Reef Restoration Techniques: The Bottle Units

The Bottle Units are a reef restoration tool utilized by all Conservations Diver Training centers, and originally developed in 2009 at our center on Koh Tao, Thailand, the New Heaven Reef Conservation Center. The units were originally developed by two of our students, James and Ames, and have been tested and refined over the years since. This cost-effective method at reef restoration is easy to build and deploy, and is highly effective at increase the available substrate for transplanting corals when restoring reef areas or creating new structure to extend the reef area and establish alternative dive training locations.

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Bottle unit coral restoration

Objectives/Purpose

The Bottle units are well suited for adding stable growing structure for the transplantation of both nursery-raised and so called “corals of opportunity,” in the process of restoring coral reefs. The units are especially applicable in areas that have experienced anchor damage, dynamite fishing, boat groundings, and other acute forms of structural damage. By being simple to build and easy to deploy, the units lend themselves to easy scalability and widespread use. They use materials that are cheap and easy to source anywhere in the world, and can be quickly constructed and deployed as a rapid response measure following disturbances to reef health.

Bottle units
Bottle units made the day after a boat grounding on Koh Tao, Thailand

The units are heavy enough to provide a secure transplant location
for coral feedstocks, but are still light enough to deploy using only basic
SCUBA and marine conservation equipment. After deployment, the units raise the transplanted
corals to a height up to 50 cm from the bottom, allowing them respite from many
threats, and providing them with ideal growing conditions. The units are structurally
complex, creating habitat for many other organisms which are essential for
restoring the ecosystem, rather than just increasing the coral abundance.

The units will last several decades, and are generally covered in corals relatively quickly. The materials used are non-toxic, and conducive to coral growth. In many island settings where glass bottle waste is a problem, they are also a form of repurposing. Because of the simplicity and artistic freedom available in construction, they are a desirable method for programs that are concurrently attempting to involve local community members, stakeholders, or groups of students. Since they can be constructed in one day and easily personalized, they make a good project for fundraisers and awareness raising events. Furthermore, because transplantation is standardized, large teams of volunteers can effectively be used in the underwater restoration programs.

Materials Required

  • A Large Plastic Tub (such as those used for hand-washing
    laundry) which is about 30-50 cm in Diameter and at least 15-30 cm tall
  • Metal rebar
  • Concrete Mix
  • Rocks/concrete aggregate
  • Sand
  • Empty glass bottles (with labels removed)
  • Spray bottle with cooking oil or sugar water
  • Shells and Pieces of coral rubble (optional)
    collected from the land, not the sea





Construction Procedure

  1. Clean all glass bottles, removing labels and
    anything which could be considered litter or may harm marine life.
  2. Spray the cooking oil or sugar water into the tubs
    that will act as the mold for the concrete depending on availability and desired
    final texture

    1. Cooking oil will help to release the concrete
      after it sets, but will leave a smooth texture to the concrete
    1. Sugar water will also help the concrete to
      release from the mold, but will leave a higher rugosity to the concrete surface
  3. Mix the concrete using the 1:2:3 rule (1 part
    water, 2 parts concrete, 3 parts sand) mixing the sand and concrete through before
    adding the water
  4. Mix in the rocks
  5. Put a metal rebar ring inside each tub for added
    weight and strength (If rebar is not availble, use binding wire)
  6. Fill the tubs with concrete to the desired level
  7. Insert 4-6 glass bottle into the concrete,
    filling them with water first so they sink into the concrete
  8. Add any rubble/shells to the top for added
    texture and recruitment points
  9. You may also choose to add a loop of rope if you
    expect to be using life bags under water for aid in deployment
  10. Allow the cement to cure overnight, remove the units
    from the mold and leave for another 12-24 hours before deployment.

How to use the Bottle Units

Freediving bottle units in sandy bottom areas

After the Bottle units have been constructed and given time to cure, they can easily be deployed to the reef using standard dive and snorkel touring boats. Each unit should be light enough to be carried by one person to the boat, where they can be stacked carefully for transport. Ensure that no bottles are broken and that if they are, all team members are notified and measures are taken to ensure nobody can be cut by the broken glass.

