Recovery of the endangered trout cod, Maccullochella macquariensis: what have we achieved in more than 25 years?

Abstract

Abstract. Recovery of threatened species is often necessarily a long-term process. The present paper details the progress towards the recovery of trout cod, Maccullochella macquariensis, an iconic, long-lived fish species first listed as threatened in the 1980s. The objectives, actions and progress over three successive national recovery plans (spanning 18 years) are assessed, documenting changes to population distribution and abundance and updating ecological knowledge. Increased knowledge (especially breeding biology and hatchery techniques, movements, habitats and genetics) has greatly influenced recovery actions and the use of a population model was developed to assist with management options and stocking regimes. Key recovery actions include stocking of hatchery-produced fish to establish new populations, regulations on angling (including closures), education (particularly identification from the closely related Murray cod, M. peelii) and habitat rehabilitation (especially re-instatement of structural woody habitats). In particular, the establishment of new populations using hatchery stocking has been a successful action. The importance of a coordinated long-term approach is emphasised and, although there is uncertainty in ongoing resourcing of the recovery program, much has been achieved and there is cautious optimism for the future of this species.

A review of on-ground recovery actions for threatened freshwater fish in Australia

“…The critical role of research in improving management approaches and outcomes is undeniable (see Ellis et al 2013;Koehn et al 2013). This review also does not deal with general river-health programs, or legislative and policy initiatives, all of which contribute to recovery of threatened freshwater fish.…”

“…Edgbaston goby, Lake Eacham rainbowfish, Melanotaenia eachamensis, Elizabeth Springs goby, Chlamydogobius micropterus) are necessarily of small spatial scale. It must also be recognised that the science of recovering threatened freshwater fish in Australia is still relatively young (the first recovery plan for an Australian freshwater fish was only published ,20 years ago; Koehn et al 2013) and many of the recovery actions are still somewhat experimental. However, mature approaches such as provision of fish passage are now being deployed at large scales through integrated programs addressing thousands of kilometres of stream (Barrett 2008).…”

“…Stock enhancement has been employed for 11 threatened freshwater species, with some programs having released more than 1 million individuals in programs spanning more than 20 years (Table 3; see Koehn et al 2013). The larger (spatially and temporally) stocking programs have focussed on largebodied individuals that were formerly favoured angling species (trout cod, Macquarie perch, eastern freshwater cod, Maccullochella ikei, Mary River cod, Maccullochella mariensis).…”

Recovering threatened freshwater fish in Australia

“…Further, there are a variety of concerns for hatchery programs around domestication and genetic integrity (Brown and Day 2002;Nock et al 2011). While captive husbandry has a significant role in the management of many threatened species, and if well managed can produce positive results (see Lyon et al 2012;Koehn et al 2013), it must be viewed as only one component of a broader recovery program, with in situ responses preferred (Lintermans 2013a).…”

“…Such breeding programs are often driven by a mix of the inability or unwillingness to invest in costly in situ actions (see Ellis et al 2013), a last-chance emergency action to prevent imminent extinction (see Hammer et al 2013) or long-standing fisheries interest for those species with historic recreational value (see Koehn et al 2013). Whatever the driver, reliance on captive breeding programs for species recovery is problematic, with such programs often an easier option than efforts to restore habitat, eradicate alien species or counter other large-scale threats (Philippart 1995).…”