Marine Creature of the Month JUNE
I was hoping to have the next Sharks at 7 & 3/4s filmed and edited by now, but the boy ran off half way through filming and then told me he doesn't want to do it because it was too stressful! So that is still in the works right now. Instead, have a #MCotM!
Manta Ray
via GIPHY
Kingdom: Animalia
Class: Chordata
Conservation Status: Vunerable (VU)
Found: International waters
Diet: Zooplankton
Weight: Up to 1,350kg (2,980lbs)
Size: From 5.5m (18ft) to 7m (23ft)
Habitat: Temperate, subtropical and tropical waters; pelagic waters.
Manta rays, known online as majestic flap flaps(!), are huge and beautiful creatures. Just look at it flap along - look at it! Fangirling aside, they are incredible. There are two species of manta ray: M. birostris (the larger of the two) and M. alfredi (named after Prince Alfred). They are both very similar in appearance, with a few key differences. As already mentioned, M. birostris are larger, but they are also darker and pointier; while M. alfredi are rounder and lighter in colour. It wasn't until 2009 that they were classed, officially, as two separate species after a study was conducted on morphology. This was a study looking into colour, meristic variations - which are the quantative features of a fish like scales and fins - and dermal denticals, as well as teeth. Like their shark cousins, manta rays' skin is made up of teeth and they also possess the same cartilaginous skeleton as they do, rather than one made of bone. But back to the dermal denticals, M. birostris' overlappes whereas M. alfredi's are more evenly spaced.
Both fish have the same overall look. They have pointed pectoral fins which help them "fly" through the water. Rays either flap or undulate to move through water, manta rays flap. They also both have the iconic "horns" at the front of their faces. These are cephalic fins, which just means they are on their face, and are used to collect food particles. They are able to wave these fins. Their eyes rest behind the cephalic fins. Manta rays are wider than they are long, by up to 2.2 times. Because of this, they have a relatively short dorsal fin and tail. They also have square teeth (fun fact: like snails)! Their lineage can be traced back to bottom dwelling stingrays, with M. birostris even still possessing a small stinging barb on its caudal spine.
Unlike most rays, manta ray's mouths are at the front of their body rather than centrally on their underside. This allows them to filter feed, which is possibly why they got so big. I mean, blue whales filter feed and they are the biggest creature to have ever lived. Manta rays need to consume 13% of its body weight each week to sustain itself. So for the largest of the rays, that would mean eating 175.5kg (387lbs) of zooplankton each week. That is a lot.
One main difference between the two species of manta ray is where they reside. M. birostris are migratory and live in temperate, subtropical and tropical waters across the world, whereas M. alfredi are found in the coastal waters of the Indo-Pacific and East Atlantic oceans. Where they live affects when they reach sexual maturity, but it usually falls between being 3-4m wide, which is about 8-10 years old. They can live as long as fifty years!
Their mating rituals are possibly triggered by the full moon, as it varies year to year when it happens scientists aren't entirely sure. Their practises remain the same year in, though female manta rays do not necessarily partake each year. I can see why though - it is a rough time for the lady manta rays! Firstly, they swim at speeds of 10km/p/h with the males close on their tails who are trying to grasp the females' pectoral fin. This is with the only thing they can grap with - their mouths! The whole process can take up to 30 minutes before the males finally bite the left pectoral fin. Scientist aren't sure why it is, but they always go for the left one as evidenced by scars on the females. They mate for 60-90 seconds then continue to swim about with the male chomped on and other males swimming behind them. After that, they part ways.
The gestation period for manta rays is twelve to thirteen months. The young start as an egg but hatch whilst still inside their mother's oviduct. Here they stay until the gestation period is done. During this time they grow to be essentially miniature adult manta rays in appearance. Once born, like their parents, they will need to continually move to keep water flowing over their gills to breathe. While in the oviduct, this is not possible and with the lack of placenta and umbilical cords (due to them starting as an egg) they rely on buccal pumping to push the oxygen over their gills. To do this they rhythmically move their mouth, which keeps the oxygen moving. After they have been born, they are left without parental guidance.
One fantastic thing about manta rays is that they breach the water's surface. Breaching is where they propel themselves out of the water, either as a group or individually. They typically have three jumps: forward leap landing on their head, forward leap landing on their tails, and a complete somersault. Scientists are not sure why they perform such feats but believe it could be for communication or part of the mating ritual. Another theory is that they use the water's surface to scratch itches and remove parasites. It could just be for fun!
Much like their shark cousins, manta rays are falling victim to senseless over fishing. This is why they are now classified as Vulnerable. Like with shark finning, manta rays are fished and killed for their gill rakers, which are used by the manta rays for filter feeding. By humans, they are used in Chinese medicine and have had no proven medicinal affect. Simply put, they are of no use to us and extremely useful to the manta rays. But this sudden demand has seen an increase in them being fished and it is driving the population numbers down rapidly. Their slow reproduction exascerbates the issue as they cannot replenish their numbers as quickly as we are dwindling them.
Their threat is being recognised and they are now protected in International Waters by the Convention on Migratory Species of Wild Animals. But they are still vulnerable in coastal waters because of tourism, plastic pollution, and ghost fishing. Ghost fishing is when nets and lines are left in waters which then trap marine life. This is especially deadly to manta rays as they need to keep moving to breathe, so, ultimately, being trapped suffocates them. Due to their size and migratory nature, it is impractical to keep them in aquariums. A major help to manta rays would be ditching the single-use plastics and protesting the gill raker trade.
Diet: Zooplankton
Weight: Up to 1,350kg (2,980lbs)
Size: From 5.5m (18ft) to 7m (23ft)
Habitat: Temperate, subtropical and tropical waters; pelagic waters.
