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Text|Broken Boat Han
Editor|Broken Boat Han
preface
Coral reef ecosystems are home to a variety of marine species, each of which plays a vital role in maintaining the delicate balance of these underwater habitats.
Among marine species, manta rays are known for their graceful gliding in marine waters, while manta rays are ecologically important.
As filter feeders, manta rays help the ocean control plankton numbers and maintain environmental balance, which can indicate the health of manta ray populations and the health of the entire coral reef ecosystem.
In order to better study the spatial ecology of manta ray populations in New Caledonia's coral reefs, experts used satellite telemetry to deeply study and reveal their horizontal behavior patterns.
By exploring the movement, habitat, and connectivity of these mysterious creatures, researchers gain valuable insights into protecting them as well as protecting the broader health of coral reef ecosystems.
Threats to manta rays
While manta rays are important, they also face threats such as habitat degradation and climate change, so a comprehensive understanding of their spatial ecology is essential to develop targeted conservation strategies to protect manta rays and the ecosystems they inhabit.
There is also a need to identify impacts and potential threats from environmental change and anthropogenic activities so that biodiversity conservation areas can be effectively prioritized.
However, some studies have shown that high-fidelity patterns of marine species are influenced by environmental barriers and biological factors.
The pelagic finned shark, driven by the continuous availability of prey, has achieved high site fidelity, and food resources are also a major factor affecting the movement of large filter-feeding species.
However, when marine resources are consistent throughout the year, manta rays appear to exhibit strong habitation patterns, with few connections between geographically close populations.
More than 150 years of photo-identifying monitoring found no link between two aggregation sites just 10 kilometers apart in Hawaii, and also in Indonesia, acoustic telemetry showed spatial isolation between populations just 150 kilometers apart.
According to the figures surveyed, the spatial ecology of coral reef manta rays is difficult to predict and local surveys may be required to fully understand their movements.
Of course, this is a vital task, and the species is being exploited in large numbers in many parts of the world because their gill plates are used in the Asian pharmaceutical trade.
In addition to this fishing pressure, manta rays exhibit a number of conserved life history traits that exacerbate this vulnerability, including small population sizes, low fecundity, and dispersed distribution.
Their strong affinity for shallow coastal waters increases their exposure to human activities such as bycatch fisheries, uncontrolled mass tourism, habitat degradation, boat strikes, and entanglement of fishing nets.
As a result, coral reef manta rays are classified as vulnerable to extinction on the IUCN Red List of Threatened Species.
Reliable information on the provision of movement patterns and habitat use of coral reef manta rays will help to design effective management and conservation measures that are critical to the conservation of this species.
Spatial analysis methods
Satellite telemetry is a common practice among approaches to spatial analysis, and a growing number of studies are using tags to track the movements of various species.
Including terrestrial species, marine birds, turtles, marine mammals and cartilaginous fish, the tool allows researchers to investigate large- and fine-scale movements.
In addition, diving behavior, as well as preferred depth and temperature, can sometimes reveal misunderstandings or accidental discoveries about the ecology of the species.
Satellite tracking devices are an effective tool for detecting unsuspected, large migrations in cartilage animals, such as basking sharks, sixgill sharks and white sharks.
On this basis, the researchers used satellite tracking to investigate the spatial ecology of Mycobacterium alfreydi in the fragmented environment of the New Caledonian Islands.
The goal of the survey is to assess fine habitat use and potential mass migration patterns by addressing the following points.
These include quantifying the use of offshore versus coastal waters, showing the range and limits of movement at high-fidelity aggregation points, defining the frequency and magnitude of connectivity between study sites, and detecting the presence of large-scale mobile and unknown critical habitats.
Manta ray behavior and habitat preferences
Manta rays belong to the manta ray family, and these docile behemoths possess an extraordinary array of physical characteristics that allow them to adapt perfectly to the marine environment.
Oceanic manta rays have wing-like fins that are as long as wings and can be up to 7 meters long, which helps them move gracefully through the water, gliding effortlessly in search of food or resting places.
One of the most attractive aspects of manta ray behavior is their feeding strategy, as mentioned earlier, manta rays are filter feeders that use specialized head fins to channel plankton-rich water into their mouths.
They target zooplankton and small fish such as krill and small crustaceans, which are abundant in their marine habitats, and this foraging behavior often leads them to congregate in areas with dense plankton, such as upwelling zones and cleaning stations.
Travel and migration patterns are another interesting aspect of manta ray behavior, and some manta ray populations are known to migrate seasonally, possibly in search of the best feeding grounds or mating opportunities.
