"Lane Cove River - Fish Ladder

The weir across the Lane Cove River was constructed in 1938 to create a freshwater lake
in one of Sydney's most popular picnic spots.. Unfortunately, the construction of the weir
has contributed towards the decline of native fish; such as the Australian bass, within the
Lane Cove River.
Native fish populations have also declined as a result of water pollution;. competition with the introduced carp and habitat loss such as the removal of in-stream logs, boulders and vegetation.

The fish ladder: - "The Alternate Pathway"
The hish ladder is designed to atlow nalive tish, such as the Australian bass, to migrate throughout the Lane Cove River system. The fish ladder is a series of gradually descending shallow rocky pools, adjacent to the main river flow, connecting the water above the weir to the water below the weir.
The pools between each step of the ladder enable the Australian bass to move and rest from one level to the next level, allowing the bass to complete their natural migratory routes. Now when migrating fish reach the weir they can travel around a once impassable barrier to their chosen destination, that is if they can
escape the white-faced heron!

A blocked passage - the need for an alternate pathway.
Unless the Lane Cove River is in flood and the
weir is covered in water, bass cannot move across, the weir and go downstream to breed in the estuary. Similarly, adult and juvenile bass already downstream of the weir cannot migrate towardsvthe freshwater reaches of the upper Lane Cove River after the breeding season.
As the adult, and juvenile fish attempt to migrate, upstream they are faced with an impassable barrier upon reaching the weir. Sadly, as a result of the barrier, the majority of the smaller fish fall prey to predators.

The Lane Cove River fish ladder canbe seen as a positive step towards restoring native fish populations, particularly populations of the Australian bass.
Referenced from the signage provided by:

LANE COVE NATIONAL PARK

Lane Cove River Catchment Management Committee.

LAND & WATER CONSERVATION.

NSW FISHERIES.

Environmental Trusts.

The Fish Ladder - Enabling native species such as the "Australian Bass" to move up and down the river:
An excerpt from the river placket found not far from the Fish Ladder.

THE AUSTRALIAN BASS

Australian bass naturally inhabit coastal freshwater and estuarine river systems of south-eastern Australia. Bass favour saggy river corners and river banks strewn with logs, boulders and reeds where they feed upon insects, crustaceans, small fish and earthworms. Australian bass (Macquaria novemaculeata) live their lives within a single river system. During winter most of the
mature fish move downstream to the salt-water estuary to spawn. In the summer, the adult and juvenile bass move upstream to the freshwater reaches of the river. The fish-ladder enables the bass to complete their migratory route.

Source:. LANE COVE NATIONAL PARK"

N P

"Completely clogged intake to fish pass at the upstream end, with thousands of Bass trying to migrate upstream :(

Whatever the maintenance regime for this is, it’s not frequent enough…"

Justine Carey

""

Sasha Gerasimov