Western Blue Groper (2020)
Date Published: June 2021
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Western Blue Groper occur along the coasts of SA and southern WA. In SA, small annual catches of Western Blue Groper are mostly taken as incidental bycatch. The average annual catch of the species in SA state-managed waters between 1999–00 and 2018–19 was <500 kg. Catch data for most seasons are confidential. In WA, the species is taken primarily in demersal gillnets. Stock structure is uncertain, but may be complex. In the absence of more detailed knowledge, this assessment is presented at the jurisdictional level. Western Blue Groper are classified as sustainable in WA, and negligible in SA.
Photo: Simon Bryars, Paul Rogers, South Australia Research and Development Institute
Stock Status Overview
|South Australia||South Australia||Negligible|
Western Blue Groper's distribution spans the coastal waters of South Australia and southern Western Australia. Stock structure has not been studied extensively, but acoustic telemetry of tagged adults in South Australia showed a high site fidelity along a narrow strip of fringing coastal reef (~1 km by ~40 m width) throughout a 12-month period [Bryars et al. 2012]. There is some ontogenetic movement towards deeper reefs as they grow [Shepherd and Brook 2007]. This suggests a complex population structure among adults. Here assessments are provided at the jurisdictional stock level.
Stock status for Western Blue Groper in South Australia is reported as Negligible due to historically low catches in this jurisdiction and the stock has generally not been subject to targeted fishing. South Australia’s commercial catch of Western Blue Groper over the past 20 years has averaged <500 kg per annum, and the species is not a major component of recreational landings. Fishing is unlikely to be having a negative impact on the stock.
The Western Blue Groper is a protogynous hermaphrodite (some change sex from female to male) that can reach ~40 kg, with exceptional longevity (71 years), slow growth rate, late onset of sexual maturity (~17 years) at a large total length (~65 cm), very late sex change (age ~35 years) at a very large total length (~82 cm), and highly variable inter-annual recruitment [Coulson et al. 2009, Norriss et al. 2016]. During sub-adulthood there is a migration from inshore protected habitats to deeper (up to 20 m) waters with increasing bottom relief, but they otherwise maintain small home ranges [Shepherd and Brook 2007, Bryars et al. 2012], making them vulnerable to localised depletion from overfishing.
|Species||Longevity / Maximum Size||Maturity (50 per cent)|
|Western Blue Groper||
71 years, 116 cm total length
~17 years, 623-693 mm TL
- Bryars, S., Rogers, P., Huveneers, C., Payne, N., Smith, I. and McDonald, B. (2012). Small home range in southern Australia’s largest resident reef fish, the western blue groper (Achoerodus gouldii): implications for adequacy of no-take marine protected areas. Marine and Freshwater Research, 63: 552-563.
- Coulson, P.G., Hesp, S.A., Hall, N.G. and Potter, I.C. (2009). The western blue groper (Achoerodus gouldii), a protogynous hermaphroditic labrid with exceptional longevity, late maturity, slow growth, and both late maturation and sex change. Fishery Bulletin, 107: 57-75.
- Norriss JV, Fisher EA, Hesp SA, Jackson G, Coulson PG, Leary T, and Thomson AW. (2016). Status of inshore demersal scalefish stocks on the south coast of Western Australia. NRM Project 12034 Final Report. Fisheries Research Report, No. 276. Department of Fisheries, Western Australia, 116 pp.
- Shepherd, S.A. and Brook, J.B. (2007), Distribution and ontogenetic shifts in habitat and abundance of the temperate western blue groper, Achoerodus gouldii (Richardson). Journal of Fish Biology, 71: 1457-1478. https://doi.org/10.1111/j.1095-8649.2007.01616.x
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