Factsheet native yarra pygmy perch...88 Fishes oF the Murray-Darling Basin An introductory guide 89 identification A small, laterally compressed fish with a deeply notched single dorsal

F i s h e s o F t h e M u r r ay- Da r l i n g B a s i n 89An introductory guide88 F i s h e s o F t h e M u r r ay- Da r l i n g B a s i n 89An introductory guide8888 F i s h e s o F t h e M u r r ay- Da r l i n g B a s i n

identificationA small, laterally compressed fish with a deeply notched single dorsal fin. Maximum size 75 mm; usually less than 65 mm. The tail is slightly rounded, and the mouth is small, reaching to just below the front of the eye. The lateral line is discontinuous. The lower, free edge of preorbital bone is straight, with the edge strongly serrated (compare with Southern pygmy perch). The body colour is gold to dusky brown-grey, paler on the belly, with dark spots or blotches in a row along the midline. The pelvic fins turn black in breeding males. The black pupil of the eye forms an imperfect circle (slightly notched compared with circular in Southern pygmy perch).

Biology and habitatIn the Basin the Yarra pygmy perch is restricted to the Lake Alexandrina region in slow-flowing waters, wetland or drainage channel habitats with abundant submerged aquatic vegetation. It is found in small groups, often mixed with Southern pygmy perch.

It breeds in spring, at water temperatures between 16 and 24°C. The diet includes microcrustaceans, molluscs and aquatic insects, such as mosquito larvae.

Distribution and abundanceIn the Basin, the Yarra pygmy perch is found only in Lake Alexandrina in the lower Murray. It is also found in coastal streams in western Vic and patchily throughout southeast SA, and it is locally common within suitable habitats in Lake Alexandrina.

Potential threatsPredation by alien species such as Redfin perch and possibly Eastern gambusia may threaten the Basin populations. Habitat alteration such as loss of aquatic vegetation in irrigation channel/drain habitats or alienation of wetland habitats may also impact on the extremely localised populations of this species in the Basin.

Common name yarra pygmy perch restricted

scientific name Nannoperca obscura (Klunzinger, 1872)

natiVe sPeCies

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F i s h e s o F t h e M u r r ay- Da r l i n g B a s i n 89An introductory guide88 F i s h e s o F t h e M u r r ay- Da r l i n g B a s i n 89An introductory guide88 An introductory guide 89

general referencesAllen et al. 2002; Cadwallader & Backhouse 1983; Hammer 2002b; Higham et al. 2005; Wedderburn & Hammer 2003; Woodward & Malone 2002.

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yarra pygmy perch habitat, Finnis river

iD VALLey 1 Avoca 2 Border rivers 3 Broken 4 campaspe 5 castlereagh 6 central Murray 7 condamine 8 darling 9 goulburn 10 gwydir 11 Kiewa 12 Lachlan 13 Loddon 14 Lower Murray 15 Macquarie 16 Mitta Mitta 17 Murrumbidgee 18 namoi 19 ovens 20 Paroo 21 upper Murray 22 Warrego 23 Wimmera

Published by the Murray-Darling Basin Commission Postal address: GPO Box 409, Canberra ACT 2601 Office location: Level 3, 51 Allara Street, Canberra City ACT Telephone: (02) 6279 0100, international + 61 2 6279 0100 Facsimile: (02) 6248 8053, international + 61 2 6248 8053 Email: [email protected] Internet: http://www.mdbc.gov.au

For further information contact the Murray-Darling Basin Commission office on (02) 6279 0100

This fish fact sheet is an extract derived from the report: Lintermans, M. 2007, Fishes of the Murray-Darling Basin: An introductory guide.

MDBC Publication No. 10/07

ISBN 1 921257 20 2

© Murray-Darling Basin Commission 2007

This work is copyright. Graphical and textual information in the work (with the exception of photographs, artwork and the MDBC logo) may be stored, retrieved and reproduced in whole or in part provided the information is not sold or used for commercial benefit and its source (Fishes of the Murray-Darling Basin) is acknowledged. Such reproduction includes fair dealing for the purpose of private study, research, criticism or review as permitted under the Copyright Act 1968. Reproduction for other purposes is prohibited without the permission of the Murray-Darling Basin Commission or the individual photographers and artists with whom copyright applies.

To extent permitted by law, the copyright holders (including its employees and consultants) exclude all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this report (in part or whole) and any information or material contained in it.

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