Freshwater mullet are one of the species that are the focus of the Mary River Threatened Species Recovery Plan. They are in decline, though the Mary is one place they still occur. Presentation given at the April MRCCC meeting.

1. Mullet movement in
the Mary catchment
• Recap on the mullet species
• Where are they in the freshwater?
• What affects their movement?
– Case study of the Mary River Barrage fish
passage upgrade

2. Mullets of the Mary
Species River Estuary Coastal
Freshwater mullet Myxus
petardi
√ √ √
Sea mullet Mugil cephalus √ √ √
Flat-tail mullet Liza argentea Likely (young only) √ √
Green-backed mullet Liza
subviridis
Likely (young only) √ √
Sand mullet Myxus elongatus Likely (young only) √ √
Fantail mullet Valamugil georgii Likely (young only) √ √

3. Sea mullet
• Snout short and rounded
• Andipose eyelid present
• Silvery bluish dorsal
colour
• Axillary process at top of
pectoral fin
Freshwater mullet
• Snout pointed and longer
than eye diameter
• No eyelid
• Olive green dorsal colour
• No axillary process at top
of pectoral fin
Axillary processEyelid

4. Where are
they?
Official mullet records
Conondale
Gympie
Maryborough

5. Mullet movement in the Mary
• Both Sea Mullet and Freshwater Mullet
migrate out of the freshwater to breed
– Sea Mullet in winter
– Freshwater Mullet in summer to autumn
• Both return to freshwater as juveniles
• Barriers effect their ability to move, breed
and survive
• The freshwater mullet are most vulnerable

6. Case study of improved fish
passage
• Mary River Barrage
– built 1982
– 59.2 km upstream of
Maryborough
• Fishway upgrade 2001
- was pool and weir design
- converted to vertical slot fishway
-Study by A.P Berghuis and S.A Piltz (2002-2003)

7. BEFORE
AFTER

10. Improved fish passage
• Improved design:
– Increased daily passage of fish by 97%
– Species increased from 8 (~12) to 32
– Freshwater mullet were recorded using the new
design
Maximum number of fish successfully
migrating upstream in one day?
50, 895!

11. Selection of species observed
Species Successfully
Migrating up
Size Range
Sea Mullet 2,694 21-473 mm
Freshwater Mullet 55 300-510 mm
Bony herring (bony bream) 17,321 16-362 mm
Blue catfish 6,729 57-625 mm
Estuary Perchlet 922 17-84 mm
Long-finned eel 120 330-1300 mm
Yellow-finned bream 44 53-379 mm
Australian Bass 18 222-428 mm
Barramundi 9 97-216 mm
56 sampling days, based on large fish trip only

12. Remaining infrastructure without
effective fish passage devices
• Tallegalla Weir
• Imbil Weir
• Borumba dam
• Baroon Pocket dam
• Cedar Pocket dam
• Gympie Weir Fish ladder on Tallegalla Weir
– ineffective for native fish,
including
Freshwater mullet
Photo: Stephen Howell