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

OBIS biodiversity data  |  Status assessment and management recommendations

 

 

EBSA overview

Browns Bank includes benthic and pelagic habitats of the outer shelf and shelf edge along the western continental margin of South Africa. The area includes reef-building cold-water corals and untrawled hard grounds. It is an important fish spawning area for demersal and pelagic species. The spawning area is linked to nursery grounds on the inshore area of the west coast and the Agulhas Bank, and has better retention than that of areas further north. The Agulhas and Southern Benguela ecoregions meet at the south-eastern boundary of the area and sporadic shelf edge upwelling enhances the productivity along the outer margin. The area is important for threatened habitats and species, including a Critically Endangered benthic ecosystem type and overlapping substantially with two proposed marine Important Bird Areas, namely for Cory’s Shearwater and Atlantic Yellow-nosed Albatross. The area was also identified as a priority area through two systematic biodiversity plans, meeting targets for habitat representation, hake spawning, and fragile and sensitive habitat-forming species. The boundary of this EBSA has been refined since its first description to improve precision based on focus-area delineation for national MPA expansion, threat status of benthic ecosystem types, and presence of vulnerable, sensitive, fragile and slow-growing species.

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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

Boundary refined, 1 new reference added and relatively minor editing of the previous description. No further research has been conducted in the area.

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Revised EBSA description

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

 

General Information

Summary

Browns Bank includes benthic and pelagic habitats of the outer shelf and shelf edge along the western continental margin of South Africa. The area includes reef-building cold-water corals and untrawled hard grounds. It is an important fish spawning area for demersal and pelagic species. The spawning area is linked to nursery grounds on the inshore area of the west coast and the Agulhas Bank, and has better retention than that of areas further north. The Agulhas and Southern Benguela ecoregions meet at the south-eastern boundary of the area and sporadic shelf edge upwelling enhances the productivity along the outer margin. The area is important for threatened habitats and species, including a Critically Endangered benthic ecosystem type and overlapping substantially with two proposed marine Important Bird Areas, namely for Cory’s Shearwater and Atlantic Yellow-nosed Albatross. The area was also identified as a priority area through two systematic biodiversity plans, meeting targets for habitat representation, hake spawning, and fragile and sensitive habitat-forming species. The boundary of this EBSA has been refined since its first description to improve precision based on focus-area delineation for national MPA expansion, threat status of benthic ecosystem types, and presence of vulnerable, sensitive, fragile and slow-growing species.

 

Introduction of the area

The area is along the outer shelf and shelf edge of the western continental margin of South Africa, south and slightly east of Cape Agulhas. It includes benthic habitats, including rocky, sandy and reef substrates (Sink et al., 2019), and a pelagic ecosystem type that is characterised by elevated productivity and frequent fronts due to shelf-edge upwelling (Lutjeharms et al., 2000, Lagabrielle 2009, Roberson et al., 2017). The area ranges from approximately 150 m – 800 m depth and the Agulhas and Southern Benguela ecoregions meet at the its south-eastern edge (Sink et al., 2012), with sporadic shelf-edge upwelling that enhances the productivity along its outer margin (Lagabrielle, 2009, Roberson et al., 2017). The area includes the western Agulhas Bank spawning ground, and is part of a critical area for retention of spawning products (Hutchings et al., 2002). It was identified as a priority area through a national plan to identify areas for offshore protection (Sink et al., 2011) and by a systematic biodiversity plan for the South African west coast (Majiedt et al., 2013).

 

Description of the location

EBSA Region

South-Eastern Atlantic

 

Description of location

Browns Bank includes benthic and pelagic habitats of the outer shelf and shelf edge along the western continental margin of South Africa. This area is off the southwest coast of South Africa, almost directly south of Cape Agulhas, and is completely within national jurisdiction.

 

Geolocation

SEA_39_EBSA.geojson

 

Area Details

Feature description of the area

The Browns Bank area includes unconsolidated sandy habitats, hard ground and reef habitats (Sink et al., 2019). The pelagic habitat is characterised by elevated productivity and frequent fronts due to shelf edge upwelling (Lutjeharms et al., 2000, Lagabrielle 2009, Roberson et al., 2017). The biodiversity at Browns Bank includes benthic macrofaunal communities characterized by high abundances of brittle stars and many species of polychaetes (Karenyi, 2014); cold-water corals, brisingid starfish, and 77 morphospecies of macroinvertebrates have also been collected within the area (Sink 2016). Further, it is a proposed marine Important Bird Area (IBA) for two species of seabirds, Cory’s Shearwater and Atlantic Yellow-nosed Albatross (BirdLife International 2013), indicating that it holds a significant proportion of the global population of these species during some periods of each year for which data are available. Wandering, Shy, Black-browed, and Atlantic yellownose albatrosses sighted in the area, and Pintado petrels are noted as commonly occurring (Sink 2016). Browns Bank is also part of the western Agulhas Bank spawning ground as described by Hutchings et al. (2002). This area has been included in annual demersal fish trawl surveys conducted by the Department of Agriculture, Forestry and Fisheries, and was surveyed during the Deep Secrets cruise in 2016 (Sink 2016).

