The overall fishery incorporates the commercial and recreational prawn fishing sectors.
We control recreational fishing with bag limits and seasonal closures.
Serious commercial prawning didn’t start in Western Australia until the 1960s, which allowed us to develop measures, including limiting the number of boats fishing, to prevent overfishing.
Over the years, we have also worked with the industry to modify fishing strategies to improve prawn quality and size to maintain economic returns.
Fishing controls include:
Seasonal closures (fishing is closed in hotter months/cyclone periods).
Temporary area closures to protect small prawns and spawning stocks and increase the proportion of larger export-grade prawns caught.
Bans on trawling in nursery areas to protect habitat.
Trawl gear and vessel restrictions.
Incorporating devices in nets to reduce the bycatch of fish and larger marine animals.
The prawn lifecycle is short and can be influenced by the environment, so annual numbers may vary. To catch prawns at the right time and place, fishers must be flexible. Our staff do regular sampling to determine prawn size and numbers, then work with the industry to decide how best to harvest them for the best returns. At the same time, we ensure stocks aren’t overfished. This cooperative arrangement is part of ‘real-time’ management used mainly in the biggest fisheries at Shark Bay and Exmouth Gulf.
Monitoring, assessment and research
Commercial prawn fishers must submit log books showing information for each trawl, each night, for each prawn species caught.
This data allows analysis of where, when and how many prawns are taken from each fishery each day, month and year. In addition, surveys of recruitment (prawns migrating onto the trawl grounds) in March and April, and spawning stocks, in June/July (Shark Bay) and August to October (Exmouth Gulf), provide checks on the health of stocks. For tiger and king prawns, numbers in March/April allow us to forecast the annual catch.
Status of major prawn fisheries 2011
| Shark Bay |
Adequate |
Acceptable |
|---|
| Exmouth Gulf |
Adequate |
Acceptable |
|---|
| Kimberley |
Adequate |
Acceptable |
|---|
| Nickol Bay |
Adequate |
Acceptable |
|---|
| Onslow |
Adequate |
Acceptable |
|---|
Research projects include:
Measuring changes in efficiency when boats change the mesh, size and number of nets used.
Investigating the way prawns and other species interact with trawling gear, larval movement patterns in Shark Bay and potential effects of area closures.
Studies of environmental factors influencing recruitment, such as the Leeuwin Current and water temperature, which help catch predictions.