Banded Morwong Biology

Biology

Banded Morwong is a large, sedentary fish that inhabits temperate reefs around south-eastern Australia and New Zealand (Gomon et al 1994). In Australia, the species distribution extends from Sydney, through Victorian and Tasmanian waters, to eastern South Australia. The species has occasionally been observed in Western Australia. Banded Morwong are long-lived, and can reach ages of at least 97 years Ewing et al. 2007). While longevity is similar among sexes, the species displays strong sexual dimorphism in growth, with males growing substantially faster and reaching larger maximum sizes than females (Ziegler et al. 2007a).

The stock structure of Banded Morwong in Australian waters is presently undefined, however observations of a long pelagic larval stage (around 6 months; Wolf 1998) suggests that single genetic stocks may occur over large areas. After settlement, fish are relatively sedentary, with tagging studies indicating little exchange among reefs (Murphy and Lyle 1999).

ParametersEstimatesSources
HabitatRocky reefs down to 50 m depth. Females and juveniles inhabit the shallow section of the reef while males dominate in the deeper section of the reef.McCormick (1989a, b)
DistributionSouth Sydney (New South Wales) through Victoria and Tasmania to eastern South Australia, also in New Zealand.Gomon et al. (1994)
DietInvertebrates, algae, crabsMcCormick (1998)
Movement and Stock StructureLimited movement of juveniles and adults, generally restricted to within 5 km of the release site.
No information on the stock structure.
Murphy and Lyle
(1999);
Ziegler et al. (2006);
Buxton et al. (2010)
Natural MortalityLow. Estimated at M = 0.05.Murphy and Lyle
(1999)
Maximum AgeFemales: 94 years
Males: 97 years
Ewing et al. (2007)
GrowthMales grow to larger sizes than females.
Growth described by the Schnute and Richards (1990
growth function:
𝐿 = 𝐿∞(1+ 𝛼𝑒(βˆ’π‘Žπ‘‘π‘))βˆ’1𝑏
where L is the length (mm), t is the age (years), 𝐿∞ is the average maximum length for the species and α, a, b and c are (year-specific) constants.
Parameters estimates (for 2007) are:
Sex________ π‘³βˆž____a_______ b_________c_______Ξ±
Female____442_____18.8____3.3e-7_____0.05___51.4
Males_____516______2.3_____0.0088____0.33___0.1
Length-weight relationship for 2007 was estimated at π‘Š = 3.563πΈβˆ’5𝐿2.875 for females and π‘Š = 3.729πΈβˆ’5𝐿2.852
for males, where W is weight (g) and L is the fork length (cm).
Schnute and Richards
(1990);
Ziegler et al. (2007a)
MaturitySize-at-50% maturity estimated at 320 mm for females (~2.5 years of age).Ziegler et al. (2007a)
SpawningSpawning occurs between mid February to late May.
Species is a serial spawner.
Murphy and Lyle
(1999)
Early Life HistoryEggs and larvae are concentrated on the surface.
Banded Morwong has a pelagic larval stage that is
distributed offshore, as suggested by the large amounts
of larvae caught off the shelf break of eastern Tasmania.
Juveniles appear in shallow water on rocky reefs and
tide-pools between September and December, after a
pelagic phase of 4-6 months.
B. Bruce, pers. comm.
Wolf (1998)
Gillnet Post Release SurvivalHigh: 97% irrespective of gillnet soak durationLyle et al. (2014a)