Triakis megalopterus.The IUCN Red List of Threatened Species 2020

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The IUCN Red List of Threatened Species™
ISSN 2307-8235 (online)
IUCN 2020: T39362A124406649
Scope(s): Global
Language: English
Triakis megalopterus, Spotted Gully Shark
Assessment by: Pollom, R., Da Silva, C., Gledhill, K., McCord, M.E. & Winker, H.
View on www.iucnredlist.org
Citation: Pollom, R., Da Silva, C., Gledhill, K., McCord, M.E. & Winker, H. 2020. Triakis megalopterus.
The IUCN Red List of Threatened Species 2020: e.T39362A124406649.
https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T39362A124406649.en
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THE IUCN RED LIST OF THREATENED SPECIES™

Taxonomy
Kingdom Phylum Class Order Family
Animalia Chordata Chondrichthyes Carcharhiniformes Triakidae
Scientific Name:ÊÊTriakis megalopterus (Smith, 1839)
Synonym(s):
• Mustelus megalopterus Smith, 1839
Common Name(s):
• English: Spotted Gully Shark
• Afrikaans: Sloephaai
Taxonomic Source(s):
Fricke, R., Eschmeyer, W.N. and Van der Laan, R. (eds). 2020. Eschmeyer's Catalog of Fishes: genera,
species, references. Updated 02 March 2020. Available at:
http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp.
Assessment Information
Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2020
Date Assessed: August 1, 2019
Justification:
The Spotted Gully Shark (Triakis megalopterus) is a medium-sized (to 208 cm total length) demersal
houndshark endemic to southern Africa in the Southeast Atlantic and Western Indian Oceans from
Angola to KwaZulu-Natal, South Africa. It inhabits shallow sandy areas and rocky crevices on the
continental shelf to a depth of 50 m. The species has a late age-at-maturity and a long gestation period
that lead to low productivity and vulnerability to overfishing. It is caught extensively in recreational line
fisheries and occasionally as a minor bycatch species in beach seine, longline, and trawl fisheries.
Recreational fishers typically release this species. Catches of the Spotted Gully Shark in the commercial
and recreational line fisheries in False Bay, South Africa peaked in 1990 and declined thereafter. Trend
analysis of 21 years of catch-per-unit-effort data from 1996–2017 from the De Hoop Marine Protected
Area (MPA), South Africa indicate an increase in population over the past three generation lengths (60
years). Commercial fishing for Spotted Gully Shark is prohibited in South Africa with minimal bycatch of
this species and recreational fishing permitted but regulated. Hence, this data from the MPA may
approximate the trends of the species in the region. There are currently no data available from other
areas, but given an estimated increase in South Africa over the past three generations (60 years), the
typical release of this species by recreational fishers, likely low post-release mortality, and mostly low
fishing pressure elsewhere, it is suspected that the population trend is stable over the past three
generation lengths (60 years) and is not suspected to be close to reaching the population decline
threshold. Therefore, the Spotted Gully Shark is assessed as Least Concern.
© The IUCN Red List of Threatened Species: Triakis megalopterus – published in 2020.
https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T39362A124406649.en
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For further information about this species, see Supplementary Material.
Previously Published Red List Assessments
2009 – Near Threatened (NT)
https://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T39362A10216379.en
2000 – Lower Risk/near threatened (LR/NT)
Geographic Range
Range Description:
The Spotted Gully Shark is a southern African endemic that occurs from southern Angola to KwaZulu-
Natal, South Africa in the Southeast Atlantic and Western Indian Oceans (Ebert et al. 2013).
Country Occurrence:
Native, Extant (resident): Angola; Namibia; South Africa
FAO Marine Fishing Areas:
Native: Indian Ocean - western
Native: Atlantic - southeast
© The IUCN Red List of Threatened Species: Triakis megalopterus – published in 2020.
https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T39362A124406649.en
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Distribution Map
© The IUCN Red List of Threatened Species: Triakis megalopterus – published in 2020.
https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T39362A124406649.en
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Population
There are no range-wide population size or trend estimates for this species. Population trend data of
standardized catch-per-unit-effort (CPUE) (number of fish per angler per day) for 1997–2017 (21
years) were available from the De Hoop Marine Protected Area (MPA) shore-based research angling
surveys conducted by the South African Department of Environmental Affairs (DEA, unpubl. data,
2018). The trend data were analyzed over three generation lengths using a Bayesian state-space
framework (Winker and Sherley 2019). This analysis yields an annual rate of change, a median
change over three generation lengths, and the probability of the most likely IUCN Red List category
percent change over three generations (see the Supplementary Information).