Once at the site, the bottle units can be lowered using ropes or dropped with the assistance of free divers, who will control the descent and ensure the units end up in the desired location. If it is necessary to move the units once on the bottom, we recommend one of two techniques. The first technique used in coral reef areas is to use a lift bag to achieve near-neutral buoyancy, and then a team of two divers can lift and swim the unit into place. Divers should never use their BCD’s to lift any objects underwater. The second method, used in areas with entirely sandy bottoms, is for the divers to remove their fins and walk the units into place, this is the easiest and fastest method but should never be used in areas where the benthos will be disturbed or harmed in the process.

Walking the bottle units into place on sandy bottom areas

Once the units are in their final position, divers should twist and shake them to allow them to settle slightly into the sand or rubble, this will prevent them from moving around in any large waves or currents. Next, corals can easily be transplanted to the units using marine epoxy. The units are designed to accept both corals from the table nurseries (in which the vinyl tubes are the same diameter as the bottle mouths), and corals of opportunity from the reef. Corals of opportunity are coral fragments that have been created naturally due to fish feeding, waves, and storms but may also be from human-caused disturbances such as diver contact, anchors, boat groundings, or fishing. If these fragments are larger than 10 cm, then it may be best to transfer them directly to the bottle units instead of the nurseries.

Place the coral fragment into the mouth of the bottles or within the matrix of bottles and coral rubble at the surface of the unit, and secure it with a small amount of underwater epoxy. The corals will grow quickly on the inert glass bottles or the dead coral/shells and should colonize the units quite rapidly.

Troubleshooting

The most common problems we have seen with this technique over the years are:

  • Making the units too small – If the units are too small, then they are likely to be turned over or displaced during large storms and will not provide a secure location for coral transplanting
  • Making units too light – Concrete losses about 40% of its weight in water. If rocks are not added to the concrete, then it will be too light and can be displaced in storms, potentially causing more damage to the existing reef
  • Units are not strong enough and crack or break– the units may crack and break if the concrete is not mixed in the correct proportions, is not given enough time to cure, or is not reinforced with metal rebar or wire
  • Units sink into the sand – the units are not designed for very soft sediment areas or sandy areas that have strong hydrological action; using them in such places might prove futile as they are denser then the surrounding substrate and will tend to sink over time.

A note from Conservation Diver

We hope that you experiment with this technique and that it proves valuable to your program. Remember that coral restoration is a process that should only be undertaken by those who have had training in the techniques and thoroughly understand and are familiar with the reef they are working in. Every coral restoration technique is different, and some will be more or less successful in different areas at different times. Please let us know what you think about this technique by emailing us at info@conservationdiver.com.

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Reef Restoration Review: Breeze Blocks

Are breeze blocks and effective tool in coral reef restoration? In our previous articles we have always said no, but as this technique continues to be used and even expanded in many reef restoration projects in places like Thailand, we wanted to take a closer a look at it and talk with some other experts to see what they think. The technique is quite simple, and the materials are cheap and readily available, which are both very important qualities for the large-scale implementation of any coral restoration method, and thus deserves a closer look.

How the breeze block technique is used

Breeze blocks, also known as cinder blocks, are a low density, aerated concrete product designed for non-load bearing applications in home and building construction. They are designed to be light, easy to cut to size, and cheap. Each block weighs just 8 kg or less, and costs between 3-6 Thai Baht ($0.01-0.02 USD). Generally, when used in coral restoration, small fragments of coral are affixed directly to the blocks using epoxy or cement. In more elaborate projects, holes are drilled or punched into the block and the coral is glued into it, or in some cases PVC or steel is first affixed, and then the coral fragments. Generally, between 2 and 6 corals are secured to each block, and then the blocks are set down as a sort of pavement at the restoration site. The technique is quick and cheap, and is attractive to reef managers that are looking to create large projects in a short amount of time. But, are these types of projects usually successful?

