*

Over recent decades, the Longspined Sea Urchin has extended its range southwards to VIC and TAS, reflecting the increasing influence of the south-flowing Eastern Australian Current in those latitudes. At high densities, Longspined Sea Urchins can damage kelp habitats through overgrazing, leading some jurisdictions to pursue urchin removal programs. Longspined Sea Urchin stock structure is uncertain and management arrangements differ across jurisdictions, so this assessment is presented at the jurisdictional level. Longspined Sea Urchin are classified as sustainable in NSW, TAS and VIC.

Within its historic endemic distribution along the central east coast of Australia, the Longspined Sea Urchin, Centrostephanus rodgersii, inhabits coastal reefs in habitats consisting of a mosaic of foliose and turfing algae, typically in relatively shallow water (less than approximately15 m depth). In these areas, Lonspined Sea Urchin grazing can create and maintain habitats devoid of foliose algae and dominated by crustose coraline algae-covered rock, commonly termed ‘barrens’ [Underwood et al. 1991]. Within this historic range and over the 30 years to 2020, Glasby and Gibson [2020] estimated that there had been relatively small changes in the aerial extent of barrens, with some sites showing very little change or a reduction in extent. Densities of Longspined Sea Urchins are typically lower in nearshore mosaic habitats than in barrens [Blount 2004; Ling et al. 2009], likely a reponse to food supply [Ling and Johnson 2009]. In contrast, age structures appear similar between habitats, with evidence indicating no difference in the longevity of Longspined Sea Urchins between fringing and barrens habitats [Blount et al. 2024]. 

Over the last several decades the Longspined Sea Urchin has undergone a range extension to Victoria and Tasmania from NSW due to extensions in the warm East Australia Current brought about by climate change and modulated by larval thermal tolerance limits [Johnson et al. 2005; Ridgway 2007; Ling 2008; Byrne et al. 2022]. This southerly movement is likely to continue, accompanied by density reductions in northern parts of the range [Davis et al. 2023].

The strength of connectivity between regions and the species' capacity for self-recruitment at the extremes of its distribution remain poorly understood and are currently under investigation as part of an FRDC project 'Larval dispersal for Southern Rock Lobster and Longspined Sea Urchin to support management decisions.

Understanding Longspined Sea Urchin population structure has been of particular importance as high urchin densities can damage kelp forests through overgrazing [Ling et al. 2009; Johnson et al. 2011; Marzloff et al. 2016], and this has resulted in notable habitat changes in areas of range extension. Due to this impact and the range-extending nature of this species, management measures are being actively pursued to decrease the population density in some jurisdictions.

 Due to limited knowledge regarding stock structure and different jurisdictional management objectives this species is assessed here at the jurisdictional level—New South Wales, Tasmania and Victoria.

Victoria

The Longspined Sea Urchin fishery is confined to the Victorian Eastern Zone, extending from Lakes Entrance to the Victorian–NSW border. Attempts were made to develop a fishery for this species in the 1980s, and late 1990s to early 2000s, but it is only since around 2015 that significant quantities have been landed [Bell et al. 2023]. Since this time, commercial landings have fluctuated between around 40–80 t. The species is also taken by recreational fishers, and although there is no information on recreational landings, they are likely to be minimal and insignificant in terms of impacts on the stock.

Commercial CPUE has remained very stable at approximately 175 kg/hr from 2014–15 to 2021–22. However, CPUE is likely to be more reflective of the availability of urchins with roe of marketable quality rather than the species' abundance as a whole. This is illustrated by an increase in abundance of Longspined Sea Urchins observed in fishery independent surveys over the same period, though some areas have shown a decline, which can be linked to both fishing and urchin reduction programs to prevent denudation of productive abalone reefs [VFA, 2019]. In addition, this species is very abundant on barrens in deeper waters, where little to no fishing effort occurs due to sub-optimal roe quality. 

Catch, effort, and CPUE trends for this species are largely reflective of market demand and can be influenced by changes in the availability of urchins with marketable roe. As such, it is possible that the fishery could reach maximum production (i.e. catch as many urchins with marketable roe as is financially viable) without posing a risk to the stock as a whole [Bell et al. 2023]. The above evidence indicates that the biomass of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired. The above evidence also indicates that the current level of fishing mortality is unlikely to cause the stock to become recruitment impaired.

