Genome-wide SNP genotyping reveals hidden population structure of an acroporid species at a subtropical coral island: Implications for coral restoration

1. It is essential to consider genetic composition for both conventional coral restoration management and for initiating new interventions to counter the significant global decline in living corals. Population genetic structure at a fine spatial scale should be carefully evaluated before implementing strategies to achieve self-sustaining ecosystems via coral restoration.
2. This study investigated the population genetic structure of two acroporid species at Kume Island, Okinawa, Japan. There were 140 colonies of Acropora digitifera collected from seven study sites, and 81 colonies of Acropora tenuis from six sites. In total, 384 single nucleotide polymorphism (SNP) loci for A. digitifera and 470 SNPs for A. tenuis were obtained using a comparatively economical technique, Multiplexed ISSR Genotyping by sequencing.
3. Observed heterozygosity was significantly lower than expected heterozygosity at all SNP sites in both acroporid species, suggesting deficient genetic diversity possibly caused by past massive coral bleaching. Even though both species are broadcast spawners, the population structure was different in the two species. No detectable structure was evident in A. digitifera, but two distinct clades were found in A. tenuis. The genetic homogeneity of A. digitifera at Kume Island suggests that this species could be used as a focal species for active restoration in terms of genetic differentiation at this island. By contrast, A. tenuis unexpectedly included two distinct clades with little or no admixture within a small study area, possibly representing two reproductively isolated cryptic species. Thus, when using A. tenuis, it would be prudent to avoid disturbing the genetic composition of wild populations until this question is answered.

     

Leiopathes glaberrima millennial forest from SW Sardinia as nursery ground for the small spotted catshark Scyliorhinus canicula

1. Association between habitat structuring organisms and other species has great relevance for ecosystem‐based conservation measures.
2. Those occurring in temperate areas, particularly in the upper portion of the continental margin, are mostly unknown or not properly understood because of the difficulty to discriminate co‐occurrence and real functional linkages among species.
3. Deep water coral assemblages over the Carloforte Shoal (south‐west Sardinia; 180–210 m depth) were investigated using ROV surveys.
4. During the surveys, more than 740 egg‐capsules of the spotted catshark Scyliorhinus canicula, identified after hatching experiments in captivity, were found attached exclusively to colonies of the long‐living black coral Leiopathes glaberrima.
5. Although based on a spot finding, the results show that coral forests are not only hotspots of biodiversity, but can also serve as nursery grounds for S. canicula. The protection of these millennial coral forests is therefore to be considered a priority.

     

Ecological and genetic evidence of the vulnerability of shallow‐water populations of the stylasterid hydrocoral Errina novaezelandiae in New Zealand's fiords

• 1. Some of the key life history characteristics that make modular marine invertebrates such as corals vulnerable to disturbance and stress are susceptibility to damage, slow growth, longevity, and philopatry. This may be particularly so for marginal populations at the limits of their range and, for instance, that are attractive to scuba divers.
• 2. In this study we examined the population structure and incidence of damage, quantified growth rates and estimated gene flow to assess the effects of divers on the deep‐water emergent populations of the fragile red coral Errina novaezelandiae in the Te Awaatu Marine Reserve in Fiordland, New Zealand.
• 3. We found that population structure in red corals is skewed, with small colonies the most abundant. Damage was up to eight times higher in dived than in non‐dived populations of red coral, and large colonies were more likely to be damaged. Growth in red corals can be high (up to 7 cm ^?1), although net growth is much lower (0.7 cm yr^?1) due to the effects of partial mortality. On the basis of the slow growth rate, we estimate that large corals (>20 cm diameter) will be in excess of 30 yr old. We also found high genetic subdivision among red coral populations and evidence of inbreeding, indicative of limited larval dispersal among neighbouring populations.
• 4. Overall, our results indicate the shallow‐water populations of red coral in Fiordland will be susceptible to impacts from scuba diving, and the development of a management strategy to ensure ecologically sustainable tourism and to minimize the effects of divers will be essential for their conservation.

Copyright © 2003 John Wiley & Sons, Ltd.     