Effectiveness of Breeze blocks in restoration

reef restoration fails
A Breeze Block Project Deployed in the vicinity of Sai Nuan, Koh Tao, Thailand in 2015, which experienced 100% mortality.

here at Conservation Diver, we have long been critics of this technique for several reasons, mainly that the blocks are too light to provide an effective substrate for long-term coral survival, and that they are unattractive, and tend to either move around in the waves or sink beneath the sands. The blocks, which weigh only 8 kg on land, lose about 40% of their weight in water, and due to their high surface area and low density make them unstable for long-term coral growth. We first witnessed this back in 2006, with the complete destruction of such a project on Koh Tao that was put down in 2005 by the Koh Tao Dive Operators Club in the vicinity of Sai Nuan at a depth of approximately 3-4 meters. After only 1 year, none of the corals on the blocks had survived.

The second reason why we were critical of this technique is that the resulting pavement-like reef that is created does not mimic a natural reef in structural complexity or 3-dimesnional relief. The resulting reef has little to no vertical profile, does not provide diverse habitat for symbiotic reef fishes, and is prone to smothering by sediment and moving sands. Furthermore, depending on the manufacturer, these blocks often contain a high percentage of fly-ash, which depending on the source, can contain dangerous levels of heavy metals or other toxic contaminants whihc limit coral growth or can even contribute to coral disease.

Even though these were our experiences and our assumptions, we could not effectively evaluate this technique as there are very few scientific reports available on the successes or failures of the method, and we do not imply this technique in any of our programs around the world. Online searches through the scientific literature, grey literature, and google images yielded many articles and pictures of the reefs immediately after deployment, but no follow-up reports could be found, which we felt was a major red flag. If people were only posting their nice pictures of the projects immediately after deployment but not years later, then we assumed they all must have failed, just like the ones we were familiar with.

Positive experiences with the Breeze blocks in restoration

cinder block reefs
Photo of restoration work from Maiton Island, Thailand (Image credit, Dr. Nalinee Thongtham

Although there are very few scientific reviews of the technique, the ones we were able to find showed a different story to the one we had been telling our students for over a decade. The first example comes from Maiton Island, off of Phuket Island in Thailand, in a project done by Dr. Nalinee Thongtham, and was published as a case study in the CCRES Reef Restoration Manual. The pictures of the project show great success after more than 10 years, with the blocks well covered in small corals from a variety of genera and species. However, this project differed from many of the ‘mainstream’ projects we evaluated in that the blocks used were the largest size available, and no fragments were transplanted to them, they were just left to receive coral recruits naturally. When reached for comment, Dr. Thongtham said “I just provided hard substrate for natural coral larvae to attach and grow naturally. Coral transplantation is not necessary in this area. . .There is no standard restoration method that is effective for all reefs. Different restoration methods can be used and applied to different environmental conditions. For example, providing hard substrate for coral larvae is a suitable method in areas where coral larvae are available but there is no hard substrate for them to grow."

Photo of restoration work from Maiton Island, Thailand (Image credit, Dr. Nalinee Thongtham)

The second published review of this technique which we found was in a 2012 paper by Young et al. and looked at the technique’s application for restoring branching Acropora in the Caribbean. Not much detail is given on the depth, location, or details of the method used, but their findings regarding the use of cinder blocks was considered overall positive, even though in some cases 12-56% mortality was experienced in the first month, and one project experienced 80% mortality following a hurricane. They reviewed 7 projects in Florida which used cement blocks, and the authors’ conclusion was that the coral fragments transplanted had “positive growth rates, low mortality, and were capable of sexual reproduction.” The problems they identified were “accumulation of sediment and macroalgae, susceptible to storm damage, and epoxy failure.”

We also spoke with Mr. Niphon Phongsuwan, Specialist on Marine and Coastal Ecosystem Research for the Thailand Department of Marine and Coastal Resources, who has over 20 years of experience with coral restoration. He provided photographs of a more ‘traditional’ cement block project on Koh Racha. The pictures show a high survival rate of the fragments, and a low incidence of sedimentation or movement of the blocks. Mr. Niphon stated that when using 'the breeze blocks, the place must be deep enough (I recommend deeper than 5 m and never work at the wave exposed site or strong current site). At [Koh] Racha the depth is about 8m so the blocks have no impact from waves."