The trend analysis revealed an annual rate of increase of 2.6%, consistent with an estimated median
increase of 115.3% over the past three generation lengths (60 years), with the highest probability
(99.9%) of an increase over three generation lengths. The De Hoop MPA was established in 1985 and is
a no-take reserve, and this may not be representative of the population trends in fished areas of South
Africa. However, commercial fishing for Spotted Gully Shark is prohibited in South Africa with minimal
bycatch of this species and recreational fishing is permitted but regulated. Hence, it may approximate
the trends of the species in the region.
In False Bay, South Africa, catches of this species in the recreational and commercial line fisheries
peaked in 1990, declined afterwards, and remained low suggesting over-exploitation in that locality
(Best et al. 2013). A demographic analysis of the Spotted Gully Shark in South Africa indicated that it is
sensitive to overfishing but in the absence of fishing mortality, the population is stable (Booth et al.
2011). This species is likely exposed to minimal fishing pressure in Namibia and some intense fishing
pressure in a few locations in southern Angola, with unfished areas in other parts of its Angola range.
Overall, the population is increasing in parts of its range over the past three generations lengths (60
years) and is exposed to minimal commercial fishing pressure and regulated recreational fishing across
much of its range (i.e. South Africa). Exposure to intense fishing pressure occurs only over a small
portion of its range. Thus, the population is suspected to be stable over the past three generation
lengths (60 years) and the species is not suspected to be close to reaching the population decline
threshold.
For further information about this species, see Supplementary Material.
Current Population Trend:ÊÊStable
Habitat and Ecology (see Appendix for additional information)
The Spotted Gully Shark is a demersal houndshark that inhabits shallow sandy areas and rocky crevices
on the continental shelf to a depth of 50 m, but usually less than 10 m depth (Ebert et al. 2013,
Weigmann 2016). It reaches a maximum size of 208 cm total length (TL), males mature at 125 cm TL and
females mature at 140 cm TL (Ebert et al. 2013). Reproduction is lecithotrophic viviparous with litter
sizes of 5–15 pups, a gestation period of 19–21 months, a two to three-year reproductive cycle, and size-
at-birth of 40 cm TL (Smale and Goosen 1999, Ebert et al. 2013). Female age-at-maturity is estimated as
15 years and maximum age as 25 years; generation length is therefore estimated as 20 years (Booth et
al. 2011).
© The IUCN Red List of Threatened Species: Triakis megalopterus – published in 2020.
https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T39362A124406649.en
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Systems:ÊÊMarine
Use and Trade
The meat from the Spotted Gully Shark is sometimes dried and sold locally as shark 'biltong' or jerky, or
exported fresh or frozen to Europe or Taiwan (Da Silva and Bürgener 2007, Compagno 2009). Since
prohibition on commercial catch, this species is often deliberately mislabeled so that it can be marketed
for its meat (C. Da Silva, unpubl. data, 2018).
Threats (see Appendix for additional information)
The Spotted Gully Shark is targeted in recreational line fisheries and occasionally taken as bycatch in
beach seine, commercial line, longline, and trawl fisheries (Compagno 2009, Booth et al. 2011, Best et
al. 2013, Belhabib et al. 2015, da Silva et al. 2015). Recreational fishers typically release this species in
South Africa, and some houndsharks have been shown to have low post-release mortality (Ellis et al.
2017). Effort in South African shore line fisheries has decreased as a result of a 2002 South African ban
on all-terrain vehicles on beaches. Parts of Namibia are remote and offer refuge from fishing pressure
(Belhabib et al. 2015). Since 2002, artisanal and recreational fishing pressure in a few parts of southern
Angola has increased while other areas remain unfished (Beckensteiner et al. 2016).