Revealing the coral habitat effect on benthopelagic fauna diversity in the Santa Maria di Leuca cold‐water coral province using different devices and Bayesian hierarchical modelling

1. Data from two experimental longline surveys and two video inspections carried out in Santa Maria di Leuca cold‐water coral province (Mediterranean Sea) during spring–autumn 2010 were used in order to compare the benthopelagic abundance and diversity between coral and non‐coral habitats and between different devices. The sampling was carried out in two types of habitat: a coral habitat with carbonate mounds and a non‐coral habitat characterized by intermound sea floor.
2. A Bayesian hierarchical modelling approach to accommodate factors influencing community assemblages was used considering the number of species, the Shannon–Wiener diversity index and the two most abundant species represented by the European conger (Conger conger) and blackbelly rosefish (Helicolenus dactylopterus).
3. A relevant effect of the habitat factor was observed for both the number of species and the diversity index, showing a higher species number and diversity index in the coral habitat than in the non‐coral habitat. Concerning the relevance of fixed effects from the model on the probability of observing non‐zero (positive) abundances, the devices considered, longline and baited lander, did not show different influence for either C. conger or H. dactylopterus. In the case of positive abundance, a relevant device effect was only observed for H. dactylopterus, showing higher abundances for longline than for baited lander. A habitat effect was detected, with positive abundances for both species in the coral habitat.
4. This study proves that structurally complex habitats generated by cold‐water corals influence the distribution and diversity of the benthopelagic fauna, and that the use of different devices can provide complementary useful results. Increased knowledge about the role of cold‐water corals in the associated benthopelagic fauna could lead to better conservation of one of the most important hot spots of biodiversity in the Mediterranean Sea.

     

Performance and cost‐effectiveness of sexually produced Acropora granulosa juveniles compared with asexually generated coral fragments in restoring degraded reef areas

1. Sexual and asexual modes of coral propagation are used to produce materials to actively restore coral cover on degraded reefs. It is important to evaluate growth, survival and cost‐effectiveness prior to any large‐scale intervention.
2. This study compared the growth, survival and cost of using sexually, compared with asexually, propagated Acropora granulosa at an in situ nursery and, subsequently, on degraded reef patches in the north‐western Philippines.
3. For sexual propagation, gametes spawned from gravid A. granulosa colonies were collected, fertilized and reared at an outdoor hatchery facility until they were 200‐day‐old juveniles. For asexual propagation, coral nubbins (obtained from colonies used in the sexual propagation experiment) were reared in the hatchery for 1 month before being transferred to an in situ nursery.
4. Sexually and asexually derived corals were reared at the in situ nursery and subsequently out‐planted to a degraded reef. Cumulative survival and growth of sexually derived corals were significantly higher than those of the asexually derived ones, both at the in situ nursery (for 200 days) and on coral bommies (for 382 days). At the in situ nursery, mean growth rates were 0.04 and 0.12 cm³ day^?1 for the asexually produced and sexually produced corals, respectively, while those at the bommies were 0.7 and 1.04 cm³ day^?1, respectively.
5. Production cost (including collection, hatchery‐ and in situ nursery‐rearing) is more expensive in the sexual (US$2.79/coral) than in the asexual (US$2.62/coral) mode of propagation. However, after 13 months post‐out‐planting it was clear that, in the long run, the individual cost of sexually derived corals is cheaper than the asexual counterparts, US$20.01 vs. US$88.15, respectively, owing to better survival rates.
6. Hence, sexual propagation using Acropora is a cost‐effective method with relatively high survival and growth that can be used in active restoration.

     

Scleractinian coral communities of the inner Seychelles 10 years after the 1998 mortality event

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Applying forest restoration principles to coral reef rehabilitation

• 1. Forest restoration through silviculture (gardening) programs revives productivity, biodiversity, and stability. As in silviculture approaches, the coral ‘gardening’ strategy is based on a two‐step protocol.
• 2. The first step deals with the establishment of in situ and/or ex situ coral nurseries in which corals are farmed (originating from two types of source material: asexual [ramets, nubbins], and sexual [planula larvae, spat] recruits).
• 3. The second is the reef rehabilitation step, where maricultured colonies are transplanted into degraded sites.
• 4. We compare here the rationale of forest restoration to coral reef ecosystem restoration by evaluating major key criteria. As in silviculture programs, a sustainable mariculture operation that focuses on the prime structural component of the reef (‘gardening’ with corals) may promote the persistence of threatened coral populations, as well as that of other reef taxa, thus maintaining genetic diversity. In chronically degrading reef sites this may facilitate a halt in biodiversity depletion.
• 5. Within the current theoretical framework of ecosystem restoration, the recovery of biodiversity indices is considered a core element since a rich species diversity provides higher ecosystem resilience to disturbances.
• 6. The gardening measure may also be implemented worldwide, eliminating the need to extract existing colonies for transplantation operations. At degraded reef sites, the coral gardening strategy can assist in managing human and non‐human stakeholders' requirements as is done in forest management.

Copyright © 2003 John Wiley & Sons, Ltd.     

