Barramundi Lates calcarifer

Barramundi Fishery (Northern Territory) management unit

Commercial catches in the Barramundi Fishery (Northern Territory) are stable and well within historical levels, and monitored stocks have a healthy size and age distribution³. Catch rates have increased over the past 5 years. However, there was a substantial decrease in the 2013 rate, associated with a poor wet season and several experienced operators selling their licences. Recaptures from tagging programs suggest that the annual harvest rate from all sectors combined is consistently below 5 per cent. Abundance surveys indicate high levels of recruitment during high-rainfall wet seasons³. The above evidence indicates that the stocks in this management unit are unlikely to be recruitment overfished and that current catch levels are unlikely to cause the stocks to become recruitment overfished.

On the basis of the evidence provided above, the management unit is classified as a sustainable stock.

Kimberley Gillnet and Barramundi Managed Fishery (Western Australia) management unit

The harvest strategy for Barramundi in the Kimberley Gillnet and Barramundi Managed Fishery in the Kimberley region of Western Australia is based on a constant commercial catch policy where the annual commercial catches of Barramundi are allowed to vary within the target catch range, which is based on a historical catch range that has been shown not to impair recruitment. The threshold values have been calculated as being within the range 33–44 tonnes (t), with a limit reference range of 23–54 t⁴.

The Barramundi catch in 2013 was 52.1 t, above the target catch range but below the limit range. The increase in catch was due to an increase in fishing effort in two sectors of the fishery (the Kimberley Coast and Broome). The increased catch was obtained with high catch rates (kg/block day) across the fishery, indicating that it was not a direct result of a declining stock biomass for Barramundi. Furthermore, in 2013, two licences were removed from the Broome sector of the fishery⁴, which is now only open to recreational and Indigenous fishing. This effort removal is likely to reduce levels of catch in future years. The above evidence indicates that the biomass of the stocks in this management unit is unlikely to be recruitment overfished and that current levels of fishing mortality (catch) are unlikely to cause the stocks to become recruitment overfished.

On the basis of the evidence provided above, the management unit is classified as a sustainable stock.

Southern Gulf of Carpentaria biological stock

The southern Gulf of Carpentaria contributes almost the entire Gulf of Carpentaria Inshore Fin Fish Fishery (Qld) commercial harvest and receives the greatest fishing pressure⁵. Biological monitoring and anecdotal reports indicate good numbers of large fish present in the stock. Total mortality rate estimates are stable, and fishing mortality rates have been less than natural mortality rates for the past 4 years⁵. Commercial catches of Barramundi have been increasing since 1992 and reached record levels in 2011⁵. However, the Barramundi commercial harvest in 2013 was almost 51 per cent lower than in 2011, and the lowest since 2005⁵. This was likely to be due partly to poor seasonal river flows, which are known to affect catchability of Barramundi⁶. Age-structure monitoring indicates a stock with varied but continual recruitment. Low recruitment in 2012 and 2013, possibly due to low river flows in those years, prevented 3- and 4-year-olds from fully recruiting to the estuarine fishery⁶. Queensland size limits, and seasonal and spatial closures for Barramundi ensure that a large proportion of the spawning stock is protected. As a result, the biomass of the Southern Gulf of Carpentaria biological stock is not considered to be recruitment overfished, and current fishing mortality is unlikely to cause the biological stock to become recruitment overfished.

On the basis of the evidence provided above, the biological stock is classified as a sustainable stock.

Northern Gulf of Carpentaria biological stock

Commercial catches of the northern Gulf of Carpentaria biological stock are small and variable, as the small river systems in this area are unlikely to support a large stock of Barramundi⁵. Biological evidence indicates that the growth rate of fish in this stock may be slower and fish mature earlier than in other stocks and management units⁷, such that the size limits protect a larger proportion of the spawning population⁵ . Catch from this stock has declined since 2010, mainly as a result of reductions in fishing effort for economic reasons⁵. There has been a rising trend in catch rate over the past 20 years, which indicates that the biomass of this stock is unlikely to be recruitment overfished (unpublished data from the Queensland Department of Agriculture, Fisheries and Forestry). The above evidence indicates that this stock is unlikely to be recruitment overfished and the current level of fishing pressure is unlikely to cause the stock to become recruitment overfished.

On the basis of the evidence provided above, the biological stock is classified as a sustainable stock.

Princess Charlotte Bay biological stock

Commercial catches of the Princess Charlotte Bay stock are small (4 per cent of the catch of the East Coast Inshore Fin Fish Fishery)⁵. Numbers of commercial operators in the Princess Charlotte Bay region have halved since 2008 to just five operators reporting catches in 2013. Spatial closures introduced in 2009, seasonal closures and size limits protect significant parts of the Princess Charlotte Bay spawning stock from commercial fishing. The catch history since 1993 is relatively stable, and catch rates have increased⁵. The above evidence indicates that the biomass of the Princess Charlotte Bay biological stock is not considered to be recruitment overfished and current fishing mortality is unlikely to cause the biological stock to become recruitment overfished.

On the basis of the evidence provided above, the biological stock is classified as a sustainable stock.

North-east coast biological stock

The north-east coast stock represents approximately 24 per cent of the 2013 Barramundi harvest on the Queensland east coast⁵. Summer rainfall and flow rates have had a positive effect on catches from this stock, both immediately on catchability and through a 3–4-year lag effect on enhanced recruitment⁸. Biological monitoring and anecdotal reports indicate relatively stable length and age structures over time, and good numbers of large fish are present in the stock⁵. Total mortality rate estimates are stable, and fishing mortality rates are less than natural mortality rates⁵. Although commercial catches have declined since 2011, this has been predominantly due to poor seasonal river flows. Queensland size limits, and seasonal and spatial closures for Barramundi ensure that a large proportion of the spawning stock is protected. As a result, the biomass of the north-east coast stock is not considered to be recruitment overfished, and current fishing mortality is unlikely to cause the biological stock to become recruitment overfished.

On the basis of the evidence provided above, the biological stock is classified as a sustainable stock.

Mackay biological stock

Commercial catches in the Mackay stock represent around 20 per cent of the East Coast Inshore Fin Fish Fishery (Qld) catch⁵. The catch history has been relatively stable over time, with a slight increasing trend; catch rates show a similar but somewhat stronger upward trend⁵. Queensland size limits, and seasonal and spatial closures for Barramundi ensure that a large proportion of the spawning stock is protected. The above evidence indicates that the biomass of the biological stock is not considered to be recruitment overfished and current fishing pressure is unlikely to cause the Mackay biological stock to become recruitment overfished.

On the basis of the evidence provided above, the biological stock is classified as a sustainable stock.

Central east coast biological stock

The central east coast is the major stock on the Queensland east coast, comprising 53 per cent of the 2013 East Coast Inshore Fin Fish Fishery (Qld) catch. In 2011, there was a fivefold increase in commercial catch, which has remained at high levels⁵. These high catches were due to stocked fish from Lake Awoonga moving into the Gladstone area following a flood in late 2010 to early 2011. Two subsequent high river flow years increased catchability in both the Gladstone area and Fitzroy River, with strong year-classes entering these systems during this time. Fishery-dependent monitoring shows stable length and age structures⁵. Queensland size limits, and seasonal and spatial closures for Barramundi ensure that a large proportion of the spawning stock is protected. The above evidence indicates that the biomass of the central east coast biological stock is not considered to be recruitment overfished and current fishing mortality is unlikely to cause the biological stock to become recruitment overfished.

On the basis of the evidence provided above, the biological stock is classified as a sustainable stock.