Cultivate coral fragments in an artificial nursery located in a natural habitat
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Overall effectiveness category Awaiting assessment
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Number of studies: 27
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Supporting evidence from individual studies
A controlled, before-and-after study in 1994–1995 in an artificial nursery on a coral reef in Pangasinan, Philippines (Yap et al. 1998) found that cultivating stony coral Porites cylindrica and Porites rus fragments on grids at 1 m depth led to lower survival but higher monthly mass increase than those cultivated at 10 m depth, and small fragments had a greater proportional mass increase than large fragments but similar survival. Average mass/month gained over 16 months was higher for fragments cultivated at 1 m depth (average g/30 days: small Porites cylindrica 0–5, small Porites rus 4–8, large Porites cylindrica 0–16, large Porites rus 17–24) than fragments cultivated at 10 m depth (average g/30 days: small Porites cylindrica 2–3, small Porites rus 3–6, large Porites cylindrica 0–7, large Porites rus 0–9). Small coral fragments gained less mass than large ones (average g/30 days: small Porites cylindrica 0–5, large Porites cylindrica 0–16; small Porites rus 3–8, large Porites rus 0–24), but had a greater percentage increase in mass (average %/30 days: small Porites cylindrica 0–21%, large Porites cylindrica 0–13%; small Porites rus 6–19%, large Porites rus 0–12%). Survival was lower for fragments transplanted at 1 m (6 months 67–93%, 12 months 47–86%, 16 months 0–40%) than 10 m (6 months 93–100%, 12 months 94–100%, 16 months 0–34%). There was no effect of size on survival. In July 1994, small (average weight: Porites cylindrica 19–22 g; Porites rus 37–44 g) and large (average weight: Porites cylindrica 118–168 g; Porites rus 185–203 g) wild-grown fragments of Porites cylindrica and Porites rus were stuck with superglue to Plexiglass plates. Plates were attached with plastic-coated copper wire to steel grids (5 cm mesh) raised 20 cm above the substrate at 1 m or 10 m depth (fifteen fragments/species/size/depth). From August 1994–November 1995, survival of fragments was surveyed every month, and fragments were weighed in the laboratory every two months.
Study and other actions testedA replicated study (years not given) at five artificial coral nurseries in sheltered back reefs in Puerto Rico (Bowden-Kerby 2001) found that fragments of staghorn corals Acropora cervicornis and Acropora prolifera cultivated on wire frames increased in size and grew new branches, and growth of Acropora cervicornis fragments over the frames was greater for those collected from the reef front than from the sheltered back reef. After one year, fragments of staghorn corals cultivated on wire frames increased in size (relative growth: Acropora cervicornis = 17–25 × original length; Acropora prolifera = 29–38 × original length), grew new branches (total length of new branches: Acropora cervicornis = 221–282 cm; Acropora prolifera = 349–494 cm), and grew over the frames (total of all overgrowths: Acropora cervicornis = 11–31 cm; Acropora prolifera = 13–34 cm). For Acropora cervicornis, fragments collected at the reef front had greater average overgrowth (13 cm) than those collected at the sheltered back reef (8 cm). At each of five sites, for each of four staghorn coral varieties (Acropora cervicornis and Acropora prolifera collected from reef front and back reef sites), 10–12 fragments (8–12 cm long) were attached to weighted ‘A-shaped’ wire mesh frames (1-m long, 25-cm high, 2.5 × 5 cm PVC-coated mesh), 5–10 cm above sandy substrate. Surviving fragments, new branches and overgrowth were measured after one year.
Study and other actions testedA replicated study (years not given) at four artificial coral nurseries in sheltered back reefs in Puerto Rico (Bowden-Kerby 2001) reported that cultivating staghorn coral Acropora cervicornis and Acropora prolifera fragments of 15–22 cm or 8–12 cm led to lower mortality compared to fragments of 3–5 cm. Results were not tested for statistical significance. After six months, mortality rates of 15–22 cm and 8–12 cm fragments were 25% and 4–22% for Acropora cervicornis, respectively, and 25% and 2–4% for Acropora prolifera, whereas mortality rates of 3–5 cm fragments were 32–44% for Acropora cervicornis and 32% for Acropora prolifera. At each of four sites, and for each of three coral varieties (Acropora cervicornis collected from back reef and reef front sites, Acropora prolifera collected from back reef), 10 fragments of each of three sizes (3–5, 8–12 and 15–22 cm) were attached to 5–6 m fishing lines using cable ties, spaced 10–30 cm apart. Lines were secured at one end to metal stakes randomly placed in a sheltered area of coral rubble substrate. Mortality was recorded for each fragment after six months.
