Ocean Sand Crab (2020)
Ovalipes australiensis
Date Published: June 2021
Summary
Ocean Sand Crab occurs around Australia's southerly coastlines from approximately Wide Bay in QLD to Rottnest Island in WA (including TAS). Of the three jurisdictional stocks reported here, those in SA and WA are classified as sustainable, while the NSW stock is classified as undefined.
Stock Status Overview
Jurisdiction | Stock | Stock status | Indicators |
---|---|---|---|
New South Wales | New South Wales | Undefined | Catch, standardised catch rates |
South Australia | South Australia | Sustainable | Catch, targetted nominal catch rates |
Western Australia | Western Australia | Sustainable | Catch, nominal catch rates |
Stock Structure
Ocean Sand Crab is distributed in Australia from Wide Bay in Queensland around the south and east coasts to Rottnest Island in Western Australia, including Tasmanian Waters [Kailola et al. 1993].
In South Australia, the commercial fishery for Ocean Sand Crab is heavily concentrated in and around Coffin Bay on the West Coast, and catches have also occurred in Gulf St Vincent and Spencer Gulf [Steer et al. 2020]. Commercial fishing for Ocean Sand Crab in Western Australia is currently focused on nearshore waters in and around the south coastal town of Albany.
The biological stock delineation of Ocean Sand Crab remains unclear. Here, assessment of stock status is presented at the jurisdictional level—South Australia, Western Australia, and New South Wales.
Stock Status
New South Wales
In NSW Ocean Sand Crab is caught as by-product of the Ocean Trawl Fishery (OTF), mainly from waters north of Coffs Harbour. This fishery has produced > 90 per cent of the catch of the catch of Ocean Sand Crab in NSW since 2009–10. Reported landings declined from 9.6 tonnes (t) (2013–14) to 3.2 t (2017–18) and the 1.2 t landed in 2018–19 was well below the 10-year average landings of 5.5 t. Standardised commercial catch rates (in mean CPUE kg.day-1) is likely to be the most reliable index of relative abundance for Sand Crab. For recent data analysed as mean daily catch rates (available from 2009–10 to 2018–19), catch rates have declined and were below the 10-year average over the last two years. Recreational catch is unknown [Murphy et al. 2020]. There are no data available to estimate biomass or exploitation rates. In addition, there is no knowledge on recruitment or harvestable biomass. This prevents assessment of current stock size or fishing pressure. Consequently, there is insufficient information available to confidently classify the status of this stock.
On the basis of the evidence provided above, Ocean Sand Crab in NSW is classified as an undefined stock.
South Australia
In South Australia, access to take Ocean Sand Crab is provided via a Marine Scalefish Fishery (MSF) licence endorsed with Sand Crab entitlements [PIRSA 2013]. Commercial fishers are restricted to a nominated quantity of crab nets/pots. Recreational fishers also target Sand Crabs using hoop or drop nets, and have a combined Ocean Sand/Blue Swimmer Crab bag and boat limit of 20 and 60 crabs, respectively [PIRSA 2016]. Throughout South Australia, a minimum legal size of 100 mm carapace width (measured across the widest point) has been enforced since 1992 [Jones 1995]. The fishery is largely based on the capture of male crabs, as the majority of females captured are below the minimum legal size [Jones and Deakin 1997].
The most recent stock assessment [Steer et al. 2020] used data up to 31 December 2018. The primary measures of biomass and fishing mortality for the South Australian jurisdiction are the total commercial catch and targeted nominal CPUE. Comparisons between recent catch and CPUE trends and values in the past decade is considered to provide a reliable proxy for relative biomass and fishing mortality.
Trends in commercial catches of Sand Crab have generally declined since 2005. The total harvest in 2018 was 44.2 t, this was below the ten-year average (2008–17; 67.7 ± 5.9 t). Recreational catch levels are considered to be relatively low, and the most recent estimate was 9.9 t in 2013–14 [Giri and Hall 2015]. Commercial catch rate has been highly variable, however, and there has been a general increase since 2007. In 2018, the targeted crab net/pot catch rate was 131 kg/fisherday, which was above the 10-year average (2008–17; 113.4 ± 4.3 kg/fisherday). Increasing catch rates and decreasing catch and effort levels are likely a result of increases in efficiencies in the fishery, rather than evidence of a decline in recruitment. The above evidence indicates that biomass of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired. Furthermore, the above evidence indicates that the current level of fishing mortality is unlikely to cause the stock to become recruitment impaired.
On the basis of the evidence provided above, Ocean Sand Crab in South Australia is classified as a sustainable stock.
