General facts about Rays.
Like dozens of kites flying without strings, a school of Rays is a truly beautiful sight. Often seen gliding effortlessly through the ocean, our friends Batoidea are flat-bodied, boneless marine fish. Much like their Shark cousins, they have cartilage instead of bone mass, which creates the illusion of one giant gliding fin! Rays are a diverse group of fish, with over 600 species in 26 families known as Batoids. Most of these species live on the seafloor in tropical and subtropical waters.
Currently, there are 4 recognized orders of Batoids: Sting Rays, Skates, Electric Rays, and Shovel-Nosed Rays. Rays date back to the Jurassic period. In this blog, we will be exploring the largest species in this long-standing family: The Manta Ray!
Introduction:
The Manta Ray is a large, distinct Batoid. Its intricate black designs differentiate it from all others and vary depending on where it lives. There are two species of this friendly ocean dweller in the Mobulidae family. Giant Manta Rays inhabit all the world’s oceans, and the Reef Manta Ray, inhabits the Indo-Pacific Ocean.
Our friends are more than just a pretty face! They have been found to have the largest brain (relative to body size) out of any cold-blooded fish. This gives them the same high cognitive function that can be found in Dolphins, Primates, and Elephants. The most impressive function is their highly developed long-term memory. Manta Rays have been observed creating mental maps of their environment through visual cues and scent!
The Manta Ray is still a marvel and mystery to many scientists. Because they are so large, very few are kept in captivity, limiting observations to ocean-bound Rays. Additional research on our friends’ intelligence in the future will surely uncover fascinating results.
The Manta Ray: Out of the Blue!
What is the size, weight & colour of the Manta Ray?
The Giant Manta is the largest Ray in the ocean: with a wingspan of up to 7 meters! The Reef Manta Ray is smaller, with a maximum wingspan of 5 meters. Giant Manta Rays can weigh up to 3,000kgs, while Reef Mantas can weigh up to 1270kgs. The visual similarity between these two species causes juvenile Giant Mantas to be often mistaken for Reef Mantas.
Both of these rays sport the colours black, dark brown, and grey-blue. To spot the difference between species, you must pay attention to their white dorsal lines. The Reef Manta has a Y shape, while the Giant Manta has a T shape.
What type of vision does the Manta Ray have, and what sounds do they make?
Manta Rays have been known to project “battle cries” when attacking prey. This is unusual considering their Shark cousins lack this ability. The sound has been observed as a high pitched, bubbling screech.
Scientists are unsure how well Mantas can see, as they rely on scent to seek out prey. Their eyes are located on each side for panoramic vision, with the drawback of blind spots directly in front and behind. They also cannot see while they are eating because their mouth is directly under their blind spot.
Are there any special or unique physical attributes?
Because of their weak sight, the Manta Ray has developed stronger sensory tools. This includes a lateral line system, which allows them to feel currents created by distant prey. They also have a strong sense of hearing and smell, which is supplemented by their ampullae of Lorenzini. These ampullae detect electric signals from other fish and create an aura around them. These heightened senses allow the Manta Ray to easily detect prey hidden under the seafloor.
How fast is the Manta Ray?
The Manta Ray is a smooth operator, gliding effortlessly through the ocean currents. With no trouble at all, these friends can reach 14 km/h, which is nearly double the speed of Michael Phelps! If they want to go faster, they can easily reach speeds of 35 km/h.
What are their Migration Routes?
The Giant Manta Ray migrates more than the Reef Manta in search of warm, temperate waters. Because Manta Rays enjoy eating plankton, they often follow the currents that carry their prey. These are often streamlined currents, allowing the Manta Ray to travel 1,100km in a straight line!
The Reef Manta Ray earned its name “Resident Manta Ray” by being less migratory, staying closer to the coastline. Their daily migrations can still cover a lot of ground, approximately 70km in search of plankton and other small fish.
These Rays are often loners but have been seen congregating in large numbers where food is plentiful. These hotspots include tropical waters such as Mexico, Hawaii, and Thailand.
How do they hunt, and what do they eat?
Much like the Blue Whale, the Manta Ray is a well-known filter feeder! Our friends hunt by swimming with their mouth open, trapping zooplankton and krill. These small fish are sifted through the rakes that line their mouths, also known as gill plates. Watching these friends hunt is a fascinating sight, as they have been seen forming cyclones in the water to trap food in a single spot.
What are their natural enemies?