Conservation Actions (see Appendix for additional information)
This species was declared a prohibited commercial species in 2005 (DEAT 2005). However, since this
prohibition, deliberate misreporting as other species in order to sell it illegally is an ongoing issue (C. Da
Silva, unpubl. data, 2018). In South Africa, the Spotted Gully Shark is a legislated recreational species
and recreational anglers in South Africa are restricted to one shark per species per day (maximum of 10
individuals per day) (DEAT 2005), although enforcement is an ongoing issue. A number of protected
areas occur in South Africa across its range, including: the West Coast National Park, the iSimangaliso
Marine Protected Area (MPA), and the uThukela MPA. Further research is needed on population size and
trends.
Credits
Assessor(s): Pollom, R., Da Silva, C., Gledhill, K., McCord, M.E. & Winker, H.
Reviewer(s): Dulvy, N.K. & Kyne, P.M.
Contributor(s): Herman, K. & Rigby, C.L.
Facilitator(s) and
Compiler(s):
Kyne, P.M., Pollom, R. & Dulvy, N.K.
Authority/Authorities: IUCN SSC Shark Specialist Group (sharks and rays)
© The IUCN Red List of Threatened Species: Triakis megalopterus – published in 2020.
https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T39362A124406649.en
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Bibliography
Beckensteiner, J., Kaplan, D.M., Potts, W.M., Santos, C.V. and O’Farrell, M.R. 2016. Data-limited
population-status evaluation of two coastal fishes in southern Angola using recreational catch length-
frequency data. PLOS ONE 11(2): e0147834.
Belhabib, D., Willemse, N.E. and Pauly, D. 2015. A fishery tale: Namibian fisheries between 1950 and
2010. Working Paper Series. Working Paper #2015-65. Fisheries Centre, University of British Colombia.
Best, L.N., Attwood, C.G., da Silva, C. and Lamberth, S.J. 2013. Chondrichthyan occurrence and
abundance trends in False Bay, South Africa, spanning a century of catch and survey records. African
Zoology 48(2): 201–227.
Booth, A.J., Foulis, A.J. and Smale, M.J. 2011. Age validation, growth, mortality, and demographic
modeling of spotted gully shark (Triakis megalopterus) from the southeast coast of South Africa. Fishery
Bulletin 109(1): 101-112.
Compagno, L.J.V. 2009. Triakis megalopterus. The IUCN Red List of Threatened Species 2009:
e.T39362A10216379. Available at: http://dx.doi.org/10.2305/IUCN.UK.2009-
2.RLTS.T39362A10216379.en.
Da Silva, C. and Bürgener, M. 2007. South Africa’s demersal shark meat harvest. TRAFFIC Bulletin 21:
55–65.
da Silva, C., Booth, A.J., Dudley, S.F.J., Kerwath, S.E., Lamberth, S.J., Leslie, R.W., McCord, M.E., Sauer,
W.H.H. and Zweig, T. 2015. The current status and management of South Africa's chondrichthyan
fisheries. African Journal of Marine Science 37(2): 233-248.
Department of Environmental Affairs and Tourism (DEAT). 2005. Marine Living Resources Act, 1988.
Amendments to Regulations. No. 329 6 April 2005. Government Notice, Government Gazette South
Africa (No. 27453).
Ebert, D.A., Fowler, S. and Compagno, L. 2013. Sharks of the World. Wild Nature Press, Plymouth.
Ellis, J.R., McCully Philips, S.R. and Poisson, F. 2017. A review of capture and post‐release mortality of
elasmobranchs. Journal of Fish Biology 90(3): 653–722.
IUCN. 2020. The IUCN Red List of Threatened Species. Version 2020-2. Available at: www.iucnredlist.org.
(Accessed: 13 June 2020).
Smale. M.J. and Goosen, A.J.J. 1999. Reproduction and feeding of spotted gully shark, Triakis
megalopterus, off the Eastern Cape, South Africa. Fishery Bulletin 97: 987-998.
Weigmann, S. 2016. Annotated checklist of the living sharks, batoids and chimaeras (Chondrichthyes) of
the world, with a focus on biogeographical diversity. Journal of Fish Biology 88(3): 837-1037.
