The Shark Bay Prawn Managed Fishery (SBPMF) is WA’s highest producing prawn fishery.
The fishery primarily targets Western King prawn (Penaeus latisulcatus) and Brown Tiger prawn (Penaeus esculentus), but also takes a variety of smaller prawn species including Endeavour prawns (Metapenaeusspp.) and Coral prawns.
The Shark Bay Scallop Managed Fishery (SBSMF) catches the saucer scallop (Amusium balloti) and is usually WA’s most productive scallop fishery.
Both the geographic area and fishing season of the two fisheries overlap and vessels that operate within the prawn fishery are also licensed to retain scallops under the SBSM.
Management of the prawn and scallop fisheries is based on input controls, which include limited entry, seasonal and area openings and closures, gear controls and limits on crew
numbers. Both fleets use otter trawl systems and each fleet has a separate standard net size and gear configuration.
Bycatch reduction devices (‘grids’) are mandatory for all prawn and scallop trawl nets and in addition, secondary bycatch reduction devices (fish escape devices) are mandatory for the nets of prawn boats because they fish with small size mesh cod ends.
Because dedicated scallop boats have bigger 100mm mesh cod ends that results in only a small amount of bycatch during trawling, they do not require the secondary devices.
The key harvest strategy for these fisheries is ‘constant escapement’ through the use of real time management of spatial and temporal fishing effort. The Department of Fisheries Research Division regularly surveys the catch and uses target catch rates to provide advice on when to close areas to fishing.
The Vessel Monitoring System (VMS) monitors the location of all activities by licensed fishing boats in these fisheries and adherence to permanent closures.
The seasonal operations of the prawn fishery are dynamic because they depend on the strength and timing of recruitment which, in turn, affects the opening and closing of the fishing season.
These dates vary each year depending on environmental conditions, moon phase and the results of fishery-independent surveys to estimate recruitment strength.
The timing and spatial pattern informs the harvest of the current season’s recruits and the large residual prawns not caught in the previous fishing season. Permanently closed nursery areas within the fishery prevent the catch of small prawns and protect habitat, while spatio-temporal closures serve to target prawns at optimum sizes for market requirements and maintain Tiger prawn breeding stocks.
The opening date of the scallop fishing season is based on a compromise between maintaining breeding stock levels and the seasonal decline in meat condition associated with spawning.
A target estimated scallop catch level for Denham Sound and northern Shark Bay determines when fishing can start in either area each season.
The most recent figures available indicated that survey’s showing low abundance of scallops meant no landings of scallops were allowed in 2013.
The prawn and scallop industries are a major contributor to regional employment and in 2013, approximately 100 skippers and other crew were employed in the prawn fishery.
There was an additional 55 processing and support staff directly employed at Carnarvon.
NorWest Seafood is based in Carnarvon with administration, wharf and engineering staff based at the small boat harbour and a processing factory at Babbage Island. Approximately 70 per cent of the work force is permanently resident in Carnarvon.
The prawn sector also utilises, wherever possible, Western Australian service companies that provide engineering supplies, packaging, transport logistics, ship stores and fuel.
Key Species Fished
|Brown Tiger prawn|
|Endeavour and Coral prawns|
|Western King prawn|