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EBSA overview  |  Delineation |  Summary of description updates  | Revised description

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EBSA overview

The Agulhas Bank is an area of wider shelf on the South African south coast, along the otherwise narrow east-coast shelf. It includes Critically Endangered mud habitats and unique high-profile volcanic offshore reefs that support cold-water coral communities. It is the only warm temperate nursery area for species that spawn on the narrow shelf in the north, and is important for retention and recruitment processes, with dense benthic copepod communities supporting food provisioning. Species that spawn here include fish, some of which are threatened endemics or overexploited linefish species, and squid. It is the centre of abundance of numerous warm-temperate species, including several endemic sparids, and is frequented by migrating Near Threatened loggerhead and Critically Endangered leatherback turtles. 

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Delineation

Open or collapse the legend as a sidebar by clicking the icon in the top left corner of the map. In the legend you can turn on/off the old/new extents of the EBSA. You can zoom in/out using the mouse or the +/- buttons on the map, and click on the features for more information.

 

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Summary of updates and revisions to the EBSA description

6 new references added; major revisions to the feature description of the area, Criterion 2: importance for life-history stages, and Criterion 3: importance for threatened species.

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Revised EBSA description

NOTE: Read this here, or download the Word document on the right sidebar.

 

General Information

Summary

The Agulhas Bank, a spawning ground and nursery area, is the centre of abundance of numerous warm-temperate species, including several endemic sparids. The bank is an area of wider shelf along the otherwise narrow east-coast shelf of South Africa. It is the only warm temperate nursery area for species that spawn on the narrow shelf in the north, and is important for retention, recruitment, and food provision. Dense benthic copepod communities provide a rich food source. The area includes Critically Endangered mud habitats and unique high-profile volcanic offshore reefs that support cold-water coral communities. There is a spawning aggregation area for the threatened endemic reef fish, Petrus rupestris, within this area. This area has been identified as important in two systematic planning initiatives.

 

Introduction of the area

This area, within the Agulhas Bank on the southeast coast of South Africa, includes benthic and pelagic features. The area ranges from the 30-m depth contour to approximately 250 m deep. Key benthic features include Critically Endangered mud habitats, high-profile volcanic deep reefs, low-profile deep reefs and rare gravels. The Agulhas Bank is important for numerous ecological processes, including spawning, larval retention, recruitment, connectivity and provision of nursery and foraging areas (Hutchings et al., 2002). This area is the centre of abundance of numerous warm temperate species, including several endemic sparids. Some of these species are threatened or overexploited (sparids and sciaenids), and the deep-reef habitats are considered important for the recovery of overexploited deep-reef fish species. A spawning area for the threatened endemic reef fish, Petrus rupestris, is located within this area, and aggregations of this species have recently been observed within this area (Sink et al., 2010). The Agulhas Bank area has been identified using data provided through a national systematic planning initiative (Sink et al., 2011). Hutchings et al., (2002) emphasise the importance of this area as one of three key nursery areas in South Africa and the only one in the warm temperate ecoregion.

 

Description of the location

EBSA Region

Southern Indian Ocean

 

Description of location

The area is bounded by latitudes of approximately 34.4°S to 35.7°S and longitudes of approximately 20.4°E and 23.2°E, roughly between De Hoop and Mossel Bay in the Western Cape. The area is entirely within the exclusive economic zone (EEZ) of South Africa.

