Rehabilitating Elwood Canal and Elster Creek, Victoria:
An Assessment of Impacts on Native Freshwater Fishes
Continued
Results
Diversity, Abundance and Distribution of Fish
A total of 763 fish representing six species was recorded during this survey (Table 1). Four are freshwater species, of which two species, namely short-finned eel (Anguilla australis) and common galaxias (Galaxias maculatus) are native migratory species. These two species require free passage between freshwater and estuarine or marine habitats to complete their life cycles. Flat-headed gudgeon (Philypnodon grandiceps) is a non-migratory native species and gambusia (Gambusia holbrooki) is an introduced exotic species. The two remaining species, blue spot goby (Pseudogobius sp. 9) and yelloweyed mullet (Aldrichetta forsteri) are estuarine.
Blue spot goby was the most dominant taxa recorded making up nearly 50 % of the catch. Blue spot gobies were present at all sites on both sampling dates, except site 1 (the most upstream site) in January. Common galaxias was the second most abundant species making up 35 % of the catch and was recorded from all sites on both sampling dates, except for the estuarine reach (site 3) in January. Short-finned eels were present throughout the system, but were most abundant in the estuarine reach and made up 4 % of the total catch. Gambusia was recorded at the freshwater sites (1 and 2) in January and abundances made up 10 % of the total catch. One flat-headed gudgeon was recorded at site 2 in January and one yelloweyed mulllet was caught at site 3 in December.
Table 2. Mean total length (mm) ± standard deviation, (length range) and total number of each species caught at three sites in the lower reaches of Elster Creek catchment.
Date
Site
Method
Species
Length
Total
13 Dec 2001
1&2
Electro Fishing
Gm
49±9(35-69)n=30
121
P.sp.9
44±7(31-59)n=19
19
Aa
74n=1
3
3
Larval Net
P.sp.9
41±4(30-47)n=30
56
Gm
39n=1
1
Af
39n=1
1
21Jan 2002
1
Electro Fishing
Gm
60±10(41-81)n=30
104
Gh
33±9(14-52)n=30
73
Gm
56±9(42-75)n=30
55
P.sp.9
37±10(20-49)n=30
58
Pg
37n=1
1
Aa
-
11
Gh
29±1(28-31)n=6
6
21 Jan 2002
3
Larval Net
P.sp.9
43±13(21-66)n=30
240
Fyke Net
Aa
-
15
Abreviations denote species as: Gm, Galaxias maculatus, common galaxias; Aa, Anguilla australis, short-finned eel; P.sp.9, Pseudogobius species 9, blue spot goby species 9; Af, Aldrichetta fosteri, yelloweyed mullet; Pg, Philypnodon grandiceps, flat-headed gudgeon; Gh, Gambusia holbrooki, gambusia. Site numbers are 1: New St to St Kilda St; 2: St Kilda St to Glenhuntly Rd.; 3: upstream of Barkely St. (estuarine reach)
To Continue to Discussion - Elwood Canal Fish Biodiversity