Mantas of the Maldives
Part 1: Introduction to Manta ecology and
distribution
By Dr. Anne-Marie Kitchen Wheeler
Project Fo...
Two species of manta ray:
Manta birostris (Walbaum 1792) (MB)
Common name: GIANT or OCEANIC MANTA

Manta alfredi (Krefft 1...
Two species of manta ray:
Manta birostris (Walbaum 1792) (MB)
Common name: GIANT or OCEANIC MANTA

Manta alfredi (Krefft 1...
Two species of manta ray:
Manta birostris (Walbaum 1792) (MB)
Common name: GIANT or OCEANIC MANTA

Manta alfredi (Krefft 1...
Manta birostris (MB)

Manta alfredi (MA)

5
Manta birostris (MB)

Manta alfredi (MA)

6
Manta birostris (MB)

Manta alfredi (MA)

7
Manta birostris (MB)

Manta alfredi (MA)

2

2

8
Manta birostris (MB)

2

Manta alfredi (MA)

2

9
Manta birostris (MB)

Manta alfredi (MA)

10
Manta birostris (MB)

Manta alfredi (MA)

11
Manta birostris (MB)

Manta alfredi (MA)

4
4

4

4

4

12
Manta birostris (MB)

Manta alfredi (MA)

4
4

4

4

4

13
Manta birostris (MB)

Manta alfredi (MA)

2

2

4
4

TEETH ON:
o UPPER JAW
o LOWER JAW

4

4

4

TEETH ON:
o LOWER JAW
14
Manta birostris (MB)

Manta alfredi (MA)

4
4

4

4

4

15
Manta birostris (MB)

Manta alfredi (MA)

4
4

4

4

4

?

16
Manta birostris (MB)

Manta alfredi (MA)

4
4

4

4

4

17
Manta birostris (MB)

Manta alfredi (MA)

4
4

4

4

4

18
There are black variants of each species but are exceedingly rare in Maldives
and only black MB have so far been reported....
There are black variants of each species but are exceedingly rare in Maldives
and only black MB have so far been reported....
There are black variants of each species but are exceedingly rare in Maldives
and only black MB have so far been reported....
Manta rays can be individually identified from their ventral markings

Marks in central and abdominal
areas are used to id...
Manta rays can be individually identified from their ventral markings

Visual identification can be used
instead of taggin...
24
Manta Lifecycle (MA)
The age to which mantas live is still not fully understood but a

Male’ based manta ray known as Bren...
Manta Lifecycle (MA)
Age and growth studies in other elasmobranchs have been based
on ring (or band) measurements of verte...
Manta Lifecycle (MA)

Examples of known longevity of other elasmobranchs in the
wild include the common spiny dogfish Squa...
Manta Lifecycle
Female mantas give birth to fully formed live young. Examples
born in aquaria measured 1.92-1.96 m disc wi...
Manta Lifecycle

Pregnancy last around

12.5 months

29
Manta Lifecycle
Heavily pregnant females are frequently seen at cleaning
stations nearby large sheltered lagoons
e.g. Rasf...
Diurnal Activity
From dawn and throughout daylight hours mantas may be
observed at cleaning stations and feeding areas at ...
Diurnal Activity
From dawn and throughout daylight hours mantas may be
observed at cleaning stations and feeding areas at ...
Diurnal Activity
From dawn and throughout daylight hours mantas may be observed at
cleaning stations and feeding areas at ...
Diurnal Activity

This pattern has been shown from independent study in
Okinawa prefecture (Japan), Komodo (Indonesia) and...
Distribution

Red: MB circumtropical plus temperate
Blue: MA Indo-Pacific tropical
35
Distribution

Red: MB circumtropical plus temperate

36
Distribution

Blue: MA Indo-Pacific tropical

37
Distribution
MB has been reported from offshore islands (Revillagigedos/Mexico,
Galapagos/Ecuador, French Polynesia, Okina...
Distribution
MA has been reported from Maldives, Hawaii, Okinawa
prefecture islands, throughout Indonesia, Malaysia and Fr...
Distribution