A traditional Breeze Block Coral Restroation Project, showing 8 months and 1 year post-deployment (pictures provided by Mr. Niphon Phongsuwan)

Concerns about breeze blocks for coral restoration

We also talked to some experts who opposed the use of the breeze blocks, for several reasons. When we contacted Dr. James True who has extensive experience with coral restoration in Australia, Hong Kong, and Thailand, he said “My feeling is that (of the many potential concrete-based solutions) breeze blocks are the least effective substrate alternative.  Even threaded together by lengths of rebar, they are prone to displacement, shattering & burial by wave action. Railway ties, molded modules, pipe clusters, even power poles or the typical fisheries hollow box elements are all more stable and provide better long-term alternative substrate. As mats, they provide no vertical relief, no complexity and no hydrological advantage over sand.”

When we asked Spencer Arnold, the director and designer of artificial reefs for Conservation Diver, he said that he preferred purpose-built structures which provide more complexity and act as a better habitat for reef organisms, and also are more attractive to divers. He went on to state that “from an aesthetic perspective, cinder blocks as an artificial reef design hold all the appeal of a parking lot. If you like parking lots, you'll love a cinder block reefs.”

The Colony Artificial reef
"The Colony" an artificial reef built by Spencer Arnold

The method of coral transplantation and propagation also plays a major role in the long-term success of such projects, and is something we are always highly cognizant of in our restoration efforts. Previously, we have strongly spoken out against programs that rely on asexual propagation and the use of donor corals for the reduction they cause in genetic variability and thus the resilience of the restored reefs. This was also mentioned by Dr. Thongtham, who stared that “genetic diversity is a major key to sustainability of coral reef restoration. As shown from our study during a mass bleaching in 2010, high mortality of transplanted corals occurred in areas where mother colonies were used while in areas where there were natural recruits, most of the coral recovered very well.” Indicating that it may not be that the technique is inherently good or bad, but like most things, that it all depends on how it is applied.

Conclusions

For over a decade we strongly opposed this technique for coral restoration, and instead focused our efforts on using stronger, heavier, and more structurally diverse artificial substrates when replacing lost structure or expanding reefs through our global projects. However, that may have been a slightly draconian view to adopt, as indicated by the limited sucess and positive experiences of others while using this technique. However, in saying that, we must stress the caveat that this technique should be used carefully, as it will not be successful in all applications. Based on the case studies and our experiences, we would recommend only using this technique if the following consideration are met:

  • The blocks should only be used in areas where there is little to no wave action or likelihood of large storms (ie sheltered bays, deep areas), and where sedimentation is not a major issue.
  • The blocks should ideally be used in conjunction with other structures which provide complexity and habitat to fishes and other reef organisms, many of which are symbiotic and essential to healthy coral growth and reef development.
  • Care should be taken when removing corals from the sea for attachment, and methods which do not require removing the corals from the water are generally preferred.
  • If using prefabricated breeze blocks and other types of low density or aerated concrete, the largest size should be selected, and efforts should be made to consolidate them or lock them in place to reduce storm related mortality.
  • Coral propagation (asexual fragmentation) and the use of donor corals is never advised, as the long-term genetic effects lead to reduced resilience and survival through mechanisms such as genetic bottlenecking, inbreeding depressions, and reduced reproductive success.

In our programs, we will continue to use other techniques, and see very little reason to use cinder blocks when so many better materials and designs are readily available. However, after talking with more experts we recognize that there is a place for these techniques, and for programs using unskilled volunteers and working with limited budgets this technique can be useful in building community awareness, involving a wide range of stakeholders.


Does coral restoration also enrich fish communities?

When we perform coral restoration activities, the goal is to not only increase the amount of living coral, but to enrich the entire ecosystem, including the fish communities. Restoration programs tend to focus on bringing back living coral, under the idea that by bringing back the foundation of the ecosystem, the rest of the reef organisms will follow. But is that truly the case?

A recent publication headed by Dr. Margaux Hein investigated whether long-term coral restoration programs did in fact bring back fish communities, and the results were not as significant as some restoration practitioners might expect. The study, titled “Effects of coral restoration on fish communities: snapshots of long‐term, multi‐regional responses and implications for practice,” was published in April in the Journal of Restoration Ecology. It analyzed four coral restoration sites, all of which had been ongoing for 8 years or longer, two from the Caribbean and 2 from the Indo-Pacific. The studies where completed in the same locations as her publication on the effectiveness of long-term coral restoration, and builds upon the lessons learned from that study.

