Western Rock Lobster (2020)
Date Published: June 2021
Western Rock Lobster is found only in WA. The stock is sustainable, with steady increases in biomass in recent years. It is a highly valued commercial species and a popular recreational catch.
Stock Status Overview
|Western Australia||West Coast Rock Lobster Managed Fishery||Sustainable||Catches, catch rate, recruitment, egg production, harvest rate|
Western Rock Lobster is a single biological stock, with a distribution along the mid–lower west coast of Western Australia [Kennington et al. 2013], with most of the stock (> 95 per cent) being accessed by the West Coast Rock Lobster Managed Fishery (WCRLMF). As such the assessment of stock status is presented at the biological stock level—West Coast Rock Lobster Managed Fishery (Western Australia).
West Coast Rock Lobster Managed Fishery
The stock status for Western Rock Lobster (Panulirus cygnus) is determined using a weight of evidence approach based on empirical and modelled estimates of a range of indices, including catches, catch rates, recruitment, egg production and harvest rate [de Lestang et al. 2012, de Lestang et al., 2016]. The stock assessment process is reviewed annually as part of the Marine Stewardship Certification (MSC https://fisheries.msc.org/en/fisheries/australian-western-rock-lobster/) process and intermittently by international stock assessment experts (e.g. de Lestang et al. 2012; de Lestang et al. 2019).
The most recent assessment shows that catches in the West Coast Rock Lobster Managed Fishery (Western Australia) have increased slightly over the past few seasons due to small increases in quota and an increase in recreational catch however, they remain 45 per cent lower than the historical average level of catch. Standardised commercial catch rates indicate that biomass has increased in recent years and is now over three times greater than under input controls. Under current exploitation rates, catch rates are predicted to remain stable or increase. The Integrated Population Model (IPM) indicates that catch rates in all locations of the fishery will continue to increase with a continuation of fishing at similar or slightly higher total allowable commercial catches (TACCs) than in the recent past.
Puerulus (post-larval lobsters) monitoring indicates that the current settlement levels are slightly below the historic average. The IPM suggests that this is sufficient to maintain/increase stock abundance at current harvest levels. The IPM currently indicates that the fishery is operating at harvest rates of between 20–30 per cent and these will continue to decline at current or slightly higher TACCs. Fishery-independent egg production indices at all sites are well above long-term levels and above threshold reference levels. These indices indicate high levels of spawning stock exist throughout the fishery. The IPM indicates that the biomass and egg production in all locations of the fishery is currently at the highest levels recorded since the mid-1970s, and that a continuation of fishing at similar or slightly higher TACCs will continue to result in increasing biomass and catch rates.
The above evidence indicates that the biomass of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired. Furthermore, the current level of fishing mortality is unlikely to cause the stock to become recruitment impaired.
On the basis of the evidence provided above, the West Coast Rock Lobster Managed Fishery (Western Australia) biological stock is classified as a sustainable stock.
Western Rock Lobster biology [de Lestang et al. 2012]
|Species||Longevity / Maximum Size||Maturity (50 per cent)|
|Western Rock Lobster||
20+ years, > 150 mm CL
6–7 years, 65–80 mm CL, depending on location
|Traps and Pots|
|Traps and Pots|
|Traps and Pots|
|Traps and Pots|
|Total allowable catch|
|Bag and possession limits|
|Recreational||459 t (2018/19)|
Western Australia – Commercial (catch) The commercial fishing season spans 15 January–14 January the following year. Catches have been presented in this report by calendar year.
Western Australia – Indigenous (catch) (a) The recreational fishing season runs year round but catches in this report have been presented by calendar year; (b) Subject to the defence that applies under section 211 of the Native Title Act 1993 (Cth), and the exemption from a requirement to hold a recreational fishing licence, the non-commercial take by Indigenous fishers is covered by the same arrangements as that for recreational fishing.
- de Lestang S, Caputi N and How J 2016, Western Australian Marine Stewardship Council Report Series No. 9: Resource Assessment Report: Western Rock Lobster Resource of Western Australia. Department of Fisheries, Western Australia.
- de Lestang, S, Caputi, N, How, J, Thomson, A and Stephenson, P 2012, Stock assessment for the West Coast Rock Lobster Fishery, Fisheries Research Report 217, Western Australian Department of Fisheries, Perth.
- de Lestang, S, How, J, Caputi, N, Tuffley, E and Rossbach, M 2019. Summary of the West Coast Rock Lobster Managed Fishery Science and Modelling Review, Fisheries Research Report 295, Western Australian Department of Fisheries, Perth.
- Kennington, WJ, Cadee, SA, Berry, O, Groth, DM, Johnson, MS and Melville-Smith, R 2013. Maintenance of genetic variation and panmixia in the commercially exploited western rock lobster (Panulirus cygnus). Conservation Genetics, 14(1), pp.115–124.