Manta rays, known online as majestic flap flaps(!), are huge and beautiful creatures. Just look at it flap along - look at it! Fangirling aside, they are incredible. There are two species of manta ray: M. birostris (the larger of the two) and M. alfredi (named after Prince Alfred). They are both very similar in appearance, with a few key differences. As already mentioned, M. birostris are larger, but they are also darker and pointier; while M. alfredi are rounder and lighter in colour. It wasn't until 2009 that they were classed, officially, as two separate species after a study was conducted on morphology. This was a study looking into colour, meristic variations - which are the quantative features of a fish like scales and fins - and dermal denticals, as well as teeth. Like their shark cousins, manta rays' skin is made up of teeth and they also possess the same cartilaginous skeleton as they do, rather than one made of bone. But back to the dermal denticals, M. birostris' overlappes whereas M. alfredi's are more evenly spaced.
Both fish have the same overall look. They have pointed pectoral fins which help them "fly" through the water. Rays either flap or undulate to move through water, manta rays flap. They also both have the iconic "horns" at the front of their faces. These are cephalic fins, which just means they are on their face, and are used to collect food particles. They are able to wave these fins. Their eyes rest behind the cephalic fins. Manta rays are wider than they are long, by up to 2.2 times. Because of this, they have a relatively short dorsal fin and tail. They also have square teeth (fun fact: like snails)! Their lineage can be traced back to bottom dwelling stingrays, with M. birostris even still possessing a small stinging barb on its caudal spine.
Unlike most rays, manta ray's mouths are at the front of their body rather than centrally on their underside. This allows them to filter feed, which is possibly why they got so big. I mean, blue whales filter feed and they are the biggest creature to have ever lived. Manta rays need to consume 13% of its body weight each week to sustain itself. So for the largest of the rays, that would mean eating 175.5kg (387lbs) of zooplankton each week. That is a lot.
One main difference between the two species of manta ray is where they reside. M. birostris are migratory and live in temperate, subtropical and tropical waters across the world, whereas M. alfredi are found in the coastal waters of the Indo-Pacific and East Atlantic oceans. Where they live affects when they reach sexual maturity, but it usually falls between being 3-4m wide, which is about 8-10 years old. They can live as long as fifty years!
Their mating rituals are possibly triggered by the full moon, as it varies year to year when it happens scientists aren't entirely sure. Their practises remain the same year in, though female manta rays do not necessarily partake each year. I can see why though - it is a rough time for the lady manta rays! Firstly, they swim at speeds of 10km/p/h with the males close on their tails who are trying to grasp the females' pectoral fin. This is with the only thing they can grap with - their mouths! The whole process can take up to 30 minutes before the males finally bite the left pectoral fin. Scientist aren't sure why it is, but they always go for the left one as evidenced by scars on the females. They mate for 60-90 seconds then continue to swim about with the male chomped on and other males swimming behind them. After that, they part ways.
The gestation period for manta rays is twelve to thirteen months. The young start as an egg but hatch whilst still inside their mother's oviduct. Here they stay until the gestation period is done. During this time they grow to be essentially miniature adult manta rays in appearance. Once born, like their parents, they will need to continually move to keep water flowing over their gills to breathe. While in the oviduct, this is not possible and with the lack of placenta and umbilical cords (due to them starting as an egg) they rely on buccal pumping to push the oxygen over their gills. To do this they rhythmically move their mouth, which keeps the oxygen moving. After they have been born, they are left without parental guidance.
One fantastic thing about manta rays is that they breach the water's surface. Breaching is where they propel themselves out of the water, either as a group or individually. They typically have three jumps: forward leap landing on their head, forward leap landing on their tails, and a complete somersault. Scientists are not sure why they perform such feats but believe it could be for communication or part of the mating ritual. Another theory is that they use the water's surface to scratch itches and remove parasites. It could just be for fun!
 |
| Breaching the water. Picture from spotmydive.com |
Much like their shark cousins, manta rays are falling victim to senseless over fishing. This is why they are now classified as Vulnerable. Like with shark finning, manta rays are fished and killed for their gill rakers, which are used by the manta rays for filter feeding. By humans, they are used in Chinese medicine and have had no proven medicinal affect. Simply put, they are of no use to us and extremely useful to the manta rays. But this sudden demand has seen an increase in them being fished and it is driving the population numbers down rapidly. Their slow reproduction exascerbates the issue as they cannot replenish their numbers as quickly as we are dwindling them.
Their threat is being recognised and they are now protected in International Waters by the Convention on Migratory Species of Wild Animals. But they are still vulnerable in coastal waters because of tourism, plastic pollution, and ghost fishing. Ghost fishing is when nets and lines are left in waters which then trap marine life. This is especially deadly to manta rays as they need to keep moving to breathe, so, ultimately, being trapped suffocates them. Due to their size and migratory nature, it is impractical to keep them in aquariums. A major help to manta rays would be ditching the single-use plastics and protesting the gill raker trade.
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| Picture from newscientist.com |
Fun Facts
- "Manta" comes from the Spanish and Portuguese for mantle, which was a blanket shaped trap used to catch rays.
- Rays, including the manta, are shark cousins - coming from the same evolutionary branch.
- They are very intelligent and there is evidence they can recognise themselves in the mirror.
- There is little fossil evidence of manta rays due to their cartilaginous skeleton, which doesn't mineralise like bone does.
- Typically they are dark on top and light on their underside, but some all black morphs do exist though it is rare.
- Manta rays are covered in a mucus to prevent and protect from infection.
- They can dive to over 400m (1312.34ft).
They are beautiful and fascinating it's just... being able to see so much *inside* when they swim towards you gives me the heebie jeebies a bit.
ReplyDeleteI take it you are not a fan of whale sharks and basking sharks for similar reasons XD
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