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

Eastern Freshwater ikei

March 2017, Primefact 178, Third edition Threatened Unit, Port Stephens Fisheries Institute

Figure 1: An (Image: B. Vercoe)

Introduction more commonly less than 66 cm and 5 kg. They have an elongated body with a distinctly concave Eastern Freshwater Cod (also known as profile, relatively small eyes and a short snout. Clarence Cod) are a large predatory They are generally yellow green to golden in freshwater belonging to the family colour with a speckled pattern of black to very Percichthyidae. The species was once prolific in dark green spots. the Clarence and Richmond in north- eastern NSW, however populations collapsed in Eastern Freshwater Cod are similar in the 1920s and 1930s and continued to decline appearance to and . until the 1980s when the species was protected. Remnant (non-stocked) populations are now only and ecology found in parts of the Clarence River and its • Eastern Freshwater Cod are typically found in tributaries. No remnant populations remain in the clear slow-flowing streams with rocky system, however stocked substrate and large amounts of in-stream populations persist in some local tributaries. cover. They are generally found in areas that Eastern Freshwater Cod is listed as an have boulders or large woody debris (‘snags’). under both NSW and Such areas provide complex for each Commonwealth law. There are heavy penalties stage of the species’ life cycle and influence for harming, buying, selling or possessing them, the quality and quantity of food and shelter. or for harming their habitat (see ‘Legal • Adult fish are territorial and aggressive and implications’). generally display strong home-site fidelity. Description • Eastern Freshwater Cod are , preying mainly on , , other Eastern Freshwater Cod can grow to over 1 as well as a variety of terrestrial metre in length and to 41 kg in weight, but are

Eastern Freshwater Cod – Maccullochella ikei

such as , birds and mice. relatively small in these areas. Recent research and aquatic insects are the main also indicates that stocking may have contributed food source for larvae. to genetic decline in the largest wild population, demonstrating the importance of using genetic • They are sexually mature at 4 or 5 years old, information in breeding and stocking programs. and between 700 g to 1.5 kg. The species spawns in late-August and early-September when temperatures rise from 16 to 18ºC. Recovery plan review During the spawning season, males have The review of the Eastern Freshwater Cod been observed moving distances of up to 30 Recovery Plan was finalised in 2016. The review km to locate suitable spawning sites. assessed the implementation of recovery actions • Breeding fish are territorial and aggressive. in NSW and detailed progress made toward Females produce large (3 mm) adhesive meeting the recovery plan objectives. that attach to hard substrates such as rocks The review found that many specific recovery and logs. Nesting sites are usually located plan objectives have been completed over the under either large boulders or bedrock last 10 years or are ongoing. There has been a shelves. significant increase in the understanding of the • Larvae begin to hatch after 8 days and remain size, distribution, ecological requirements, and on the substrate at the nest for between 5 and historical and existing genetic status of the 6 days before swimming away. species, as well as an increase in the coordination of community awareness and Artificial breeding and stocking education programs. However the review also highlighted several A stocking program for Eastern Freshwater Cod areas where more work is required to assist with involving a commercial hatchery commenced in recovery, including improving protection of the 1990s and ceased in 2003. The stocking took Eastern Freshwater Cod habitat and more place at various locations throughout the strategic implementation and monitoring of Clarence and Richmond River systems. While recovery action outcomes. surveys and angler reports indicate that stocked fish have survived, the populations remain

Figure 2: The indicative distribution of Eastern Freshwater Cod in NSW based on survey records, predicted occurrence and expert opinion.

