Northern Prawn Fishery (Commonwealth) Blue Endeavour Prawn management unit
Blue Endeavour Prawns are assessed as part of the integrated bioeconomic model constructed for the Northern Prawn Fishery (Commonwealth)1. Commercial catches of Endeavour Prawn are disaggregated into separate species using a model incorporating historical fishery-independent survey data2. For Blue Endeavour Prawns, the estimate of the breeding stock size at the end of 2010 was 118 per cent (range 107–122 per cent) of the breeding stock size that would be required for maximum sustainable yield (SMSY)1. As a result, the management unit is not considered to be recruitment overfished. The commercial catch in 2010 (~316 tonnes [t]), was below the estimate of MSY (base case 873 t; range 629–893 t). This level of effort is unlikely to cause the management unit to become recruitment overfished.
On the basis of the evidence provided above, the management unit is classified as a sustainable stock.
Northern Prawn Fishery (Commonwealth) Red Endeavour Prawn management unit
Although stock assessments have been attempted for Red Endeavour Prawns, there is currently no reliable assessment to confidently classify the status of this stock3. On this basis, the management unit is classified as an undefined stock.
Torres Strait Prawn Fishery (Commonwealth) Blue Endeavour Prawn management unit
The most recent assessment4 estimates that biomass in 2007 ranged from 71 to 85 per cent of the unfished (1967) level. As a result, the management unit is not considered to be recruitment overfished. The reported commercial catch of Blue Endeavour Prawns in 2010 was 109.6 t. This is well below the estimates of MSY from the most recent assessment (range 899–1368 t). This level of effort is unlikely to cause the management unit to become recruitment overfished.
On the basis of the evidence provided above, the management unit is classified as a sustainable stock.
East Coast Otter Trawl Fishery (Queensland) Red and Blue Endeavour Prawn management unit
Since 1998, there has been a general upward trend in the unstandardised catch per unit effort (CPUE)5. The average annual CPUE for recent years (2007–10) is 65 kg/day, which is about 60 per cent higher than the long-term average. The management unit is not considered to be recruitment overfished.
The average annual commercial harvest of Blue and Red Endeavour Prawns (combined) in recent years (2007–10) was 496 t, which is half of the long-term average of 988 t for the years 1990–20065. The fishing effort associated with the harvest of this catch (7005 days) is only 31 per cent of the long-term average of 22 802 fishing days. This level of catch and effort is unlikely to cause the management unit to become recruitment overfished.
On the basis of the evidence provided above, the management unit is classified as a sustainable stock.
Exmouth Gulf Prawn Managed Fishery (Western Australia) Blue Endeavour Prawn management unit
The Exmouth Gulf Prawn Managed Fishery (Western Australia) constitutes the majority of the commercial landings of Blue Endeavour Prawns in Western Australia. There is no formal assessment for Blue Endeavour Prawns, which are byproduct species whose distribution overlaps that of Brown Tiger Prawn (Penaeus esculentus). In the Exmouth Gulf Prawn Managed Fishery (Western Australia) management unit, the breeding biomass of Blue Endeavour Prawns is considered to be adequate because a significant portion of the Blue Endeavour Prawn breeding biomass is protected by the Tiger Prawn spawning closures. As a result, the management unit is not considered to be recruitment overfished.
With respect to fishing mortality, a target catch range is set at 120–300 t, based on historical catches between 1989 and 1998, when it was considered that the target Brown Tiger Prawn was not overfished. Since Blue Endeavour Prawns are not targeted, catch rates may not be an indication of abundance (biomass) and cannot be used to assess the status of this species. Total catch (138 t) in 2010 was within the target catch range and below the average catch over the past 15 years (216 t)6. This level of effort is unlikely to cause the management unit to become recruitment overfished.
On the basis of the evidence provided above, the management unit is classified as a sustainable stock.
North Coast Prawn Managed Fisheries (Western Australia) Blue Endeavour Prawn management unit
Blue Endeavour Prawns are landed in low numbers in the North Coast Prawn Managed Fisheries (Western Australia), since they are not the target species. Therefore, catch-and-effort data cannot be used to determine the status of the species in these fisheries. Hence, the management unit is classified as an undefined stock.
Commercial harvest of Endeavour Prawns remains at historically low levels after a series of declines in both effort and numbers of active vessels since the late 1990s. These declines resulted from overall prawn trawl effort removal, decreasing prices for Endeavour Prawns and increasing fuel prices3,11. Although the distributions of Tiger and Endeavour Prawns overlap in most fisheries and the latter are often secondary target species, the decline in Endeavour Prawn harvest has been much greater than that for Tiger Prawn, as a result of fishers targeting the more valuable Tiger Prawn4.
In the Northern Prawn Fishery (Commonwealth), Endeavour Prawns are a byproduct taken when fishing for Tiger Prawns3. The Endeavour Prawn commercial catch of 429 t in 2010 was above the 346 t taken in 2009. In 2002, measures to reduce effort on Tiger Prawn stocks by 40 per cent were introduced, which also led to a decline in catch of Endeavour Prawns12. The 2010 harvest of Endeavour Prawns in the Torres Strait Prawn Fishery (Commonwealth) was 108 t. The proportion of Endeavour Prawns in the commercial catch in 2010 was the lowest on record, as a result of fishers targeting the more valuable Tiger Prawn, which had the highest CPUE on record in 2010. The 2010 commercial harvest of Endeavour Prawns (predominantly Blue Endeavour Prawns—80 per cent) in the East Coast Otter Trawl Fishery (Queensland) was 579 t. Historically low catches are the result of fishers targeting the higher value Tiger Prawns and much lower fishing effort in the East Coast Otter Trawl Fishery overall5,11.
Catches from Western Australian fisheries in 2010 contributed about 10 per cent of the national landings. Endeavour Prawns are principally caught as secondary target (or byproduct) species within multispecies prawn fisheries, especially in the Exmouth Gulf Prawn Managed Fishery (Western Australia). Minor landings of Endeavour Prawns are reported from the North Coast Prawn Managed Fisheries (Western Australia), and negligible quantities are reported from Shark Bay. Low fishing effort and targeting of Banana and Brown Tiger Prawns in the North Coast Prawn Managed Fisheries (Western Australia) contributed to low Endeavour Prawn landings.