|Scientific Name:||Panulirus cygnus George, 1962|
Panulirus longipes ssp. cygnus George, 1962
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Butler, M., Cockcroft, A., MacDiarmid, A. & Wahle, R.|
|Reviewer(s):||Collen, B., Livingstone, S. & Richman, N.|
|Contributor(s):||Batchelor, A., De Silva, R., Dyer, E., Kasthala, G., Lutz, M.L., McGuinness, S., Milligan, H.T., Soulsby, A.-M. & Whitton, F.|
Panulirus cygnus has been assessed as Least Concern. This species is harvested throughout its range along the coast of Western Australia, however catch per unit effort data indicates stability in the stock. The fishery is well managed and appropriate restrictions have been introduced when catch declines have been highlighted by ongoing monitoring. There is substantial research supporting this fishery that ensures it remains sustainable. Continued monitoring and regulation mean this species is currently not threatened by extinction.
|Range Description:||This species is restricted to the coast of Western Australia, from Northwest Cape to Hamelin Harbour including offshore islands (Holthuis 1991).|
Native:Australia (Western Australia)
|FAO Marine Fishing Areas:|
Indian Ocean – eastern
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There are no detailed population data for this species. It has been said to be an abundant species in areas of suitable habitat, with the Western Australia Rock Lobster fisheries catching over 10,000 mt annually (Holthuis 1991).|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||This species can be found sheltering in vegetated rocky reefs and coral reefs at a depth range of 0 - 120 m, although is more commonly found to depths of 90 m (Holthuis 1991).|
|Generation Length (years):||7.5-10|
|Use and Trade:||
This species is commercially harvested throughout its range, and is currently Australia's most valuable single species fishery with an average annual income of US$ 300 million (Phillips and Melville-Smith 2006). Over the last twenty years annual landings have ranged between 8,000 - 14,000 tonnes (FISHSTAT Plus 2000). The recreational fishery currently harvests an average of 600 tonnes per year (Melville-Smith et al. 2004). There are currently 545 boats operating on this fishery, deploying a total of 57,000 pots.
"The western rock lobster fishery is the most valuable single-species fishery in Australia and usually represents about twenty per cent of the total value of Australia's fisheries" (The Department of Fisheries 2004). The majority of the catch is made up of Panulirus cygnus, although there are seven other species of rock lobster in Western Australia. Catch is exported as whole lobsters (frozen or fresh) to the USA, and Asia (China, Taiwan, Hong Kong, Japan), with a significant shift to the Asian market in the 1990s (The Department of Fisheries 2004).
During the open season (November - June) the lobsters are fished using baited pots. The sustainable catch for this fishery is estimated at between 10,000 and 15,000 tonnes per year, although the size of the actual catch varies between 8,000 and 14,500 tonnes (The Department of Fisheries 2004).
Catch Per Unit Effort (CPUE)
Over the last 50 years CPUE has declined from approximately 2 kg per pot, to approximately 1 kg per pot, however this level has remained relatively stable since the late 1970s (Wallace et al. 1998). This trend may be complicated by changes in efficiency that have been noted over this time frame and changes in fishing effort spatially (Wallace et al. 1998).
The fishery is split into three management zones: Stock status is assessed annually in each zone using both fishery dependent and fishery independent data on breeding stock biomass, log book estimates on berried female biomass, depletion estimates of residual biomass, harvest rate and efficiency increases (Caputi et al. 2008).
Status of Zone A
Catches in 2004 through to 2006 are the highest on record, with a harvest rate of 85% based on depletion analysis which is currently considered as sustainable. There has been an increase in fishing efficiency and in increase in the return of berried females. The fishery independent breeding stock index (BSI) indicates a decline since the 1997/1998 season to 2005/2006 from approximately 1.75 to just below 1, though in the 2006/2007 there was an increase to just above 1. This is in contrast to the model-derived BSI which indicates that breeding stock biomass is well above the 1980 level. Size at maturity is currently below the minimum legal size for harvest (Caputi et al. 2008).
Status of Zone B
Harvest rate has increased since 1995/1996 although since 2002 this has levelled off at approximately 80%. In 2005/2006, a 15% reduction in effort was implemented. The effects of this are yet to be seen. Over the past 13 years there has been a rapid increase in efficiency. Overall there has been a decline in the number of berried females being returned to the water. The fishery-independent BSI is currently said to be above the biological reference point (BRP) of 1980, which is in agreement with the fishery-dependent BSI and model-derived BSI, however it is very close to the BRP and stock status is of concern (Caputi et al. 2008).
Status of Zone C
Harvest rate has increased slightly and is currently at approximately 70% which is considered sustainable. There is a noted increase in efficiency, though this is still lower than that seen in Zone B. Numbers of berried females being returned to the water is currently at a record high. Both the fishery dependent and fishery independent BSIs indicate that breeding stock is above the BRP, however the fishery independent BSI indicates that levels are above the BRP to a lesser degree. Catches have been below average which was predicted until 2009/2010 as a result of below average puerulus settlement. Settlement rates are said to have been impacted by weak Leeuwin Currents; this may impact spawning stock biomass in the future (Caputi et al 2008).
In summary, the breeding stocks in both Zones A and C are considered relatively healthy however BRP levels are needed for the BSI in Zone A, and continued monitoring of the settlement rate in Zone C is required. Zone B is the most heavily exploited of all three zones with BSI limits now close to the BRP. This needs to be monitored as any continued decrease in this level will result in dramatic declines in the annual catch.
Despite the high exploitation rate the fishery is well managed (see Conservation section), and in 2000 was one of the first fisheries in the world to become Marine Stewardship Council certified as an ecologically sustainable fishery (The Department of Fisheries 2004).
This species is harvested throughout its range. Overall harvesting does not pose a threat to this species, however it does appear to be more vulnerable in some areas where exploitation is greatest (Caputi et al. 2008). Despite coastal development along Western Australia the species does not appear to impacted by this threat (The Fisheries Department 2004).
The following fishery management measures are in place to ensure sustainable practices (The Department of Fisheries 2004):
The Department of Fisheries staff act as advisers to the Rock Lobster Industry Advisory Committee (RLIAC) and there is close consultation between this body, the Department of Fisheries, the fishing industry and the Minister on the status of the rock lobster fishery. Public submissions are welcomed and considered by the RLIAC (The Department of Fisheries 2004). Continued monitoring will ensure the population of this species is sustained, and prevent over-exploitation.
In 2000, the fishery was awarded the Marine Stewardship Council certificate for operating in an ecologically sustainable way.
|Citation:||Butler, M., Cockcroft, A., MacDiarmid, A. & Wahle, R. 2011. Panulirus cygnus. The IUCN Red List of Threatened Species 2011: e.T170073A6725821.Downloaded on 20 October 2017.|
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