The study assumed, like most of the coral restoration industry, that efforts to bring back corals and structure would also attract a wide range of reef fishes, thereby restoring the function and value of the ecosystem. Not only are the corals essential for the survival of the fishes, but the fishes (especially the herbivores and detritivores ones) help to maintain the dominance of corals on the reef over macroalgae. In general, more fish biomass is thought to represent a healthier ecosystem, and also leads to more value for local economies through tourism and fisheries. So, reef restoration efforts should be concerned with the abundance and biodiversity of fish communities when evaluating the effectiveness of their efforts.

batfish coral nursery

In Dr. Hein’s study, she looked to see which of the various restoration methodologies most positively affected fish communities, and hypothesized that locations which had the highest structural complexity of corals would also have the highest abundance and diversity of fishes. She and her team carried out transect surveys for fish at four locations around the globe, and looked at three site types for each location; restored reefs, unrestored reefs (adjacent to and degraded to a similar extent as the restored reefs, but with no actions being implemented), and control reefs (those with little relative degradation and no restoration, but similar in composition). Each location had three replicates per site type, for a total of at least nine replicates per location studied. They categorized reef fishes into three groups by size (small, medium, and large), and by genera.

coral restoration graph

Although in the last study they found significant differences between the coral communities at each location, results regarding the fish communities where far less significant. In fact, only one site, the one at Koh Tao, operated by our partners at the New Heaven Reef Conservation Program, showed any increase in fish biomass or diversity, and it was not statistically significant. At Koh Tao, the restored sites had the most fish, a 2-fold increase, but only among the smaller fishes, and only of the damsel fish family. At other locations, the fish abundance did not vary greatly between sites, and in the Caribbean was actually highest at the control sites (again, not significantly). When it came to medium and large fish, they were generally lower in the restored sites than the unrestored or control sites.
The study went on to point out that, on Koh Tao, a variety of methods where utilized, including transplanting corals to the natural reef as well as to artificial substrates, whereas at all the other locations only one strategy was utilized. Thus, interning again that taking a holistic approach to restoration may be preferred over focusing all time and resources to just one method, as in the other programs assessed. By increasing the structural diversity and available habitat on the reef through the creation of artificial reef structures while also increasing the amount of living coral on natural reef areas more consistent benefits are realized.

fish restoration graph

In the end, the study did not find significant differences in fish community biomass and diversity, contrary to the original hypothesis. The authors discussed possible reasons for this, and gave recommendations to future studies and restoration programs for improvement. The study concluded that:

“Coral restoration efforts aiming at increasing fish abundance and diversity on degraded reefs should strive to substantially increase both coral cover and structural complexity by maximizing coral diversity, and use a diverse set of artificial transplantation substrata where possible. Importantly, there is likely no “one size fits all” approach to restoration when it comes to maximizing the response of fish communities. Rather, to realize such a goal requires a location-specific understanding of the community, that will need to be incorporated at all stages of the design of the restoration efforts, from site-selection, planting design and monitoring regime. “

We at Conservation Diver wanted to know a little bit more about what Dr. Hein felt was the most vital aspects to coral restoration, as she has published many studies on the various aspects of it, and has visited many reef restoration programs around the world, here is what she said:

Q1: Your study found that there was little in the way of significant improvements at the restored sites at all of the locations studied, despite the hypothesis to the opposite. What do you think are the main things that restoration is missing that would improve fish abundance and biodiversity?

The limited response of fish to restoration I observed might very well be due to my study-design and the fact that I only got a “snapshot” of what fish population looked like at each location, with a one-off survey. Fish move (haha), so properly documenting their response to restoration would require repeated surveys from the very beginning of the restoration efforts. Still, I think there are ways in which coral restoration programs could be better designed to improve fish abundance and diversity:
1. Site selection should be based on local knowledge of fish communities’ dynamics and connectivity
2. Restoration designs should maximize 3-dimensional structural complexity
3. Restoration designs should improve coral diversity

Q2: Since you have dived at many different artificial reefs/restoration projects around the globe, what technique do you think works best to attract a diverse population of fishes?