 

Geo-Location

SIO_1_EBSA.geojson

 

Area Details

Feature description of the area

Key benthic features include sandy and mud habitats, high-profile volcanic deep reefs, low-profile deep reefs and rare gravels. The Agulhas Bank is an important nursery area for species that spawn on the narrow shelf further north, including shad (Pomatomus saltatrix) and the sciaenid (Attractoscion aequidens). Squid also spawn in this area, and their paralarvae that hatch from the benthic eggs are dispersed across the bank, where they feed on a dense layer of copepods that occurs close to the seabed in this area (Hutchings et al., 2002). The Agulhas Bank area is moderately productive but has areas of relatively higher productivity within the broader area. There is a cold ridge of water on the central Agulhas Bank, which is a prominent subsurface feature during most summers (Swart and Largier 1987) and is associated with elevated phytoplankton concentrations (Probyn et al., 1994) and dense concentrations of copepods (Verheye et al.1994) and clupeoid fish eggs (Roel et al., 1994). The area is also frequented by migrating Near Threatened loggerhead and Critically Endangered leatherback turtles (Harris et al., in review). Threatened habitat types in the area include Critically Endangered Agulhas muddy inner shelf, Endangered Agulhas hard inner shelf and the Vulnerable Agulhas hard outer shelf, Agulhas sandy inner shelf and Agulhas gravel outer shelf (Sink et al., 2012). Overexploited and threatened linefish include the endemic red steenbras (Petrus rupestris, Endangered), Dageraad (Chrysoblephus cristiceps, Endangered) and black musselcracker (Cymatoceps nasutus,Vulnerable) (Sink et al., 2012; Sink et al., 2010). The area is also important for juvenile silver kob (Argyrosomus inodorus; Lombard et al., 2010, Attwood et al., 2011). The reef habitats range from low to very high profile, mostly have low rugosity, and support a variety of wall sponges, corals, red algae, kelp, gorgonians, fish and sharks (Gotz et al., 2014; Makwela et al., 2016).

 

Feature conditions and future outlook of the proposed area

South Africa’s National Biodiversity Assessment 2011 (Sink et al., 2012) indicated a range of conditions (fair to poor) in this area (based on pressure data and an ecosystem-pressure matrix), with the condition of the broader area ranging from poor to good. There are deep reefs in the Agulhas Bank Nursery Area that are estimated to be in good condition, even though pressures elsewhere have led to these habitats being considered threatened. Key activities in the area include commercial demersal trawl and longline fisheries, a midwater trawl fishery, trap fisheries for rock lobster, linefishing and expanding petroleum activities.

 

References

Attwood CG, Petersen SL, Kerwath SE. 2011. By-catch in South Africa's inshore trawl fishery as determined from observer records. ICES Journal of Marine Science 68: 2163-2174. DOI:10.1093/icesjms/frs162.

Downey-Breedt, N.J., Roberts, M.J., Sauer, W.H.H., Chang, N. 2016. Modelling transport of inshore and deep-spawned chokka squid (Loligo reynaudi) paralarvae off South Africa: the potential contribution of deep spawning to recruitment. Fisheries Oceanography: 25, 28–43.

Götz, A., Kerwath, S.E., Samaai, T., da Silva, C., Wilke, C.G., 2014. An Exploratory Investigation of the Fish Communities Associated with Reefs on the Central Agulhas Bank, South Africa. African Zoology 49, 253-264.Griffiths, MH. 2000. Long-term trends in catch and effort of commercial linefish off South Africa’s Cape Province: snapshots of the 20th century. South African Journal of Marine Science 22: 81-110.

Harris, L.R., Nel, R., Oosthuizen, H., Meyer, M., Kotze, D., Anders, D., McCue, S., Bachoo, S. Managing conflicts between economic activities and threatened migratory marine species towards creating a multi-objective blue economy. Conservation Biology, in review.

Hutchings L, Beckley LE, Griffiths MH, Roberts MJ, Sundby S, van der Lingen C. 2002. Spawning on the edge: spawning grounds and nursery areas around the southern African coastline. Marine and Freshwater Research 53: 307-318.

Lagabrielle E. 2009. Preliminary report: National Pelagic Bioregionalisation of South Africa. Cape Town: South African National Biodiversity Institute.

Lombard AT, Attwood C., Sink K. Grantham H. 2010. Use of Marxan to identify potential closed areas to reduce by-catch in the South African trawl fishery. Cape Town: WWF South Africa and the Responsible Fisheries Alliance.

