Here we would like to give some information about this nice looking Pocillopora meandrina branches collected from a broken colony that is located on your coral frame. They are also known as the cauliflower coral and are quite common around the Maldives. Pocillopora meandrina occurs on shallow reefs and amongst coral communities on rocky reefs, at depth from 3-27 m and their radiating branches can reach up to 40 cm in diameter. In this species many or most of the branches are flattened on the ends and some may be curved and their colors may vary from cream, green or pink. Pocilloporid corals, not excluding P. meandrina, are generally amongst the strongest coral competitors with relatively high rates of calcification. However, coral species exhibiting high rates of calcification usually have relatively high mortality rates
The Chromis viridis , known commonly as green puller, has found in your coral frame its home. This particular fish is known also as green damselfish. They only reach an adult size of 3-4 inches (7.6-10 cm).There are several contestants for the title of most important reef fish family, but the Damselfish are certainly one of the front-runners. Not only are there numerous species, but also many of these species are present on Maldivian reefs in prodigious numbers. The green damselfish that you can see in the picture is associated with isolated coral heads in sheltered inshore habitats. Like all damselfish, they can be territorial and aggressive, especially as they get older.
We would like to give some information about this colony of Acropora digitifera that lives on your coral frame. This species forms digitate colonies; the branches may be 1 cm in diameter and up to 10 cm long. This species strongly prefers shallow water. It is usually cream or light brown in color with blue branch tips, but can also be brown with purple tips. It is common near reef crests’ as it prefers strong water movement and it is very common in the Maldives. The most important known threat is the reduction of coral reef habitat due to bleaching, disease and predation. However, it seems to be strong enough to resist to habitat loss more than other species of corals. However, since the current situation with multiple stresses (mainly rising temperature of the ocean) acting simultaneously the species is considered Near Threatened by the International Union for Conservation of Nature (IUCN).
Look at this amazing visitor to your frame! These are just a few of the species that would often visit the coral frames and are extremely helpful at times when cleaning the frames. This species is called the Moon Wrasse (Thalassoma lunare) a very typical and brightly colored species of fish found in the Maldives. It belongs to the wrasse family which consists of over 600 described species that range on average around 20 cm although the Humphead and Napoleon wrasse can grow up to 2 meters! They are carnivores by nature, feeding on a wide range of small invertebrates such as crabs or snails. Many smaller wrasses follow the feeding trails of larger fish, picking up invertebrates disturbed by their passing.
The Dascyllus aruanus, known commonly as humbug damselfish, has found in your coral frame its home. This particular fish is known by multiple common names, such as three stripe damselfish, humbug dascyllus, or black and white damselfish. They only reach an adult size of 3-4 inches (7.6-10 cm). Sporting three broad black stripes on a white body, the humbug damselfish has a zebra like appearance. The stripes run slightly off vertical through the eyes and mouth, midbody and bisecting the caudal peduncle, making it half black and half white. There are several contestants for the title of most important reef fish family, but the Damselfish are certainly one of the front-runners. Not only are there numerous species, but also many of these species are present on Maldivian reefs in prodigious numbers. The humbug damselfish that you can see in the picture is associated with isolated coral heads in sheltered inshore habitats. Like all damselfish, they can be territorial and aggressive, especially as they get older.
This is your 6 month frame progress update. Your frame is doing fantastic!
Looking at your frame, we can see lots of new growth, especially of the acropora corals (the branching & fast growing corals). We can see some of the corals are competing for space, which is a good problem to have, it means your frame is thriving. We can also see that your frame is contributing to the overall health of the coral ecosystem. We see lots of life such as little fish, crabs, worms and mollusks around your frame. Overall your frame has survived the warm months of March, April and May just fine, unfortunately some of the other frames in our colony weren’t so lucky.
Over the following months we will continue with maintenance to keep harmful algae and predators off your frame and to give your frame the best chance for successful growth.
What is biodiversity? Biodiversity is the variety of living species that can be found in a particular place, for instance the number of coral species on your coral fame. Coral reefs are said to have the highest biodiversity of any ecosystem on the planet—even more than a tropical rainforest. In this particular image you can see two species of the Acropora genus, one of the fastest growing species of coral. Since we collect broken fragments from the bottom and not original colonies, the biodiversity on the frames is often between 1 and 4 species of corals, depending on location of collection. You will see that these small pieces have already grown quite a bit since in the one year since construction. Of course we always try to keep the diversity high between all of the frames and during maintenance we often add new pieces onto the frame. We will soon see that lots of marine life occupying your frame and this is what we are aiming for with our coral conservation project.
