Tactical Research Fund: cost-benefit analysis of implementing alternative techniques for rehabilitating reefs severely depleted by Abalone Viral Ganglioneuritis epidemic
In May 2006 an epidemic caused by Abalone Viral Ganglioneuritis (AVG) began infecting wild stocks of abalone in the Victorian western zone, rapidly spreading through the zone causing mortality rates of 40-95%. In response infected reefs have been closed since infection and to date remain closed resulting in the zonal TAC being reduced by >90%. It is the observation of WADA’s divers that, having been closed to fishing for several years, the reefs that suffered relatively lower mortality rates (75%) are, to this time, recovering well. Supported by an FRDC TRF project ‘Indicators and strategies for resumption of harvesting following catastrophic loss of abalone’ WADA members agreed that these ‘lightly’ impacted reefs should be closed for at least threes closure before being re-opened (some in 2009) with conservative size limits and catches.
In contrast to reefs that suffered relatively low mortality rates WADA’s divers observe that a number of formerly important reefs which suffered high mortality rates (>90%) do not appear to be recovering. Worryingly Californian studies suggest disease related reductions of abalone grazing pressure can lead to overgrowth of suitable settlement surfaces which retards natural rates of re-colonisation. WADA estimates one ‘high mortality’ reef, Kilarney, lost 100-200t of biomass and members are concerned that without intervention there will be a semi-permanent loss of productivity from some important reefs.
To prevent this WADA’s members are discussing initiating in 2009 rehabilitation projects for heavily impacted reefs by alternatively:
• Re-seeding of hatchery produced juveniles,
• Translocation of adults from other reefs in the western zone
• Long term closure to allow natural recruitment processes.
A cost-benefit analysis of alternative rehabilitation techniques is needed to inform members of the relative merits of alternative rehabilitation techniques and the likely magnitude of cost for rehabilitating at the scale of entire reefs.
Final report
Tactical Research fund: Economic viability of Pipi (Donax deltoides) reseeding
In the 2007/2008 FRDC application round, the SQAA (pipi gatherers Assoc.) has submitted a proposal for a Pipi breeding program in order to maintain stocks at an optimum which will accommodate increases in production to meet the demands of an expanding market. This along with an effective management regime will result in the long term profitably and sustainability of the pipi industry.
FRDC Board concerns over this program were:
1) concerns over the economic feasibility of the application
2) concerns on the ability to monitor the re-seeding progress and success
3) there is little evidence that management measures currently in place will ensure sustainability of fishery if re-seeding is successful."
The timing of the original application prevented NSW FRAB consideration of the proposal before submission, however they have subsequently seen the application and in their response to the applicant reinforced the boards concerns and stated "The FRAB suggests that a proposal be submitted to the TRF for bioeconomic analysis and, if this provides a positive result, an application should be submitted in next year’s funding round."
The SQAA believes the concerns of the FRDC Board and the FRAB have been addressed as outlined in a modified application to be concurrently submitted in this FRDC funding round. However, the SQAA has acknowledged the value of bioeconomic analysis and the need to demonstrate potentially feasibility. Accordingly, this program has been proposed and will be used as a critical decision point for further research. In the event of an unfavourable outcome, reseeding research will not be progressed and the accompanying applications will be withdrawn until fundamental changes occur that alter the underlying assumptions of the model developed.