Change transplant attachment method

Overall effectiveness category Awaiting assessment
Number of studies: 3
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Background information and definitions

Coral fragments can be naturally generated (e.g. broken off due to storm or wave action) or be taken from a donor colony for the purposes of transplanting to restore a degraded reef. Unattached fragments can be subjected to burial and abrasion (Dizon et al. 2008) and have a lower survival rate (Forrester et al. 2011). Therefore, fragments are usually attached to the substrate using man-made material most commonly an adhesive substance (such as marine epoxy or super-glue) is used to ‘stick’ the fragment to the substrate or the fragment is ‘tied on’ using cable ties wire string etc.

This action specifically refers to the type of attachment method used to attach coral to the substrate. Studies describing transplanting wild-grown coral onto natural substrates or nursery-grown corals onto natural or artificial substrates are covered in Transplant nursery-grown corals onto natural substrate; Transplant nursery-grown corals onto artificial substrate; Transplant wild-grown corals onto natural substrate; and Transplant wild-grown corals onto artificial substrate.

^{Dizon R.M. Edwards A.J. & Gomez E.D. (2008) Comparison of three types of adhesives in attaching coral transplants to clam shell substrates. Aquatic Conservation: Marine and Freshwater Ecosystems 18 1140-1148. https://doi.org/10.1002/aqc.944}

Study locations

Key messages

Three studies evaluated the effects of using different material to attach transplanted coral fragments to the substrate. One study was in the Phillipines, one in the British Virgin Islands, and one in the USA.

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (3 STUDIES)

