Vol. 17: 169–178, 2012 ENDANGERED SPECIES RESEARCH Published online May 23 doi: 10.3354/esr00414 Endang Species Res Contribution to the Theme Section ‘Endangered river fish: threats and conservation options’ OPENPEN ACCESSCCESS Conservation biology and management of the endangered Oxleyan pygmy perch Nannoperca oxleyana in Australia James T. Knight1,*, Angela H. Arthington2, Gabrielle S. Holder1, R. Bill Talbot1 1NSW Department of Trade and Investment, Regional Infrastructure and Services, Port Stephens Fisheries Institute, Nelson Bay, New South Wales 2315, Australia 2Australian Rivers Institute and DIVERSITAS, Griffith University, Nathan, Queensland 4111, Australia ABSTRACT: The global biodiversity crisis particularly affects freshwater fishes. Currently, 20% of Australia’s highly endemic freshwater fishes are formally recognised as being of conservation concern under national, state and territory listings. Four of the 5 described species of Nannoperca (Percichthyidae) are threatened with extinction, with N. oxleyana Whitley listed as endangered under Australian legislation and internationally by the IUCN. National recovery planning has commenced with the objective of returning this species to a position of ‘viability in nature’ in New South Wales (NSW) and Queensland. This paper describes the conservation biology of N. oxleyana, providing a case history for a small species of no commercial importance threatened by the classical triumvirate of habitat degradation and loss; small, declining and fluctuating popula- tions driven more by environmental conditions than demographic forces; and the effects of intro- duced species. A process for declaring critical habitat for N. oxleyana has commenced in NSW. Habitat protection involves managing threats, including run-off originating from unsealed roads, herbicide use, fire management activities and disturbance by recreational users such as 4-wheel drivers and campers. Information on the distribution and breeding patterns of N. oxleyana has been provided to local and state government authorities to assist in managing drainage and devel- opment schemes that might impact N. oxleyana habitat. Monitoring has confirmed the persistence of many N. oxleyana populations in both jurisdictions. KEY WORDS: Endangered fishes · Conservation biology · Threat analysis · Recovery planning Resale or republication not permitted without written consent of the publisher INTRODUCTION of the continent’s 258 freshwater fish species (Hoese et al. 2006a), 20% (51 species) are listed as threat - Global biological diversity is rapidly declining as a ened under Commonwealth, State and/or Territory consequence of human activities (Sala et al. 2000, legislation. Sutherland et al. 2009). Fresh waters and their fishes Australian Commonwealth, State and Territory leg- are experiencing major losses in diversity (Duncan & islation provides for the protection, conservation and Lockwood 2001, Dudgeon et al. 2006). The endemic recovery of threatened species, populations and eco- fish fauna of Australia is no exception, with the geo- logical communities. Statutory recovery plans aim to graphic range and abundance of many species de- return a species, population or ecological community clining significantly since European settlement to a position of ‘viability in nature’, and outline the ac- (Wager & Jackson 1993, Pusey et al. 2004). Currently, tions that government agencies and other organisa- *Email: [email protected] © Inter-Research 2012 · www.int-res.com 170 Endang Species Res 17: 169–178, 2012 tions have agreed upon to promote recovery. Recov- SPECIES DESCRIPTION AND BIOGEOGRAPHY ery planning largely involves mitigating hu man im- pacts by implementing management ap proa ches Nannoperca oxleyana is a small fish with a maxi- based on a strong understanding of a species’ conser- mum total length of 60 mm but more commonly vation biology (Dudgeon et al. 2006). The scientific growing to 45 mm and 2.8 g. Meristics include 6 to 8 knowledge base must include an understanding of a dorsal spines, 7 to 9 dorsal rays, 3 anal spines and 7 to species’ evolutionary biogeography, patterns of ge- 9 anal rays. The body is moderately compressed and netic variation, habitat associations and environmen- lacks a lateral line. The mouth is relatively small with tal tolerances, life history strategy and population dy- jaws reaching to below the anterior part of the pupil. namics within the context of the biophysical factors The body colour is light brown to olive, darker on the and threatening processes influencing long-term via- back, with paler, mottled sides and 3 to 4 patchy dark bility (Burgman & Lindenmayer 1998, Meffe et al. brown bars extending from head to tail (Fig. 1). The 2006). Unfortunately, much of this