Lutjeharms JRE, Cooper J, Roberts M. 2000. Upwelling at the inshore edge of the Agulhas Current. Continental Shelf Research, 20(7): 737 – 761.

Makwela, M.S., Kerwath, S.E., Götz, A., Sink, K., Samaai, T. & Wilke, C.G. 2016. Notes on a remotely operated vehicle survey to describe reef ichthyofauna and habitats – Agulhas Bank, South Africa. Bothalia: 46, a2108.

Mhlongo, N., Yemane, D., Hendricks, M., Van Der Lingen, C.D. 2015. Have the spawning habitat preferences of anchovy (Engraulis encrasicolus) and sardine (Sardinops sagax) in the southern Benguela changed in recent years?

Probyn, T. A., Mitchell-Innes, B. A., Brown, P. C., Hutchings, L., and Carter, R. A. 1994. A review of primary production and related processes on the Agulhas Bank. South African Journal of Science: 90, 166–73.

Roel, B. A., Hewitson, J., Kerstan, S., and Hampton, I. 1994. The role of the Agulhas Bank in the life cycle of pelagic fish. South African Journal of Science 90, 185–96.

Sink KJ, Atkinson LJ, Kerwath S, Samaai T. 2010. Assessment of offshore benthic biodiversity on the Agulhas Bank and the potential role of petroleum infrastructure in offshore spatial management. Report prepared for WWF South Africa and PetroSA through a SANBI initiative. Cape Town: South African National Biodiversity Institute.

Sink KJ, Attwood CG, Lombard AT, Grantham H, Leslie R, Samaai T, Kerwath S, Majiedt P, Fairweather T, Hutchings L, van der Lingen C, Atkinson LJ, Wilkinson S, Holness S, Wolf T. 2011. Spatial planning to identify focus areas for offshore biodiversity protection in South Africa. Unpublished Report. Cape Town: South African National Biodiversity Institute.

Sink K, Holness S, Harris L, Majiedt P, Atkinson L, Robinson T, Kirkman S, Hutchings L, Leslie R, Lamberth S, Kerwath S, von der Heyden S, Lombard A, Attwood C, Branch G, Fairweather T, Taljaard S, Weerts S, Cowley P, Awad A, Halpern B, Grantham H, Wolf T. 2012. National Biodiversity Assessment 2011: Technical Report. Volume 4: Marine and Coastal Component. South African National Biodiversity Institute, Pretoria.

Swart, V. P., and Largier, J. L. 1987. Thermal structure of Agulhas Bank water. In ‘The Benguela and Comparable Ecosystems’. (Eds A. I. L. Payne, J. A. Gulland and K. H. Brink.) South African Journal of Marine Science 5, 243–53.

Verheye, H. M., Hutchings, L., Huggett, J. A., Carter, R. A., Peterson, W. T., and Painting, S. J. 1994. Community structure, distribution and trophic ecology of zooplankton on the Agulhas bank with special reference to copepods. South African Journal of Science 90,154–66.

Weidberg, N., Porri, F., Von der Meden, C.E.O., Jackson, J.M., Goschen, W., McQuaid, C.D. 2015. Mechanisms of nearshore retention and offshore export of mussel larvae over the Agulhas Bank. Journal of Marine Systems, 144 70–80.

 

Other relevant website address or attached documents

SIO_1_EBSA-GIS shapefile.zip (/api/v2013/documents/7A1016B9-7B13-1A6A-7768-C5F4E7B12A83/attachments/SIO_1_EBSA-GIS%20shapefile.zip)

 

Status of submission

Areas described as meeting EBSA criteria that were considered by the Conference of the Parties.

