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REPRODUKSI HIU (SHARKS REPRODUCTION)

REPRODUKSI HIU (SHARKS REPRODUCTION). Overview. Reproductive Organs Courtship Mating Development Parturition Species Examples Human Impact. Cloacal opening between pelvic fins Internal ovaries Paired Two forms Eggs travel through ostium to oviduct then through shell gland

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REPRODUKSI HIU (SHARKS REPRODUCTION)

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  1. REPRODUKSI HIU (SHARKS REPRODUCTION)

  2. Overview • Reproductive Organs • Courtship • Mating • Development • Parturition • Species Examples • Human Impact

  3. Cloacal opening between pelvic fins Internal ovaries Paired Two forms Eggs travel through ostium to oviduct then through shell gland Most eggs develop in uteri Female Reproductive Organs Cloacal opening shown on a female shark

  4. Reproductive Organs of a Female Porbeagle Shark

  5. Male Reproductive Organs • Claspers • Internal Testes • paired • Urogenital sinus • Sperm is released into groove of claspers and then into female Claspers of a mature Male shark

  6. Reproductive Organs of a Male Porbeagle Shark

  7. Maturity • Age and size at maturity differs among species • Can range from 5 to 18 years to reach breeding age • Sharks are usually about 75% of their maximum size at maturity • Males are on average about 10% smaller than females at maturity • Females reach maturity about 34% faster than males

  8. Courtship and Mating • Little known • Appears to be violent • Females have thicker skin than males • Mate selection shown in some species Courtship and Mating circle of the Basking Shark

  9. Mating Mating Mating wounds– bite marks on pectoral fin of female Porbeagle

  10. Mysterious Shark Birth • January 2002 • Henry Doorly Zoo in Nebraska • Female Bonnethead gave birth after being in captivity without access to males for three years Bonnethead Shark, Sphyrna tiburo

  11. Development • Three types of development of embryos • Oviparous • “egg laying” • No parental care • Ovoviviparity/Aplacental • Most common • Embryos in uterus with yolk sac • Viviparity/Placental • Embryos in uterus with yolk sac and placental connection

  12. Considered most primitive Most common with bottom dwelling sharks Yolk sac for nurishment Egg casing to protect young Eggs are released near ocean floor with no more parental care Egg receives no other care or nutrition Development continues for up to a year inside the egg Examples: Cat Shark Port Jackson Shark Horn Shark Zebra Shark Whale Shark Oviparous

  13. Oviparous Development 1—Shark egg case after it is laid 2—The egg develops in the shell. 3—The young is fed by the yolk sack 4—The developed young breaks away from the shell.

  14. Examples of Egg Cases Egg case of a oviparous shark Egg case of a Port Jackson Shark

  15. Development of a Swell Shark Swell shark develops within a tough, leathery egg case.

  16. Fertilized eggs kept inside mother until born Most common form of development Eggs get nutrition through yolk sac Produces large embryos Eggs hatch inside mother and then are born Provides better shelter Examples Dogfish Sharks Cow Shark Angel Shark Frill Shark Tiger Shark Ovoviviparous

  17. Ovoviviparity Portuguese shark with developing eggs in ovaries

  18. Oophagy and Embryophagy • Oophagy– eating eggs within the mother’s uteri • Examples: • Lamnoid Sharks • Makos • White Sharks • Threshers • Crocodile Sharks • False Catsharks • Embryophagy—eat siblings in uteri • Example: • Sand Tiger Shark 50cm Shortfin Mako Sharkembryo distended stomach, full of egg yolk 35cm Porbeagle Shark distended stomach of this specimen is full of egg yolk from ingested eggs

  19. Develop placenta or uterine milk to feed to young Similar to development of mammals Considered the most advanced form Embryo develops internally Has an umbilical cord attached to mother Gestation is typically 9 months Examples: Hammerhead sharks Requiem sharks Viviparous

  20. Examples of viviparous development • Illustration of viviparous embryo showing the yolk sac placenta, yolk sac, uterus and embryo • Hammerhead shark showing umbilical cord

  21. Number of embryos born to a mother varies Typically born after a period of 9 to 12 months Most born tail first Usually give birth in shallow coastal areas Parturition Birth of a baby shark

  22. Great White Shark • Maturity at 9 to 15 years • 7 to 11 per litter • Young 1 meter at birth • Gestation time unknown • Ovoviviparity and oophagy, but canabalism as once believed • Give birth every two years

  23. Bull Sharks • Viviparous • Sexual maturity reached at 8 to 10 years • Breed in summer • Litters up to 13 pups • Breed in brackish waters

  24. Goblin Shark • Little is known about reproduction • Male mature at 2.6 meters • Ovoviviparious

  25. Whale Shark • Only recently began to study • Up to 300 pups • Oviparous • Don’t know where or when give birth or what early life is like

  26. Sand Tiger Shark • Long gestation period • Large, well developed young at birth • Only one or two pups • Ovoviviparity, oophagy, and Embryophagy

  27. Silky Shark • Not very much known about reproduction • Live bearing shark • Litters of 2 to 14 • Pup on edges of continental shelves • Newborns stay in nursery areas

  28. Port Jackson Shark • Return to same area to breed • Oviparous • Tough egg case about 7-8 cm wide and 15 cm long • Mature at 8-14 years

  29. Females mature at 62 cm and males at 52 cm total length No evidence of a seasonal reproductive cycle Ovulation occurs when ova reach diameter of 40-45 cm Average number of ova is 12.7 Sexes segregate in adults except to mate Southern Lantern Shark

  30. Great Hammerhead Shark • Viviparous • Mature at a length of 3 meters • Litters of 20 to 40 pups • Young are born during summer • 70 cm in length

  31. Shortfin Mako • Reach maturity at around 2 meters • Females are usually about 2.8 meters • Size at birth is about 70 cm • Litter size 4 to 16 • Placental viviparity • Oophagous

  32. Angel Shark • Gestation lasts 11 months • Synchronized by population • Ovulation occurs in summer and birth takes place in Spring • Gestation has two phases

  33. Bonnethead Shark • Placental viviparity • Shortest gestation period known in sharks • Store sperm for months • Use hormones to regulate cycle

  34. Spiny Dogfish • Gestation period is about two years • Pup remains in uteri and the fluid surrounding it resembles sea water • Reasons for sea water environment not known

  35. Basking Shark • Difficult to study • Observed 25 different courtship episodes • Mature sharks were 5 to 8 meters • Took about 1.8 hours in courtship rituals

  36. Human Impact • Because of slow reproductive rates and small amount of pups, shark populations can not rebuild after being over fished by humans • Environmental degradation and development threatens the nursery areas of many species • Shark finning slaughters hundreds of thousands of sharks each year • Could take decades to centuries for populations to recover Shark fins on sale in Hong Kong market

  37. FINISH THANK YOU

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