We have some unfortunate news this month as we are starting to see some evidence of bleaching around the coral frames. Coral bleaching can be ascribed to warming ocean waters for extended periods of time where the symbiotic algae (Zooxanthellae) living inside the tissue coral is expelled by their host and in turn leave behind a bleaching white skeleton. This algae shares a mutualistic relationship with the corals; the coral provides shelter to the algae and in turn the algae can provide as much as 90% of the nutrients produced by photosynthesis which is used towards their growth. Corals can survive bleaching events such as this, but if they are subject to more stress or prolonged heated waters, they will surely die. Unfortunately, your frame is also showing minor signs of bleaching of around 15%. This is a rough estimate based on the amount of bleaching fragments of the entire frame. As you can see from the images, their white skeletons are not something anyone can miss, especially in the water. The degree of bleaching on your frame is not too serious as we only saw few surface bleaching (those directly facing the sun’s rays) and one or two completely bleached fragments. We have also noticed that there is some “glowing corals” on your frame. Corals produce a fluorescent chemical which act like sunscreen to protect them against increasing heated waters caused by climate change and as a result produce the most vivid colors, although spectacular to look at, this is the ultimate warning that our oceans are in trouble.
Unfortunately, there is not much we can do at this stage, but wait to see whether they recover or not in the next months. Should they not recover and they are completely dead, they will be removed from the frame and replaced with new live ones. This is of course a major setback for our coral conservation project, but it is also the reality we are dealing with today.
As you can see from the picture, your coral frame are colonized by some little, brown and green organisms called Ascidia. The species is called Didemnum molle (also known as the green barrel sea squirt or the green reef sea-squirt.) and is very common in the Indo-Pacific area. Ascidia is a filter-feeder, feeding on suspended plankton and detritus and its green color is given by the algae living in symbiosis with them, in this way the algae is protected by the predation and the Ascidia can receive energy from its little hosts. Luckily they don’t possess any threat to the corals when they are few in numbers, however they can colonize quite quickly on the frames through asexual budding, as such they are regularly removed to minimize competition with growing corals.
Remember that we used plastic cable ties on your frame. Well look at this, here you will see the partial shape of the cable tie that we used to stabilize this particular fragment to the iron frame. Here you can see how much this new Acropora fragment have started to overgrow this plastic tie and in just a few months it will soon be part of the skeleton forever. Plastic cable ties are a good compromise for attaching corals to the structure, since the material is cheap, resistant and the results are great, however we are looking into using different materials to improve our techniques of reducing plastics in the ocean. When this colony have reached the minimum size for spawning it will release its gametes in the water that ultimately leads to the formation of new colonies elsewhere on the reef
In some unfortunate cases, much like we can see in nature, there are some dead fragments on your frame such as this one pictured. This is often the result when corals undergoes very high level of stress where they cannot seem to recover. This is not because your frame isn’t suitable, but since all the fragments were collected from the sand they already received lots of stress before attached onto your frame, so it happens from time to time that fragments might receive further high stress levels due to increased water temperatures and they lose the symbiotic algae Zooxanthellae that they need to survive. They will turn bleach white and if stress conditions persist they will die completely since they have no more animals for feeding or defending the corals and then they are often competing with invasive algae that grow over the polyps when this happens they will also die off. During the maintenance these pieces of dead coral is usually removed while the live part remains attached.
Looking at your frame, you will see that it is doing amazing and the corals are really growing well since the last update even after the heated months and some stormy weather. We have done some recent maintenance on all the frames which include cleaning them, removing the invasive algae and coral predators to maximize growth. In the upcoming post we will show you close-ups of your frame and the coral fragments, with some interesting facts and findings about those that are on your frame. After 6 months you will see a similar post showing once again the progress of your frame.
Corals are subject to predation by many organisms such as mollusks, crustaceans or echinoderms. Among those, coral eating fish are also included such as the Parrotfish or the Titan Triggerfish. In this picture, you will notice that many of the tips of the branches have been removed or damaged, possibly by a parrotfish. Parrotfish species are herbivores that spend much of their time eating algae that is covering rocks and dead corals, or the unicellular algae contained in the coral tissue. Thus, in this case they may have removed part of this digitate Acropora because of its high content in unicellular algae. The damage is not lethal and the white scars may soon recover.
