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Home , Eastern freshwater cod, Mary River cod, Murray cod

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Eastern Freshwater ikei Fisheries Unit, Port Stephens Fisheries Institute

Illustration by Pat Tully

A recovery plan has been developed for Eastern Introduction Freshwater Cod and work on recovery actions is The (Maccullochella ikei), well underway. often called Eastern Cod or Clarence River Cod, is similar in appearance to Description (Maccullochella peelii). It belongs to the family The Eastern Freshwater Cod is a large, elongated, Percichthyidae and is native to the Clarence and deep-bodied with relatively small eyes. It has a systems of north-eastern NSW. short, rounded, depressed snout with a distinctly Another similar , the concave profile. The Eastern Freshwater Cod has (Maccullochella peeli mariensis), occurs in a protruding lower jaw and a large mouth that and is also considered threatened. extends to below the back of the eye. The species Although once prolific in the Clarence and has been recorded to weigh 41 kg but is more Richmond Rivers, remnant (non-stocked) commonly less than 5 kg and 660 mm. populations are now only found in parts of the The Eastern Freshwater Cod is generally a yellow Clarence River and its tributaries. No remnant green to golden colour, with a speckled pattern of populations remain in the Richmond River system. black to very dark green spots. Between 1988 and 1997, hatchery bred Eastern Freshwater Cod were stocked throughout parts of and ecology the Clarence and Richmond Rivers. While Fisheries’ surveys and angler reports indicate that • The Eastern Freshwater Cod was once stocked fish have survived, the populations remain abundant in both the Clarence and Richmond relatively small in these areas. River systems downstream of tablelands waterfalls, with fish weighing up to 27 kg The Eastern Freshwater Cod is listed as an frequently caught in the Clarence and Orara under both NSW and Rivers. The species apparently declined in the Commonwealth law. There are heavy penalties for Richmond River and much of the Clarence harming, buying, selling or possessing them, or for River system from the late 1920s and 1930s. harming their habitat, without appropriate authority (see ‘Legal implications’). • Prior to the commencement of the conservation stocking program in the late

November 2012 http://www.dpi.nsw.gov.au/factsheets for updates , Conservation and Marine Parks Primefact 179 Second edition

1980’s, the species was considered to have • Releases of contaminated water from tailings become locally extinct in the Richmond River dams at gold and tin mines are thought to have catchment and only small numbers were caused the death of Eastern Freshwater Cod in recorded from remnant populations in parts of the Clarence system. tributaries such as the Nymboida, Guy Fawkes, • River regulation and water extraction reduce Boyd, Mann and Washpool Rivers where some flows, alter water temperatures, and can affect pristine habitat remained. seasonality of flows, detrimentally impacting on • The distribution and abundance of the remnant the Eastern Freshwater Cod. populations of Eastern Freshwater Cod has • Habitat degradation including sedimentation of increased significantly over the last 20 years deeper holes, changes to stream substrates, since their protection. The species is now and reduction of aquatic vegetation. relatively common in the Nymboida and Mann Rivers and patchily distributed in other major • Loss of riparian vegetation contributing to tributaries of the Nymboida/Clarence system. reduced bank stability, reduction in water quality, reduced shading, increased water • The Eastern Freshwater Cod is often found in temperatures, and reduced habitat quality for clear, flowing streams with rocky beds and Eastern Freshwater Cod and their food deep holes. The species is generally found in sources. areas that have plenty of boulders or large woody debris (snags). Riparian vegetation, • Introduced species such as Banded Grunter large boulders and snags provide a complex (Amniataba percoides) may pose threats from array of for each stage of the Eastern disease, competition, predation and habitat Freshwater Cod life cycle and influence the degradation. quality and quantity of food and shelter. • Illegal fishing practices directly reduce Eastern • The Eastern Freshwater Cod is sexually Freshwater Cod numbers, remove breeding mature when 4 or 5 years old, and between age adults and disturb breeding activities 700 g to 1.5 kg. The breeding season occurs in including and larvae guarding, leading to spring and spawning takes place from increased predation of and juveniles by September to November. other fish, eels and turtles. • Breeding fish are territorial and aggressive. Eastern Freshwater Cod lay large (3 mm) Artificial breeding and stocking strongly adhesive eggs onto hard surfaces The NSW Department of Primary Industries (NSW such as rocks and logs. The number of eggs DPI) developed artificial breeding techniques for produced is relatively low and similar to Murray Eastern Freshwater Cod at the Grafton Research Cod (3.2 - 7.6 eggs/gram of female Centre in 1988 and the first release of hatchery bodyweight). Hatching begins after 8 days, and bred stock soon followed. is complete 12 days after fertilisation at 17º - 20º C. Larvae start feeding on 12 A stocking program involving a commercial days after hatching. hatchery commenced in the late 1990’s and ceased in 2003. NSW DPI is currently assessing • The adult Eastern Freshwater Cod is a the effectiveness of the stocking program and territorial and aggressive fish with no distinct other recovery actions and undertakes regular migration pattern. The species is known to prey monitoring of Eastern Freshwater Cod populations. upon , , and a variety of terrestrial such as , birds and mice. Zooplankton and aquatic insects are the main food source for larvae.

