By Wayne Koster
18 December 2013
Why I really like this species – I like the smell of cucumbers, nah just kidding. I really like the Australian grayling because they can be such an elusive fish and their ecology has long puzzled researchers, starting with the work of Allport and Saville-Kent way back in the late 1800′s.
The Australian grayling is a nationally threatened amphidromous fish species that inhabits coastal streams in south-eastern Australia (Crook et al 2006). The species has a strong cucumber odour and grows to a length of about 300 mm.
The New Zealand grayling (Prototroctes oxyrhynchus), the only other member of the genus, appears to be extinct (McDowall 1976). For many years, the spawning and movement behaviours of adult Australian grayling remained a mystery. However, recent research using novel approaches (egg/larval surveys combined with acoustic telemetry) has provided some important insights. In particular, adult Australian grayling have been shown to undertake large (e.g. 30 km) downstream spawning migrations to the lower reaches of rivers in autumn coinciding with increases in river flow (Koster et al. 2013). This downstream spawning migration strategy appears to be relatively rare among the amphidromous fishes. Interestingly, following downstream migration, adult Australian grayling also tend to migrate back upstream to the same area they previously occupied. The Australian grayling can be a difficult-to-find species at times. In smaller, clear rivers a useful technique, especially on sunny days, can be to walk or drive along the river bank and polaroid for schools of fish. The Australian grayling sometimes displays surface activity, especially in the early morning, which can also be a useful technique for locating fish. The migratory behaviours of juvenile Australian grayling, including the importance of river flow as an upstream migration cue, are poorly understood and is an important area for future research. The Australian grayling is a delicate species and does not tolerate handling well.
Allport, M. (1870). No title. Monthly Notices of Papers and Proceedings of the Royal Society of Tasmania for 1869 6.
Crook, D. A., Macdonald, J. I., O’Connor, J. P. and Barry, B. (2006). Use of otolith chemistry to examine patterns of diadromy in the threatened Australian grayling Prototroctes maraena. Journal of Fish Biology 69, 1330–1344.
Koster, W.M., Dawson, D.R. and Crook, D.A. (2013). Downstream spawning migration by the amphidromous Australian grayling (Prototroctes maraena) in a coastal river in south-eastern Australia. Marine and Freshwater Research 64, 31–41.
McDowall, R.M. (1976). Fishes of the family Prototroctidae (Salmoniformes). Marine and Freshwater Research 27, 641–659.
Saville-Kent, W. (1885). Fisheries Department. Report for the year terminating 31st July, 1885. Tasmanian Parliamentary Paper No. 90.