Study and other actions testedA replicated study (years not given) at four artificial coral nurseries in sheltered back reefs in Puerto Rico (Bowden-Kerby 2001) found that cultivating younger fragments of staghorn corals Acropora cervicornis and Acropora prolifera led to lower mortality compared to when older fragments were cultivated. After six months, overall mortality rates were lower for younger coral fragments collected from outer branches of colonies (17%) compared to older fragments collected from >10–15 cm below the apex (0–10%). The same was true when older fragments collected from >20–25 cm below the apex (30–50%) were compared to younger fragments collected from outer branches (0–10%). At each of four reef sites, for each of three coral varieties (Acropora cervicornis collected from back reef and reef front sites, Acropora prolifera collected from back reef), 10 × 8–12 cm fragments of each of two relative ages (younger fragments collected from outer branches, older fragments collected from >10–15 cm below the apex) were attached to 5–6 m fishing lines using cable ties. Three additional lines had 10 Acropora cervicornis fragments collected from >20–25 cm below the apex and 10 younger fragments collected from outer branches. Lines were secured at one end to metal stakes randomly placed in a sheltered area of coral rubble substrate. Mortality was recorded for each fragment after six months.
Study and other actions testedA replicated study (years not given) at four artificial coral nurseries in sheltered back reefs in Puerto Rico (Bowden-Kerby 2001) found that cultivating fragments of staghorn corals Acropora cervicornis and Acropora prolifera on wire frames or coral rubble led to greater survival than fragments placed directly on sand, and fragments on frames suspended above the sand had greater growth than those in contact with sand. After six months, no coral fragments placed directly on sand survived, whereas 15–30% of fragments placed on coral rubble survived, and 1–49% of fragments on wire frames survived. After one year, relative growth (length gained as a proportion of original length) was greater for fragments suspended on frames 5–10 cm above the sand (12–22 × original length) than for those with their bases in contact with sand (7–17 × original length; difference not statistically tested). At each of four sites, for each of 3–4 staghorn coral varieties (Acropora cervicornis and Acropora prolifera collected from back reef and reef front sites), 10–12 fragments (8–12 cm long) were either scattered directly on sand, supported on weighted ‘A-shaped’ wire mesh frames (1-m long, 25-cm high, 2.5 × 5 cm PVC-coated mesh) with 0.5–1 cm of fragment bases covered with sand, supported on wire mesh frames 5–10 cm above the sand, or scattered directly on coral rubble. Mortality of each fragment was recorded after six months. Relative growth was recorded for the three largest fragments/treatment/frame after one year.
Study and other actions testedA replicated study in 1998–1999 at three reef sites in La Paraguera, Puerto Rico (Ortiz-Prosper et al. 2001) found no difference in survival between fragments of stony coral transplanted onto artificial reef structures compared to fragments attached to dead coral. After 12 months, overall survival was 90%. There was no difference in survival between structures with 42/45 fragments (93%) surviving on the artificial structure and 20/23 (85%) on the dead coral. In addition, after 12 months, corals on the artificial structure had grown <0.5 cm (data not analysed). In March 1998, three Bay Ball artificial reef structures were constructed with holes (9 cm diameter) over the surface of the ball (see paper for details). Small fragments (< 20 cm diameter) of several species of stony coral (Diplora spp., Montastraea spp., Colpophyllia spp., and Siderastrea siderea) were collected from shallow (<0.5 m) reefs near the survey site. Most fragments were found unattached on the sea bed. Fragments were attached to the Bay Balls and dead coral heads using underwater cement. Bay Balls™ were deployed 3 – 5 m deep on sandy substrate at Enrique Reef (east and west) and Mario Reef. Dead coral heads were located in Enrique and Mario Reefs. Survival was recorded 12 months after Bay Balls were installed.
