Australian Geographic – July-August 2019

Solving an

ecological mystery

Ancient Aboriginal knowledge is helping to fill in the missing details

of epic migrations made by Australia’s freshwater eel species.

Story by Angela Heathcote

18 Australian Geographic

Navigating their way through drains

and stormwater networks can be a

game of chance.

“When they have the urge to

migrate they are determined and pretty

resilient,” says ecologist Dr Jarod Lyon

from the Victoria-based Arthur Rylah

Institute for Environmental Research,

which has carried out various studies

on Australian eel populations since the

1970s. “Historically, they’ve been able

to get past most barriers, as long as

there’s enough rain.”

There’s plenty we don’t know about

the migration of these eels. And much

of what we do know comes from

anecdotal evidence of eel fishers.

At about the age of 25 years for

longfins and 15 years for the shortfin

species, they begin to move out of the

freshwater systems where they’ve spent

most of their lives, and turn a silvery

colour. Following this transformation

they head for the ocean, but after that

it’s largely a mystery.

“We know very little about how

long it takes for them to get to their

destination,” Jarod says.

“It has been estimated to take

somewhere between six and 18 months

E

ACH AUTUMN, the adults of two
species of Australian eel – the
longfin and southern shortfin
eel (Anguilla reinhardtii and A. australis)

• prepare for an epic journey to a
  location thought to be in the Coral
  Sea between Papua New Guinea and
  New Caledonia, where they breed
  and then die.
  Starting from estuaries, dams and
  rivers along eastern Australia as well as
  ponds and wetlands in urban enclaves,
  such as Centennial Park, in Sydney, and
  Melbourne’s Royal Botanic Gardens,
  they can travel thousands of kilometres. ILLUSTRATION BY ROD SCOTT/AUSTRALIAN GEOGRAPHICSCIENTIFIC NAME:

Anguilla reinhardtii