Community Concerns about Mussel Farm Expansion

On 14 April 2025 members of the Bay and Basin Citizen Science Club (BBCSC) attended the Callala Beach Progress Association meeting to hear Sam Gordon from South Coast Mariculture provide a community update on the Jervis Bay Mussel Farm. Sam was invited to talk following the approval of the expansion and relocation of the three commercial mussel farm leases in Jervis Bay Marine Park. BBCSC members have been concerned about commercial farming in the Jervis Bay Marine Park since it was first proposed, due to the potential damage to the integrity of the marine ecosystem in a designated marine park. Marine parks are designed to protect marine life and their habitats from human impacts, to help increase the resilience of the marine ecosystem. 

Strong and conflicting opinions about the impact of the mussel farm were voiced at the meeting. 

Sam started by explaining the environmental benefits of mussel farming. He claimed that mussels are one of the top 10 most sustainable foods. He believes that mussels contribute to ocean health, have low environmental impact during farming and offer a nutritious and affordable food source. He said The Nature Conservancy states that mussel farms are ‘cleaning the other marine parks’ and increasing diversity. Sam said he is proud of what they are doing and proud that he can do it within a marine park. 

Sam then explained the economic benefits of mussel farming. He noted that the NSW government aims to double the value of the state’s aquaculture industry to $300 million by 2030. They see opportunities for economic growth. The Jervis Bay mussel farm has been years in planning and South Coast Mariculture has made an investment of $18m to date. Sam noted that the mussel farm now employs ~35 people locally. 

Sam advised that the mussel farm expansion was ‘offered’ as compensation due to a Department of Primary Industries and Regional Development (DPIRD) error in lease coordinates which resulted in a need for boundary adjustment. 

Many of these points are contested by visual evidence and marine scientists.

The Jervis Bay dive community noted that they are finding mussels where they have never seen before (over the 40+ years memory of current divers). They claim there has been a significant spread of mussels in the few years since the first commercial harvest of mussels in 2021, in locations where the clockwise current system operating within Jervis Bay would spread them from the mussel farm. 

The dive community has photos and videos showing mussels blanketing the reefs from the surface down to 3m, and in some areas down to 8m. Divers are concerned that these mussel concentrations are present in sanctuary zones that are meant to have the highest level of protection. The divers believe the proliferation of mussels is threatening sensitive ecosystems. The mussels are outcompeting other epifaunal organisms like corals and sponges which are being displaced and redusing biodiversity. They fear that within 10 years, all the shallow reefs of Jervis Bay could be covered in an invasive species of mussel, changing the biodiversity of the Jervis Bay ecosystem. Jervis Bay boat owners also reported a previously unseen amount of mussel growth of up to 3 inches long on the hulls of their boats and also causing a clogging of inlet and outlet water systems on moored vessels. 

Sam responded that South Coast Mariculture (supported by scientists from NSW Department of Primary Industries and Regional Development (DPIRD), the mussel farm proponent) believes the explosion of mussels in Jervis Bay is part of a natural boom-bust cycle. He said the same thing has been seen up and down the coast, outside the range of spat from the Jervis Bay mussel farm. Sam also noted that DPIRD will carry out testing and monitoring of spatfall as a result of concerns raised in the application process. 

Divers and environment groups raised concerns that the full impact is not currently known, but it has the potential to be severe. They are asking authorities to take preventive measures (in accordance with the precautionary principle) such as pausing farming, and further scientific studies, given the damage that is already being seen, and the potential threat of serious and irreversible damage. 

All parties agreed there is a need for more scientific studies. Those with concerns (including NSW Department of Climate Change, Energy, Environment and Water) wanted more scientific research to be undertaken before the expansion was approved. South Coast Mariculture wants to proceed with the mussel farm expansion while the research is being done. 

Objectors at the meeting noted that pushing forward would not just risk significant damage to the Jervis Bay Marine Park environment, it could also cause widespread economic harm, including to other nearby farming and fishing industries such as the oyster farms in nearby Shoalhaven estuaries, and also putting at risk the long term and growing income from ecotourism in Jervis Bay. Concerns were raised about biosecurity risks in collecting spat from Twofold Bay in Eden, which has international boat traffic, and concerns around ballast water being released into local ecosystems. Environment groups say any concerns relating to marine biosecurity should be taken seriously, especially in an area protected for conservation. 

There was discussion and disagreement around the exact species being farmed, and a complex debate about whether they are endemic to Jervis Bay, or non-native, and the associated impacts. South Coast Mariculture (supported by DPRID scientists) argue that they are collecting Mytilus galloprovincialis from the wild (Twofold Bay, Eden) and they believe that the species that they farm (M. galloprovincialis, M.planulatus and hyrbrids) are endemic to Jervis Bay. However, many scientists at the meeting argued that Mytilus galloprovincialis is not native and further, stated it is known to be one of the most invasive species of mussel worldwide. Sam Gordon argued that it can’t be invasive if it is endemic.  Regardless of whether these species are endemic, the divers argued that just because a species is present, doesn’t mean there should be more of it. There is agreement that there has been breeding between native and non-native species resulting in hybrids. Geneticists and some other scientists argue that it is an invasive species and that the resulting hybrids are genetic pollution. 

There was a question from the audience regarding selling oysters and mussels farmed in other locations, from the Huskisson retail outlet, with the claim that they are local. Sam said the packaging noted that the shellfish may derive from other locations. 

Due to the robust debate that took place, Sam was unable to finish his planned PowerPoint presentation before the meeting was closed. 

Further information is available here: https://www.dpi.nsw.gov.au/dpi/fishing/aquaculture/Spotlight/jervis-bay-mod-1-approval