Study and other actions testedA randomized, replicated study in 1996–1998 at a reef and an ex-situ marine laboratory in Bolinao, Philippines (Yap & Molina 2003) found that cultivating stony coral Porites cylindrica and Porites rus fragments in an artificial nursery in a natural habitat led to a higher survival rate and, for Porites cylindrica, a higher rate of growth than fragments cultivated in an ex-situ nursery. After nineteen months, survival rate was higher for fragments in the artificial nursery in natural habitat (P. cylindrica: 44%; P. rus: 42%) than ex-situ (P. cylindrica: 12%; P. rus: 0.5%). Average growth rate was higher for artificial, natural habitat nursery (0.8–3.75 g/30 days) than ex-situ P. cylindrica fragments (0.17–0.76 g/30 days). There was no statistical difference in growth rate for P. rus (natural habitat nursery: 3.5–8.5 g/30 days; ex-situ: 1.6–5.2). Actual growth was higher for natural habitat nursery than ex-situ fragments of both species (P. cylindrica: natural habitat nursery 78 g, ex-situ 18 g; P. rus: natural habitat nursery 165 g, ex-situ 80 g). In November 1996, sixty fragments each of P. cylindrica and P. rus were collected from wild colonies and transported to an ex-situ marine laboratory, trimmed, and attached to acrylic plates using cyanoacrylate glue (superglue). Thirty fragments from each species were combined and taken to a sandy lagoon. Fragments were distributed evenly across six 1 m2 steel grids, 20 cm above the seabed. The remaining sixty fragments were similarly mixed and placed on plastic grids, but in one of three seawater-filled plastic tanks in the laboratory. Fragments were cleared of all fouling organisms and mortality was recorded every two weeks. Growth was measured every two months then extrapolated to determine growth/30 days.
Study and other actions testedA replicated, paired study in 1996–1998 at an artificial coral nursery on sandy substrate near Henchun, southern Taiwan (Soong & Chen 2003) found that cultivating fragments of wild grown branching stony coral Acropora pulchra cut from below the final branching point led to fragments developing new branches sooner and having increased skeletal growth compared to fragments cut from above the final branching point. Three months after being attached to the nursery frame, there were more below-final-branch cut fragments showing new branch growth (16/19) compared to above-final-branch cut fragments (6/19), however there was no difference after four months (below: 18/18, above: 17/18). Average skeletal growth was greater for below-final-branch cut fragments after two months (0.75 cm) and three months (1.03 cm) compared to above-final-branch cut fragments (two months: 0.46 cm, three months: 0.82 cm). In 1996–1998, twenty branches of healthy branching stony coral were collected from the wild. Two 4 cm length fragments were cut from each branch – one from below and one from above the final branching point. Fragments were tied to a rack and suspended vertically 30 cm above the sea floor 6 m deep. New branch growth was counted after three and four months. Skeletal growth (cm/30 days) was measured one, two and three months after fragments were attached to the rack (months and years not provided).
Study and other actions testedA replicated study in 1996–1998 at an artificial coral nursery on sandy substrate near Henchun, Taiwan (Soong & Chen 2003) found that cultivating wild-grown stony coral Acropora pulchra fragments of 7 cm or 4 cm led to greater new branch growth and skeletal growth compared to fragments of 1 cm. Although there was no difference after three months in the number of fragments with new branch growth between 7cm (8/20), 4 cm (6/19) and 1 cm (3/17) fragments, after four months the number of 7cm (18/20) and 4cm (17/19) fragments with new branch growth was higher than for 1 cm fragments (8/17). Skeletal growth was higher for 7 cm (0.99 cm) compared to 4 cm (0.76 cm) and 1 cm fragments (0.23 cm) and greater for 4 cm compared to 1 cm fragments. In 1996–1998, sixty fragments (20 each of 7 cm, 4 cm, and 1 cm length) taken from branches of healthy stony coral were tied to a rack and suspended vertically 30 cm above the sea floor 6 m deep. New branch growth was counted after three and four months. Skeletal growth (cm/30 days and cm/30 days/cm fragment) was measured three months after fragments were attached to the rack (months and years not given).
