Mary River Cod, Maccullochella mariensis (Rowland 1993)

Other Names: East Coast Cod

Summary:

This large cod is one of Australia's most endangered freshwater fishes. Although the species reached 40 kg and 120 cm in the past, fish larger than 5 kg and 70 cm are now uncommon.

Identifying features:
Golden-yellow to dark greenish or brown above with dark green to blackish reticulated mottling, whitish below;
Soft dorsal, anal and caudal fins with thin white margins, pelvic fins relatively long;
Head profile concave, protruding lower jaw, mouth large, extending beyond eye;
Caudal peduncle relatively deep and short.

Video of a Mary River Cod in an aquarium.

Cite this page as:

Gomon, M.F. & Bray, D.J. 2023, Maccullochella mariensis in Fishes of Australia, accessed 20 Apr 2024, https://fishesofaustralia.net.au/home/species/3000

Mary River Cod, Maccullochella mariensis (Rowland 1993)

More Info

Distribution	Endemic to the Mary River catchment in south-eastern Queensland. The species has been stocked in impoundments in SE Qld for recreational angling since 1983 - upstream of the walls of Cressbrook, Hinze, Maroon, Moogerah, North Pine, Somerset and Wivenhoe Dams and lakes Dyer (Bill Gunn dam) and Clarendon. The Mary River Cod occurs in freshwater habitats ranging from high gradient rocky upland streams to large, lowland slow-flowing pools. Individuals in lowland areas prefer deep, shaded habitats with mud/clay substrates and woody debris. Upland populations prefer areas of low flow with undercut banks rocky ledges, boulders and woody debris such as submerged logs and snags. The species is now estimated to occur in less than 30% of its historic range in the Mary River System.
Features	Meristic features: Dorsal-fin spines/rays XI, 15; Anal-fin spines/rays III, 13; Pectoral-fin rays 18-20; Caudal-fin rays 16-18; Pelvic-fin spines/rays I, 5; Lateral line scales: 65-80. Body deep, elongate, rather stout and slightly compressed; head broad, depressed, width 47.8-64.6% HL; snout rounded; eye medium-sized, 10.0-13.8% HL, dorso-lateral; dorsal profile weakly convex from nape to caudal peduncle; slope of head concave above eye; mouth terminal, large, gape extending to beyond eye; jaws equal; lower jaw protruding slightly in large specimens; jaws, vomer and palatines with irregular rows of villiform, recurved teeth; operculum with fleshy margin and two spines, lower larger and more distinct. Body covered by small scales, mostly ctenoid, some cycloid; cheeks and opercula scaled; snout without scales; lateral line follows dorsal profile, extends on to base of caudal fin; scale rows below lateral line 30-34. Single dorsal fin consisting of a low anterior spiny portion and a higher posterior soft portion, partially separated by a notch, spines strong; anal fin rounded and opposite soft part of dorsal fin, with 3 stout spines; pectoral fins large, rounded; upper rays longer than lower rays; ventral fins inserted in front of pectoral fins, with first ray elongated into two filaments; caudal fin large, rounded.
Size	Known to reach 23.5 kg and historically up to almost 40 kg and 120 cm, but now mostly less than 70 cm TL and 5 kg.
Colour	Colour varies from golden-yellow to dark green to dark brown dorsally with dark green to black mottling extending over the grey or whitish ventral surface. Dorsal pectoral, caudal and anal fins clear to dark with mottling on bases. Soft dorsal, anal and caudal fins with thin whitish margins.
Feeding	Carnivore - feeds on a variety of prey including other fishes, spiny freshwater crayfish, yabbies, shrimp, freshwater mussels, frogs, small reptiles. Large individuals feed mostly on other fishes, while juveniles usually prey on crustaceans such as yabbies and shrimp. Larvae consume zooplankton and aquatic insects, especially chironomid larvae.
Biology	Spawns in spring when water temperatures are higher than 20ºC. Females deposit large (3-3.5 mm diameter), adhesive eggs onto hard surfaces such as submerged logs, rocks or clay banks. Larvae hatch after 4 days at 5-7 mm TL with a large yolk sac. During incubation, males guard the eggs, and then guard the larvae for 7-10 days after hatching. Larvae feed on zooplankton and aquatic insects.
Fisheries	The Mary River Cod is a NO TAKE SPECIES if captured outside of the following Queensland stock impoundments - upstream of the walls of Cressbrook, Hinze, Maroon, Moogerah, North Pine, Somerset and Wivenhoe Dams and lakes Dyer (Bill Gunn dam) and Clarendon. Bag limits: One fish with a minimum size - of 50 cm from listed stocked impoundments only. Fish that are caught accidentally should immediately and carefully be returned to the water.
Conservation	EPBC Act 1999 : Endangered IUCN Red List : Not Evaluated The Mary River Cod Research and Recovery Plan (Simpson & Jackson 1996) Reasons for the decline in Mary River Cod populations inlcude the to loss of riparain vegetation and the de-snagging of waterways.
Remarks	Originally described as a subspecies, this fish is now regarded as a species in its own right. Historically, Mary River Cod were found in the Mary, Brisbane-Stanley, Albert-Logan and Coomera River systems (Wager and Jackson 1993). Cod are now very rare or extinct in all but the Mary system.
Similar Species	The Mary River Cod differs externally from the Murray Cod in having a deeper, shorter caudal peduncle, and longer pelvic fins. Murray Cod also grow to a much larger size. The Clarence River Cod differs in having a less deep caudal peduncle, shorter postorbital head length, larger eye, smaller interorbital width, more scale rows behind the lateral line, and longer fifth and sixth dorsal-fin spines.
Species Citation	Maccullochella peelii mariensis Rowland, 1993, Rec. Aust. Mus. 45(2): 132, Fig. 4. Type locality: Bungawatta Station, Tinana Creek, 25°48'S, 152°42'E, Queensland, Australia.
Author	Gomon, M.F. & Bray, D.J. 2023

