Colombo’s new coral reef found on port city premises

Colombo’s new coral reef found on port city premises

Sri Lanka’s coral reefs are a valuable biodiversity feature that almost all local and foreign tourists are eager to visit. Mr Piyal de Silva, the former Navy Commander, was the first to meet this coral reef, and he observed this while participating in diving training in 2019. He describes the experience as follows. “In 2019, I was conducting a training diving session with members of the Sri Lanka Navy in the area where the ship Asterica ran around near the Colombo Sea. However, we were still looking for the boat there. Therefore, we decided to shift to another place, and I selected the inner side of the port’s breakwater. The breakwater was created from a few raw materials: stone and a synthetic product called interlocking concrete. Surprisingly, I observed more coral reefs in both types of rocks. Also, I thought that this would continue to grow as a beautiful coral reef like other country reefs,” he added.

The waters surrounding Sri Lanka are home to several coral reef formations, attracting local and international visitors interested in marine life and snorkelling or diving experiences. Sri Lanka’s coral reefs are mainly found along the country’s western, southern, and eastern coasts. Popular coral reef locations include Hikkaduwa, Trincomalee, Pigeon Island, and Kalpitiya. Sri Lanka’s coral reefs are known for their high biodiversity, supporting many marine species.

These reefs provide habitats for numerous colourful fish, sea turtles, crustaceans, and other invertebrates. The coral species in Sri Lanka’s reefs include hard corals (stony corals) and soft corals. Hard corals build the framework of the reefs, while soft corals are known for their vibrant colours and flexible structures.

Former navy commander Piyal de Silva explains that after investigating these corals, he informed the Managing Director of Port City and, with his support conducted research. He studied these corals two to three times per year. He saw corals distributed throughout the breakwater area of the port city premises. Also, he investigated some broken corals since he decided to start a conservation project.

 Conservation efforts of corals

Considering the conservation techniques of corals, there are two things. We can save the remaining corals by prohibiting damage or pollution and restoration of corals. The first is that everyone can think and do, but the second cannot. Because it needs knowledge and practice.  Methods of coral restoration can be grouped into three categories:

(1) Asexual propagation methods

(2) Sexual propagation methods

(3) Substrate enhancement

Let’s briefly consider some of these methods.

Asexual propagation methods

Asexual propagation refers to any coral restoration technique that results in transplanting coral colonies (coral fragments covered with live coral polyps) from a healthy reef or coral farming operation to a degraded reef. These methods typically do not harness any elements of the natural coral spawning process.

Direct Transplantation

This means directly transforming coral colonies from healthy reefs to degraded ones or new environments. It is one of the oldest, simplest, and most common methods to counteract coral reef decline.

The success of transplantation depends on various factors, such as the size and health of coral fragments, transportation to the target site, water conditions (turbidity, light), and species composition. And also the density of “out planted” coral, the solidness of the attachment to a substrate, and the presence of algae and predatory fish that feed on coral.  The former commander further explains that retired navy officers continuously support removing pollutants from the sea surfaces. And says it is everyone’s responsibility to make some efforts to mitigate climate change.  

Coral Farming

Coral farming involves cultivating coral colonies from tiny fragments of live coral in nurseries and then out-planting those colonies and usually attaching them to a degraded reef after they have grown large enough to be viable without additional human intervention.

Sexual propagation methods

Sexual propagation involves measures to restore coral reefs by implementing techniques that utilise the natural coral spawning process but aim to improve recruitment significantly.

1. Ex situ larval enhancement methods

This approach to larval propagation involves cultivating (ex-situ) or collecting coral gametes, nurturing them during the larval stage, and then allowing them to settle on artificial objects in land-based saltwater tanks.

2. In situ larval enhancement methods

In situ, larval enhancement methods begin by collecting coral gametes on coral reefs during spawning events. The timing of the collection must be perfect since the opportunity occurs only once a year. The gametes and fertilised embryos are held in saltwater pens or booms until they become planulae ready for settlement. More can be read from here

Substrate enhancement

Reef restoration approaches in this group aim to provide favourable conditions for coral recruitment without cultivating or propagating coral colonies. However, transplanting coral fragments is often carried out with substrate enhancement efforts. More can be read from   here 

1. Artificial reefs

Creating artificial reefs involves the placement of human-made objects on the sea floor to simulate the structural characteristics (projections, overhangs, and hiding places) of a natural coral reef and to attract marine life, including corals and all the other forms of marine life present on a healthy coral reef.

2. Stabilization of substrates

Restoration efforts involving the reinforcement and stabilisation of substrates are essential in areas where previous coral formations have been extensively damaged by storms or ship groundings, resulting in a bottom characterised by unstable fragments and rubble.