Based on the available evidence the Victorian Longspined sea urchin is classified as a sustainable stock.

.

Distribution of reported commercial catch of Longspined Sea Urchin.

New South Wales – Indigenous (Management Methods). https://www.dpi.nsw.gov.au/fishing/aboriginal-fishing

Victoria – Indigenous (Management Methods). A person who identifies as Aboriginal or Torres Strait Islander is exempt from the need to obtain a Victorian recreational fishing licence, provided they comply with all other rules that apply to recreational fishers, including rules on equipment, catch limits, size limits and restricted areas. Traditional (non-commercial) fishing activities that are carried out by members of a traditional owner group entity under an agreement pursuant to Victoria’s Traditional Owner Settlement Act 2010 are also exempt from the need to hold a recreational fishing licence, subject to any conditions outlined in the agreement. Native title holders are also exempt from the need to obtain a recreational fishinglicence under the provisions of the Commonwealth’s Native Title Act 1993.

Tasmania - Living Marine Resources Management Act 1995. https://www.legislation.tas.gov.au/view/html/inforce/current/act-1995-025

Commercial catch of Longspined Sea Urchin - note confidential catch not shown.

1. Andrew, NL, Worthington, DG, Brett, PA, Bentley, N, Chick, RC and Blount, C 1998, Interactions between the abalone fishery and sea urchins in New South Wales. NSW Fisheries Research Institute. Cronulla, Australia. Fisheries Research and Development Corporation Project No. 93/102. NSW Fisheries Final Report Series No.12. ISN 1440-3544.
2. Bell, JD, Ingram, BA, Gorfine, HK and Conron, SD 2023, Review of key Victorian fish stocks — 2022, Victorian Fisheries Authority Science Report Series No. 38, First Edition, June 2023. VFA: Queenscliff. 105pp.
3. Blount, C 2004, Density-dependent aspects of the ecology of the sea urchin Centrostephanus rodgersii. PhD Thesis, University of Sydney, Sydney, NSW, Australia.
4. Blount, C, Chick, RC and Worthington, DG 2017, Enhancement of an underexploited fishery – Improving the yield and colour of roe in the sea urchin Centrostephanus rodgersii by reducing density or transplanting individuals. Fisheries Research 186, 586-597.
5. Blount, C, Worthington, DG, Byrne, M, Chick, RC and Andrew, NL 2024, Aging of the sea urchin Centrostephanus rodgersii using demi-pyramid. Fisheries Research 270 (106899).
6. Byrne, M and Andrew, N 2020, Centrostephanus rodgersii and C. tenuispina. In: Lawrence, J (Ed.) Sea Urchins: Biology and Ecology, Elsevier B.V. California. 281–297.
7. Byrne, M, Andrew, NL, Worthington, DG and Brett, PA 1998, Reproduction in the diadematoid sea urchin Centrostephanus rodgersii in contrasting habitats along the coast of New South Wales, Australia. Marine Biology 132, 305-318.
8. Byrne, M, Gall, ML, Campbell, H, Lamare, MD and Holmes, SP 2022, Staying in place and moving in space: contrasting larval thermal sensitivity explains distributional changes of sympatric sea urchin species to habitat warming. Global Change Biology 28: 3040–3053.
9. Chick, RC 2022, Fishery statistics summary 2022 – Sea Urchin and Turban Shell Fishery – Red Sea Urchin (Heliocidaris tuberculata). NSW Department of Primary Industries. Fisheries NSW, Port Stephens Fisheries Institute: 19 pp.
10. Chick, RC 2022, Fishery statistics summary 2022—Sea Urchin and Turban Shell Fishery – Red Sea Urchin (Heliocidaris tuberculata). NSW Department of Primary Industries. Fisheries NSW, Port Stephens Fisheries Institute: 19 pp.
11. Cresswell, K, Hartmann, K, Gardner, C and Keane, J 2023, Tasmanian Longspined sea urchin fishery assessment 2021/22
12. Cresswell, KA, Keane, JP, Ogier, E and Yamazaki, S 2019, Centrostephanus subsidy program: initial evaluation. Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania.