 

COP Decision

dec-COP-12-DEC-22

 

Assessment of the area against CBD EBSA criteria

C1: Uniqueness or rarity High

Justification

Rare habitats within this area include Agulhas muddy inner shelf and Agulhas gravel inner shelf (Sink et al., 2012a). The volcanic offshore Alphard Bank is a unique feature that supports kelp (Ecklonia maxima), soft corals, stylasterine corals, and sponges (Sink et al., 2010; Makwela et al., 2016).

C2: Special importance for life-history stages of species High

Justification

The Agulhas Banks Nursery Area is of particular importance for the life-history stages of multiple fish species, including inter alia endemic, threatened, and commercially important species. Fish that use the area for spawning, are: Red steenbras (Petrus rupestris, Endangered) and other linefish species (Hutchings et al., 2002) including anchovy (Mhlongo et al., 2015). There have also been recent observations of spawning aggregations of the endemic reef fish Petrus rupestris within this area (Sink et al., 2010). It also serves as a nursery area for silver kob (Argyrosomus inodorus; Attwood et al., 2011), geelbek, shad, white stumpnose (Hutchings et al., 2002). This area also supports a relatively high proportion of juvenile hake (Merluccius capensis; Sink et al., 2011). Squid paralarvae (Downey-Breedt et al., 2016) and mussel larvae are also present, with mussel veligers found in high abundances up to 87 km from the shore (Weidberg et al., 2015).

C3: Importance for threatened, endangered or declining species and/or habitats High

Justification

Threatened habitat types in this area include Agulhas muddy inner shelf (Critically Endangered), Agulhas hard inner shelf (Endangered) and Agulhas hard outer shelf, Agulhas sandy inner shelf and Agulhas gravel outer shelf (Vulnerable; Sink et al., 2012). This area has also been identified through systematic planning as containing habitat important for overexploited and threatened linefish. This includes the endemic overexploited sparids such as red steenbras (Petrus rupestris), Dageraad (Chrysoblephus cristiceps, Endangered) and black musselcracker (Cymatoceps nasutus, Vulnerable) (Sink et al., 2012). The area is also recognized as important for the recovery of the overexploited silver kob (Argyrosomus inodorus; Attwood et al., 2011), and the reefs serve as aggregating structures for some overexploited fish species, such as the carpenter (Argyrozona argyrozona; Gotz et al., 2014). The overexploitation of linefish species is reported by Griffiths (2000). Further, Near Threatened loggerheads and Critically Endangered leatherbacks frequent this area on their migrations, also using the Agulhas Banks as a foraging ground (Harris et al., in review).

C4: Vulnerability, fragility, sensitivity, or slow recovery Medium

Justification

High-profile deep reefs and hard grounds with stylasterine corals, black corals, gorgonians and wall sponges have been observed in this area through in-situ ROV surveys (Sink et al., 2010; Makwela et al., 2016).

C5: Biological productivity Medium

Justification

The Agulhas Bank area is moderately productive (Hutchings et al., 2002 and references therein) but has areas of relatively higher productivity within the broader area. There is a cold ridge of water, which is a prominent subsurface feature during most summers on the central Agulhas Bank (Swart and Largier 1987) and is associated with elevated phytoplankton concentrations (Probyn et al., 1994) and dense concentrations of copepods (Verheye et al.1994) and clupeoid fish eggs (Roel et al., 1994).

C6: Biological diversity Medium

Justification

There is high sparid and invertebrate biodiversity (core of the distribution of several endemic species) in the Agulhas Bank Nursey Area. Further, this area was selected as a priority in systematic planning because of the relatively higher habitat diversity and thus opportunities to meet multiple biodiversity targets efficiently.

C7: Naturalness Medium

Justification

There is only one pelagic habitat type (Ab2) within this area, which is in good condition (Sink et al., 2012). Benthic condition ranges from poor to good (Sink et al., 2012), but some deep reefs are apparently untrawled and in good condition. The volcanic feature known as the Alphard Banks is in good condition (Sink et al., 2010).

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