The NSW coastline has long been renowned for its pristine waters and thriving oyster farms. However, these picturesque landscapes hold more than just natural beauty - they bear the traces of a historical past that offers both the good and the bad. One historical challenge faced by oyster farmers in the region is the removal of old tar pits and our ongoing efforts here at Australia's Oyster Coast (AOC) to preserve Australia's oyster heritage.

Removing tar pits is a complex and meticulous process that requires careful planning and execution and is a crucial step towards safeguarding the country's oyster heritage and being a responsible oyster industry custodian.

Tar pits like the one pictured above have been historically used in oyster farming. Liquid tar was used to coat in-water oyster farming infrastructure e.g. timber trays were dipped into tar pit routinely. Tar pits were used to hold the liquid tar, allowing sticks, trays etc. to be dipped/submerged in tar to coat them. Tar sticks (sticks covered with liquid tar) were traditionally put into the estuary to catch spat (juvenile oysters). The spat covered tar sticks could then be relocated to other oyster leases suitable to be grown to larger food grade size.

The following is an extract from Roc Partners 2022 responsible Investing Report. As a Roc Partners agribusiness portfolio company, this report included a section on our tar removal initiative.

Australia's Oyster Coast Tar Removal Project

For many years, tar pits and tar sticks were the mainstay of the oyster industry’s culture practices, used to increase the durability of cultivation infrastructure in the harsh estuarine environment, protecting it from wood boring marine organisms. Timber trays and lease marker posts were also tar covered to prolong their life, similar to oiling a timber deck to preserve it.

However, using tar in oyster production creates the potential for hydrocarbon contaminants to enter the estuarine ecosystem.

AOC is committed to removing tar pits and phasing out tar treated infrastructure by implementing more sustainable farming methods. The company has prioritised removing tar sticks and converting to floating bags, introducing recycled plastic trays, using recycled plastic sleeved timber posts, and favouring low-impact long-lines systems.

Converting to these recycled plastic products reduces ongoing maintenance requirements and associated costs, and more importantly eliminates potential hydrocarbon contaminants entering the estuarine ecosystem.

AOC farms no longer cultivate any oysters on tar sticks, with all farms having transitioned to floating bags and other sustainable cultivation infrastructure. One farm at Wallis Lake has some tarred trays still in use, although they are no longer recoated. These trays will be replaced with recycled plastic trays over the next three financial years, meaning AOC will have no tarred infrastructure in use by 2025.

Decommissioning tar pits

While AOC has never had ‘operational’ tar pits, it has inherited three historical pits from previous farm owners at Merimbula Lake, Bermagui River and Hastings River. During the year, AOC successfully decommissioned these tar pits and is in discussions to safely dispose of the tar at licenced Environmental Protection Agency (EPA) approved waste management facilities. AOC is committed to assisting and supporting other oyster farmers to safely decommission and dispose of tar from culture practices.

Read more from Roc Partners.

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