Why are Eastern Freshwater Cod threatened? • Historical decline of Eastern Freshwater Cod is thought to have been caused by a combination of over-fishing, including by the use of explosives, with a series of catastrophic natural events where heavy rains followed severe bushfires, causing a deterioration of water quality and leading to widespread fish kills. Eastern Freshwater Cod habitat. Photo: NSW DPI

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Conservation and recovery actions • Implement the Protected, Threatened and Pest • Allocate and manage environmental flows in Species Sighting Sheet Program: Report any regulated rivers to lessen the impacts of sightings of the species on the NSW DPI 24 unnatural flow and temperature patterns, and to hour automated message-taking service by maintain natural flow seasonality. calling (02) 4916 3877. • Educate fishers about the identification and protected status of Eastern Freshwater Cod. Legal implications • Develop and implement control programs for, It is illegal to attempt to catch, buy, sell, possess or and prevent translocation of, pest species such harm Eastern Freshwater Cod (or any other as Banded Grunter. threatened species in NSW) without a specific permit, licence or other appropriate approval, and • Modify stream and river crossings on farms and significant penalties apply. For endangered public roads in accordance with NSW DPI species, these penalties can include fines of up to guidelines for fish passage. $220,000 and up to 2 years in prison. • Enhance compliance with fishing regulations. There can also be significant penalties for causing • Prevent sedimentation and poor water quality by damage to the habitat of a threatened species improving land management practices, through actions such as dredging riverbeds, conserving and restoring riparian vegetation and removing large woody debris and constructing using effective erosion and sediment control barriers that block the free passage of fish without measures. approval. • Evaluate the need for fishways and removal of Clearing activities authorised by a property redundant weirs to improve fish passage and vegetation plan approved under the Native reconnect aquatic habitats. Vegetation Act 2003 are permitted provided the • Monitor Eastern Freshwater Cod populations to native vegetation reform package had the benefit assess the effectiveness of recovery plan of biodiversity certification at the time the property vegetation plan was approved. actions. • Continue targeted research on key aspects of Clearing that constitutes a routine agricultural the biology of Eastern Freshwater Cod to management activity, and certain routine farming improve understanding of the species. practice activities (other than clearing) are permitted, provided the activities are to the

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minimum extent reasonably necessary and all NSW Fisheries 2004. Eastern (Freshwater) Cod other relevant statutory approvals or authorities (Maccullochella ikei): Recovery Plan. have been obtained. Threatened Species Unit, NSW Fisheries, Port Stephens Fisheries Centre 37pp. Available at The impacts of developments or activities that http://www.dpi.nsw.gov.au/fisheries/species- require consent or approval in accordance with the protection/conservation/what/recovery/efc. Environmental Planning and Assessment Act 1979 must be assessed and considered by consent or Rowland SJ 1993. Maccullochella ikei, an determining authorities. Where such actions are endangered species of freshwater cod (Pisces: likely to result in a significant impact on a Percichthyidae) from the Clarence river threatened species or its habitat, a detailed system, NSW and M. peelii mariensis, a new Species Impact Statement must be prepared. subspecies from the Mary river system, Qld. Records of the Australian Museum, 45: 121- Strategies to be adopted for promoting the 145. recovery of Eastern Freshwater Cod to a position of viability in nature must be set out in the NSW DPI Priorities Action Statement. For further information A recovery plan has been prepared for Eastern See the NSW DPI website: www.dpi.nsw.gov.au Freshwater Cod in accordance with the provisions Contact NSW DPI Threatened Species Section: of the Fisheries Management Act 1994 to promote the recovery of the species to a position of viability Port Stephens Fisheries Institute in nature. Locked Bag 1 Nelson Bay NSW 2315 Fax: (02) 4916 3880 Bibliography and further reading Email:[email protected] Harris JH & Rowland SJ 1996. Family Percichthyidae: Australian Freshwater © State of New South Wales through Department of Trade and Investment, Regional Infrastructure and Services 2012. You and Basses. Pp. 150-163 in: McDowell, R.M. may copy, distribute and otherwise freely deal with this (ed.), Freshwater Fishes of South-Eastern publication for any purpose, provided that you attribute the (second edition). Reed Books, Department of Trade and Investment, Regional Infrastructure Sydney, 247pp. and Services as the owner. Butler GL & Rowland SJ 2009. Using underwater ISSN 1832-6668 cameras to describe the reproductive Disclaimer: The information contained in this publication is behaviour of the endangered eastern based on knowledge and understanding at the time of writing freshwater cod Maccullochella ikei. Ecology of (November 2012). However, because of advances in Freshwater Fish. 18:3 pp.337-349. knowledge, users are reminded of the need to ensure that information upon which they rely is up to date and to check Nock JR, Ovenden JR, Butler GL & Wooden I currency of the information with the appropriate officer of the 2011. Population structure, effective population Department of Primary Industries or the user’s independent size and adverse effects of stocking in the adviser. endangered Australian eastern freshwater cod Published by the Department of Primary Industries, a part of the Maccullochella ikei. Journal of Fish Biology. Department of Trade and Investment, Regional Infrastructure 78:1 pp. 303-321. and Services. PUB08/84

Eastern Freshwater Cod habitat. Photo: NSW DPI Eastern Freshwater Cod. Photo: NSW DPI

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