I think the key is habitat structural complexity and diversity. Fish are attracted to places for food and shelter, and complex structures provides refuges of different sizes as well as diverse feeding surfaces. Maximizing habitat complexity can be done by adding artificial structures and maximizing coral diversity.
Then obviously, site selection is very important, making sure that the restored area is somehow connected to healthy fish populations – the ideal scenario being for the restored sites to be within no-take marine protected areas. The more the restoration efforts can be integrated within resilience-based management, the better success we’re likely to see in the long-term.

Q3: Which fishes do you think are most important to attempt to attract when planning a restoration project?

That’s a tricky question- I think it all depends on the initial goals of the project. If initial goals are focused on enhancing fish nursery habitat for local fishermen, then it’s important to specifically look at the response of fish species that are important for these fisheries. These may have specific food and shelter requirements that the restoration efforts can accommodate. If initial goals are focused on restoring ecological function and resilience, then we need to look at the response of functionally important fish species and restoring key ecological processes such as herbivory. These goals are not necessarily mutually exclusive, but better defining goals is important when planning and designing restoration efforts.

Q4: You have now written several papers and book chapters on coral reef restoration, what are the main lessons you have learned, that you think the industry needs to heed in order to be more successful in the future?

I would say that the most important lesson I have learned is that there is a lot more to coral restoration than growing and planting corals. In particular, it can be a useful educational tool that encourages tangible behavioral changes and improves the social resilience of local communities as well as the ecological resilience of the reef. But there is no “one size fits all” approach. To be successful it needs to be carefully planned and designed against specific long-term goals, integrate stakeholder engagement, and most importantly be integrated within a greater reef management plan that act on stressors such as MPAs, water quality and predator control, and the obvious elephant in the room: climate change.


We want to wish our sincerest congratulations to Dr. Margaux Hein for this valuable and encouraging study, and also a big congratulations to her co-author, and our board member Eloise "Elle" Haskin, on her first scientific publication! Surely many more are to come.


Also be sure to check out what Dr. Hein is currently working on by checking out her marine restoration and consultancy company website.

Artificial reef fish

How effective are our coral restoration techniques?

restored branching corals following a boat grounding

As coral restoration techniques becomes more mainstream, it is important that the industry takes every measure to ensure that the techniques used are valid and effective. Today there are many groups out there doing various forms of corals restoration, and the importance of their work is becoming more and more apparent as recent reports have found that more than 50% of the world’s coral reefs are already gone, and the rest are not doing well. Coral bleaching events are becoming much more frequent and severe, and so are coral disease outbreaks. No reefs are safe from these global effects, both those in marine protected areas and those without strict protections are being lost at similar rates, which is why we no longer have the luxury to put our efforts into only preservation without also focusing on restoration.

But are the coral restoration techniques being used by various groups working? Its hard to say, the database for coral restoration developed earlier this year found that 60% of projects do not monitor their work for more than 18 months, with many not doing any post-transplant monitoring. How can any coral restoration program claim success if they don’t have long-term monitoring? Just growing corals in a nursery is not restoring the reefs, in order for the project to be a success it must improve the long-term resilience of the reefs, ensuring biodiversity and the corals ability to withstand and adapt to various chronic and acute stresses.

A recent publication led by Dr. Margaux Hein of James Cook University, seeks to evaluate the long-term impact of 4 different coral restoration programs that have been in action for more than 10 years, two from the Indo-Pacific and two from the Atlantic. In her paper, titled “Coral Restoration Effectiveness: Multiregional Snapshots of the Long-Term Responses of Coral Assemblages to Restoration,” she evaluates the programs based on 5 factors: (1) Benthic Cover, (2) Structural Complexity, (3) Coral Health, (4) Generic Richness, and (5) Juvenile Recruitment; based on surveys of both the restoration sites and control sites. Of the 4 locations studied, only our program on Koh Tao showed improvement in all 5 factors, indicating that our techniques are the only ones which not only increase the amount of coral on the reef, but also preserve the structure and function of the reef while enriching its resilience to future threats.