Studies of these migration patterns reveal the wide range of manta rays traveling, highlighting the need for international cooperation to protect manta rays.
Often referred to as the "rainforest of the sea," coral reefs play an important role in the life of manta rays, and these docile behemoths are often found to haunt coral reef ecosystems and engage in a variety of activities there.
Cleaning stations, which are places where clean fish remove parasites and dead skin for manta rays, are especially important to understand manta ray habitat preferences.
Manta rays have cleaning behaviors and actively seek out these cleaning stations to maintain health and hygiene, and these interactions also provide opportunities for social interaction between manta rays to help understand their complex social dynamics.
However, environmental factors such as water temperature, water quality and ocean currents play a crucial role in manta ray behavior and habitat selection.
Coral reefs grow in warm, nutrient-rich waters, which coincide with the plankton feeding habits of manta rays, and ocean currents can also affect the distribution of plankton, which in turn affects the food source of these filter-feeding organisms.
Of course, human activities also have a direct or indirect impact on manta rays and their habitats, and the rise of marine tourism brings economic benefits, but also unexpectedly interferes with the natural behavior of manta rays.
Ecotourism, in the context of sustainable management, contributes to the conservation of these animals by raising awareness and supporting local economies, but irresponsible tourism practices put pressure on manta rays and their habitats.
Cooperation between governments, conservation organizations and local communities is essential to mitigate these threats and ensure the long-term survival of these beautiful creatures.
Efforts to protect manta rays are gaining momentum globally, and the establishment of marine protected areas and fishing regulations are a step in the right direction.
In addition, advances in technologies such as satellite tagging and tracking have allowed researchers to gain a deeper understanding of manta ray behavior and activity patterns.
All continued research into manta ray behavior and habitat preferences remains crucial, and by further demystifying manta ray life, scientists can provide the necessary knowledge to develop targeted conservation strategies.
In addition, public participation and educational activities play a crucial role in creating awareness of the conservation of these animals and their habitats.
discuss
In New Caledonia, reef manta rays tend to be close to the coast and coral reefs, and all but one male individual has been recorded within 35 km of the nearest reef.
Several studies documenting the movement of coral reef manta rays have reported consistent use of coastal and coral reef areas in Australia, the Red Sea, the Seychelles and the British Indian Ocean Territory.
The use of coastal habitats by reef manta rays and other planktonic cartilage animals is linked to food availability, with coastal areas of islands surrounded by deep water being most prone to congregate conditions.
In addition to food resources, the coastal areas and shallow waters of the lagoon also provide more protection for predators such as large sharks, thus providing a suitable environment for potential nurseries.
In addition, the reef is also home to many cleaning stations that are essential for the well-being and health of manta rays, as well as mating and socialization.
Sheltered waters also act as shelters, with closed shallow water significantly warmer than seawater, and in this study, manta rays were observed to prefer relatively higher temperatures but were also able to face colder water.
For example, in deep diving, basking in warm, shallow water after a deep dive regulates body temperature, which is an important part of the behavior of Lepidoptera and other cartilage animals, and the presence of warm sheltered water near deep feeding grounds may be essential.
Although reef manta rays have been shown to be associated with coastal affinity, reef manta rays have been observed in waters up to 2720 meters deep.
The continental shelf of the New Caledonian archipelago is relatively narrow, especially off the east coast of the main island and around the Loyalty Islands, and the depth of water is rapidly declining.
This supports the researchers' previous findings that reef manta rays have been recorded commuting between islands separated by deep water, or between eastern Australia and the Maldives, transiting through deep water for food resources.
conclusion
This work used satellite telemetry to confirm that reef manta rays inhabit coastal waters and have shown strong site fidelity in New Caledonia.
However, the species' ability to migrate relatively long distances appears to favor but is not limited to coastal and shallow water paths, where deep water may be a limiting factor.
But not a complete barrier to connectivity, these results raise concerns about threats related to habitat degradation, human exploitation, and disturbance.
The species' home range may also be farther than previously thought, particularly in habitats segmented by deep water, raising concerns about potential movement outside protected jurisdictions.
In New Caledonia, limited attention has been paid to species conservation because coral reef manta rays are not targeted by fisheries, human activity is still relatively low, and this enabling environment is rare, making New Caledonia's coral reef manta ray population a reference to be preserved.
As stewards of the ocean, we have a responsibility to understand, appreciate and protect these majestic creatures!
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