true

ISRA FACTSHEETS

WESTERN INDIAN OCEAN REGION

ISRA FACTSHEETS

WESTERN INDIAN OCEAN REGION

Baie Ternay ISRA

66/125

Baie Ternay ISRA

Baie Ternay

Summary

Baie Ternay is located on the northwestern side of Mahé Island, Republic of Seychelles. This area is situated on the wider Mahé plateau, an underwater shelf that comprises the Seychelles Inner Islands. The seabed within this area is composed of seagrass meadows, carbonate and granitic coral reefs, coral rubble fields, and sandy substrates. Baie Ternay overlaps with an Ecologically or Biologically Significant Marine Area, a Key Biodiversity Area, and a marine protected area. Within this area there are: threatened species and undefined aggregations (Spotted Eagle Ray Aetobatus ocellatus).

Baie Ternay

Baie Ternay

DESCRIPTION OF HABITAT

Baie Ternay is a shallow bay located on the Mahé plateau, Republic of Seychelles. The prevailing environmental conditions are governed by the monsoon seasons, trade winds, and currents that drive the Seychelles’ oceanography (Novozhilov et al. 1992). From May to September, the winds blow from the southeast. From December to March, they blow from the northwest. The transitional period in April and October/November usually features calm seas and low wind speeds (Novozhilov et al. 1992). Sea surface temperatures are warmer during positive Indian Ocean Dipole and El-Nino events (Burns & Subrahmanyam 2016). During the southeast monsoon, the area is sheltered and features exceptionally calm seas.

The seabed within Baie Ternay is variable and features several habitats including seagrass meadows, carbonate and granitic coral reefs, coral rubble fields, and sandy substrates (Jennings et al. 1996). The coral reef extends from just below the surface (exposed at low tide) to a depth of ~28 m in the centre of the bay. The granitic reef extends below 30 m on the edges of the bay, especially around the northwestern point of the bay and the ‘Lighthouse’ dive site (N Fassbender pers. obs. 2022). The main reef area follows the outline of the bay and is a large U-shape, with a gap in the southeast where a sandy channel extends into the shallow water.

The area overlaps with the Mahé, Alphonse and Amirantes Plateau Ecologically or Biologically Significant Marine Area (EBSA) (CBD 2023), the Cap Ternay / Baie Ternay Marine National Park Key Biodiversity Area (KBA 2023), and the Baie Ternay Marine National Park.

This Important Shark and Ray Area is benthopelagic and is delineated from inshore and surface waters (0 m) to 25 m based on the observations of the Qualifying Species in the area.

CRITERION A

VULNERABILITY

The one Qualifying Species within the area is considered threatened with extinction according to the IUCN Red List of Threatened SpeciesTM. The Spotted Eagle Ray is assessed as Endangered (Finucci et al. Submitted).

CRITERION C

SUB-CRITERION C5 – UNDEFINED AGGREGATIONS

Baie Ternay is an important area for undefined aggregations of one ray species.

Marine megafauna is recorded as part of an ‘incidental sightings’ data collection program by Global Vision International (GVI) Seychelles. GVI conducts monitoring of marine fish, corals, and invertebrates at 24 dive sites around Northwest Mahé, of which five dive sites fall into the Baie Ternay area. An incidental sighting is defined as any encounter with marine megafauna, whereby the diver encountering the animal records the species, number of individuals, estimated size, depth, and time. Incidental sightings are recorded during monitoring dives, training or recreational dives conducted by GVI Seychelles. The monitoring dives alone consist of at least 34 dives per site per year.

Observation records between 2007–2022 from these sites show regular and predictable observations of Spotted Eagle Ray in the area, year-round, with a total of 1,093 individuals observed (Global Vision International – Seychelles unpubl. data 2023). Aggregations of four animals or more were recorded on 247 occasions with a mean group size of 10 individuals (maximum = 45). These individuals had an estimated mean size of 55 cm disc width (DW) (range: 20–150 cm DW). The mean depth of these observations was 8.4 m (range: 5 – 12 m). Further information is required to determine the function of these aggregations.

Baie Ternay

SUBMIT A REQUEST

ISRA SPATIAL LAYER REQUEST

To make a request to download the ISRA Layer in either a GIS compatible Shapefile (.shp) or Google Earth compatible Keyhole Markup Language Zipped file (.kmz) please complete the following form. We will review your request and send the download details to you. We will endeavor to send you the requested files as soon as we can. However, please note that this is not an automated process, and before requests are responded to, they undergo internal review and authorization. As such, requests normally take 5–10 working days to process.

Should you have questions about the data or process, please do not hesitate to contact us.

    * indicates required

    Industry or sector (*)

    Under the terms and conditions of our User License Agreement , full and appropriate acknowledgement is required in any materials and publications derived from the data (and copies should be sent to the IUCN SSC Shark Specialist Group through the contact form). For any publications making substantial use of the data, the ISRA welcomes the opportunity for co-authorship, collaboration, and to comment prior to publication.


    Furthermore, we need to know whether you are a commercial or non-commercial user. Non-commercial includes scientific research, education or conservation. Commercial is defined as follows: any use by, on behalf of, or to inform or assist the activities of a commercial entity (that operates ‘for profit’) or use by a non-profit for the purposes of revenue generation

    Type of use(*):

    Please specify which layer (ex. all layers, layers within a specific Region, layers within a Jurisdiction or a single ISRA): Purpose (*):

    Please provide a description of how you intend to use the ISRA GIS Dataset. The more details you provide, the faster we can respond to your request. We may require further clarification prior to providing access. (min. 100 characters – max 1,000 characters)



    File format request (*)

    By providing your personal data, you consent to its processing as described below. The IUCN SSC Shark Specialist Group will use the information you provide on this form to send the documents you requested. You can change your mind at any time by writing to the ISRA Data Coordinator www.sharkrayareas.org/contact. All personal details provided will be treated with respect. For any information you can visit our Privacy Policy.
    Please read the User License Agreement and ISRA Layer Metadata Description

    This form uses Google reCaptcha to reduce spam. Privacy - Terms