Thank you for signing up to keep in touch with the Coral Conservation Project. Pictured above, you will find your coral frame as it was few days after construction. Your personal page will allow you to see more regular updates and amazing facts about the corals and animals living on your frame. By now having all the updates on one page, seeing the progress of your frame will be much easier and convenient. If you want to satisfy your curiosity even more, you can take a look at our Marine Blog Life and videos from the Marine Lab Diary or connect with us for more information.
Here is the start of a healthy coral reef relationship!
Have you ever wondered why some corals are more colorful than others… That is because some corals increase the production of colourful protein pigments (such as these purple tips) when they are exposed to more intense sunlight and this colony, of a branching Acropora, is simply amazing. Scientist have found that these pink, blue and/or purple proteins act as sunscreens for the corals by removing substantial light components that might otherwise become harmful to the algae hosted in their tissue. Corals rely on these light-dependent miniature plants, the so-called zooxanthellae, since they provide a substantial amount of food. Furthermore, these tips consist of a particular polyp called an “apical polyp”. It is responsible of the growth of the particular branch. For instance, it will reproduce asexually by cloning itself, potentially an infinite number of times throughout its lifetime. Here and there, one of the “radial polyps” will differentiate becoming a new apical polyp with its distinguished purple color, driving the growth of a new branch.
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.
Have you ever wondered how corals are eating and defending themselves … here you will see some small extensions/tentacles protruding from each of the polyp housings. They are referred to as the defensive/offensive stinging mechanisms similar to sweeper tentacles and are often linked to their feeding and defending. Inside each of the polyps are the small animals that look similar to an upside-down jellyfish with tentacles that surround the mouth part, depending on the coral species, the amount of tentacles may vary. They will move around to collect small particles floating in the water, usually plankton. These tentacles are also used for defending themselves against predators such as the coral eating snail, Drupella sp or the invasive Crown of Thorns Starfish. They also keep smaller predators such as crabs and invertebrates away. These tentacles are seldom seen, but do come out when they are feeling threatened or during feeding.
This beautiful creature is known as the reeftop pipefish (Corythoichthys haematopterus), also known as the Bloodspot pipefish, Dragonface Pipefish or Yellowstreaked Pipefish. The Pipefish is in the same family as Seahorses and has the same head and snout. Pipefish feed on small animals that life on the bottom of the seafloor; they use their snout like a straw to suck up their food. They are often difficult to see when they are on the sandy seafloor, as their colors camouflage them very well. They are a common species around the coral frames and are often spotted moving in and out of the frame. They can grow up to 30 cm in length and are usually found at depths around 0 – 20 meters. An interesting fact is that Pipefish are like seahorses in that the male gives birth! The female deposits their eggs after fertilization into the males pouch, located under their tail to incubate the eggs for one month before giving birth.
What you see in this picture is a stony coral, more specifically a massive stony coral. These corals are especially important reef builders; this means they are the pillars of the coral reef. Because stony corals are especially hard in structure they are the perfect foundation for coral reefs. Stony corals are often referred to be the “architects” of coral reefs. Because stony corals are very slow growing yet incredibly massive they are especially resistant to disease and bleaching and therefore can stand the change of time. Some of the oldest corals in the ocean can easily be 600 years, some are even over 1000 years old.
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.
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).
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.
Looking closely to one particular fragment branch on your fame, you can see that there is some damage to the coral branches here due to some predation. Since we are creating entire new reefs where there have been none before, we can see lots of fish species moving around the frames. Often times we can see damage of this kind that is the result of a Titan triggerfish or parrotfish biting down on the coral branches and eating the fresh tissue below. Many fish spend time grazing on corals due to the high content of algae, especially dead corals where you can also see their scratch-bite marks, many times the damage is not as great as this with only some polyps that has some damage. Looking closely at this particular fragment, you will see that the polyps are already recovering and we should see new branches in the next few months.
It is unfortunate to see that some coral frames are exposed to greater mortality compared to others mainly due to environmental factors, such as predation, high water temperature or diseases. Often times we see that broken fragments used for frame construction is not recovering due to prolonged stress from lying in the sediment and then exposed to the sun and human contact and as a result they slowly die and become covered with competing algae. In other cases, the fragments may also be heavily exposed to predation from a mollusk called Drupella spp. It is a corallivore species which feeds mainly on adult corals of Acropora genus. During our maintenance we remove the predators from the frames, although the result of their feeding is quite severe in some cases, in which case, the fragment is unlikely to survive. When we see a high number of dead fragments, we remove them completely and replace them with new ones.
We have noticed that some fragments such as this one pictured have some damage and as a result they die completely. This happens from time to time that fragments might receive very high stress levels due to increased water temperatures and they lose the symbiotic algae Zooxanthellae that they need to survive. Sometimes corals also need to compete with invasive algae that grow over the polyps and 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 really 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.
Here is some more information about Porites lobata or the more common name, lobe coral, which is growing on your coral frame. This species forms colonies that can reach large sizes, many meters across, depending on its location. Their surface is smooth to undulating and can be clusters of lumps. This is a common species in shallow reef environments, and it can be brown or greenish yellow. The genus is not particularly susceptible to bleaching, but more prone to diseases compared too many other corals. Growth rates are very slow, sometimes being as little as 1 centimetre (0.39 in) per year, and this means that large corals are very old.