Study and other actions testedA replicated study in 1996–1998 at an artificial coral nursery on sandy substrate near Henchun, Taiwan (Soong & Chen 2003) found that cultivating fragments of wild grown stony coral Acropora pulchra when 6cm fragments were divided into two 3 cm lengths led to greater skeletal growth compared to when they were left intact. Average skeletal growth was greater for the combined growth of each pair of 3 cm fragments after two (1.6 cm) and three months (2.2 cm) compared to single 6 cm fragments (two months: 1.3 cm, three months: 1.4 cm). There was no difference after one month (combined 3 cm fragments: 0.8 cm; 6 cm fragments: 0.9 cm). In 1996–1998, twenty-nine 6 cm long fragments were taken from branches of healthy stony coral. Fifteen were kept intact and 14 were divided into two 3 cm lengths. All fragments were tied to a rack and suspended vertically 30 cm above the sea floor 6 m deep. Skeletal growth (cm/30 days) was measured one, two and three months after fragments were attached to the rack (months and years not given)
Study and other actions testedA replicated study in 1996–1998 at an artificial coral nursery on sandy substrate near Henchun, southern Taiwan (Soong & Chen 2003) found that cultivating fragments of wild grown stony coral Acropora pulchra at 5 m deep led to more new branch development and greater skeletal growth compared to fragments cultivated at 10 m. After four months, new branch growth was recorded on more fragments at 5 m (18/20) compared to fragments at 10 m (8/17), although there was no difference after three months (5 m: 9/20, 10 m: 3/17). After two and three months, average skeletal growth was higher for fragments at 5 m (two months: 0.6 cm, three months: 0.9 cm) compared to fragments at 10 m (two months: 0.3 cm, three months: 0.5 cm), although there was no difference after one month (5 m: 0.02 cm, 10 m: 0.04 cm). In 1996–1998, thirty-seven 4 cm long fragments cut from branches of healthy stony coral were tied to racks and suspended vertically 30 cm above the sea floor. One rack (20 fragments) was placed at 5 m deep and one rack (17 fragments) at 10 m. New branch growth was recorded after three and four months. Skeletal growth rate (cm/30 days) was measured one, two and three months after fragments were attached to the rack (months and years not given).
Study and other actions testedA replicated study in 1996–1998 at an artificial coral nursery on sandy substrate near Henchun, Taiwan (Soong & Chen 2003) found that the upward-pointing cut-end of fragments of wild grown stony coral Acropora pulchra cultivated in an artificial nursery developed more new branches compared to downward-pointing cut ends regardless of their original orientation on the donor colony, but there was no difference in skeletal growth. New branch growth was recorded on 16/29 upward pointing ends compared to 3/29 downward pointing ends. There was no difference in skeletal growth between upward and downward pointing ends (data not reported). In 1996–1998, twenty-nine 4 cm long fragments were cut from branches of healthy stony coral and the end tip cut off to create two cut ends on each fragment. Fragments were tied to a rack (15 with original end tip pointing up and 14 with original end tip pointing down) and suspended vertically 30 cm above the sea floor 6 m deep. Skeletal growth (cm/30 days) was measured, and new branch growth was recorded four months after fragments were attached to the rack (months and years not given).
Study and other actions testedA replicated study in 1996–1998 at an artificial coral nursery on sandy substrate near Henchun, Taiwan (Soong & Chen 2003) found that suspending fragments of wild grown stony coral Acropora pulchra horizontally resulted in skeletal growth and new branch growth. After four months, average skeletal growth from the two cut ends was 0.77 cm/30 days (range 0.48–1.03 cm/30 days) and 0.42 cm/ 30 days (range 0–1.08 cm/30 days). New branch growth was also recorded (data not provided). In 1996–1998, twenty 6 cm fragments of stony coral were cut from wild colonies. Fragments were suspended 30 cm above the seabed from iron and plastic racks 6 m deep. Skeletal growth (cm/30 days) was measured, and new branch growth was recorded four months after fragments were attached to the rack (months and years not given).
Study and other actions testedA replicated study in 1996–1998 at an artificial coral nursery on sandy substrate near Henchun, southern Taiwan (Soong & Chen 2003) found that cultivating damaged fragments of wild grown stony coral Acropora pulchra led to more new branch growth from the middle of the fragment, but slower new branch growth from the ends and less skeletal growth compared to undamaged fragments. After three months, more damaged fragments showed new branch growth from the middle of the fragment (7/13) compared to undamaged fragments (1/15), although there was no difference after two months (damaged: 5/13, undamaged: 1/15). After two months, none of the 13 damaged fragments showed new branch growth from the cut end compared to 9/15 undamaged. There was no difference after three months (damaged: 4/13, undamaged: 9/15). After one, two and three months, skeletal growth was less for damaged fragments (one month: 0.3 cm, two months: 0.7 cm, three months: 0.8 cm), compared to undamaged (one month: 0.8 cm, two months: 1.3 cm, three months: 1.4 cm). In 1996–1998, twenty-eight 6 cm fragments were cut from branches of healthy stony coral. A 1 cm wide band of tissue was removed from the central section of 15 fragments and 13 fragments were left undamaged. All fragments were attached to a rack and suspended vertically 30 cm above the sea floor 6 m deep. New branch growth was recorded after two and three months. Skeletal growth (cm/30 days) was measured one, two and three months after the fragments were attached to the rack (months and years not given).