Survival (3 studies): One replicated study in the Philippines found that using marine epoxy or epoxy resin to attach transplanted coral fragments to the substrate resulted in a lower detachment rate and a shorter time to self-attachment compared to using cyanoacrylate glue (superglue). One replicated controlled study in the British Virgin Islands found that attaching transplanted fragments to the substrate using adhesive cable-ties or cement led to a higher survival rate compared to fragments left unattached although there was no difference between attachment methods. One replicated, controlled study in the USA found no difference in survival between coral fragments attached using cement, epoxy, or cable ties and nails.
Condition (1 studies): One replicated controlled study in the British Virgin Islands found that using adhesive cable-ties or cement to attach transplanted fragments to the substrate led to a higher increase in live tissue growth compared to unattached fragments although there was no difference between attachment methods.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A replicated study in 2005 at three sites on a coral reef near Bolinao, north-western Philippines (Dizon et al. 2008) found that using marine epoxy or epoxy putty to attach wild-grown coral nubbins (small fragments) to the natural substrate resulted in fewer nubbins becoming detached and a shorter time for nubbins to self-attach (naturally grow onto the substrate) than those attached using cyanoacrylate glue (superglue), but no difference in survival or the number of nubbins that self-attached. Detachment rates after five months were significantly lower for nubbins attached using marine epoxy (4/180) or epoxy putty (15/180) than those attached using cyanoacrylate glue (43/180). In addition, the time taken for nubbins to self-attach to the substrate was significantly shorter for marine epoxy (2.4 months) and epoxy putty (1.9 months) than for cyanoacrylate glue (2.9 months). The number of nubbins that self-attached did not differ significantly between adhesives (marine epoxy: 76, epoxy putty: 87, cyanoacrylate glue: 62). Similarly, survival rates did not vary between adhesive types (marine epoxy: 93, epoxy putty: 101, cyanoacrylate glue: 116). In June 2005 and August 2005, a total of 540 nubbins (fragments 2-3 cm in length) were collected from wild-grown colonies of 11 stony and one non-stony coral species at two donor sites. Substrates were created using 15 giant clam Tridacna gigas half-shells deployed at each of three sites at a depth of 2–4 m. Twelve nubbins (one/species – see original paper) were attached to each shell using one of the three adhesives (total 180 nubbins/adhesive). Five shells/adhesive type were deployed at each of three sites (15 shells/site). Monitoring took place every two weeks for five months (dates not given).
Study and other actions tested
Referenced paper
Dizon R.M., Edwards A.J. & Gomez E.D. (2008) Comparison of three types of adhesives in attaching coral transplants to clam shell substrates. Aquatic Conservation: Marine and Freshwater Ecosystems, 18, 1140-1148.
A replicated, controlled study in 2007–2009 at coral reef sites near Guana Island, British Virgin Islands (Forrester et al. 2011), found that attaching transplanted storm-generated fragments of elkhorn Acropora palmata coral using adhesive, cable-ties or cement led to higher survival and increase in live tissue growth compared to unattached fragments, but there was no difference between attachment methods. After one year, survival of re-attached fragments was higher (2007: 56%; 2008: 62%) compared to unattached fragments (2007: 3%; 2008: 12%). However, there was no difference in survival for fragments re-attached in 2007 (data not reported) or 2008 using different attachment methods (cable-ties: 56%; Z-spar epoxy: 50%; PC marine epoxy: 44%; cement: 66%). In addition, there was no significant difference in percentage increase in live tissue coverage between attachment types in 2007 (cable tie: 444%; Z-spar epoxy: 298%) or 2008 (cable tie: 153%; Z-spar epoxy: 83%; PC marine epoxy: 114%; cement: 97%). In July–August 2007 and 2008, eighty-six (2007) and 280 (2008) storm-generated fragments of elkhorn coral were collected from coral reefs. These were re-attached to the substrate (ensuring live tissue was in contact with the attachment surface) using cable ties (2007: 29 fragments; 2008: 103 fragments), Z-spar epoxy resin (2007: 28 fragments; 2008: 58 fragments), PC Marine Epoxy Putty (2008: 36 fragments), or cement (2008: 40 fragments), or left unattached at the collection site (2007: 29 fragments; 2008: 43 fragments). Survival was recorded after one year and growth measured after two and 12 months using scaled photographs.
Study and other actions tested
Referenced paper
Forrester G.E., O'Connell-Rodwell C., Baily P., Forrester L.M., Giovannini S., Harmon L., Karis R., Krumholz J., Rodwell T. & Jarecki L. (2011) Evaluating methods for transplanting endangered Elkhorn Corals in the Virgin Islands. Restoration Ecology, 19, 299-306.
A replicated, controlled study at a coral reef restoration site off Florida, USA (Unsworth et al. 2021) found that attaching staghorn coral Acropora cervicornis fragments to natural substrate using a range of concrete mixtures or epoxy resulted in similar survival compared to when nails and cable ties were used. Transplants using a range of cement mixes or epoxy found average tissue mortality of 2% (cement) or 0% (epoxy) after eight days, with no additional mortality after one month and recovery after five months. Comparisons of the best performing cement and nails and cable ties found similar tissue mortality across all methods (0–27% partial mortality, 0–13% full mortality). Divers were able to transplant around 11 corals/dive using cement compared to six corals/dive using nails and cable ties (result was not tested for statistical significance). A total of 225 coral fragments were used to compare cement mixes and epoxy. Five bases (8–10 cm diameter) were deployed for each mix, and three fragments were placed in each base. Survival was assessed after 8 days and then again at one and five months. A further 50 fragments were used to compare the best performing cement with the nail and cable tie method (25 fragments/method) and coral survival was assessed after one and four months. Costs Transplanting nursery grown coral in 2019 cost $0.05/coral when using cement, $0.47 when using epoxy and $0.50 using the nail and cable tie method. Costs included materials only and did not include any shipping costs for materials.
Study and other actions tested
Referenced paper
Unsworth J.D., Hesley D., D'Alessandro M. & Lirman D. (2021) Outplanting optimized: Developing a more efficient coral attachment technique using Portland cement. Restoration Ecology, 29, e13299.

Please cite as:

Thornton A., Morgan, W.H., Bladon E.K., Smith R.K. & Sutherland W.J. (2024) Coral Conservation: Global evidence for the effects of actions. Conservation Evidence Series Synopsis. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Coral Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Transplant wild-grown coral onto artificial substrate Action Link	Awaiting assessment	24	Synopsis Link
Transplant nursery-grown coral onto natural substrate Action Link	Awaiting assessment	22	Synopsis Link
Transplant nursery-grown coral fragments onto artificial substrate Action Link	Awaiting assessment	15	Synopsis Link