Former commander Piyal de Silva explains that they start with 2000 corals in the nursery using this technique, showing 60% – 70% -success. So, they used artificial net to replant corals, and he says one more surprising thing also happened. One day they observed one giant cuttlefish lay eggs on there, and the team observed nearly 2000 baby cuttles come out. Since their efforts aren’t wasted, he further explains that many fish species widely use these corals and all benefit from this.

Mr Piyal de Silva also explains that they were now investigating 35 different coral species and more than 100 fish species that used these corals. He says it is a good sign of sustainable development of the port city as well they are willing to open this place to the public shortly.

Threats to these beautiful corals

Like many coral reef ecosystems worldwide, Sri Lanka’s corals face various threats. These include overfishing, destructive fishing practices, pollution from land-based sources, coastal development, climate change, and coral bleaching events caused by rising sea temperatures.

1. CORAL BLEACHING

Coral reefs thrive in a short temperature range. Under raised temperatures, corals are stressed, and their mutualistic relationship with the algae living on them is disrupted. As a result, the corals lose some or all of the zooxanthellae with their nutrients and colour.

Global coral reefs decreased by 16%, with up to 50% losses in the Indian Ocean. Following another warming event, an international bleaching event occurred in 2016. The chart below displays the impacts of the 1998 coral bleaching event on reefs found in the Bar Reef and Hikkaduwa marine parks in Sri Lanka. The coral reef percentage plummeted from approximately 80% in the Bar Reef and 60% in Hikkaduwa to less than 10% following the bleaching event. 

Source: Data obtained from Arjan Rajasuriya/NARA, CORDIO, and GCRMN, extracted from Wilkinson (2008) Status of Coral Reefs of the World 2008

In the Indian Ocean, the coral bleaching of 1998 and destructive human activities caused more damage to coral reefs than the Tsunami of 2004 since you can imagine how dangerous it is.

2. OCEAN ACIDIFICATION

With the ocean absorbing more than 93% of the greenhouse gases over the last four decades, carbon dioxide levels in the sea have increased. Dissolved carbon dioxide forms carbonic acid, which reduces reef building properties of corals.

3. COASTAL DEVELOPMENT

Exploration, land reclamation, deforestation and erosion all negatively impact coral reefs. Dredging and land reclamation can remove the habitats of these coral reefs and increase sedimentation in the waters, along with deforestation and poor land management practices.

4. PREDATOR ATTACKS

The Crown of Thrones (COT) is a starfish that feeds on coral reefs by digesting the zooxanthellae through digestive juices.

5. OTHER THREATS

Other threats to coral reefs include harmful tourism practices such as the use of glass-bottom boats and careless behaviour of tourists, which led to the destruction of coral reefs and marine pollution. Other forms of marine pollution from land-based activities (e.g. heavy metal pollution) and sea-based pollution (oil spills, discharge of ballast water from ships etc.) also negatively impact corals.  Furthermore, overfishing of algal grazing fish also threatens coral reefs. This is because grazing fish help maintain types of algae that grow on corals which can smother the coral reefs. More can be read from here

 Sri Lanka’s Legislative Protection of Corals 

The Fauna and Flora Protection Ordinance protects all hard and soft corals in Sri Lanka.

The Fauna and Flora Protection Ordinance

“An ordinance to provide for the protection, conservation and preservation of the fauna and flora of Sri Lanka; for the prevention of the commercial exploitation of such fauna and flora; and to provide for matters connected in addition to that or incidental to it.” This protection ordinance safeguards Colombo’s reef like other reefs of the country, prohibiting commercial use, carrying, damaging, or killing any coral life.

The Fisheries and Aquatic Resources Act

This Act provides for managing, regulating, conserving and developing fisheries and aquatic resources in Sri Lanka. It comprises 67 sections in 10 Parts.

Part I deals with fisheries administration. Part II deals with licenses. A license must be obtained for fishing which must be practiced by the conditions attached to the right. Any infringement of Sri Lanka fisheries legislation can lead to the withdrawal of the license. Part III deals with Fishing boat registration. The Director is responsible; all boat owners wishing to fish in Sri Lanka must register their vessels. Aquatic resource protection measures are dealt with in Part IV. Prohibitions and restrictions are imposed on specific fishing methods, harming corals. Likewise, this Act empowers the Minister of Fisheries to issue regulations for fishing zones, prohibiting unauthorized mining, collecting, and gathering of corals to ensure coral growth is not adversely affected by human intervention, especially for the commercial use of corals.

Conclusion

Sri Lanka is known for its diverse marine ecosystems, and coral reefs play a significant role in its coastal biodiversity.  Sri Lanka has taken steps to protect its coral reefs and marine ecosystems. Marine protected areas (MPAs) have been established to safeguard important reef areas and limit harmful activities. Public awareness campaigns and educational initiatives aim to promote responsible tourism and reduce human impact on coral reefs.

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