| Species | Hyporhamphus melanochir |
| Common Name | Southern Garfish |
| Importance | Key |
| Habitat | Shallow inshore water in association with seagrass beds |
| Depth | ≤ 20 m (Gomon et al., 2008) |
| Distribution | Endemic to Australia, from Eden (New South Wales) to Perth (Western Australia), including Bass Strait and Tasmania (Gomon et al., 2008) |
| Diet | Predominantly herbivorous (seagrass, algal filaments) but also consuming planktonic crustaceans, worms, diatoms and stray insects landing on the surface (Edgar, 2008; Klumpp and Nichols, 1983) |
| Stock Structure | Four genetically distinct populations distributed across Western Australia, western South Australia, eastern South Australia/Victoria, and Tasmania; likely at least two subpopulations exist in Tasmania, as indicated by different size and age characteristics on the north vs. east coasts (Grant, 1991; Jones et al., 2002) |
| Movement | Schooling fish, highly mobile, near surface at night and close to bottom during day |
| M (Natural Mortality) | High (55% for adults ≥ 4 years on the east coast) (Jones, 1990) |
| Maximum Age (years) | 9 (Jordan et al., 1998) |
| Unsexed K (von Bertalanffy growth parameter) | -0.54 (from 6 months of age) |
| Unsexed t0 (age (years) when length = 0) | 0.23 (from 6 months of age) |
| Unsexed L∞ (asymptotic von Bertalanffy length (fork length; cm)) | 34.3 (from 6 months of age) |
| (FL; fork length (cm)) – Weight (W; g) Relationship | W=0.0011L^3.4403) (Jordan et al., 1998; Hartmann and Lyle, 2011) |
| Size at Maturity (length (fork length; cm) at which 50% of population are sexually mature) | 19.9 (females), 17.1 (males) (Hartmann and Lyle, 2011) |
| Spawning Season | October – February (peak October – December) |
| Spawning Location | Concentrated in shallow (<5m) waters over beds of drift algae in eastern Tasmania |
| Additional Spawning Information | Eggs negatively buoyant, sinking to bottom after fertilisation and becoming attached to drift algae (Jordan et al., 1998) |
| Batch Fecundity (F; number of eggs) to Fork Length (FL; cm) | F=188.75L-3585.8 (Hartmann and Lyle, 2011) |
| Egg Size | 2.93 mm diameter (Jordan et al., 1998) |
| Early Life History | After estimated incubation period of one month, large hatchlings (7.8 – 8.5 mm) are assumed to stay in shallow sheltered waters as indicated by the presence of small juvenile (0+ cohort) in coastal waters of eastern Tasmania (Jordan et al., 1998) |