Sea Turtle at our artificial reef
A Green Sea Turtle hangs out by one of our artificial reef structures

(1) Benthic cover

The study found that coral cover was more than twice as high
in the restored reefs then the unrestored ones in three out of the 4 locations,
in the fourth, coral coverage was still higher, but not significantly. So all the
programs are increasing coral coverage through their efforts, but the effects
on reef resilience are more nuanced, as we will see in the next few sections.

(2) Structural complexity

All four sites showed higher structural complexity on the restored reefs than the unrestored ones, however only 1 showed structural complexity higher than the control reefs, our program. The structural complexity of our restored reefs was twice that of the unrestored ones, and slightly higher than the control reefs. This is probably due to our widespread use of artificial reefs as a way to increase the available habitat for corals and other reefs organisms in addition to our work transplanting corals back to the natural reef areas. By taking a holistic approach in our coral restoration techniques we have been able to not only bring back corals, but continue to improve the available habitats on our reefs.

Juvenile corals produced through our coral spawning program
Juvenile corals on our nursery, produced through our larval culturing program

(3) Number of coral juveniles

The two sites in the Atlantic could not be analyzed for this parameter as too few juveniles were found, however, for the Indo-Pacific sites only ours showed an increase in coral juveniles, with a 3 fold increase between the restored and control sites, with no juvenile corals found in the unrestored sites. These were primarily on our concrete artificial reef structures, but may also be because of our coral spawning and larval culturing programs.

(4) Coral generic richness

Increases in coral species richness only occurred in our restoration sites on Koh Tao. In the two Atlantic programs, coral diversity was about the same, and in the other Indo-Pacific project it was actually lower in the restored sites than the unrestored or control ones. This is probably the biggest ‘win’ for our coral restoration techniques, as it has been what our program has focused on since the beginning. Instead of asexually reproducing the fastest growing corals on the reef like many programs, our aim as always been to create feedstocks for restoration by collecting ‘corals of opportunity’ over a wide spatial and temporal scale, and these results justify that philosophy, and further adds credibility to our arguments against coral fragging.

(5) Coral Health

Again, we were the only program to show significant differences
in coral health between the unrestored sites and the restored ones. At our
reefs, the restored reefs had a 4-fold lower incidence of problems with coral
health over the unrestored reefs, and our restored reefs were also slightly
healthier than the control reefs. In the Atlantic programs, where asexual propagation
is widely utilized, coral health was worse in the restored areas than they
control or unrestored reefs. Implying that the effects of reduced genetic diversity
resulting from asexual cloning have real, long-term negative impacts on reef resilience.

This is the first study of its kind, to evaluate and compare various long-term coral restoration techniques based not just on how many corals they have planted, but what the long-term implications of their work is on the sustainability and survival of the reefs. We couldn’t be more proud of our program, as we have worked so hard over so many years just trying to do something good. To have this study justify our philosophies, methods, and techniques is one of the greatest outcomes we could ever hope for, after of course seeing our reefs thrive once again. This is a great honor for us, and give us even more motivation to continue our work. We must also give a huge thanks to the thousands of people who have helped us along the way, primarily the staff, students, and interns at the New Heaven Reef Conservation Program on Koh Tao.

New Heaven Reef Conservation Program
My Family - the ones who helped me every step of the way, with Pau photoshopped in as Buddha Rock.

The Fight for the Last of Life

Forward

The reasons behind this latest electrified underwater sculpture installation The Fight for the Last of Life, deployed by Conservation Diver, Coral Aid and the NHRCP in Ao Leuk Bay on the 28th of August 2019 (Koh Tao, Thailand) are manifold. The most fundamental and perhaps arguably it’s most important purpose, Read more


Working with Island Livelihoods Institute and Corals Blue in the Maldives, May 2016

In May of 2016, Conservation Diver Trainers Pau Urgell and Kait Harris were invited by the Island Livelihood Institute to come and help with marine conservation projects and education in the Maldives. The team spent several weeks in the Maldives sharing their knowledge of coral reef ecology and coral restoration. The project could not have happened at a more salient time, as coral reef bleaching was very severe during the period.