Coral communities of Biscayne Bay,Florida and adjacent offshore areas: diversity,abundance, distribution,and environmental correlates

• 1. Hardbottom habitats of Biscayne Bay, a shallow lagoon adjacent to the city of Miami, Florida, USA, contain a limited number of coral species that represent a small subset of the species found at nearby offshore hardbottom and reef habitats of the Florida Reef Tract. Although the physical characteristics of this basin make it a marginal environment for coral growth, the presence of dense populations of Siderastrea radians and Porites furcata indicate that these, as well as other corals that are found at lower densities, are able to tolerate extreme and fluctuating conditions. Three factors, temperature, sedimentation, and salinity, appear to limit coral abundance, diversity, and distribution within Biscayne Bay.
• 2. Temperatures exhibit high frequencies of extreme high and low values known to cause coral stress and mortality elsewhere. Similarly, sedimentation rates are very high and sediment resuspension caused by currents, storms and boating activities commonly bury corals under sediment layers. Sediment burial was shown experimentally to influence growth and mortality of S. radians.
• 3. The salinity of Biscayne Bay is influenced by freshwater inputs from canal, sheetflow and groundwater sources that create a near‐shore environment with low mean salinity and high salinity fluctuation. Coral communities along this western margin have the lowest coral density and species richness. Chronic exposure to low salinity was shown experimentally to cause a decrease in the growth of S. radians.
• 4. The location of Biscayne Bay, downstream of a large restoration effort planned for the Everglades watershed, highlights the need to understand the relationship between the physical environment and the health of benthic communities. The data presented here provide the type of scientific information needed so that management decisions can take into account the potential impacts of human activities on the health of coral populations that are already near their tolerance limits for temperature, salinity, and sedimentation.

Copyright © 2003 John Wiley & Sons, Ltd.     

Distribution of lipids and fatty acids in the zooxanthellae and host of the soft coral Sinularia sp.

The lipid classes and the fatty acid (FA) compositions of the zooxanthellae, the host tissue, and intact coral were determined for the first time in a soft coral, Sinularia sp. The contents of monoalkyldiacylglycerol (MADAG), triacylglycerol, and polar lipids differed significantly between the zooxanthellae and the host fractions. The zooxanthellae were rich in polar lipids, whereas neutral lipids were concentrated in the host. MADAG comprised 35% of the host lipids and was practically absent in zooxanthellae. Hence, MADAG is only synthesized in animal tissues and serves as a biomarker for the host in the host–zooxanthellae association of these soft corals. Similar to the zooxanthellae of reef-building corals, the main FA in the zooxanthellae of Sinularia sp. were 18:4n-3, 20:5n-3, and 22:6n-3. In addition, 16:3n-4 and 16:4n-1 (8.9% in total) were found in these zooxanthellae. The ratios of 16:3n-4, 16:4n-1, 18:4n-3, 20:5n-3, and 22:6n-3 in the zooxanthellae to those in the host tissue were 4.2, 11.2, 10.1, 11.0, and 9.1, respectively. The proportions of some FA and lipid classes in the intact coral and its fractions showed that zooxanthellate lipids comprised 36 ± 15% of the total lipids in Sinularia sp. Two tetracosapolyenoic acids (24:5n-6 and 24:6n-3) are proposed as a biomarkers of the animal tissue and indicators of the purity of the zooxanthellae fractions from soft corals.     

New sites expanding the “Sardinian cold‐water coral province” extension: A new potential cold‐water coral network?

1. Cold‐water coral (CWC) ecosystems are protected both in national and international waters. They are considered Vulnerable Marine Ecosystems and, in addition, meet the criteria to be defined ecological or biological significant areas.
2. Two new sites of the “Sardinian CWC province” were discovered by means of remotely operated vehicle surveys in two submarine canyons in the north‐eastern portion of the Sardinian continental margin, at depths ranging from 230 to 430 m.
3. Dense and healthy patches of small and medium‐sized Madrepora oculata colonies were found dwelling on rocky walls and inclined silted soft bottoms.
4. A rich and diverse associated megafauna was found within both live and dead portions of the coral framework. In addition, the presence of benthic litter and derelict fishing gears were also documented.
5. These results further extend the “Sardinian CWC province” extension, providing insights of a potential CWC network along the Sardinian continental margin with implications for the Mediterranean mosaic of CWC provinces, further stressing the need for urgent conservation measures for these habitats.