13. Davis, T., Knott, N., Champion, C., Przeslawski, R 2023, Impacts of Climate Change on Densities of the Urchin Centrostephanus rodgersii Vary among Marine Regions in Eastern Australia. https://doi.org/10.3390/d15030419
14. Edgar, GJ and Barrett, NS 1997, Short term monitoring of biotic change in Tasmanian marine reserves. Journal of Experimental Marine Biology and Ecology 213:261-279
15. Glasby, TM and Gibson, PT 2020, Decadal dynamics of subtidal barrens habitat. Marine Environmental Research 154, https://doi.org/10.1016/j.marenvres.2019.104869
16. Henry, GW and Lyle JM 2003, The National Recreational and Indigenous Fishing Survey. Tasmanian Aquaculture and Fisheries Institute, Hobart. FRDC 99/158.
17. Johnson, CR, Banks, SC, Barrett, NS, Cazassus, F, Dunstan, PK, Edgar, GJ, Frusher, SD, Gardner, C, Haddon, M, Helidoniotis, F, Hill, KL, Holbrook, NJ, Hosie, GW, Last, PR, Ling, SD, Melbourne-Thomas, J, Miller, K, Pecl, GT, Richardson, AJ, Ridgway, KR, Rintoul, SR, Ritz, DA, Ross, DJ, Sanderson, JC, Shepherd, SA, Slotvvinski, A, Swadling, KM and Taw, N 2011, Climate change cascades: Shifts in oceanography, species' ranges and subtidal marine community dynamics in eastern Tasmania. Journal of Experimental Marine Biology and Ecology 400:17-32.
18. Johnson, CR., Ling, SD, Ross, J, Shepherd, S and Miller, K 2005, Establishment of the longspined sea urchin (Centrostephanus rodgersii) in Tasmania: first assessment of potential threats to fisheries. Fisheries Research and Development Corporation
19. Ling, SD 2008, Range expansion of a habitat-modifying species leads to loss of taxonomic diversity: a new and impoverished reef state. Oecologia 156:883-894.
20. Ling, SD and Keane, JP 2018, Resurvey of Longspined sea urchin (Centrostephanus rodgersii) and associated barren reef in Tasmania. Hobart.
21. Ling, SD, Johnson, CR 2009, Population dynamics of an ecologically important range-extender. Marine Ecology Progress Series 374, 113–125. doi:10.3354/meps07729
22. Ling, SD, Johnson, CR, Frusher, SD and Ridgway KR 2009, Overfishing reduces resilience of kelp beds to climate-driven catastrophic phase shift. Proceedings of the National Academy of Sciences of the United States of America 106:22341-22345.
23. Marzloff, MP, Little, LR and Johnson, CR 2016, Building Resilience Against Climate Driven Shifts in a Temperate Reef System: Staying Away from Context-Dependent Ecological Thresholds. Ecosystems 19:1-15.
24. Murphy, JJ, Ochwada-Doyle, FA, West, LD, Stark, KE and Hughes, JM, 2020, The NSW Recreational Fisheries Monitoring Program - survey of recreational fishing, 2017/18. NSW DPI - Fisheries Final Report Series No. 158.
25. Murphy, JJ, Ochwada-Doyle, FA, West, LD, Stark, KE, Hughes, JM and Taylor, MD 2022, Survey of recreational fishing in NSW, 2019/20 – Key Results. NSW DPI – Fisheries Final Report Series No. 161. ISSN 2204-8669.
26. Przeslawski, R, Chick, R, Day, J, Glasby, T and Knott, N 2023, Research Summary – New South Wales Barrens. NSW Department of Primary Industries.
27. Ridgway, KR 2007, Long-term trend and decadal variability of the southward penetration of the East Australian Current. Geophysical Research Letters 34
28. Underwood, AJ, Kingsford, MJ and Andrew, NL 1991, Patterns in shallow subtidal marine assemblages along the coast of New South Wales. Aust. J. Ecol. 16: 231-249.
29. VFA 2019, Spatial and temporal trends in the abundance of long-spined sea urchins (Centrostephanus rodgersii) in Eastern Victoria using available fishery and fishery independent information. Victorian Fisheries Authority Science Report Series No. 10.
30. West, LD, Stark, KE, Murphy, JJ, Lyle JM and Doyle, FA 2015, Survey of recreational fishing in New South Wales and the ACT, 2013/14. Fisheries Final Report Series No. 149.
31. Worthington, DG and Blount, C 2003, Research to develop and manage the sea urchin fisheries of NSW and eastern Victoria. FRDC Project No. 1999/128. NSW Fisheries Final Report Series No. 56. ISSN 1440-3544.