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Irrawadi dolphines

Irrawadi dolphines






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    Irrawadi dolphines Irrawadi dolphines Presentation Transcript

    • Irrawaddy DOLPHINS
      Presentation by
      Dr MadhusudanSubudhi
    • Taxonomy
      Kingdom _ Animalia
      Phylum _ Chordata
      Class _ Mammalia
      Order _ Cetacea
      Family _ Platanistidae
      Genus _ Orcaella
      Species _ OrcaellaBrevirostris
    • Physical description
      Slaty blue to slaty grey
      Under parts are slightly paler
      180 to275 cms
      Body weight
      May go up to 190 kg(418 lbs)
    • Gross Anatomy
    • Gross anatomy
      Bulging fore head
      A very short beak
      Pectoral fin is broadly triangular
      Small dorsal fin towards posterior end of the back
      U shaped blowhole opens to the front(unlike other sps)
      12 to 19 teeth on each side of each jaw. Narrow pointed peg like teeth about 1cm length
    • Gross Anatomy (contd)
      Two unique anatomical features of this sps:
      Stomach is divided into two into two compartments
      Muscular part & glandular part
      Cardiac sphincter is absent
    • Male reproductive organ of dead Irrawadidolphinedesected by Dr M.subudhi & MrMumtajalli khan.
    • Grossly healthy kidneys of a dead Irrawady dolphin dissected by Dr M.Subudhi & Mr.Mumtazalli Khan
    • Physical behavior
      They prefer coastal, brackish & fresh water of tropical & subtropical Indo pacific.
      Feeds on fishes ,crustaceans, cephalopods & fish eggs.
      Breathes at 70 to 150 seconds intervals.
      Usually dives for an average of 30 to60 seconds but larger dives up to 12 minutes have been recorded.
      Swim rate recorded up to 25 kms/hour.
    • Physical behavior(contd)
      Irrawadi dolphins are less active than other dolphins
      Only the uppermost part of dorsal fin becomes visible during a slow rolling dive
      They never bow ride
    • Breeding behavior
      Sexually mature around 4to 6 years age
      Gestation period is 14 months
      In Semeyang lake/Mahakam river(Malaya) mating season recorded to be April toJune
      But in Jakarta calves borne between July to december
      New borne measures 96cm,body weight 12.3kg.Body weight at weaning aapx.45kg.
      Though calves consume fish at 6months age but nursed up to 2 years
    • Origin
      Ayeyarwady river or Irrawaddy river which flows from north to south in Myanmar.
      Name derived from the Sanskrit word Iravati(minor Goddess in Indian mythology) or from her son Airabat the elephant
      Irrawaddy is the largest river of Burma about 2170 km long
    • Panoramic view of Irrawaddy river
    • Panoramic view of Irrawaddy river
    • World wide habitats & population
    • Panoramic view of Irrawaddy river
    • Bangladesh as fresh,brackish & salt water habitat
      Sundarban delta
      Mangrove forest
    • Chilika lake as brackish water habitat
      Chilika near sea mouth
    • Panoramic view of inner Malampaya sound (Philipines)Brackish water habitat
    • Brackish water habitat of Sangkhala lake(Thailand)
    • Categorization of IUCN red list
      Ex- Extinct
      Ew- Extinct in the wild
      Cr- Critically endangered
      En- Endangered
      Vu- Vulnerable
      Lower list
      NT- Near threatened
      LC- Least concerned
      Cd- Conservation dependant
    • Analysis of threat as per IUCN red list
      Irrawaddy dolphin is classified as VULNERABLE
      on the IUCN red list and listed in appendix-1 of
      CITES (Conservation of International trade in endangered species)
      In Mahakam river & Malampaya sound classified as
      critically endangered
    • Threats
      Irrawaddy dolphins are more susceptible to
      human conflicts than most other dolphins
      who live farther in the ocean.
      Drowning in gillnets is the main threat throughout their range.
      Majority of reported deaths in all subpopulations is due to accidental capture
      and drowning in gill nets, dragnets, bottomset crab nets(in philipines).
    • Gillnetting the No 1 threat forIrrawaddy dolphin
    • Threat:Chilika experience
      Author has conducted post murtem of 10 dead dolphins between2005 to 2008.
      4 were putrified enough to opine any cause of death.
      5 deaths are due to traping followed by drowning in gill nets bearing injuries on tongue,base of the tail and skin exfoliations.
      1 death is due to lungs desease (focal necrosis
      of lungs)
    • Decomposed dolphin
    • Lungs of dead Irrawaddy dolphin with focal necrotic lesions
    • Researchers working on threat analysis & conservation strategies
    • Threat:Chilika experience
      Unregulated fishing
      Introduction newer varieties of fishing nets which are almost invisible under water.
      Motorized propeller boats, large in number
      Tourist boats approach much closer to dolphins, even sometimes chase them.
      Pollution of water, change in salinity, change in water temperature and siltation are less emphasized.
    • Ongoing conservation initiativesChilika experience
      Mapping dolphin population, distribution and
      movement by using GPS.
      Imposition of fines on gill and seine netting in Satpada region.(Orissa marine fisheries regulation act)
      Fines on tourist boats found chasing dolphins
      Ongoing training in dolphin watching guide- lines by CDA funded by WDCS.
      Distribution of booklets and pamphlets on sustainable fisheries
    • Action plan
      Establishing core conservation areas where gillnets and motorized boats are to be banned.
      Promoting net attendance rules and providing training on safe release of entangled dolphins.
      Providing alternative or diversified employment to gillnet fishermen.
      Research & development with acoustical deterr-ants and reflective nets.