MA is reported year round at the majority of locations
where sighted and at most locations the local
populat...
Thank you for your attention
contact details: amkw9@sky.com
41
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  • The two species have distinguishing sets of markings. Next slide Size, teeth etc
  • The two species have distinguishing sets of markings. Next slide Size, teeth etc
  • The two species have distinguishing sets of markings. Next slide Size, teeth etc
  • The two species have distinguishing sets of markings. Next slide Size, teeth etc
  • The two species have distinguishing sets of markings. Next slide Size, teeth etc
  • The two species have distinguishing sets of markings. Next slide Size, teeth etc
  • The two species have distinguishing sets of markings. Next slide Size, teeth etc
  • The two species have distinguishing sets of markings. Next slide Size, teeth etc
  • The two species have distinguishing sets of markings. Next slide Size, teeth etc
  • The two species have distinguishing sets of markings. Next slide Size, teeth etc
  • The two species have distinguishing sets of markings. Next slide Size, teeth etc
  • The two species have distinguishing sets of markings. Next slide Size, teeth etc
  • The two species have distinguishing sets of markings. Next slide Size, teeth etc
  • The two species have distinguishing sets of markings. Next slide Size, teeth etc
  • Next slide has examples
  • Next slide has examples
  • Worldwide distribution next
  • Mantas of maldives part 1

