Biology

Species	Nemadactylus macropterus
Common Name	Jackass Morwong
Importance	Minor
Habitat	Exposed sand and silt
Depth	5 – 400 m (Edgar, 2008)
Distribution	Central Queensland to southern Western Australia, around Tasmania, New Zealand, southern Africa, South America (Edgar, 2008)
Diet	Polychaetes, crustaceans, molluscs, echinoderms (Godfriaux, 1974)
Stock Structure	Existence of at least three sub-populations: Tasmania, New South Wales/Victoria, Great Australian Bight; no genetic variation in southern Australia indicates larval mixing (Grewe et al., 1994; Elliott and Ward, 1994; Richardson, 1982; Thresher et al., 1992).
M (Natural Mortality)	0.10 (New Zealand population) (Parker and Fu, 2011)
Maximum Age (years)	50 (Edgar, 2008)
Maximum Length (total length; cm)	70 (Kailola et al., 1993)
Maximum Weight (g)	2900 (Kailola et al., 1993)
Female K (von Bertalanffy growth parameter)	0.36 (Jordan, 2001a)
Male K (von Bertalanffy growth parameter)	0.42
Female t0 (age (years) when length = 0)	-0.07
Male t0 (age (years) when length = 0)	0.15
Female L∞ (asymptotic von Bertalanffy length (total length; cm))	38.4
Male L∞ (asymptotic von Bertalanffy length (total length; cm))	36.2
Size at Maturity (length (total length; cm) at sexual maturity)	25
Age at Maturity (years)	3 (Edgar, 2008)
Spawning Season	February – June
Spawning Location	At least two spawning areas: northern (probably southern New South Wales and eastern Victoria), southern (probably western and southern Tasmania) (Bruce et al., 2001a; Lyle and Ford, 1993)
Recruitment	No-stock recruitment relationship established
Early Life History	Planktonic larval stage 7 – 10 months; larvae drift ≤ 30 mm drift with current on surface ≤ 250 km east of Tasmania; settlement at 7 – 9 cm length; juveniles live near shallow reefs (Francis, 2001; Bruce et al., 2001a; Kailola et al., 1993)
Gillnet Post Release Survival	Moderate: 52% (Lyle et al., 2014)