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Facts about Staghorn Corals

[Phylum: Cnidaria] [Class: Hexacorallia] [Order: Scleractinia (stony corals)] [Family: Acroporidae]

Several global factors (e.g. climate change) threaten the survival of most corals found in shallow tropical reefs and lagoons because it interrupts the symbiotic relationship they have with algae.

This section contains detailed facts and information about staghorn coral and the significance of healthy 'bush-like' coral species for fish families and other reef organisms.

What is the Coral Species called Staghorn?

The common name used for this particular species of coral comes from its resemblance to the branching antlers of male deer.

From solid bases anchored to ocean floors, staghorns start to produce cylinder-shaped branches, almost shrub-like in appearance.

In some places, dense thickets of staghorn coral can reach almost two metres in height (6 feet) and ten metres in lateral growth (30 feet).

Not many coral reef ecosystems grow faster than staghorns. In fact, it has an impressive growth rate of up to twenty centimetres per year (8 inches).

These fast-growing reef-builders usually have a pale brown or dark grey colouring. But, other species can have a more vibrant appearance, including blue, pink, or even purple.

Important: Staghorn corals found at dive sites in Southeast Asia have the scientific name of Acropora muricata (previously called Acropora formosa). But, Acropora cervicornis is a variety that is native to areas in Florida and the Caribbean.

Is Staghorn Coral a Plant or Animal?

In fact, all corals are animals - even though some actually look like they are a plant or a solid rock. These tiny reef producing corals are called polyps and they are examples of marine invertebrates that can create large underwater structures as they grow.

Reef polyps vary in size, but many are as tiny as a pinhead. Even so, they often form large colonies by secreting a hard calcium carbonate shell to create a hard limestone skeleton.

Note: In a nutshell, staghorn coral is an animal. It is alive and, unlike plants, it does not make its own food. Check out another section that answers the popular question of 'what is coral made of' in greater detail.

What Does Staghorn Coral Need to Survive?

Unfortunately, most staghorn species (such as elkhorn corals) start to die without clear, oxygenated, warm water - and limited wave action.

Thus, you will find these animals more often in sheltered, shallow areas around five metres (15 feet). Nonetheless, healthy species can survive even at depths around thirty (30) metres (98 feet).

Interesting Facts and Information about Staghorn CoralCorals belonging to the Acropora genus use minute, stinging tentacles (cnidocytes) to eat their regular diet 'zooplankton'.

In short, they hunt at night and feed by snatching these tiny aquatic animals that drift in the water column.

Symbiotic Relationships for Extra Nutrition

Most corals can enhance their diet through the absorption of nutrients created by zooxanthellae (single-celled algae).

Algaes convert sunlight into energy, providing additional nutrients for corals to eat. Sequentially, Symbiodiniaceae (photosynthetic symbionts in cnidarians) are happy to use the tissues as a 'safe' place to live.

Interesting Fact: The prefix 'phyto' defines the main difference between zooplankton and phytoplankton, as it refers to small plants (e.g. algae, diatoms).

What Eats Staghorn Coral?

In the main, there are two animal species that prey upon staghorn corals - butterfly fish and nudibranchs (a soft-bodied mollusk).

Furthermore, large parrot fish species create another threat to staghorn's existence. They will bite off parts of the branches to get at its prey sheltering within.

Staghorn Coral Reproduction Process

Being hermaphrodites (bisexual animals) means they have male and female reproductive organs. Hence, staghorn corals can reproduce sexually and asexually.

They will reproduce sexually one time per year, usually towards the end of summer. This is when they release huge clouds of eggs and sperm all together into the water column.

Here's the thing:

Staghorn coral colonies do not self-fertilise. Thus, they will need the sperm from a different colony for a successful fertilisation. Some of the fertilised eggs will develop into coral larvae (called planula) before they eventually settle in the benthic zone (seabed) and start to form new colonies themselves.

Because they are one of the fragile coral species, it is common for a broken 'branch' of staghorn to attach itself to the substrate and start to grow after 'asexual reproduction'.

Global Threats to Staghorn Corals

The IUCN Red List of Threatened Species cites staghorn coral as being 'Critically Endangered'. Research shows that climate change and rising sea temperatures create the biggest threat to its survival (through coral bleaching).

These fragile ecosystems are also susceptible to fatal coral diseases (e.g. pathogens, fungi, and bacteria). Some of the most severe spread at an alarming rate, killing entire colonies.

Several other major threats include:

Staghorn Coral Lifespan

One of the lesser known facts about staghorn coral is that it has a low resistance and tolerance to bleaching. So much so that it often takes longer to recover than other classifications.

Bleaching results in the removal of algae, which turns corals white. Despite being 'alive', this state renders it less resistant to stress and disease.

In general, it takes three to five years of growth for the staghorn coral to mature. Studies suggest the generation length is around ten (10) years. In fact, healthy polyps can live for over one hundred years.

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