information is lack- opercular flap has a blue iridescent sheen, and the ing for many of Australia’s threatened fishes (Wager ctenoid scales have dusky outlines. A round black & Jackson 1993, Morris et al. 2001, Pusey et al. 2004). spot with orange margin is prominent at the base of The present paper reviews known aspects of the the truncated caudal fin. Fins are mainly clear except conservation biology of, and current threats to, the during breeding, when males develop more intense Oxleyan pygmy perch Nannoperca oxleyana Whit- red and brown fin and body colouration than females ley, a small, threatened freshwater fish endemic to and have jet black pelvic fins (Pusey et al. 2004, Australia. This synthesis of information is discussed Knight et al. 2007a). in the context of the recovery planning process and Nannoperca oxleyana has the most northerly the actions set out in the national recovery plan for N. geographic range of the genus. The species typi- oxleyana through which detailed biological infor - cally occupies shallow, swampy habitats in dys- mation is utilised to help restore populations to a trophic freshwater streams, lakes and swamps position of viability in nature. The value of recovery drain ing through sandy lowland wallum (Banksia- planning is demonstrated not only through these dominated heathland) ecosystems of north-eastern conservation activities but also by the fact that many NSW and south-eastern Queensland (Fig. 2). It has of these measures are founded on scientific research a very re stricted, fragmented and patchy distribu- driven by initial recovery planning efforts (Arthing- tion along approximately 534 km of coastline, ex - ton 1996), followed by the national recovery plan tending from Coongul Creek on Fraser Island, (NSW DPI 2005). Queensland (25° 16’ S, 153° 09’ E) south to an un- named tributary of the Wooli River, NSW (29° 56’ S, 153° 09’ E) (Keller & Brown 2008, Knight & Arth - TAXONOMY AND CONSERVATION LISTING ing ton 2008). Since 1990, N. oxleyana has been documented from 110 water bodies within 80 dis- Pygmy perches in the family Percichthyidae (Jerry crete drainage systems in 5 mainland catchments et al. 2001, Hoese et al. 2006b) are a group of small and on 3 offshore islands (Table 1; Knight & Arth - (≤ 90 mm total length) freshwater fishes endemic to ington 2008, J. T. Knight unpubl. data), with 72% the freshwater drainage systems of southern Aus- of the discrete systems located in NSW. Indeed, N. tralia. Four of the 5 described species of Nannoperca oxley ana is rarer and has a more fragmented dis- are threatened with extinction (Morris et al. 2001, tribution in south-east Queensland. Small popula- IUCN 2009), with N. oxleyana formally recognised as tions inhabit 6 isolated, mainland drainages, while the most threatened species. This species is listed as the remainder are distributed across Fraser, More- Endangered by the International Union for Conser- ton and North Stradbroke Is lands (Fig. 2). Through- vation of Nature (IUCN 2009), the Australian Society out its range, most water bodies supporting this for Fish Biology, under the Australian Common- species are situated within 8 km of the coast at wealth ‘Environment Protection and Biodiversity elevations of less than 30 m above sea level Conservation Act 1999’ and under the New South (Knight & Arthington 2008). There is evidence of a Wales (NSW) ‘Fisheries Management Act 1994’. It is range contraction in the south over the last 30 yr, also listed as vulnerable under the Queensland and N. oxleyana is no longer found in several ‘Nature Conservation Act 1992’. A National Recov- localities where it was collected between 1929 and ery Plan for N. oxleyana was prepared in 2005 (NSW 1976 (Bookram Creek, Cassons Creek and near DPI 2005). Coraki, NSW; Fig. 2). Knight et al.: Nannoperca oxleyana biology and management 171 Prior to the commencement of the national recovery planning process in 2000, Nannoperca oxleyana had been recorded from only a few locations in NSW (Fig. 3) and little was known of its distribution and con- servation status (Knight & Butler 2004). A need for baseline data stimulated an extensive survey of over Fig. 1. Nannoperca oxleyana Whitley. Photo: NSW Depart- 300 sites in the state’s north-east. The species is now ment of Trade and Investment known to inhabit 74 water bodies within 58 discrete systems draining the coastal floodplains of the Rich- mond and Clar ence Rivers (Table 1, Fig. 2). The preva- lence of N. oxleyana on NSW coastal floodplains has been attributed to intermittent connection among water bodies during high rainfall events or large floods emanating from the Richmond and Clar ence Rivers. These conditions may facilitate dispersal, thereby allowing the species to colonise new systems