Description

Adults: 11.3-43.2 cm TL; body proportions of pre-spawning specimens, as percentage of TL (based on 125 prespawning specimens measuring 11.3-42.1 cm TL): 8.5-11.3 prebranchial length, 7.1-9.8 branchial length, 60.4-68.3 trunk length, 14.4-20.1 tail length, 1.1-1.7 eye length and 4.9-6.6 disc length. Body proportions of spawning male specimens, as percentage of TL (based on 8 spawning males measuring 27.7-37.6 cm TL): 11.4-16.6 prebranchial length, 8.8-10.1 branchial length, 60.1-65.3 trunk length, 13.3-15.7 tail length, 8.1-11.2 disc length. Mature males with some loose skin in gular region. Urogenital papilla not prominent in mature adults; trunk myomeres, 84-96. Adult dentition: 2 triangular supraoral laminae each with 3 unicuspid teeth, 1 per apex; infraoral lamina, 7-9 unicuspid teeth of various size (these teeth become greatly enlarged with sexual maturation); 5-7 endolateral plates on either side each bearing 2-3 unicuspid teeth, usually 3; endolateral formula, typically 2-3-3-3-3-3 in immature individuals and 5-7 individual cusps on either side in mature individuals; 1 row of anterials; first row of anterials, 2 unicuspid teeth plus 1-2 bicuspid teeth or 3 unicuspid teeth flanked on either side by 1 bicuspid tooth; 1 row of exolaterals on each side; 1 row of posterials; first row of posterials, 12-14 posterial plates, the 2-4 lateralmost tricuspid and the internal ones bicuspid in immature individuals and 12-14 unicuspid teeth in mature individuals; transverse lingual lamina w-shaped, with 29 unicuspid teeth, the median one and the 2 subterminal ones slightly enlarged; longitudinal lingual laminae interrupted j-shaped, each with an undetermined number of unicuspid teeth. Velar tentacles in adults, 3-4, smooth. Body coloration (live) of immature adults brownish gray on dorsal surface and silvery on ventral surface; lateral line neuromasts darkly pigmented; caudal fin pigmentation, 25% to <75% coverage; caudal fin shape, spade-like; oral papillae, 25-45 (Ref. 89241).

Common Names

Taxonomic Hierarchy

Kingdom: Animalia

Phylum: Chordata

Class: Petromyzonti

Order: Petromyzontiformes

Family: Mordaciidae

Genus: Mordacia

Species: Mordacia mordax (Richardson, 1846)

Climate Zone

Biology

Adults inhabit the sea for an undetermined period and are parasitic on fishes; enter freshwater to breed. Majority of adulthood is spent in estuaries or at sea. Upstream spawning migrants occur in fast-flowing sections of rivers with a mud, sand or silt substrate, sometimes seen congregated below barriers to upstream movement such as weirs. Ammocoetes live in slow-flowing streams, burrowed in mud or silt. Common length is 35-40 cm (Ref. 44894). Larval life is 3.5 yrs. During the spawning migration, adults burrow in the substrate of rivers during the day and migrate upstream during the night. Fecundity, 3,789-13,372 eggs/female. De Castelnau (1872) states that the adults from the lower Yarra River, Victoria, are considered good food (Ref. 89241).

Habitat

freshwater

Conservation Status

Least Concern

Threat to Humans

Harmless