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Vongoles are found in southern coastal waters. They occur in the intertidal zone of shallow bays and estuaries. SA has three management zones, with one zone depleting, one undefined and  one depleted. The stock in TAS is depleted. The WA stock is negligible.

Vongole (Katelysia spp.) is a species complex that inhabits southern coastal waters from Augusta in Western Australia to Port Jackson in New South Wales. They are found on sand banks in shallow bays and estuaries from the intertidal zone to a depth of 5 m [Cantin 2010]. Stock structure is unknown. However, given the short larval life span, ~16 days for K. rhytiphora hatchery animals [Gluis and Li 2014], it is likely that Vongole in individual bays would constitute separate stocks.

Due to the potential for there to be a large number of stocks, assessment of stock status is presented at the management unit level—Western Australian Vongole Fishery; Ansons Bay Vongole Fishery (Tasmania); Coffin Bay Cockle Fishing Zone, Port River Cockle Fishing Zone, and West Coast Cockle Fishing Zone (South Australia).

Ansons Bay Vongole Fishery

The harvest strategy for Vongole in Tasmania in the Shellfish Fishery Policy Document [DPIW 2007] uses biomass and size-composition as performance indicators but does not define a limit reference point below which the stock would be classified as recruitment impaired. Biomass surveys of the Ansons Bay Vongole fishery are conducted every 2–3 years with total allowable commercial catches (TACC s) determined to be up to 10 per cent of the biomass estimate (at the 95 per cent confidence interval).

The 2018 estimate of biomass available to the Ansons Bay Vongole Fishery was 23.61 tonnes (t) (19.49–27.73 t), a level that is 11.6 per cent of the peak biomass recorded in 2001. Exploitation rates have been below the maximum of 10 per cent and minimum legal limits (32 mm shell length, SL) are set at a size that enables the majority of Vongole to reproduce at least once prior to being available for harvest.

Despite these measures, large stock declines occurred in 2014 and in 2015 there was no evidence of recruitment (no pre-recruits or juveniles identified). The Ansons Bay Vongole Fishery has been closed to commercial fishing from 1 September 2015 on the basis of being recruitment impaired.

The 2018 biomass estimate was the lowest on record and is likely attributable to a combination of mortality of Vongole as a result of extreme rainfall and flood events in the north-east of Tasmania in 2014, followed by recruitment failure in 2015–17 [Keane and Gardner 2017]. Low abundances of juveniles were observed in the 2018 survey but are unlikely to lead to significant stock rebuilding in the short term. Preliminary results from the 2019 stock assessment indicate no sign of stock rebuilding.

The above evidence indicates that spawning stock biomass is likely to have been depleted to the point where average recruitment levels are significantly impaired, primarily as a result of substantial environmental impacts.

On the basis of the evidence provided above, the Ansons Bay Vongole Fishery (Tasmania) management unit is classified as a depleted stock.

Vongole biology [Riley et al. 2005, Gorman et al. 2010, Dent et al. 2012]

Active Vessels Vongole can be collected from beaches and bay on foot therefore, ‘vessels’ are not always used. Hence, numbers of licences and fishers are presented here instead of vessel numbers. Licences refer to the number of licence holders with an endorsement to take Vongole for sale.   

1. Cantin, A 2010, Population biology of two sympatric mud cockles, Katelysia peronii and K. scalarina (Bivalvia: Veneridae), with implications for their management, PhD thesis, Flinders University, Adelaide.
2. Dent, J, Mayfield, S and Carroll, J 2016, Harvestable biomass of Katelysia spp. in the South Australian commercial Mud Cockle Fishery, Report to Primary Industries and Regions South Australia, Fisheries and Aquaculture, SARDI Publication F2014/000191-2, SARDI Research Report Series 898, SARDI, Adelaide.
3. Dent, J, Mayfield, S, Burch, P, Gorman, D and Ward, TM 2012, Distribution, harvestable biomass and fisheries biology of Katelysia spp. in the South Australian commercial Mud-Cockle Fishery, Fishery assessment report for Primary Industries and Regions South Australia Fisheries and Aquaculture, SARDI Publication F2010/000263-2, SARDI Research Report Series 595, South Australian Research and Development Institute (Aquatic Sciences), Adelaide.
4. Department of Primary Industries and Water 2007, Shellfish fishery policy document, Wild Fisheries Management Branch, DPIW, Hobart.
5. Gluis, MR and Li, X 2014, Hatchery manual for larval rearing of Vongole Katelysia rhytiphora, Fisheries Research and Development Corporation Project 2009/208, South Australian Research and Development Institute (Aquatic Sciences), Adelaide.
6. Gorman, D, Mayfield, S, Burch, P and Ward, TM 2010, Distribution, harvestable biomass and fisheries biology of Katelysia spp. In the South Australian commercial mud cockle fishery, Fishery assessment report for PIRSA Fisheries, SARDI Publication F2010/000263-1, SARDI Research Report Series 442, South Australian Research and Development Institute (Aquatic Sciences), Adelaide.
7. Heldt, K and Mayfield, S 2020, Harvestable biomass of Katelysia spp. in the South Australian Vongole Fishery. Report to PIRSA Fisheries and Aquaculture (PDF 3.3 MB). South Australian Research and Development Institute (Aquatic Sciences), Adelaide. SARDI Publication Number. F2014/000191-2. SARDI Research Report Series No. 1060. 40pp
8. Keane, JP and Gardner, C 2017, 2017 Small Bivalve Fishery assessment. Institute for Marine and Antarctic Studies Report, University of Tasmania, Hobart.
9. Primary Industries and Regions South Australia 2013, Management plan for the South Australian Commercial Marine Scalefish Fishery, South Australian Fisheries Management Series: Paper 59, PIRSA, Adelaide.
10. Riley, SP, Green, RM, Zacharin, W and Maguire, GB 2005, Growth models and age determination for the intertidal venerid clam Katelysia scalarina (Lamarck 1818) from three sites in Tasmania, Australia, Fisheries Research and Development Corporation Project 93/232, in GB Maguire (ed) Enhancing Tasmanian clam resources, FRDC, Tasmania.