2 NSW Department of Primary Industries, March 2017 Eastern Freshwater Cod – Maccullochella ikei

• Maintain bans on the taking of Eastern Why are Eastern Freshwater Cod Freshwater Cod and enforce compliance with threatened? fishing regulations. • Historic decline of Eastern Freshwater Cod is • Ensure that all fish stocking activities within thought to have been caused by a the natural distribution of Eastern Freshwater combination of factors. Many fish were killed Cod comply with the NSW Freshwater Fish in the late 1920s when dynamite was used for Stocking Fisheries Management Strategy. the construction of the north coast railway. • Educate the community about the protected Dynamite was also used in the late 1930s as status of Eastern Freshwater Cod and how a method of catching fish and killed thousands they can assist with recovery of this species. of fish. • Allocate environmental flows in regulated • Fish kills were also observed in the 1920s and rivers to restore natural seasonal flow 1930s when water quality deteriorated due to patterns, improve or maintain fish passage heavy floods, which were followed by long dry and reduce the impact of cold water pollution periods, extensive bushfires and heavy downstream of dams. summer rains. • Prevent sedimentation and poor water quality • Releases of contaminated water from tailings by improving land management practices, dams at gold and tin mines are thought to conserving and restoring riparian vegetation have caused the death of many Eastern and using effective erosion and sediment Freshwater Cod in parts of the Clarence control measures. system. • Reinstate large woody debris at key sites. • Over-harvesting by recreational and commercial fishers has contributed to past • Evaluate the need for fishways and removal of declines. Eastern Freshwater Cod are now redundant weirs to improve fish passage and totally protected in NSW, but illegal fishing reconnect aquatic habitats. and hooking injuries in accidentally caught • Report any sightings of the species via the fish still pose a threat. Targeted or indirect NSW DPI online form. capture of Eastern Freshwater Cod can directly reduce their numbers by removing • A full list of strategies that have been adopted breeding age adults and disrupting breeding for promoting the recovery of Eastern activities such as and larvae guarding. Freshwater Cod is set out in the NSW DPI Priorities Action Statement. • The current threats to Eastern Freshwater Cod include habitat degradation through changes to natural river flows, removal of large woody debris, water extraction and sedimentation caused by land clearing activities. These factors reduce bank stability, water quality and shading as well as increasing water temperatures. As a result, they reduce quality habitat for Eastern Freshwater Cod and their food sources, leading to spawning failures and reduced fish dispersal. • Introduced species such as Banded Grunter (Amniataba percoides) may also pose threats Figure 3: The distinct pattern of the Eastern from disease, competition, predation and Freshwater Cod (Image: B. Vercoe) habitat degradation. Legal implications Conservation and recovery It is illegal to catch and keep, buy, sell, possess actions or harm Eastern Freshwater Cod (or any other • Continue to implement the NSW DPI Eastern threatened species in NSW) without a specific Freshwater Cod Recovery Plan which aims to permit, licence or other appropriate approval, and recover the species to a position of natural significant penalties apply. For endangered viability within its former range. species, these penalties can include fines of up to $220,000 and up to 2 years in prison.

3 NSW Department of Primary Industries, March 2017 Eastern Freshwater Cod – Maccullochella ikei

There can also be significant penalties for NSW Department of Primary Industries (2016) causing damage to the habitat of a threatened Review of the Eastern Freshwater Cod Recovery species without approval, through actions such Plan. NSW Department of Primary Industries, as dredging river beds, removing large woody Port Stephens Fisheries Institute, NSW. debris and constructing barriers that block the free passage of fish. For further information Clearing that constitutes a routine agricultural See the NSW DPI website: www.dpi.nsw.gov.au management activity, and certain routine farming Contact the NSW DPI Threatened Species Unit: practice activities (other than clearing) are PO Box 1305 permitted, provided the activities are to the Crows Nest NSW 1585 minimum extent reasonably necessary and all Email: [email protected] other relevant statutory approvals or authorities have been obtained. © State of through the Department of Industry, Skills and Regional Development, 2017. You may copy, distribute and The impacts of developments or activities that otherwise freely deal with this publication for any purpose, provided that you attribute the NSW Department of Primary Industries as the require consent or approval in accordance with owner. the Environmental Planning and Assessment Act Disclaimer: The information contained in this publication is based on 1979 must be assessed and considered by knowledge and understanding at the time of writing (March 2017). However, because of advances in knowledge, users are reminded of consent or determining authorities. Where such the need to ensure that information upon which they rely is up to date actions are likely to result in significant impact on and to check currency of the information with the appropriate officer of the Department of Primary Industries or the user’s independent a threatened species or its habitat, a detailed advisor. species impact statement must be prepared. ISSN 1832 6668 To protect breeding Eastern Freshwater Cod, PUB08/84 all fishing is prohibited from August to October inclusive in the Mann River and all of its tributaries upstream of its junction with the Clarence River and the Nymboida River. The possession of fishing gear in, or adjacent to closed waters is also an offense.

Bibliography and further reading Butler, G.L. (2009) Biology and conservation of the endangered eastern freshwater cod Maccullochella ikei Rowland. PhD thesis, Southern Cross University, Lismore, New South Wales. Figure 4: An Eastern Freshwater Cod (Image: B. Butler, G.L., Rowland, S.J., Baverstock, P.R. and Vercoe) Brooks, L. (2014) Movement patterns and habitat selection of the endangered eastern freshwater cod Maccullochella ikei in the Mann River, . Endangered Species Research, 23: 35- 49. Nock, C.J., Ovenden, J.R., Butler, G.L., Wooden, I., Moore, A. and Baverstock, P.R. (2011) Population structure, effective population size and adverse effects of stocking in the endangered Australian eastern freshwater cod Maccullochella ikei. Journal of Fish Biology, 78: 303 – 321. NSW Department of Primary Industries (2004) Eastern (Freshwater) Cod (Maccullochella ikei) Recovery Plan. NSW Department of Primary Figure 5: Typical Eastern Freshwater Cod habitat Industries, Port Stephens Fisheries Institute, (Image: J. Wright) NSW.

4 NSW Department of Primary Industries, March 2017