Mary River Cod, Maccullochella mariensis (Rowland 1993)

References

Allen, G.R., Midgley, S.H. & Allen, M. (2002). Field Guide to the Freshwater Fishes of Australia. Western Australian Museum, Perth, Western Australia

Anonymous (2004) Advice to the Minister for the Environment and Heritage from the Threatened Species Scientific Committee (TSSC) on Amendments to the list of Threatened Species [pertaining to Murray cod] under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). Department of Environment and Heritage (DEH). Online at: http://www.deh.gov.au/biodiversity/threatened/species/m-peelii-peelii.html

Curtis, L.K., A.J. Dennis, K.R. MacDonald, P.M. Kyne S.J.S. Debus. 2012. Queensland's Threatened Animals. CSIRO Publishing : 472 pp.

Harris, J.H. & S.J. Rowland (1996). Family Percichthyidae - Australian freshwater cods and basses. Pp. 150-163. In: McDowall, R.M. (ed.) Freshwater Fishes of South-eastern Australia. Chatswood, Sydney: Reed Books.

Mayne, B., Espinoza, T., Roberts, D., Butler, G.L., Brooks, S., Korbie, D., & Jarman, S. 2021. Nonlethal age estimation of three threatened fish species using DNA methylation: Australian lungfish, Murray cod and Mary River cod. Molecular Ecology Resources 21(7): 2324-2332. https://doi.org/10.1111/1755-0998.13440

Nock C.J., Elphinstone M.S., Rowland S.J. & Baverstock, P.R. 2010. Phylogenetics and revised taxonomy of the Australian freshwater cod genus, Maccullochella (Percichthyidae). Marine and Freshwater Research 61: 980–991.

Prokop, F. 1991. The story of our eastern freshwater cod. Freshwater Fishing Australia 14 (Autumn 1991) : 62-68.

Pusey, B.J, A.H. Arthington & M.G. Read. 1993. Spatial and temporal variation in fish assemblage structure in the Mary River, south-eastern Queensland: the influence of habitat structure. Environmental Biology of Fishes 37(4): 355-381.

Pusey B., Kennard M. & Arthington A. 2004 Freshwater Fishes of North-Eastern Australia. CSIRO Publishing Collingwood, Victoria. 684 pp.

Rowland, S.J. 1985. Aspects of the biology and artificial breeding of the Murray cod, Maccullochella peelii and the Eastern Freshwater Cod, M. ikei sp. nov. Ph.D. Thesis. Macquarie University, Ryde, NSW.

Rowland, S.J. 1993. Maccullochella ikei, an endangered species of freshwater cod (Pisces: Percichthyidae) from the Clarence River system, NSW and M. peelii mariensis, a new subspecies from the Mary River system, Qld. Records of the Australian Museum 45(2): 121–145. PDF

Simpson, R. 1994. An investigation into the habitat preferences and population status of the endangered Mary River Cod (Maccullochella peelii mariensis) in the Mary River System, south-eastern Queensland. Dept Primary Industries, Brisbane.

Simpson, R.R. & Mapleston, R.J. 2002. Movements and habitat use by the endangered Australian freshwater Mary River cod, Maccullochella peelii mariensis. Environmental Biology of Fishes 65: 401–410.

Wyville Thomson, C. 1880. Report on the Scientific Results of the Voyage of H.M.S. Challenger - Zoology - Volume I. Her Majesty's Stationery Office, London. (as Oligorus macquariensis)