     

Biodiversity value of a geographically restricted soft coral species within a temperate estuary

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Coral community decline at a remote Caribbean island: marine no‐take reserves are not enough

• 1. Coral reefs around the world have been deteriorating over decades owing to anthropogenic pressure. In the Caribbean recent rates of decline are alarming, particularly for coral reefs under high local human impact, many of which are severely degraded, although regions with lower direct anthropogenic influence seem less affected.
• 2. Little Cayman is a relatively undeveloped island, with less than 150 permanent residents. About 20% of its reefs have been protected by no‐take marine reserves since the mid‐1980s. We analysed the dynamics of coral communities around the island from 1999 to 2004 in order to test the hypothesis that a lack of major local anthropogenic disturbances is enough to prevent decline of coral populations.
• 3. Live hard coral coverage, coral diversity, abundance, mortality, size, and prevalence of disease and bleaching were measured using the Atlantic and Gulf Rapid Reef Assessment methodology (line transects) at nine sites. Despite the apparent undisturbed condition of the island, a 40% relative reduction of mean live coral coverage (from 26% to 16%, absolute change was 10%) was recorded in five years. Mean mortality varied from year to year from 23% to 27%. Overall mean diameter and height have decreased between 6% and 15% on average (from 47 to 40 cm for diameter, and from 31 to 29 cm for height).
• 4. The relative abundance of large reef builders of the genus Montastraea decreased, while that of smaller corals of the genera Agaricia and Porites increased. Disease prevalence has increased over time, and at least one relatively large bleaching event (affecting 10% of the corals) took place in 2003.
• 5. Mean live coral cover decline was similar inside (from 29% to 19%) and outside (from 24% to 14%) marine no‐take reserves. No significant difference in disease prevalence or clear pattern in bleaching frequency was observed between protected and non‐protected areas. It is concluded that more comprehensive management strategies are needed in order to effectively protect coral communities from degradation.

Copyright © 2007 John Wiley & Sons, Ltd.     

Monitoring of South Sinai coral reefs: influence of natural and anthropogenic factors

• 1. To monitor any impacts to coral reefs related to the exponential growth of tourism in the South Sinai region of the Egyptian Red Sea, nine stations were established at key reef sites over 2002–2003. At each station coral cover was determined using a video survey method at depths of 3, 7 and 16 m, and fish abundance by underwater visual census at depths of 3 and 10 m.
• 2. Mean total coral cover (hard plus soft) ranged from 58% to 23% at 3 m, 50% to 14% at 7 m, and 52% to 13% at 16 m, and hard coral cover from 37.5% to 15.7% at 3 m, 32.8% to 7.0% at 7 m, and 17.8% to 2.2% at 16 m. Analyses confirmed differences in coral assemblage related to depth and wave exposure.
• 3. Fish abundances and assemblages also varied with depth and proximity of deep water. Also the one site subject to fishing had lower abundances of some commercial fish families and greater abundances of some herbivores.
• 4. Transects subject to greater tourist use did not segregate from those subject to less tourist use, despite evidence from other work of an effect from visitor damage to corals at some sites. This may be because visitors were more attracted to sites that had higher coral cover.
• 5. Comparison of the present data with that from past studies is difficult because of the differences in sites and method employed, but several observations suggest a moderate decline in coral cover during recent decades. Such a decline would be compatible with the recorded impact of an outbreak of crown‐of‐thorns starfish, Acanthaster planci, as well as with other evidence of accumulating damage by visitors.
• 6. Further monitoring using the same stations and consistent protocols is urgently required.

Copyright © 2008 John Wiley & Sons, Ltd.     

Genetic diversity of the pan‐European freshwater mussel Anodonta anatina (Bivalvia: Unionoida) based on CO1: new phylogenetic insights and implications for conservation

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Comparing the management effectiveness of a marine park and a multiple‐use collaborative fisheries management area in East Africa

• 1. The coral reefs across the international border between Kenya and Tanzania, where historical differences in government policy and socio‐economic conditions created two different management systems, were examined: a large permanent closed area and a collaborative fisheries management project that used gear management and small voluntarily and temporary closed areas, respectively. The diversity and ecology of the reefs in these two management systems were compared spanning a seven‐year period to evaluate the effectiveness of the management and to assess the ecological response to a large‐scale water‐temperature anomaly in 1998.
• 2. Comparisons of rates of predation on sea urchins and of herbivory, using a seagrass assay, were made along with measures of benthic cover and fish abundance and diversity.
• 3. The collaborative fisheries management system was successful in increasing fish stocks, reducing erect algae, and maintaining ecological diversity and stability across the thermal anomaly. This management system, however, was not successful in protecting the expected full biodiversity of fish, predation rates on sea urchins, or the sensitive, branching coral species. Management of the fishery also increased fish stocks in the adjacent, large, permanently closed area, compared to Kenyan parks without this management.
• 4. The large, permanently closed area in the other system maintained high diversity, high predation rates on sea urchins and high herbivory rates, which maintained erect algae abundance and diversity at low levels. The temperature anomaly was destructive to a number of the dominant delicate branching coral species, but overall coral cover and diversity were maintained, although dominance switched from branching Porites spp. to Seriatopora spp. over this period. The large closed area system protected the undisturbed ecology of these reefs and associated ecological processes, and the full diversity of fish and coral, including sensitive species such as branching corals and slow‐growing fish.
• 5. Collaborative fisheries and large permanent closed area management have different attributes that, when combined, should achieve the multiple purposes of sustainable fisheries, ecosystem functions and protection of fishing‐sensitive species.

