., Struthers, C.D., McGrouther, M.A. & A.L. Stewart. 2011.Validity of Scorpaena jacksoniensis and a redescription of S. cardinalis, a senior synonym of S. cookii (Scorpaeniformes: Scorpaenidae).Ichthyological Research. 58:315–332.
6. Paxton, J.R., D.F. Hoese, G.R. Allen & J.E. Hanley. 1989. Zoological Catalogue of Australia Vol.7 Pisces Petromyzontidae to Carangidae. Canberra: Australian Biological Resources Survey. pp. i-xii, 1-665.
7. Pollard, D.A & P. Parker in McDowall, R.M. 1996. Freshwater Fishes of South-eastern Australia. Reed Books. Pp. 247.
8. Poss, S.G. 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.