The boundary of this EBSA has been refined since it was first described. The new boundary falls almost entirely within the old boundary, comprising an area about two thirds of the original delineation. It was refined to improve precision based on selection frequency in the two systematic biodiversity plans covering this area (Sink et al., 2011; Majiedt et al., 2013), new focus area delineations for MPA expansion in South Africa, presence of fragile and sensitive habitat-forming species, and benthic ecosystem types that are threatened. The site is presented as a Type 1 EBSA because it contains “Spatially stable features whose positions are known and individually resolved on the maps” (sensu Johnson et al., 2018).

 

Feature conditions and future outlook of the proposed area

According to Wilkinson (2009) there are three areas of untrawled hard grounds on the shelf edge within this area, suggesting they are still intact. However, a recent assessment of cumulative pressures to South Africa’s marine environment showed that there is a small portion of the EBSA that is in good ecological condition, some parts in fair condition, but that most of the EBSA has been heavily modified and is in poor ecological condition (Sink et al., 2019).

 

References

BirdLife International, 2013. Marine e-Atlas: Delivering site networks for seabird conservation. Proposed IBA site ‘Atlantic, Southeast 19 – Marine’. Available online: http://54.247.127.44/marineIBAs/default.html. Accessed 11 March 2013

Holness, S., Kirkman, S., Samaai, T., Wolf, T., Sink, K., Majiedt, P., Nsiangango, S., Kainge, P., Kilongo, K., Kathena, J., Harris, L.R., Lagabrielle, E., Kirchner, C., Chalmers, R., Lombard, A., 2014. Spatial Biodiversity Assessment and Spatial Management, including Marine Protected Areas. Final report for the Benguela Current Commission project BEH 09-01.

Hutchings, L., Beckley, L.E., Griffiths, M.H., Roberts, M.J., 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.

Johnson, D.E., Barrio Froján, C., Turner, P.J., Weaver, P., Gunn, V., Dunn, D.C., Halpin, P., Bax, N.J., Dunstan, P.K., 2018. Reviewing the EBSA process: Improving on success. Marine Policy 88, 75-85.

Karenyi, N. 2014. Patterns and drivers of benthic macrofauna to support systematic conservation planning for marine unconsolidated sediment ecosystems. PhD thesis. Nelson Mandela Metropolitan University, Port Elizabeth.

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

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

Majiedt, P., Holness, S., Sink, K., Oosthuizen, A., Chadwick, P. 2013. Systematic Marine Biodiversity Plan for the West Coast of South Africa. South African National Biodiversity Institute, Cape Town.

Roberson, L.A., Lagabrielle, E., Lombard, A.T., Sink, K., Livingstone, T., Grantham, H., Harris, J.M. 2017. Pelagic bioregionalisation using open-access data for better planning of marine protected area networks. Ocean & Coastal Management, 148: 214-230.

Santos, J., Rouillard, D., Groeneveld, J.C. 2014. Advection-diffusion models of spiny lobster Palinurus gilchristi migrations for use in spatial fisheries management. Marine Ecology Progress Series, 498: 227–241.

Sink, K. 2016. Deep Secrets: the outer shelf and slope ecosystems of South Africa. Cruise Report: ALG 230 – ACEP_DSC.

Sink, K.J., Attwood, C.G., Lombard, A.T., Grantham, H., Leslie, R., Samaai, T., Kerwath, S., Majiedt, P., Fairweather, T., Hutchings, L., van der Lingen, C., Atkinson, L.J., 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. 2012a. National Biodiversity Assessment 2011: Technical Report. Volume 4: Marine and Coastal Component. South African National Biodiversity Institute, Pretoria.

Sink, K.J., van der Bank, M.G., Majiedt, P.A., Harris, L.R., Atkinson, L., Karenyi, N., Kirkman, S. (eds) 2019. National Biodiversity Assessment 2018 Technical Report Volume 4: Marine Realm. South African National Biodiversity Institute, Pretoria. http://hdl.handle.net/20.500.12143/6372.

Sink, K.J., Wilkinson, S., Atkinson, L.J., Sims, P.F., Leslie, R.W., Attwood, C.G. 2012b. The potential impacts of South Africa’s demersal hake trawl fishery on benthic habitats: historical perspectives, spatial analyses, current review and potential management actions. Unpublished report. Cape Town: South African National Biodiversity Institute.

Wilkinson, S. 2009. Ring Fencing the Trawl Grounds. South African Deep-sea Trawling Industry Association. Report prepared by Capricorn Fisheries Monitoring cc. Cape Town.

 

Status of submission

The Browns Bank EBSA was recognized as meeting EBSA criteria by the Conference of the Parties. The revised description and boundaries still need to be submitted to COP for approval.

