Native and feral fish distribution i l d l k d tl d f thin enclosed lakes and wetlands of the

southern Swan Coastal Plain

Mathew Hourston & Chris BirdDepartment of Fisheries W.A., 

Australia

YanchepStudy area

Perth

Enclosed water bodies

“N ti fi h”“Native fish”Finfish that naturally occur in theoccur in the water bodies of the catchments of the study area.

Busselton

Mapped perennial tl d

Perennial wetlands 2008

wetlands

Perennial wetlands 2008Look as though th t i t May have water 1019 (50%)they contain water

Look as though th t i t

Perennial wetlands 2008

they contain water May have water 1019

Likely to have water 806

(50%)

(40%)

Look as though th t i t

Perennial wetlands 2008

they contain water May have water 1019

Likely to have water 806

(50%)

(40%)

Wetlands that werei it d i th fi ld

Perennial wetlands 2008

visited in the field May have water 1019

Likely to have water 806

(50%)

(40%)

Visited in the field 366

Perennial wetlands 2008Lakes visited that

t i d t May have water 1019

Likely to have water 806

(50%)

(40%)

contained water

Visited in the field 366

Accessible lakes th t t i d t

Perennial wetlands 2008

that contained water May have water 1019

Likely to have water 806

(50%)

(40%)

Visited in the field 366

Sampled wetlands 114

Perennial wetlands 2008Accessible lakes th t t i d t May have water 1019

Likely to have water 806

(50%)

(40%)

that contained water

Visited in the field 366

Sampled wetlands 114

Fish were caughtPerennial wetlands 2008

May have water 1019

Likely to have water 806

(50%)

(40%)

Visited in the field 366

Sampled wetlands 114

Fish present 88 (77%)

Native freshwater fishPerennial wetlands 2008

May have water 1019

Likely to have water 806

(50%)

(40%)

Visited in the field 366

Sampled wetlands 114Western minnow

Swan River gobyPseudogobius olorum

23

= 32

Fish present

Native fish presentWestern pygmy perchEdelia vittata

Western minnowGalaxias occidentalis

= 23

= 10

88

50

(77%)

(44%)Edelia vittata

NightfishBostokia porosa = 8

Western hardyheadLeptatherina wallacei = 4

Black-stripe minnow 1Black stripe minnowGalaxiella nigrostriata = 1

Western pygmy perch

Western minnow

NightfishNightfish

Swan River goby

David Morgan

Western hardyhead

David M

Black-stripeminnow

Morgan

minnow

Mark Allen

Feral freshwater fishPerennial wetlands 2008

May have water 1019

Likely to have water 806

(50%)

(40%)

Visited in the field 366

Sampled wetlands 114

MosquitofishGambusia holbrooki = 72

G ldfi h Fish present

Native fish present

Feral fish present

GoldfishCarassius auratus = 10 88

50

76

(77%)

(44%)

(66%)

ONLY feral f h t fi h

Perennial wetlands 2008

freshwater fish May have water 1019

Likely to have water 806

(50%)

(40%)

Visited in the field 366

Sampled wetlands 114

Fish present

Native fish present

Feral fish present

88

50

76

(77%)

(44%)

(66%)

Only feral fish present 37 (32%)

Mosquitofish

DavidDavidMorgan

ONLY native f h t fi h

Perennial wetlands 2008

freshwater fish May have water 1019

Likely to have water 806

(50%)

(40%)

Visited in the field 366

Sampled wetlands 114

Fish present

Native fish present

Feral fish present

88

50

76

(77%)

(44%)

(66%)

Only native fish present 11 (9%)

Only feral fish present 37 (32%)

ONLY native f h t fi h

Perennial wetlands 2008

freshwater fish May have water 1019

Likely to have water 806

(50%)

(40%)

Visited in the field 366

Sampled wetlands 114

Fish present

Native fish present

Feral fish present

88

50

76

(77%)

(44%)

(66%)

Only native fish present 11 (9%)

Only feral fish present 37 (32%)

(0.5%)Native fish in mapped perennial wetlands

Take home message

Our native freshwater fish species are under threatOur native freshwater fish species are under threat from multiple aspects

Drying lakesDrying lakesFeral introductions

What is needed?

A comprehensive survey of permanent water bodiesA t f th i t ti b t f l d ti iAssessment of the interactions between feral and native speciesAssessment of the remnant native fish populations