Study and other actions testedA replicated study in 1996–1998 at an artificial coral nursery on sandy substrate near Henchun, southern Taiwan (Soong & Chen 2003) found that when cultivating fragments of wild grown stony coral Acropora pulchra, clearing problematic algae from the nursery rack led to a higher survival rate for 1 cm, but not 6 cm fragments, and no difference in skeletal growth for 1 cm or 6 cm fragments, compared to fragments on racks where algae was not cleared. After four months, all seventeen 1 cm fragments survived when algal growth was regularly cleared from the nursery rack compared to 7/17 fragments where algae was not cleared. There was no difference in survival for 6 cm fragments (algae cleared: 18/18, algae not cleared: 19/20 survived). There was no difference in skeletal growth for 1 cm or 6 cm fragments where algal growth was cleared compared to where it was not cleared (data not reported). In 1996–1998, thirty-four 1 cm and thirty-eight 6 cm fragments were taken from branches of healthy stony coral. Seventeen 1 cm and eighteen 6 cm fragments were tied to a rack and suspended vertically on fishing line 30 cm above the sea floor 6 m deep. Each month, algae was removed from the line. The number of surviving coral fragments was recorded after four months. Skeletal growth (cm/30 days) was measured four months after fragments were attached to the rack (months and years not given).
Study and other actions testedA controlled study in 2005–2006 on two artificial coral nurseries in a lagoon in Pangasinan, the Philippines (Shaish et al. 2003) found that cultivated fragments of stony coral on suspended or fixed nursery structures all grew, and there was no difference in survival or detachment between fragments on different structures. After one year, there was no difference in survivorship or detachment for any species between suspended (average: survivorship: 91%; detachment: 5%) and fixed (average: survivorship: 85%; detachment: 5%) coral nurseries. On average, all species increased in size (branching species: height: 0.57–1%/day, width: 0.92–3.15%/day; non-branching species: surface area growth: 0.08–0.87%/day). See paper for details of individual species. In June–September 2005, two adjacent nurseries were constructed: a suspended nursery (seventy 60 × 80 cm plastic mesh trays on a PVC frame buoyed by floats and tethered at 0.5–1 m above the lagoon floor), and a fixed nursery (fifty 60 × 80 cm plastic mesh trays on a PVC frame attached to the floor on 1 m legs). Seventy wild-grown fragments of Merulina scabricula, Montipora digitata, Echinopora lamellosa and Pocillopora damicornis were transplanted in both nurseries, and 70 Acropora formosa, Porites rus and Montipora aequituberculata were transplanted only in the suspended nursery. Fragments were glued with cyanoacrylate glue (superglue) to plastic tubing inserted into the mesh trays or directly onto the mesh. Monitoring was carried out for one year with fragments monitored fortnightly for survival and 10 fragments/tray photographed monthly to monitor growth. Construction materials cost $1,645 (2005 value) and the project used 2,610 person-hours (including time spent constructing the nurseries and preparing and attaching fragments).
Study and other actions testedA replicated study in 2006 at an artificial coral nursery in a natural habitat near a fish farm in Eilat, Israel (Shafir et al. 2009) found that stony coral Stylophora pistillata fragments cultivated on frames painted with anti-fouling paint had similar survival rates to those on unpainted frames, but survival was lower when pins or pinheads that corals were attached to were also painted. After four months, average survival rates were similar for coral fragments cultivated on frames painted with anti-fouling paint (83% survived, 13% detached, 4% died) and unpainted frames (85% survived, 14% detached, 1% died). Survival rates were lower when paint was also applied to pins (62% survived, 8% detached, 29% died) or pinheads (11% survived, 58% detached, 31% died) which the fragments were attached to. Cleaning time was reduced by 90% for corals on painted frames (2 min/10 coral tips) compared to unpainted frames (5 min/10 coral tips plus 15 min to clean nets). Corals on painted pins/pinheads did not require cleaning. In April 2006, four treatments were each applied to 12 PVC frames (30 × 50 cm) containing plastic nets (0.25 cm2 mesh) and pins (9-cm long, 2-cm diameter head): paint applied to entire frame and pins; paint applied to frame and pins but scraped off pinheads; paint applied to frame only; no paint applied. Two coats of anti-fouling paint (Aqua-guard M250) were used. Coral fragments were glued onto pins (60 fragments/frame). Frames were suspended at a depth of 8 m, approximately 10 m from a fish cage. After 126 days, surviving, detached and dead coral fragments were counted. Surviving corals were cleaned following protocols regularly used during coral nursery maintenance or before transplantation.