 

COP Decision

dec-COP-12-DEC-22

 

Assessment of the area against CBD EBSA criteria

C1: Uniqueness or rarity High

Justification

When first described, Browns Bank was identified by two systematic plans as a priority area because it is the only place where targets for the Southern Benguela Gravel Outer Shelf habitat (which is Critically Endangered) can be met (Majiedt et al., 2013, Sink et al., 2011). It should be noted that this ecosystem type has a limited extent with an estimated total area of less than 450 km2. Since the revision of the National Marine Ecosystem Type Map (Sink et al., 2019) and the EBSA boundary, this is still true; however, the ecosystem type is now called Southern Benguela Rocky Shelf Edge Mosaic. It is still Critically Endangered, but does extend a little beyond the extent of the EBSA along the shelf edge; the most intact parts of this ecosystem type are included in the EBSA.

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

Justification

This area is part of the western Agulhas Bank spawning ground as described by Hutchings et al. (2002). The gadoid Cape hakes Merluccius capensis and M. paradoxus, the gempylid Thyrsites atun (snoek) and the clupeid Etremeus whiteheadii (round herring) move to the western Agulhas Bank and southern west coast to spawn, generally in late winter and early spring when offshore Ekman losses are at a minimum. The eggs and larvae drift northwards and inshore to the west coast nursery grounds. Browns Bank, an apex area of the Agulhas Bank, is recognized as a critical area for retention of spawning products because eddies in this area help to re-circulate water inshore and link important nursery areas with this spawning habitat on the shelf edge. Strong jet currents on the west coast oblige adult hake to shift southwards to spawn, to ensure that juveniles enter the west coast nursery grounds downstream (Hutchings et al., 2002). The area is also important for juvenile spiny lobsters (Santos et al., 2014). This shelf-edge area also constitutes foraging area for offshore seabirds (BirdLife International 2013). Limited tracking datasets have shown that the shelf edge is heavily used by a diversity of pelagic seabirds. In particular, the Browns Bank site is a proposed marine IBA for two species of seabird: Cory’s Shearwater and Atlantic Yellow-nosed Albatross (BirdLife International 2013). Additional seabird tracking datasets may result in this site being an IBA for additional species in future.

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

Justification

The Atlantic Yellow-nosed Albatross is globally Endangered, and Browns Bank is a proposed marine IBA site for this species, indicating that it holds a significant proportion of the global population of this species during some periods of each year for which data are available (BirdLife International 2013). This area also contains the last moderately intact patches of Southern Benguela Rocky Shelf Edge Mosaic, a rare habitat type that is considered Critically Endangered (Sink et al., 2012a,b, 2019). Wandering albatross, Shy, Black browed, Atlantic yellownose and Pintado petrels are common in area (Sink 2016).

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

Justification

This area has hard ground habitats on the outer shelf and shelf edge that are considered sensitive to demersal trawling and mining (Sink et al., 2011, 2012a, 2012b). Recently, fisheries observers collected two species of cold-water corals within this area (Capricorn Fisheries Monitoring, unpublished information). The specimens are in the invertebrate collection at iZiko, the South African Museum in Cape Town. Further, recent samples of coral, Thouarella, hermit crabs, and brisingid sea stars have been collection or seen, and 77 invertebrate morpho-species were identified from the area in a recent survey (Sink 2016).

C5: Biological productivity Medium

Justification

The Agulhas and Southern Benguela ecoregions meet at the southeastern boundary of the area and sporadic shelf edge upwelling enhances the productivity along its outer margin. Based on tracking data, the area holds a significant proportion of the global population of at least two species of seabirds, namely Cory’s Shearwater and the globally Endangered Atlantic Yellow-nosed Albatross (BirdLife International 2013).

C6: Biological diversity Low

Justification

The national marine ecosystem map indicates a moderate number of ecosystem types within the area (Sink et al., 2019).

C7: Naturalness Medium

Justification

There are three areas of untrawled hard grounds on the shelf edge within this area (Wilkinson 2009). The Southern Benguela Rocky Shelf Edge Mosaic ecosystem type is in poor condition and there is no remaining area of this ecosystem type left in good condition, and only fragments in moderate condition (Sink et al., 2012a,b, 2019). Across the EBSA, 2% of the habitat is in good ecological condition, 26% is in fair ecological condition and 72% is in poor ecological condition (Sink et al., 2019).

 

Other relevant website address or attached documents

Summary of ecosystem types and threat status for the Browns bank EBSA. Data from Sink et al. (2019).

Threat Status

Ecosystem Type

Area (km2)

Area (%)

Critically Endangered

Southern Benguela Rocky Shelf Edge Mosaic

1197.1

21.2

Least Concern

Agulhas Outer Shelf Reef Coarse Sediment Mosaic

385.5

6.8

 

Agulhas Rocky Shelf Edge

414.8

7.3

 

Southeast Atlantic Upper Slope

1938.1

34.3

 

Southern Benguela Sandy Outer Shelf

1541.7

27.2

 

Southwest Indian Upper Slope

180.5

3.2

Grand Total

 

5657.7

100.0

 

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