Western Australia
No commercial catches of Ocean Sand Crab had been reported in WA prior to the issue of a five-year Instrument of Exemption (IOE) in 2016 that endorsed a single commercial fisher to target sand crabs using purpose-designed hourglass traps in waters along the South Coast between Cape Leeuwin and Hopetoun. Fishing between 2016 and 2019 has concentrated along coastal beaches in and around Albany, with fishing effort primarily driven by market demand (annual catches ranging from around 1–2 t). Although occasional catches have been reported by boat-based recreational fishers, Ocean Sand Crab is not considered an important recreational species in WA. No Ocean Sand Crab catches were reported by boat-based recreational fishers in WA during 2017–18 [Ryan et al. 2019]. While stock size and relative exploitation along the south coast is not yet fully understood, the level of commercial and recreational catch and effort remains very low.
On the basis of the evidence provided above, Ocean Sand Crab in Western Australia is classified as sustainable stock.
Biology
Species | Longevity / Maximum Size | Maturity (50 per cent) |
---|---|---|
Ocean Sand Crab | Ocean Sand Crabs grow to slightly more than 100 mm carapace width [Jones and Morgan 1994]. Longevity of Ocean Sand Crabs is unknown. |
Size and age at maturity are unknown for Ocean Sand Crabs. A study on the reproductive biology of Ocean Sand Crabs in Coffin Bay (SA) determined that they are winter spawners with reproductive activity peaking in July and berried females present until late August [Deakin 1996]. |
Tables
Western Australia | New South Wales | South Australia | |
---|---|---|---|
Commercial | |||
Gillnet | |||
Crab Trap | |||
Otter Trawl | |||
Various | |||
Unspecified | |||
Pots and Traps | |||
Recreational | |||
Various |
Method | Western Australia | New South Wales | South Australia |
---|---|---|---|
Commercial | |||
Egg bearing females protected | |||
Fishing gear and method restrictions | |||
Limited entry | |||
Spatial closures | |||
Spatial restrictions | |||
Indigenous | |||
Customary fishing management arrangements | |||
Recreational | |||
Bag and possession limits |
Western Australia | New South Wales | South Australia | |
---|---|---|---|
Commercial | 1.21t | 63.59t | |
Recreational | Nil recorded (2017–18) | Unknown (2017–18) |
New South Wales – Indigenous (Management Methods) https://www.dpi.nsw.gov.au/fishing/aboriginal-fishing
New South Wales – Recreational (Catch) Murphy et al. [2020].
Western Australia - 2017–18 boat based recreational catch nil [Ryan et al. 2019]
References
- A field guide to crustaceans of Australian waters. Reed, Chatswood NSW. 157 & 162.
- Deakin S (1996) Reproductive biology of the sand crab (Ovalipes australiensis) found in the Farm Beach/Point Longnose area. Honours Thesis- Adelaide University, South Australia. 54 pp.
- Giri, K., & Hall, K. (2015). South Australian recreational fishing survey. Fisheries Victoria Internal Rep ort Series No. 62.
- Jone GK and Deakin S (1997). Sand crabs (Ovalipes australiensis ). Fisheries Assessment Report to PIRSA for the Marine Scalefish Fishery Management Committee, South Australian Fisheries Assessment Series 97/12. 20 pp.
- Jones GK (1995). A review of the catch and effort and fisheries biology of the Coffin Bay Sand Crab (Ovalipes australiensis) fishery. SARDI Reserach Report Series, No. 7. 23 pp.
- Kailola P, Williams MJ, Stewart PC, Reichlet RE, McNee A, Grieve C (1993). Australian fisheries resources. Bureau of Resource Sciences and Fisheries Research and Development Corporation, Canberra.
- Murphy, J.J., Ochwada-Doyle, F.A., West, L.D., Stark, K.E. and Hughes, J.M., 2020. The NSW Recreational Fisheries Monitoring Program - survey of recreational fishing, 2017/18. NSW DPI - Fisheries Final Report Series No. 158.
- PIRSA (2013). Management Plan for the South Australian Commercial Marine Scalefish Fishery. PIRSA Fisheries and Aquaculture, Adelaide, 143 pp The South Australian Fishery Management Series, Paper No. 59.
- PIRSA (2016). Review of size, bag and boat limits in South Australia's recreational fishing sector, marine and freshwater. Support document for the Management Plan for recreational fishing in South Australia. PIRSA Fisheries and Aquaculture, Adelaide, 54 pp.
- Ryan, K.L., Hall, N.G., Lai, E.K., Smallwood, C.B., Tate, A., Taylor, S.M. and Wise, B.S., 2019. State-wide survey of boat-based recreational fishing in Western Australia 2017/18. Fisheries Research Report No. 297, Department of Primary industries and Regional Development, Western Australia. 195pp.
- Steer MA, Fowler AJ, Rogers PJ, Bailleul F, Earl J, Matthews D, Drew M and Tsolos A (2020). Assessment of South Australian Marine Scalefish Fishery in 2018. Report to PIRSA Fisheries and Aquaculture. South Australian Research and Development Institute (Aquatic Sciences), Adelaide. SARDI Publication No. F2019/000427-3. SARDI Research Report Series No. 1049. 214 pp.