Study and other actions testedA replicated study in 2015 at an artificial offshore coral nursery in a natural habitat near Looe Key, Florida, USA (Lirman et al. 2010) found that cultivating nursery-grown fragments of staghorn coral Acropora cervicornis by suspending them on lines resulted in greater linear growth but lower skeletal density compared to fragments cultivated on blocks attached to the seabed, but there was no difference in buoyant weight. After six months, average length was greater for line-suspended (15 cm) compared to block-attached fragments (10 cm). Skeletal density was lower for line-suspended (0.05 g cm3) compared to block-attached fragments (0.10 g cm3). There was no difference in buoyant weight (line-suspended: 15.2 mg/day, block-attached: 16.3 mg/day). Six months after the fragments were attached (6th October), fragments were completely bleached (but still living) following a bleaching event in summer but three weeks later (28th October) all fragments were dead. In April 2015, twenty-one stony coral branch tips (average length 6.8 cm) were collected from nursery-grown colonies on site. Nine fragments were suspended using fishing line from a PVC ‘tree’ attached to the seabed 6.4 m deep. Twelve fragments were attached to PVC discs using epoxy putty and bolted onto a PVC pipe attached to a cement block placed on the seabed 7.9 m deep. Average linear growth (cm/day), skeletal density (mg/day) and buoyant weight (mg/day) were calculated on 30 October 2015.
Study and other actions testedA replicated study in 2005–2006 at an artificial nursery off Silaqui Island, Phillipines, (Guest et al. 2011) found that cultivating fragments of wild-grown stony and blue coral on giant clam shells attached to a pvc frame resulted in variations in attachment time and survival rates depending on species and fragment size. Acropora muricata fragments were quickest to attach to the substrate (average time: large fragments 31 days, small fragments 39 days) and Echinopora lamellosa fragments were slowest (average time: large >250 days, small 167 days). Survival rate after seven months was lowest for Acropora muricata (80 – 88%) compared to 100% for Heliopora coerulea, Montipora digitata, Hydnophora rigida, Porites cylindrica, Porites rus, Pocillopora damicornis. In December 2005–January 2006, fifty small (average diameter 27 mm) and 50 large (average diameter 60 mm) fragments of 10 stony (see paper for full list) and one blue Heliopora coerulea coral were collected from reefs near the study site. Fragments (one/species) were attached to giant clam Tridacna gigas shells (small: 11 fragments/shell, large: 11 fragments/two shells) using epoxy clay. Shells were fixed to a pvc frame 0.5 m above the seabed 2.9–3.4 m deep at five sites 50–220 m apart. Attachment (measured as the percentage of coral tissue attached to the substrate or the number of secondary attachment points) was recorded after one month then every two weeks for seven months.
Study and other actions testedA replicated study in 2007 at an artificialnursery off Silaqui Island, Phillipines, (Guest et al. 2011) found that cultivating fragments of wild-grown stony corals Acropora huacinthus and Acropora digitifera on on giant clam shells attached to a pvc frame led to a faster attachment time than cultivated fragments of Acropora muricata. After seven days, fragments of Acropora huacinthus and Acropora digitifera had started attaching to the substrate whereas Acropora muricata took 10 days. More than 50% of Acropora huacinthus and Acropora digitifera fragments had fully attached to the substrate after 16 days compared to 24 days for Acropora muricata fragments. After 34 days, all Acropora huacinthus and Acropora digitifera fragments had fully attached to the substrate compared to 35/50 (70%) of Acropora muricata fragments. In April 2007, 50 fragments (average diameter 34 mm) were taken from 25 colonies each of Acropora huancinthus, Acropora digitifera, and Acropora muricata (two fragments/colony). Fragments were attached to 50 empty giant clam Tridacna gigas shells (one fragment from each species/shell) using epoxy clay. Shells were fixed to a pvc frame 0.5 m above the seabed 2.9–3.4 m deep at five sites 50–220 m apart (10 shells/site). Attachment (% of fragment attached and the time taken for fragments to fully attach) was recorded every 3 or 4 days for 34 days.