The first stop for the team was the island of Fainu. Here the team was involved in training local islanders, children, in the techniques of coral reef education and action of Conservation Diver, and also strengthening ties with a local conservation group, Corals Blue. They spent some time teaching children of grades 8-10 about the reefs, and detailing some of the local and global threats facing the reefs the islanders depend upon. The following day they put theory into practice by taking the students on a beach clean-up, and having a competition to see who could collect the most rubbish. In all, over 70 bags of plastic bottles, rope, wrappers and Styrofoam were collected over the space of an hour. After the clean-up, the students learnt a little bit about the Coral Blue gardening project, and why it is so important as a restoration method. For demonstration purposes, they practiced the proper attachment technique using dead coral fragments found on the beach and attaching them to the domes.

Read more


Mineral Accretion Technology

Mineral Accretion Technology Basics & Techniques

The Mineral Accretion Technology Basics & Techniques Course is designed to give students an introduction to the impacts of climate change on coral reefs around the planet, and also on tools that can be used to protect corals in the face of bleaching events.  The course teaches students the basics of ocean chemistry, sea water electrolysis, and the construction/maintenance of low-voltage mineral accretion devices.

https://youtu.be/lsEImageYus

Prerequisites

  • Be 12 years of age or older
  • Be certified as an Advanced diver under a leading diving organization (PADI, SSI, RAID, etc) or an Open Water diver who has satisfactorily completed a buoyancy appraisal with a professional diver
  • Demonstrate proper diving ability at an advanced Level and be proficient in buoyancy and self-awareness
  • Be certified in our Ecological Monitoring Program and the Artificial Reef Theory and Techniques courses

Standards

  • Understand the global effects of climate change on coral reefs
  • Understand various techniques utilized by reef managers to manage reefs in the face of climate change
  • Learn about ocean chemistry and the relationship between ocean pH and reef growth
  • Learn about low voltage sea water electrolysis, and the benefits such technology can have for coral restoration and protection projects
  • Learn how to construct and maintain a mineral accretion device
  • Practice coral restoration and site maintenancen at a mineral accretion device artificial reef

Requirements

  • Attend the lecture on climate change impacts to coral reefs, and mineral accretion devices
  • Visit a mineral accretion device for data collection, monitoring, and maintenance
  • Complete and pass the written exam

Expected course time about 9 hours

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Artificial Reef Theory & Techniques

Artificial Reef Theory & Techniques

Artificial reefs have a wide range of uses in both coral reef restoration and problem mitigation. Artificial reefs (or structural restoration) can replace structure in disturbed areas, expand reef areas, provide alternative dive sites and diver training aids, or provide interesting art installations. Although they can be made simply, there is a lot of planning and theory behind any artificial reef instalment, and this course will give you the knowledge and skills you need to begin.

Prerequisites

  • Be 12 years of age or older
  • Be certified as an Advanced diver under a leading diving organization (PADI, SSI, RAID, etc) or an Open Water diver who has satisfactorily completed a buoyancy appraisal with a professional diver
  • Demonstrate proper diving ability at an advanced Level and be proficient in buoyancy and self-awareness
  • Complete the knowledge-building section of the Coral Restoration Theory and Techniques Course

Standards

  • Understand the use and applications of artificial reefs and the differences between different artificial reefs types and materials
  • Learn the practical standards and techniques for maintaining and monitoring artificial reefs
  • Be able to identify the threats/disturbance history to a coral reef area and decide if artificial reefs are necessary, and which type of structure to use.
  • Understand potential reasons for failure in artificial reef projects and the importance of proper planning and regular, long term maintenance.
  • Learn to design and build an artificial reef structure specific to a chosen location using local techniques and standards
  • Visit various artificial reefs that have been constructed from a range of materials and methods and evaluate the strengths and weaknesses of each type
  • Deploy an artificial reef and understand how to transplant corals onto the structure

Requirements

  • Attend the artificial reef knowledge development sessions (2) and complete the written exam
  • Construct and deploy an artificial reef structure
  • Attend 3 dive briefings
  • Perform 3 artificial reef dives (1) Maintenance and observation dive (2) monitoring and data Collection (3) deployment and attachment of coral from the coral nursery
  • Understand or practice at least 3 different transplanting techniques

Minimum course duration 10 hours

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Publications and Articles Related to this Course

Scientific Publications

Articles