On 5 May 2017, the EPA Director issued a draft determination reducing the overall biomass cap for Macquarie Harbour from 1 June 2017 to 12,000t, allowing each of the three salmon companies farming in the harbour to stock their leases at 13t/ha.
The Director was satisfied that the reduced biomass cap was necessary, as recent IMAS data shows the harbour is “under a level of stress that may not be sustainable in the long term” and two recent mass fish mortality incidents highlight the need for caution.
Despite this finding, the Director’s determination will allow companies who install an “approved waste collection system” to stock up to 28t/ha. Last week, Tassal indicated that, due to the volume of fish it already has growing in the Harbour, it expected overall biomass to reach 18,000t during late 2017.
The “approved waste collection system”, effectively a tarpaulin installed beneath pens allowing fish waste to be collected and removed, is currently untested. The Director said:
While waste collection is technically feasible, it will be a challenging endeavour in Macquarie Harbour and will need to be carefully planned, executed, monitored and subject to ongoing review.
Tassal proposes to trial an experimental waste collection system beneath one of its existing pens – the proposal will be assessed by the EPA and, if approved, managed under an Environment Protection Notice.
In his statement of reasons, the Director noted Huon Aquaculture’s view that the environmentally compromised harbour cannot sustain more than 10,000t, but considered the proposed biomass cap was appropriate given recent signs of recovery. He said the proposed cap would “encourage remediation of harm and promote mitigation of any adverse effects that fish farming has on the Harbour.”
The Director noted the “social and economic” consequences to Tassal of destocking, and considered that “removal of the excess fish prior to planned harvesting [in December 2017] will significantly impact the community.” His decision to allow for an approved waste collection system was to provide Tassal with an opportunity to harvest its current stock while minimising environmental impacts.
It is unclear whether there will be any opportunity for public comment on the proposed waste collection system.
Are you confused about what’s been going on in Macquarie Harbour? Check out our timeline of key events.