Study and other actions testedA replicated study (year not given) at an in-situ coral nursery in a natural habitat in Florida, USA (Lohr & Patterson 2017), found that transplanting nursery-grown fragments of staghorn coral Acropora cervicornis of different genotypes (genetic makeup) led to differences in buoyant weight, linear growth, and number of branches between some fragments. Thirteen months after transplanting, net buoyant weight of fragments was higher for genotypes U41 (74 g), K2 (72 g) and U73 (69 g) than for U25 (33 g). Growth (total linear extension) was greater for U41 (133 cm), K2 (124 cm) and U73 (117 cm) compared to U25 (43 cm). There were no other significant differences in buoyant weight or growth between fragments. The number of branches recorded after 291 days ranged from 8–30/fragment and average number of branches/fragment varied between genotypes (numbers not reported). Ten known genotypes (K1, K2, K3, U25, U41, U44, U47, U73, U77, U78) of staghorn coral were selected. Four non-branched tips (~5 cm) were clipped from each of three colonies/genotype (12 fragments/genotype). Fragments were each weighed and randomly suspended from one of four PVC tree structures using monofilament and aluminium crimps. Tree structures were placed on the sea floor. Buoyant weight was recorded at the start then at days 122 and 390 (the end of the experiment). Linear growth and number of branches were recorded at the start and every 45 days.
Study and other actions testedA replicated study in 2014–2015 at an in-situ nursery in a natural habitat in Florida, USA (O'Donnell et al. 2017) found that cultivating nursery-grown fragments of staghorn Acropora cervicornis coral by suspending them from tree structures led to fragments growing longer, a later onset of bleaching and fewer breakages, but a lower survival rate than fragments attached to concrete blocks. After one year, linear growth of tree-cultivated fragments was higher (238 mm) than block-cultivated (110 mm). Bleaching was first observed on tree-cultivated fragments later (278 days) than block-cultivated (246 days). None of the tree-cultivated fragments broke compared to 19% of block-cultivated fragments. However, tree-cultivated fragments did not survive as long (297 days) as block-cultivated (305 days). In December 2014, two hundred and forty staghorn fragments from four genetically different colonies were collected (wild- or nursery-grown not specified). One hundred and twenty fragments were attached to individual cement disks using epoxy. Disks were attached to PVC pipes placed in groups of 10 vertically in concrete bases, on the seabed 8 m deep. The remaining 120 fragments were suspended from branches of a tree-structure (material not specified), 4–6 m deep. Monitoring was carried out monthly for one year. Growth (total linear extension) was measured for each fragment (colony) and evidence of disease or bleaching, and any breakages were recorded.
Study and other actions testedA review of six restoration projects established in 2007–2010 at locations in natural habitats in Florida and Puerto Rico, USA, (Schopmeyer et al. 2017), reported that most staghorn coral Acropora cervicornis fragments cultivated in an artificial nursery in a natural habitat survived and grew, and fragments attached to floating arrays had a higher growth rate than those attached to concrete blocks. After 1–2 years, the average survival for nursery-cultivated fragments was 91% (85–96%). Growth was higher for fragments on floating arrays (53 cm/year) compared to fragments on concrete blocks (average 18 cm/year, range: 11–30 cm/year). This paper presents survival and growth results from six projects cultivating staghorn coral fragments. Wild-growing staghorn coral colonies (>25 cm diameter) were selected and 3–4 branches or ≤10% of the colony were taken. Branches were broken into smaller fragments and attached to concrete blocks on the substrate (5/6 projects) or floating underwater arrays (1/6 projects). Survival (including fragments with partial tissue loss) was determined by counting the number of fragments with some live tissue. Growth (total linear extension) was measured using a flexible ruler. Fragments were monitored for 1–2 years.
Study and other actions testedA replicated study in 2015 at an artificial offshore coral nursery in a natural habitat near Looe Key, Florida, USA (Kuffner et al. 2017) found that cultivating nursery-grown staghorn coral Acropora cervicornis fragments by suspending them on lines resulted in greater linear growth but lower skeletal density compared to fragments cultivated on blocks attached to the seabed, but there was no difference in buoyant weight. After six months, average length was greater for line-suspended (15 cm) compared to block-attached fragments (10 cm). Skeletal density was lower for line-suspended (0.05 g cm3) compared to block-attached fragments (0.10 g cm3). There was no difference in buoyant weight (line-suspended: 15.2 mg/day, block-attached: 16.3 mg/day). By 6th October (six months after the fragments were attached), fragments were completely bleached (but still living) following a bleaching event in summer but by 28 October all fragments were dead. In April 2015, twenty-one stony coral branch tips (average length 6.8 cm) were collected from nursery-grown colonies on site. Nine fragments were suspended using fishing line from a PVC ‘tree’ attached to the seabed 6.4 m deep. Twelve fragments were attached to PVC discs using epoxy putty and bolted onto a PVC pipe attached to a cement block placed on the seabed 7.9 m deep. Six months later, average linear growth (cm/day), skeletal density (mg/day) and buoyant weight (mg/day) were calculated.