Winker, H, Pacoureau, N. and Sherley, R.B. 2020. JARA: 'Just Another Red List Assessment'. BioRᵴiv
Preprint: http://dx.doi.org/10.1101/672899.
Citation
Pollom, R., Da Silva, C., Gledhill, K., McCord, M.E. & Winker, H. 2020. Triakis megalopterus. The IUCN Red
List of Threatened Species 2020: e.T39362A124406649. https://dx.doi.org/10.2305/IUCN.UK.2020-
2.RLTS.T39362A124406649.en
© The IUCN Red List of Threatened Species: Triakis megalopterus – published in 2020.
https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T39362A124406649.en
6

Disclaimer
To make use of this information, please check the Terms of Use.
External Resources
For Supplementary Material, and for Images and External Links to Additional Information, please see the
Red List website.
© The IUCN Red List of Threatened Species: Triakis megalopterus – published in 2020.
https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T39362A124406649.en
7

Appendix
Habitats
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Habitat Season Suitability Major
Importance?
9. Marine Neritic -> 9.2. Marine Neritic - Subtidal Rock and Rocky Reefs Resident Suitable Yes
9. Marine Neritic -> 9.4. Marine Neritic - Subtidal Sandy Resident Suitable Yes
Use and Trade
(http://www.iucnredlist.org/technical-documents/classification-schemes)
End Use Local National International
Food - human No No No
Threats
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Threat Timing Scope Severity Impact Score
5. Biological resource use -> 5.4. Fishing & harvesting
aquatic resources -> 5.4.1. Intentional use:
(subsistence/small scale) [harvest]
Ongoing Minority (50%) No decline Low impact: 4
Stresses: 2. Species Stresses -> 2.1. Species mortality
5. Biological resource use -> 5.4. Fishing & harvesting
aquatic resources -> 5.4.3. Unintentional effects:
(subsistence/small scale) [harvest]
Ongoing Majority (50-
90%)
No decline Low impact: 5
Stresses: 2. Species Stresses -> 2.1. Species mortality
5. Biological resource use -> 5.4. Fishing & harvesting
aquatic resources -> 5.4.4. Unintentional effects:
(large scale) [harvest]
Ongoing Majority (50-
90%)
No decline Low impact: 5
Stresses: 2. Species Stresses -> 2.1. Species mortality
Conservation Actions in Place
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Conservation Action in Place
In-place research and monitoring
Action Recovery Plan: No
Systematic monitoring scheme: No
In-place land/water protection
© The IUCN Red List of Threatened Species: Triakis megalopterus – published in 2020.
https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T39362A124406649.en
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Conservation Action in Place
Conservation sites identified: No
Area based regional management plan: No
Occurs in at least one protected area: Yes
Invasive species control or prevention: Not Applicable
In-place species management
Harvest management plan: Yes
Successfully reintroduced or introduced benignly: No
Subject to ex-situ conservation: No
In-place education
Subject to recent education and awareness programmes: No
Included in international legislation: No
Subject to any international management / trade controls: No
Research Needed
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Research Needed
1. Research -> 1.2. Population size, distribution & trends
Additional Data Fields
Distribution
Lower depth limit (m): 50
Upper depth limit (m): 0
Habitats and Ecology
Generation Length (years): 20
© The IUCN Red List of Threatened Species: Triakis megalopterus – published in 2020.
https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T39362A124406649.en
9

The IUCN Red List of Threatened Species™
ISSN 2307-8235 (online)
IUCN 2020: T39362A124406649
Scope(s): Global
Language: English
The IUCN Red List Partnership
The IUCN Red List of Threatened Species™ is produced and managed by the IUCN Global Species
Programme, the IUCN Species Survival Commission (SSC) and The IUCN Red List Partnership.
The IUCN Red List Partners are: Arizona State University; BirdLife International; Botanic Gardens
Conservation International; Conservation International; NatureServe; Royal Botanic Gardens, Kew;
Sapienza University of Rome; Texas A&M University; and Zoological Society of London.
THE IUCN RED LIST OF THREATENED SPECIES™
© The IUCN Red List of Threatened Species: Triakis megalopterus – published in 2020.
https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T39362A124406649.en
10