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REEF SHARKS

23rd June, 2023

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Context

  • The study, findings published in the Science journal, was conducted in 391 coral reefs spreading across 67 countries of the world.
  • It was undertaken as a collaboration called Global FinPrint project.
  • It studied 5 key species of reef sharks namely –
    • Caribbean reef shark
    • Nurse shark
    • Grey reef shark
    • Blacktip reef shark and
    • Whitetip reef shark
  • This study highlighted the decline in reef sharks population by collecting and analysing video footage.

Other Details

  • It was found that there is a decline of 60 to 73 per cent in these five key species’ population.
  • Geographical areas covered were extending to
    • Indian Ocean off East Africa
    • Australia’s Great Barrier Reef
    • clusters of coral in the Caribbean
  • Apart from these reef sharks, one-third of all sharks, ray, and other related species are also on the risk of extinction due to declining population.
  • In the surveyed 391 reefs, in 34-47%, individual shark species was not found.
  • In some places, sharks were not detected in 13.6 per cent of reefs at all.
  • Most affected areas were –
    • Asia
    • Eastern Africa
    • South America, and the
    • Central-eastern Caribbean

Reef Sharks

  • They are known by the scientific name Carcharhinus perezii.
  • In marine ecosystems these sharks are considers indicator species and are the top predators of the coral reefs.
  • There are many species of sharks found in reefs some of them are –

Habitat

  • Shallow Tropic or subtropical water of coral reefs.
  • That is shallow ocean regions close to the shore.
  • Mangroves.
  • Sea grass beds.

Significance

  • These are very significant to coral reef system.
  • They help in maintaining food webs.
  • Nutrients cycling is also supported by them.
  • They can promote economy by giving a push to tourism industry.

Conservation Status

  • Current IUCN status is Near threatened.
  • However study finds that these five key species should be classified as threatened as per International Union for Conservation of Nature Red List of Threatened Species.

Threat

  • Overfishing is the key threat.
  • They are killed for meat, leather, liver oil, and fishmeal.
  • It leads to the domination of ray instead of shark which ultimately led to decline of both sharks and rays.
  • Other marine activities which pollute the oceans.
  • Degradation and destruction of Natural habitat.

Measures to be taken for conservation

  • Right management techniques.
  • Reefs could be converted or declared protected areas.
  • Special programmes to conserve them like in Philippines and Indonesia.
  • Enforcing rules and related regulations.
  • Involvement of fishermen and sensitizing them about this ecological issue.

Indicator Species

  • These are living organisms whose presence or absence indicates the changes in environment and the particular ecosystem.
  • These living organisms could be plants, animals or microorganisms.
  • These organisms are highly sensitive to any environmental changes.
  • Hence any negative changes in such species growth, health or population indicate environmental stress.
  • On the other hand good and healthy presences of them indicate the wellbeing of ecosystem and environment. For eg. Lichens.

Must read Article:

https://www.iasgyan.in/daily-current-affairs/coral-reefs

https://www.iasgyan.in/blogs/coral-reefs-around-the-world

https://www.iasgyan.in/daily-current-affairs/great-barrier-reef-40

PRACTICE QUESTION

What are indicator species? Explain in context of reef sharks. By highlighting the threat reef sharks are facing, Elaborate how they play a key role in sustainability of the coral reef ecosystem.

(150 words)

https://theprint.in/environment/reef-sharks-pushed-to-extinction-by-overfishing-up-to-73-decline-in-5-common-species-globally/1631418/