The Manta Ray is an apex predator at the top of its food chain. Because of this, it has very few natural predators. This Ray’s speed, size, and tough exterior make it a difficult and unappetizing meal for many large predators. However, juvenile Manta Rays need to avoid large Sharks and Killer Whales.
Where do they live?
Manta Rays can be found in all oceans apart from Arctic and Antarctic zones. While they prefer warmer waters, they have to follow their next meal! The sites with denser populations attract many tourists. These include: The Bahamas, Mexico, The Cayman Islands, Spain, Fiji, Thailand, Indonesia, Hawaii, Western Australia, and the Maldives.
All about Reproduction.
Like many large fish in the ocean, the Manta Ray reaches sexual maturation later in life. Most females reach this after 8-10 years. This slow process is then drawn out further with pregnancy lasting up to 13 months. Once this gestation period is over, the mother will give birth to 1 or 2 live pups in shallow, warm waters. Luckily, they do not need to feed on the mother and can survive easily without care. Females will typically repeat this process every 2-3 years.
The mating process of Manta Rays is a fascinating spectacle called “train mating”. This is where 25-30 males will compete for 1 female. The female leads the train of single-file males where they are expected to repeat her movements – demonstrating compatibility. She then takes her pick!
What is their lifespan?
Manta Rays can live up to an average of 40 years in the wild. The oldest Manta Ray found was 50 years old!
Myths
Contrary to popular belief, the Manta Ray is not a Stingray. This means they are much safer for humans who want to interact with them. But this does not dissuade humans from harming Manta Rays. For centuries, it has been believed that the gill rakers of Rays can cure various ailments. This myth has perpetuated the hunt for Manta Rays and greatly depleted their populations over time. Especially in South East Asia where these beliefs are most common.
What threats do the Manta Ray face?
The single greatest threat to Manta Rays is human activity. This comes in various forms, whether it be plastic pollution, climate change, or ocean acidification killing their plankton. Many fisheries use unethical fishing nets in pursuit of large-scale hauls, which entangle Manta Rays. There is also a high demand for their gill rakers in Mexico, Peru, Thailand, and Somalia, where there are directed fisheries. Whether it be hunting, pollution, or larger apex fish hunting juveniles, the Manta Ray has many threats to contend with.
Endangered Ranking – IUCN.
Both the Reef Manta Ray and the Giant Manta Ray are listed as vulnerable by the IUCN. Their numbers are observed to be rapidly dropping. Soon they will be listed as endangered alongside 33% of Ray species threatened with extinction. Currently, by region, their populations are small. In many places where Manta Rays were once plentiful, you will find numbers ranging from just 100-1000 specimens.
Why are they endangered?
Manta Rays are easily endangered because their reproductive rate is slow and produces few pups. While other fish can replenish their numbers easily, large fish have the most difficulty regaining their populations.
Luckily, many places have placed a ban on fishing for Manta Rays. This is due to the booming tourism industry surrounding our friends. Manta Rays are a safer species of Ray for humans to scuba dive with. Many countries see them as more valuable alive than dead. However, human activity is still a great concern for the safety of our friends. Habitat loss and food depletion will continue to affect many of the ocean’s inhabitants.
Why should you care?
The Manta Ray is an important member of the food chain! Our friends control the populations of plankton and regulate nutrient cycling through the water. Their consumption of these small fish aid in the transfer of atmospheric carbon. Small fish left unregulated have disastrous effects on the oxygen levels of the ocean. It may be a small contribution from the Manta Ray, but it is essential to the health of the ecosystem.
The Manta Ray is also a prized feature of ecotourism. The tourism industry surrounding our friends provides jobs and livelihoods to many people in coastal regions. Without Manta Rays as an attraction, many people will be left jobless in impoverished areas.
What can you do to help?
- Ethical Consumption: Chinese medicine has been refuted by scientists for decades. Refuse to consume any part of Manta Rays for medicinal purposes. If you are struggling with health problems, seek medical advice from qualified doctors and practitioners.
- Spread the word! Talk to family members and friends about what they’re doing to help the cause. Inform people on ways they can help protect the Manta Rays habitat. If you live in coastal regions, take part in your local ocean conservation efforts.
- Get Involved: Lastly, spend time signing petitions and getting involved in online spaces. Bring attention to the depleting Manta Ray population and offer to take part in coastal clean-ups!
If there is a public demand for change, then change will come. With everyone’s help, we can create new standards for the Ocean and all of its inhabitants! With safer habitats, we will hopefully see the Manta Ray populations stabilize.
