Abalone stock enhancement remains one of the few viable alternatives for increasing the profitability and biomass of a fishery without compromising the current fishery in terms of access or allowable catches. Economically viable stock enhancement could provide the fishery with stock numbers towards virgin levels, thus increasing catch rates and ultimately economic efficiency and profitability. However, there is a need for a project to develop the R&D that will create a commercially viable stock enhancement industry. This is the subject of a current Seafood CRC project (2010/784 - Commercialisation of abalone stock enhancement).

Prior to the commercialisation the industry wants to understand the biosecurity risks of the larger scale stock enhancement project; in other words to weigh up the potential economic gains against biosecurity risks. The recent AVG outbreak in Tasmania highlighted the requirement for industry to be vigilant regarding potential disease vectors.

In order to protect the valuable abalone industry from potential biosecurity threats, there is a need to undertake a risk assessment to quantify raw and residual risks associated with commercialization of abalone stock enhancement. Although being carried out in WA, this risk assessment has national significance to the abalone industry.

The RAC supported the concept of developing a single, consumer oriented publication on the health benefits of seafood. This project will provide text for an e-book to the Australian Seafood CRC (ASCRC) based on the best available evidence associated with seafood consumption and human health.

The ASCRC communications company (Fuller) will lay out and design the e-book (including graphics) as part of the ASCRC 'Super Seafood' branding and packaging of information.

In 2012, diseased P. monodon from North-QLD farms were investigated by QDAFF, Townsville. All prawns tested negative using an OIE-endorsed YHV-1 specific PCR test but positive to GAV (YHV-2) and to YHV-1 using OIE-endorsed nested PCR tests designed to co-detect and differentiate YHV-1 from GAV. However, consistent with the YHV-1 specific PCR test data, none of the diseased P. monodon displayed histopathology consistent with acute YHV-1 infection.

Analyses undertaken at CSIRO-AAHL confirmed the presence of GAV but not YHV-1. In two OIE-endorsed PCR tests, GAV sequences were also amplified by primers supposed to be specific for YHV-1. When an OIE-endorsed PCR test designed to detect all YHV genotypes was applied to tissue from healthy P. monodon broodstock imported into QLD from NT, sequence analyses identified an undescribed unique genotype designated tentatively as YHV-7. YHV-7 was also amplified by a CSIRO in-house real-time PCR test designed to be specific to the YHV-1.

Wild QLD broodstock are increasingly being replaced by wild NT broodstock to produce resilient fast growing P. monodon for aquaculture. The finding of YHV-7, with unknown pathogenic potential and distribution, highlights the potential risks of translocated broodstock spreading unwanted new pathogens to regions with substantial aquaculture interest, and supports a need to update decade-old data on what viruses might exist in NT and QLD populations of P. monodon.

Collectively these discoveries highlight urgent needs to (i) re-evaluate genotype specificities of OIE-endorsed PCR tests for different YHV genotypes (ii) redesign PCR tests to improve their power to discriminate YHV-1 from less virulent genotypes and (iii) re-assess the prevalence of GAV and related genotypes (YHV-7) and other endemic viruses potentially problematic to aquaculture (MoV, MBV, HPV, SMV, IHHNV) in wild P. monodon broodstock sourced from the NT and QLD.