Aquaculture Pen / Cage Maintenance SWMS

Aquaculture pen and cage maintenance encompasses routine net cleaning, mooring inspection and adjustment, feed delivery system servicing, and structural repairs on floating sea-cage infrastructure used across Australian salmon, tuna, kingfish and barramundi operations. The work is performed from workboats, walkways and submerged positions, frequently involving commercial divers, lifting of biofouled nets exceeding 500kg, and exposure to open marine conditions. Under WHS Regulation 2011 r291, work performed over or near water where there is a risk of drowning, together with diving work and the handling of heavy plant components, is classified as High Risk Construction Work mandating a documented Safe Work Method Statement before commencement. The Marine Safety (Domestic Commercial Vessel) National Law and AS/NZS 2299.1 commercial diving standards add concurrent duties. A SWMS is the legal mechanism that translates these overlapping obligations into task-level controls, communicated to every worker at sign-on and reviewed when conditions change.

Hazards identified

7 hazards covered, sorted by priority.

Control measures

Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.

1. 1Elimination — Remove divers from routine net inspection by deploying ROV-mounted cameras and net-cleaning robots (Flying Sharks, FNC8) for biofouling assessment before in-water work is authorised.
2. 2Elimination — Schedule mooring and structural maintenance during forecast sea states below 1.5m significant wave height, cancelling work when BoM coastal waters forecast exceeds threshold.
3. 3Substitution — Replace manual net lifting with hydraulic net-washing systems integrated to the workboat, eliminating crane-suspended biofouled net handling over personnel.
4. 4Substitution — Use in-situ net cleaning (cavitation disc systems) instead of net change-outs to reduce diving exposure hours and heavy lifting frequency.
5. 5Engineering — Install continuous fall-arrest rated handrails to AS 1657 on all pen walkways, with self-closing gates at boat transfer points and grip-rated FRP grating surfaces.
6. 6Engineering — Fit four-gas atmospheric monitors (H2S, O2, LEL, CO) on workboats and require pre-entry testing before opening mort socks or accessing enclosed feed silos.
7. 7Administrative — Implement AS/NZS 2299.1 dive plan with surface-supplied air, standby diver, dedicated dive supervisor, and two-way comms; no solo diving permitted under any circumstance.
8. 8Administrative — Conduct daily pre-start briefing using this SWMS, JSEA review of weather window, crew sign-on register, and verification of current commercial diver medicals (AS/NZS 2299.1 Appendix M).
9. 9PPE — Issue AMSA-approved Type 1 inflatable PFDs with integrated PLB and crotch strap for all deck and walkway work; lifejackets worn at all times outside accommodation.
10. 10PPE — Provide neoprene drysuits rated for water temperature, cut-resistant gloves (EN388 Level 5), and full-face dive masks with hot-water suits for sub-12°C operations.

Applicable Codes of Practice

High-Risk Construction Work triggered

Worked example

At a southern Tasmanian salmon lease, a maintenance crew of six is rostered to clean biofouled predator nets on three 168m circumference pens and replace two corroded mooring shackles. At 0600 the supervisor opens this SWMS at the pre-start brief on the workboat wheelhouse, displaying it on the bulkhead-mounted tablet. The crew works through each hazard line: the dive supervisor confirms the swell forecast is 0.8m falling, standby diver is rostered, and surface-supplied air has been function-tested per AS/NZS 2299.1. The deckhand identifies that the mooring shackle replacement requires the deck crane to lift a 380kg chain section — the supervisor cross-references the heavy plant control line and confirms the lift zone exclusion radius and tag-line procedure. Each worker signs the SWMS register, recording diver medical expiry dates. At 1030 a sudden wind shift pushes seas to 1.8m. The supervisor halts diving, reopens the SWMS, and applies the documented weather threshold control — work is suspended, the diver is surfaced via the planned ascent, and the crew transitions to deck-based net mending until conditions reassess. The SWMS amendment is logged with time, decision-maker and reason, satisfying the consultation and review obligation under r291 and creating defensible records for the SafeWork Tasmania inspector's quarterly visit.

Related legislation

• WHS Act 2011 (model)
• WHS Regulation 2025
• AS/NZS 2299 — Occupational diving operations