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Whale shark

Whale Shark

Description

 

Rhincodon typus

Common names: Mini mothu mora (S), Pulichsura (T), thimingal sura (T)

 

Length: 12+meters (maximum)

Weight: 21+ tonnes (maximum)

Females are usually larger than males.

 

The whale shark is the largest living fish (non-mammalian vertebrate) on earth. This gentle giant is a slow-moving fliter-feeding shark that feeds primarily on plankton. They inhabit tropical and subtropical oceans. Satellite tracking data by scientists has revealed both regional and long-range movements of whale sharks in their range. They have a lifespan of 70+ years and depend on healthy oceans for their well-being.

 

Whale sharks are known to aggregate seasonally near shore and along coral reefs. The timing of these aggregations often corresponds with localized blooms of phytoplankton, zooplankton or spawning of fishes. Otherwise it is a pelagic species and deep diver, capable of diving more than a 1,000 meters.

Why Protect Whale Sharks in Sri Lankan Waters

 

  • Presence and numbers of whale sharks are indicative of a healthy ocean. Whale sharks control animal populations and ensure diversity, and therefore their forced reduction could cause an ecological imbalance.

  • Whale sharks have the potential to attract large numbers of tourists each year amounting to several millions of dollars in foreign earnings. A better income generating alternative to shark finning and liver oil extraction.

  • Besides India and the Maldives, Sri Lanka should join and support international conservation and protection of whale sharks because they traverse geographic and international boundaries and interbreed during their lifespan.

Threats

 

  • Consumer demand for their fins, oil and cheap meat

  • Legal fisheries catch

  • Accidental capture in fishing nets

  • Illegal dynamiting

  • Vessel strikes by propellers

  • Plastics and other pollutants

  • Habitat damage.

Conservation Status

 

Listed as Vulnerable to extinction on the IUCN Red List of Threatened Species. It is included in Appendix II of CITES but not gazetted in Sri Lanka. As of October 2016, the whale shark is now a protected species in Sri Lankan waters joining India and the Maldives. Read more >>

Sighting Distribution Records

 

Although they are migratory, whale sharks can be found in Sri Lankan waters through all months of the year as evidenced by sighting records from various Maritime Provinces (MP).

 

Kalpitiya peninsula (Northwestern MP):        Nov to Jan, Mar to May

Negombo to Moratuwa (Western MP):           Jan, Mar, Apr, Jun

Galle to Matara (Southern MP):                      Jan to Apr, Oct

Ampara, Trincomalee (Eastern MP):              Jun to Oct

Vettalakerni (Northern MP):                            Jun

 

Dedicated surveys have not been conducted in Sri Lankan waters and therefore no baseline is available.

 

Preliminary sightings and known oceanographic data suggests that the mature phase of the monsoon and post monsoon months are likely the best sighting and feeding times for whale sharks. Juveniles tend to be found in nutrient rich neritic waters (green waters) close to shore (up to 50 m depths) and unlikely to migrate till maturity.

 
Whale Shark Watching & Swimming Best Practices

Vessels should approach animals sideways at no wake speed (maximum 3 knots) and not from the front. A vessel (less than 15 meters in length) should keep a minimum distance of 5 meters from a whale shark. A maximum of 4 snorkellers and a guide may enter the water. Use only biodegradable sunscreen lotions. Scuba equipment is not recommended as whale sharks have a tendency to swim after the air bubbles.

 

Enter the water slowly and wearing a life jacket is recommended. Whale sharks are usually indifferent to swimmers and can be playful. They pose no danger to humans but an accidental blow from the powerful tail can cause injury. So keep a minimum distance of 1.5 meters from the front of the body and 3 meters from the rear. Swimming with whale sharks is a once in a lifetime experience. You can help protect whale sharks for future generations by supporting and even participating in a research program.

Swimming with juvenile whale shark Kalpitiya Sri Lanka
Whale Shark Research Program

 

This is a new exciting program that will offer guests to get up close and personal with the magnificent whale shark – the largest fish on earth while contributing to their conservation. What’s more you may also get the opportunity to see and record baleen whales (Bryde’s and Eden’s whales), sea turtles and giant manta rays while scanning the ocean inshore for the distinctive whale shark. This study would be focussed on gathering new data on whale sharks as well as baleen whales to help with their identification and conservation.

 

While the project is underway, guests will be allowed to participate by taking photographs, video, length measurements, determination of sex, recording location details, behaviour and unusual markings, and then logging the

collated data in a global database. The data collected will help build life histories for whale sharks that have a life span of 70+ years and will have a long-term impact on global whale shark research and conservation.

 

Identification: Whale sharks can be identified by their markings. Each pattern of spots is unique and individuals can be identified using computer programs. Photos will be taken of the spot patterns behind the gills on the left side (primary pattern) and right side (secondary pattern). The data collected whilst out at sea is then logged into a database, which will scan the photos for matches to previously identified individuals using pattern-recognition software.

Whale shark Kalpitiya

Gentle giant sighted off Kalpitiya on March 15, 2015

Whale sharks caught by fishermen Ampara Sri Lanka

3 whale sharks caught by fishermen in Ampara, reported October 10, 2014