Marine aquaculture

You will need:

• development approval for aquaculture
• an aquaculture authority.

You may need development approval if your proposed development:

• removes, destroys or damages marine plants
• impacts a declared fish habitat area
• requires tidal works.

Our industry plans identify pre-assessed locations and guidelines for:

• oyster farming in Moreton Bay
• rack, line, and sea-ranching farms in the Great Sandy Marine Park.

A permit is required to collect broodstock and culture stock from Queensland waters.

Engineer-certified plan

When you submit development approval and aquaculture authority applications, an engineer-certified plan of the production system infrastructure that shows all proposed structures and works associated with an aquaculture development must be included as part of an overall scaled site plan.

You will need to engage a registered engineer to prepare a plan for the production system you propose to use.

Water quality

In river systems, areas of brackish or estuarine water decrease in salinity further upstream. While some species prefer brackish water (such as barramundi), others demand higher salinity and better coastal water (reef fish and snapper).

Salinity levels and water quality can be affected by:

• the size of tides
• rainfall and flooding
• ocean currents and water depth
• suspended solids such as clay and organic matter
• dissolved nutrients and toxic chemicals.

Adjustable longline system

Adjustable longline culture in Queensland is predominantly used to grow edible oysters. The Sydney rock oyster is the main oyster species currently farmed in Queensland waters, with some smaller-scale growth of blacklip rock oysters.

Design

An adjustable longline system consists of single lines hung between wooden, steel or plastic posts. Plastic mesh bags containing oysters can be attached to those lines.

Oyster bags are suspended high in the intertidal water column so natural processes can take place beneath.

An adjustable longline system enables lines with oyster bags attached to be raised and lowered, allowing the farmer to control shell growth, condition and cleaning.

Environmental impact

An adjustable longline system has minimal impact on the surrounding environment, but the correct location and design is important. Structures should be narrow and well-spaced, so light can penetrate to reduce the impact to seagrass and other benthic (bottom) plants and animals.

FlipFarm system

FlipFarm culture is growing in popularity in Queensland. The system is used to grow edible oysters.

Design

The FlipFarm system is semi-automated oyster farming technology.

The system uses specially designed floating baskets attached to longlines, allowing oysters to be grown near the water surface where food availability is high.

Longlines are anchored at both ends. The baskets can be mechanically 'flipped' from a work boat while remaining attached to the longlines, exposing oysters to air for short periods and greatly reducing the manual handling normally required in oyster farming.

When installed in a compatible location, the advantages of a FlipFarm system include:

• improved growth rates
• better shell strength and shape
• reduced biofouling
• increased productivity and efficiency.

Environmental impact

The FlipFarm system has minimal impact on the surrounding environment, but the correct location is important.

Structures should be adequately spaced so light can penetrate, reducing the impact to seagrass and other benthic (bottom) plants and animals. The seabed remains free of obstacles (except for anchor points) and natural processes can take place beneath the farm.

As FlipFarm longlines are only anchored at the ends, they tend to flex significantly with wind or currents. This should be considered when planning the farm layout to accommodate intentional movement.

Sea cage system

Sea cages are used for intensive marine culture of:

• barramundi
• cod
• cobia
• coral trout
• lobster
• mulloway
• snapper.

Design

Sea cage nets are commonly made of nylon mesh. Semi-rigid PVC-coated polyester, brass and galvanised steel netting are also used and may be more resistant to biofouling and to prevent predation from sharks and other marine animals.

The type, size and design of sea cages depends on the species, site conditions and environmental factors.

Sea cage culture has been successful and shown significant economic benefits domestically. In Tasmania and South Australia, financial and technical innovation applied to sea cage culture has allowed the salmon and tuna fish farming industries to expand rapidly.

Environmental impact

Sea cage finfish culture is considered an ecologically sustainable system when the farm is closely managed and good husbandry practices are followed to minimise effects on the local environment.

Sea ranching system

A sea ranching system is suitable for:

• sea cucumbers (beche de mer)
• scallops.

Scallop and sea cucumber sea ranching is only viable if the:

• culture area is closed to commercial trawl fishing while the animals grow
• animals remain in the specified culture area until harvest.

Scallops are normally grown in deep water and harvested using trawl boats. Sea cucumbers are normally harvested by hand, either by diving or hand-harvesting at low tide in shallow water.

Design

In a sea ranching production system, juveniles (also called spat) feed naturally with no input from the farmer. The environment provides the animals with all the food they need.

Hatchery-produced or wild-caught juveniles are placed into the natural environment where they are allowed to grow without containment structures. Juveniles are placed on the seabed, usually in the form of slurry, by a length of pipe or by hand.

Surface line system

A surface line system is suitable for:

• pearl oysters
• scallops
• mussels
• tunicates
• seaweeds
• sponges.

Design

In a surface line production system, filter-feeding animals are grown on structures placed in the water column.

These structures consist of a series of parallel ropes that are buoyed at the surface with floats and anchored to the seabed. Animals are grown in panel-style baskets, small cages or on ropes that are suspended below floating surface lines.

Rows of lines and floats are normally visible on the surface but are usually coloured so that they blend into the surroundings.

Environmental impact

Surface line culture is designed to reduce any negative impacts on aquatic wildlife. Lines are kept taut and are well spaced to reduce the risk of entanglement.

The seabed remains free of obstacles (except for anchor points) and natural processes can take place beneath the farm. The lines should be adequately spaced to minimise benthic (bottom) disturbance.

Subsurface line system

A subsurface line system is suitable for:

• pearl oysters
• scallops.

Design

In a subsurface line system, the horizontal mainlines and suspended culture panels are positioned well below the surface of the water. Since the mainlines are submerged, vessels can move freely over the top of the farm.

The culture panels are held off the seabed by a series of floats along the mainline. The lines and supporting floats are submerged, meaning the only structures visible on the surface are site corner markers and optional intermittent buoys to mark the location of submerged lines and anchors.

Environmental impact

Submerged lines help protect the cultured animals from the effects of swell and wave action.

As with a surface line system, lines are kept taut and well spaced to allow aquatic wildlife to move freely and reduce the risk of entanglement. Wide spacing of lines allows for flushing and good light penetration to the seabed, so natural processes can take place beneath the lines.