    1. 1. Mantas of the Maldives Part 1: Introduction to Manta ecology and distribution By Dr. Anne-Marie Kitchen Wheeler Project Founder Manta Ecology Project
    2. 2. Two species of manta ray: Manta birostris (Walbaum 1792) (MB) Common name: GIANT or OCEANIC MANTA Manta alfredi (Krefft 1868) (MA) common name ALFRED or REEF MANTA 2
    3. 3. Two species of manta ray: Manta birostris (Walbaum 1792) (MB) Common name: GIANT or OCEANIC MANTA Manta alfredi (Krefft 1868) (MA) common name ALFRED or REEF MANTA Another species? A third species has been proposed which may be a sub-species of MB or may be a new species by it’s limited range (Marshall et al. 2009). 3
    4. 4. Two species of manta ray: Manta birostris (Walbaum 1792) (MB) Common name: GIANT or OCEANIC MANTA Manta alfredi (Krefft 1868) (MA) common name ALFRED or REEF MANTA Another species? A third species has been proposed which may be a sub-species of MB or may be a new species by it’s limited range (Marshall et al. 2009). Both species are observed in the Maldives however MB is much rarer (12 vs 2220 individuals recorded Manta Ecology Project database Jan. 2014) 4
    5. 5. Manta birostris (MB) Manta alfredi (MA) 5
    6. 6. Manta birostris (MB) Manta alfredi (MA) 6
    7. 7. Manta birostris (MB) Manta alfredi (MA) 7
    8. 8. Manta birostris (MB) Manta alfredi (MA) 2 2 8
    9. 9. Manta birostris (MB) 2 Manta alfredi (MA) 2 9
    10. 10. Manta birostris (MB) Manta alfredi (MA) 10
    11. 11. Manta birostris (MB) Manta alfredi (MA) 11
    12. 12. Manta birostris (MB) Manta alfredi (MA) 4 4 4 4 4 12
    13. 13. Manta birostris (MB) Manta alfredi (MA) 4 4 4 4 4 13
    14. 14. Manta birostris (MB) Manta alfredi (MA) 2 2 4 4 TEETH ON: o UPPER JAW o LOWER JAW 4 4 4 TEETH ON: o LOWER JAW 14
    15. 15. Manta birostris (MB) Manta alfredi (MA) 4 4 4 4 4 15
    16. 16. Manta birostris (MB) Manta alfredi (MA) 4 4 4 4 4 ? 16
    17. 17. Manta birostris (MB) Manta alfredi (MA) 4 4 4 4 4 17
    18. 18. Manta birostris (MB) Manta alfredi (MA) 4 4 4 4 4 18
    19. 19. There are black variants of each species but are exceedingly rare in Maldives and only black MB have so far been reported. Black MA are common is other tropical island areas (up to 50% of MAs may be black variant) 19
    20. 20. There are black variants of each species but are exceedingly rare in Maldives and only black MB have so far been reported. Black MA are common is other tropical island areas (up to 50% of MAs may be black variant) 20
    21. 21. There are black variants of each species but are exceedingly rare in Maldives and only black MB have so far been reported. Black MA are common is other tropical island areas (up to 50% of MAs may be black variant) 21
    22. 22. Manta rays can be individually identified from their ventral markings Marks in central and abdominal areas are used to identify individuals (Kitchen-Wheeler 2010, Marshall et. al 2009) A trained observed will quickly appreciate that markings vary between individuals and that markings are unique 22
    23. 23. Manta rays can be individually identified from their ventral markings Visual identification can be used instead of tagging or physically marking individuals 23
    24. 24. 24
    25. 25. Manta Lifecycle (MA) The age to which mantas live is still not fully understood but a Male’ based manta ray known as Brenda is known to be at least 40 years old. One of the oldest Mantas in the world? 25
    26. 26. Manta Lifecycle (MA) Age and growth studies in other elasmobranchs have been based on ring (or band) measurements of vertebrae sections but these have not been found/reported in manta rays. 26
    27. 27. Manta Lifecycle (MA) Examples of known longevity of other elasmobranchs in the wild include the common spiny dogfish Squalus acanthias (Linnaeus 1758) achieving 65-70 years and grow to 170 cm total length. It is likely that manta rays live as long. 27
    28. 28. Manta Lifecycle Female mantas give birth to fully formed live young. Examples born in aquaria measured 1.92-1.96 m disc width (DW). Live young in the wild have been observed at around 1 m DW. A wild birth has not been observed. Large energy investment that the parent manta put in the offspring. 28
    29. 29. Manta Lifecycle Pregnancy last around 12.5 months 29
    30. 30. Manta Lifecycle Heavily pregnant females are frequently seen at cleaning stations nearby large sheltered lagoons e.g. Rasfari Juveniles are frequently observed in sheltered lagoons used by safari and fishing boats for anchorage so it is likely that birth occurs in the lagoons. This subject is a topic of current research 30
    31. 31. Diurnal Activity From dawn and throughout daylight hours mantas may be observed at cleaning stations and feeding areas at shallow reef areas. They are also observed hovering in current in channels and locations with strong water flow. 31
    32. 32. Diurnal Activity From dawn and throughout daylight hours mantas may be observed at cleaning stations and feeding areas at shallow reef areas. They are also observed hovering in current in channels and locations with strong water flow. After dusk mantas rays are commonly observed still feeding at inshore areas and can be attracted to feed in shallow lagoons. 32
    33. 33. Diurnal Activity From dawn and throughout daylight hours mantas may be observed at cleaning stations and feeding areas at shallow reef areas. They are also observed hovering in current in channels and locations with strong water flow. After dusk mantas rays are commonly observed still feeding at inshore areas and can be attracted to feed in shallow lagoons. At night they travel offshore to feed in deep water (50-200 m) as zooplankton rises. 33
    34. 34. Diurnal Activity This pattern has been shown from independent study in Okinawa prefecture (Japan), Komodo (Indonesia) and various Hawaiian islands and suggested by initial study in the Maldives (Yano et al. 2000; Clark 2008 ; Dewar et al. 2008). Similar behaviour has also be shown by MB (Rubin et al. 2008). 34
    35. 35. Distribution Red: MB circumtropical plus temperate Blue: MA Indo-Pacific tropical 35
    36. 36. Distribution Red: MB circumtropical plus temperate 36
    37. 37. Distribution Blue: MA Indo-Pacific tropical 37
    38. 38. Distribution MB has been reported from offshore islands (Revillagigedos/Mexico, Galapagos/Ecuador, French Polynesia, Okinawa prefecture Southern Japan, Maldives, and off most continental coastlines. In areas where it is sighted regularly it is only reported seasonally, in association with local increases in plankton productivity. 38
    39. 39. Distribution MA has been reported from Maldives, Hawaii, Okinawa prefecture islands, throughout Indonesia, Malaysia and French Polynesia. It is reported from continental coastlines including E. Africa and Australia in the Indo-Pacific but is absent from the western Atlantic and very rarely reported from W. Africa. 39
    40. 40. Distribution MA is reported year round at the majority of locations where sighted and at most locations the local populations are considered resident. 40
    41. 41. Thank you for your attention contact details: amkw9@sky.com 41

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