Rhincodon typus Whale Shark

The species became listed when environmental scientists saw a massive decrease in population and wanted to preserve the species. They worked to get the species listed. Successfully got listed in 1990 as an Indeterminate and now in 2017 the species is being protected.

Timeline

  • 2016 - Endangered (EN)
  • 2005 - Vulnerable (VU)
  • 2000 - Vulnerable (VU)
  • 1996 - Data Deficient (DD)
  • 1994 - Indeterminate (I)
  • 1990 - Indeterminate (I)
The species lives in the Indo-Pacific, and Atlantic oceans.
Geographic Range
Hunted

Threats to the whale shark include, fisheries catchers, by-catch in nets, and vessel strikes. As well as an illegal trade market. Whale sharks are fished in many locations. But it is not a direct fishing of the whale shark they will “happen” to be caught in a fishing net and they will be held instead of released. Fishing of whale sharks happens in Southern China. Previously whale sharks were targeted in large scale fisheries in Taiwan, India, and the Philippines. Hundreds of sharks were caught in each of these countries until species level protections were implemented. Whale sharks first became protected in 1995. Tuna are directly related to whale sharks in some areas and fishers would set nets around the shark in order to capture the surrounding tuna. Shipping lanes placed too close to whale shark feeding areas create high risk of vessel strikes. Inappropriate tourism is also a threat where crowding occurs or interference. Marine pollution events are also a threat to the sharks. Such event was the deep water horizon oil spill.

Population As of February 2016 there are 7,011 individual sharks sighted. While in a lab they used mitochondria to estimate the current genetic effective population size to be between 119,000-238,000 (75% Indo Pacific 25% Atlantic) Status of population trend. Atlantic sub population trend. A decline of greater or equal to 30% in the last three generations (75 years) Indo-Pacific trend. A decline of greater than 50% in the last three generations (75 years)

Whale sharks found in both coastal and oceanic habitats. Sightings are strongly correlated with temperature in the Indian and Atlantic oceans. Most sightings occur in waters with temps between 26.5C and 30C. Whale sharks spend a majority of their time in the epipelagic zone. But dive to 1,928 m. Whale shark sightings occur in known feeding areas near the surface or during fish spawning events/zooplankton blooms. Movement patterns are full migrant. Whale shark reproductive ecology is poorly known. A single female whale shark that was examined had 304 pups in various stages of development. This is the largest litter sized reported of any shark species. This also means that whale sharks are a placental viviparous. Male whale sharks begin maturing at roughly 17 years. Female whale sharks begin maturing between 19-22 years.

Whale sharks are filter feeders. Unlike other sharks who hunt food whale sharks simply filter water for food. The diet of the whale shark includes, plankton, krill, shrimp, larvae, algae, and some small fish. The whale shark is basically a moving ecosystem. You have a variety of all sizes of fish and life around a whale shark when it is feeding. Small fish eat remnants from the whale sharks filters. Where it filters food than small fish eat what is filtered. As well as having a large source of small plankton or krill that fish will naturally concentrate in that small area because of the abundance of food. Then you have a full food chain. You have a filter feeder (the whale shark) then small fish, fish that eat those small fish, bigger fish that eat those fish. Sharks are also spotted often near whale sharks when feeding. This is due to the abundance of large size fish the whale shark brings with it.

Conservation actions to protect the whale shark. Species included in Annex 1 (Highly Migratory Species) This annex provides a framework for management and conservation of fisheries. Species included in Appendix ll of the Bonn Convention for the conservation of Migratory species of Wild animals. National/territory management measures for Whale sharks in many countries. Key habitats for whale sharks are now protected by many countries. Regional fisheries management organisations (RFMO’s) have banned intentional setting of nets around feeding areas for whale sharks. Whale shark tourism is managed through certain legislations in some countries.

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