Study and other actions testedA study in 2015 and 2016 at an artificial coral nursery in a natural habitat in the Dominican Republic (Calle-Triviño et al. 2018) reported that most nursery-grown colonies of staghorn coral Acropora cervicornis spawned. In both years, 6–7 days after the full moon, approximately 80% of 500 staghorn coral colonies released egg/sperm bundles. The nursery (a 150 m2 area, 12.5 m deep) was established in 2011 and consisted of 25 structures, including ropes, frames, domes and tables. Spawning was observed on two field trips in September 2015 and August 2016.
Study and other actions testedA replicated study in 2011–2012 using an artificial line-nursery on sandy substrate off Fort Lauderdale, Florida, USA (Goergen et al. 2018) found that cultivating fragments of nursery-grown staghorn coral Acropora cervicornis by suspending them from a horizontal line led to higher survival, lower partial mortality, higher rates of self-attachment (fragment growing onto the substrate), greater linear growth, and greater new branch growth (>5 cm), compared to fragments fixed directly to vertical lines. After three months, self-attachment was higher for suspended (97%) compared to vertical fragments (79%). After 12 months, survival was higher for suspended (100%) compared to vertical fragments (43%). Average partial mortality/month was lower for suspended (1%–3%) than vertical fragments (3%–38%). Also, average linear growth was greater for suspended (61 cm) than vertical (10 cm) fragments and the average number of new branches >5 cm was higher for suspended (7.1) than vertical (0.3) fragments. In 2011, six H-shaped line-nurseries comprising one 2 m horizontal line 1 m above the seabed and two 1 m fixed vertical lines that were anchored to the seabed 7 m deep. Each frame contained 24 nursery-grown staghorn coral fragments >5 cm, twelve suspended from the horizontal line using rope, and six fixed to each vertical line. Live fragments, partial mortality (% live tissue), self-attachment (fragment grown over attachment wire), linear growth (cm/month) and number of new branches >5 cm were recorded monthly from January 2011–January 2012.
Study and other actions testedA replicated, randomized, controlled study in 2013–2014 at an artificial nursery in a natural habitat and natural reef site near Guana Island, British Virgin Islands (Forrester et al. 2019), found no difference in survival or growth between wild-grown staghorn coral Acropora cervicornis fragments cultivated in an in-situ nursery in a natural habitat before transplanting or transplanted directly onto the reef, but both had higher survival and growth than fragments placed unattached on the reef. After 15 months, there was no significant difference in survival between nursery-cultivated-then-attached fragments (49%) and directly-attached (58%) but both had higher survival than unattached fragments (7%). Growth was not significantly different between nursery-cultivated fragments (42 cm) and directly-attached (78 cm) but both were higher than unattached (28 cm). In August 2013, loose fragments of staghorn coral (780) were collected from two reefs, measured and randomly assigned to one of three treatments: nursery-cultivated-then-attached (291); directly-attached (306); unattached (183). Nursery-cultivated fragments were tied 25 cm apart to one of seven PVC-frame line-nurseries 5–7 m deep. Direct-transplanted fragments were attached to the substrate using cable ties, and unattached fragments were placed loose on the reef substrate. After three months, nursery-cultivated fragments were transplanted and attached to the reef using cable ties. The length of all live branches was recorded for each fragment using scaled photographs. Survival and growth were monitored after 12, 24, and 64 weeks. Costs: number of survivors and growth/US$ (including e.g. cable ties, and nursery-frame materials, excluding e.g. SCUBA and snorkel equipment). Nursery-cultivated 1.0 survivors, 1.8 cm growth/US$; direct transplant 3.3 survivors, 9.2 cm growth/US$.
Study and other actions tested
Where has this evidence come from?
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This Action forms part of the Action Synopsis:
Coral ConservationRelated Actions
| Actions | Effectiveness | Studies | Category | |
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Limit, cease or prohibit use of coral rock or live coral for building roads or infrastructure Action Link |
No evidence found (no assessment) | 0 |
Synopsis Link |
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Prohibit or limit the deposition or disposal of drill cuttings near coral reefs Action Link |
No evidence found (no assessment) | 0 |
Synopsis Link |
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Designate a Marine Protected Area and prohibit all types of fishing Action Link |
Awaiting assessment | 6 |
Synopsis Link |
Coral Conservation - Published 2024
Coral synopsis
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