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ISRA FACTSHEETS

ASIA REGION

ISRA FACTSHEETS

ASIA REGION

Baththalangunduwa ISRA

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Baththalangunduwa ISRA

Baththalangunduwa

Summary

Baththalangunduwa is located on the northwest coast of Sri Lanka. The area is situated on the fringes of the shallow coastal Puttalam Lagoon which is connected to three river basins providing the area with freshwater input. The lagoon is characterised by tropical wetland and nearshore habitats such as mangroves, seagrass meadows, and salt marshes. The area overlaps with two Ecologically or Biologically Significant Marine Areas (EBSA), the Sri Lankan Side of Gulf of Mannar EBSA and the Coastal and Offshore Area of the Gulf of Mannar EBSA. Within this area there are: threatened species and reproductive areas (Winghead Shark Eusphyra blochii).

Baththalangunduwa

Baththalangunduwa

DESCRIPTION OF HABITAT

Baththalangunduwa is located in the far fringes of the Puttalam Lagoon, a shallow lagoon on the northwest coast of Sri Lanka. The lagoon is 30 km long, 3–12 km wide, with a maximum depth of 1.5 m. The lagoon is connected to three river basins, Kala Oya, Mi Oya, and Moongil Ara. The Kala Oya provides the largest freshwater volume and is located at the mouth of the lagoon. The lagoon has several important tropical wetland habitats such as mangroves, seagrass meadows, and salt marshes (Dayaratne et al. 1995).

The area receives rainfall during the southwest monsoon season (June–September) and the northeast monsoon (November–December) (Domroes & Ranatunge 1993). There are seasonal variations and spatial gradients in salinity with higher salinity during the drier months with possible hypersaline periods during the drier months in the southern parts of the lagoon (Arulananthan et al. 1995).

This area overlaps with two Ecologically or Biologically Significant Marine Areas (EBSA), the Sri Lankan Side of Gulf of Mannar EBSA and the Coastal and Offshore Area of the Gulf of Mannar EBSA (CBD 2024a, 2024b).

This Important Shark and Ray Area is benthopelagic and is delineated from inshore and surface waters (0 m) to 10 m based on the bathymetry of the area.

CRITERION A

VULNERABILITY

One Qualifying Species within the area is considered threatened with extinction according to the IUCN Red List of Threatened Species. The Winghead Shark is assessed as Endangered (Smart & Simpfendorfer 2016).

CRITERION C

SUB-CRITERION C1 – REPRODUCTIVE AREAS

Baththalangunduwa is an important reproductive area for one species of shark.

The area is part of ongoing catch landing monitoring covering 87 sites across Sri Lanka (Blue Resources Trust unpubl. data 2024). Baththalangunduwa is remote which presents some challenges for surveying and data collection. Fishers travel to the area seasonally during the dry season (January–March) to fish the area, camping on the beach for a few days at a time. A single Winghead Shark was first documented during a visit to the area in March 2018 (Fernando et al. 2019). Subsequently, an agreement was set up with a reliable local fisher to report Winghead Shark landings given the significance of observing this rare species. The species is morphologically distinct and easily identified by fishers due to the shape of its head.

In February 2019, 11 individuals measuring 37.5–43.0 cm total length (TL) were captured by fishers in the area (Blue Resources Trust unpubl. data 2024). These individuals were all at, or below, the reported size-at-birth of the species (32–45 cm TL; Ebert et al. 2021) indicating that these were neonates. Of the 87 sites monitored across Sri Lanka, this is the only location where neonate Winghead Sharks have been recorded (Blue Resources Trust unpubl. data 2024). Informal interviews with fishers operating in the area suggest that encounters with Winghead Sharks are regular. An additional male specimen of 41.5 cm TL was recorded from Chilaw in January 2020 which is 100 km south of the area with the seller confirming that the specimen was caught at Baththlangunduwa, while a large Winghead Shark (42 kg; length not recorded but estimated to be ~135 cm TL based on Froese et al. 2014) was recorded in March 2024 landed at Pukkulam landing site and confirmed by the fisher to be caught in the area. The records of Winghead Sharks over four years confirms its regular presence in the area.

While the number of individuals recorded is low, there are currently no other known locations in the Western Indian Ocean or Asian regions still regularly harbouring early life-stages of this species. The species persists in northern Australia and Papua New Guinea but appears to now be largely absent from much of its historic range outside of these two countries and therefore Baththalangunduwa represents a globally important area of this rare and threatened species.

Baththalangunduwa

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