Copyright © 2005 John Wiley & Sons, Ltd.     

Cold‐water coral Madrepora oculata in the eastern Ligurian Sea (NW Mediterranean): Historical and recent findings

1. Cold‐water coral (CWC) ecosystems are long‐lived, slow‐growing and fragile, which makes them especially vulnerable to physical damage. In recent decades, CWCs have been severely threatened by fisheries, hydrocarbon extraction, pollution and other human activities.
2. In the Mediterranean Sea, some investigations have been carried out on CWC ecosystems, mostly focused on their distributions within the central and eastern basins.
3. Historical reports and fishermen's maps for the eastern Ligurian Sea (NW Mediterranean) from the 1960s document the occurrence of extensive banks of living CWC, mostly Madrepora oculata, between depths of 200 and 500 m.
4. In 2013/2014, multibeam, side scan sonar (SSS) and remotely operated vehicle (ROV) surveys were carried out in that area, specifically in the Levante Canyon, to assess the occurrence, distribution and conservation status of CWC.
5. The SSS and ROV showed numerous trawl tracks and small (10 cm high), dead, buried colonies at 300–500 m. Deeper, between 525 and 575 m, dense populations of living, 1 m high colonies of Madrepora oculata were found on the flanks of Levante Canyon. The deep sites showed colonies overturned or entangled by long‐line fishing activities.
6. The discovery of new CWC banks not yet heavily damaged by fishing activities, suggests that urgent measures for conservation should be taken in the Mediterranean and worldwide. The present limitation of trawl‐fishing to above 1000 m depth, established by the General Fisheries Commission for the Mediterranean (GFCM) in 2005, seems to be ineffective, since CWCs are mostly located at less than 1000 m depth in the Ligurian Sea. A network of high‐seas/deep‐sea marine protected areas (MPAs) would favour a better strategy for protecting substantial areas of CWCs.

     

Genetic monitoring of deep‐water exploited banks of the precious Sardinia coral Corallium rubrum (L., 1758): useful data for a sustainable management

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Coral reef organisms as bioregion indicators off Halmahera,Moluccas, Indonesia

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Repeated physical disturbances and the stability of sub‐tropical coral communities in Hong Kong,China

• 1. This paper reports on the dynamics of the coral community structure at A Ma Wan (AMW) and A Ye Wan (AYW) in Tung Ping Chau, Hong Kong, focusing on data collected before and after the summer typhoon seasons in 1997 to 1999. This period (1999) experienced the highest frequency of severe tropical cyclones to hit Hong Kong with one cyclone being the strongest to hit in the last 23 years (1984 to 2006).
• 2. This is part of a long‐term monitoring programme of subtropical coral communities that has been set up in AMW since May 1997 and AYW since May 1998 with nine fixed position 40 m long transects and 0.5 m × 0.5 m permanent quadrats laid at 5 m intervals along each transect. A total of 45 scleractinian coral species from 21 genera (12 families) was recorded, with 40 species in AMW and 32 species in AYW recorded at the beginning of the study.
• 3. Multidimensional scaling ordinations showed distinct spatial variations in the coral communities within and between sites. These variations were probably a result of the differential effects of the repeated cyclone impacts on the communities. Cyphastrea serailia, Goniopora lobata, Montipora peltiformis and Pavona decussata were the dominant species most strongly affected by cyclone impacts at AMW, experiencing a 6.2–16.2% loss of mean area cover during the study period. Some dominant species (e.g. P. decussata) in AYW also experienced a 6.5–14.3% loss of mean area cover within the same period.
• 4. Overall, these coral community structures appeared relatively stable and resistant to repeated physical disturbances. However, they may have low resilience towards more severe disturbances in the future. Preserving the resilience of coral communities/species in Tung Ping Chau should be one of the main goals of coral conservation strategies for the island.

Copyright © 2008 John Wiley & Sons, Ltd.