R. Wager and P. Jackson
Environment Australia, June 1993
ISBN 0 6421 6818 0
Species recovery outline: Clarence River Cod
Scientific name: Maccullochella sp.A
English names: Clarence River Cod, Eastern Cod, Eastern Freshwater Cod
Species taxonomic status: Formally described by Rowland (in press). Only recently recognised as distinct from Murray cod (Maccullochella peelii).
Species survival status:
- Action plan status: Endangered.
- Australian Society for Fish Biology status: Endangered.
- Proposed new IUCN criteria status: Endangered (20% probability of extinction within 20 years).
Former distribution: Clarence and Richmond River Drainages in northern New South Wales.
Current distribution: Natural populations are mostly restricted to the Nymboida and Mann Rivers in the Clarence River Drainage. Fingerlings have been stocked into the Richmond River Drainage and parts of the Clarence River Drainage.
Habitat: Clear rocky streams.
Reasons for decline:
- Recreational fishing and set-lining believed to be significant factor in decline.
- Over exploitation during early European settlement.
- Habitat degradation:
- Loss of native riparian vegetation.
- Increased catchment erosion and siltation.
- Possible loss of genetic diversity:
- Diminishing populations.
- Prevention of gene flow because of disjunct populations.
- Use of few broodstock in captive breeding population.
- Release of mass cultured fingerlings in waters that may contain relict populations of genetically distinct stocks.
- Possible hybridisation/introgression with Murray cod previously introduced into headwater streams.
Conservation reserves on which species occurs:
The following reserves include parts of the catchments of the Richmond and Clarence Rivers. It is not known if Clarence River Cod occur in all of these:
- Border Ranges National Park.
- Guy Fawkes National Park.
- Guy Fawkes Nature Reserve.
- Nymboida National Park.
- Mann River Nature Reserve
Other public lands on which species occurs:
The following State Forest areas include parts of the catchments of the Richmond and Clarence Rivers. It is not known if Clarence River Cod occur in all of these:
- Richmond Range.
- Wild Cattle.
- Cloud's Creek.
- Gilbralter Range.
- Tuckers Nob.
Also small areas of crown land near Kyogle (Richmond River) and at several locations within the Clarence River catchment.
Other land on which species occurs: Private land.
Is knowledge about species adequate for objectives and actions to be defined accurately? (If not provide list of additional studies required): No.
- General biology, especially habitat requirements of various life history stages.
- Population structure.
- Response to fishing.
- Recruitment processes.
- Maintain or expand current distribution and population sizes.
- Establish new populations within the former distribution.
Management actions already initiated:
- Review of native fish regulations proposes no change to the five year ban on taking Clarence River Cod.
- Southern tributaries of the Clarence River drainage including the Mann and Nymboida Rivers have been entered on the Australian Heritage Commission's Register of the National Estate because of Clarence River Cod habitat.
- Program of captive breeding and re-establishment of wild populations at the Eastern Freshwater Fish Research Hatchery at Grafton. Two batches of fingerlings released throughout natural range in the Clarence and Richmond Rivers. Program suspended temporarily. Monitoring of stockings occurs annually, with evidence of good survival but no recruitment. Indications that wild populations are regenerating in several areas since the imposition of the ban on capture of this species.
Management actions required:
- Declaration of additional conservation reserves: Yes.
- Reserves should be declared to preserve habitat in the Mann and Nymboida River catchments.
- Habitat management: Yes.
- Land use techniques should be managed to minimise their impact on aquatic habitat.
- Feral animal control:
- The introduction of Murray cod into the Clarence River catchment, including private farm dams should be prohibited.
- Translocation or re-establishment of populations:
- Re-establishment of populations into suitable habitat within the Clarence and Richmond River systems should continue. Introduction to other drainages is unnecessary.
- Captive breeding:
- Captive breeding program should recommence.
- Other: No.
Organisations responsible for conservation of species:
- New South Wales Fisheries.
Other organisations or individuals involved: None.
Can recovery plan be carried out with existing resources?: No.
- To determine the general biology and habitat requirements requires one biologist and one technician for three years – $220 500, plus operating costs of $20 000 each year.
- Existing facilities are inadequate for a captive breeding program. The water supply must be augmented, 8–10 new ponds constructed, existing building modified, equipment purchased and power supply augmented. Approximate total cost – $400 000. To continue breeding program one biologist and two technicians are required until Clarence cod are permanently re-established in the wild (at least three years) – $310 500.
Total: $991 000