Conservation Implications of Sabellaria spinulosa Reef Patches in a Dynamic Sandy-Bottom Environment

Biogenic reefs form biodiversity hotspots and are key components of marine ecosystems, making them priority habitats for nature conservation. However, the conservation status of biogenic reefs generally depends on their size and stability. Dynamic, patchy reefs may therefore be excluded from protection. Here, we studied epibenthos and epifauna density, richness, and community composition of patchy, dynamic Sabellaria spinulosa (ross worm) reefs in the North Sea. This study was conducted by comparing boxcore (endobenthos) and video transect (epifauna) data from two research campaigns in 2017 and 2019 to the Brown Bank area on the Dutch Continental Shelf, where S. spinulosa reefs were first discovered in 2017. The Brown Bank area is characterized by dynamic, migratory bedforms at multiple scales which potentially affect biogenic reef stability. We showed that S. spinulosa habitats had a patchy distribution and alternated with habitats comprised of plain sand. Average S. spinulosa habitat patch size was 5.57 ± 0.99 m and 3.94 ± 0.22 m in 2017 and 2019, respectively (mean ± SE), which especially in 2019 closely resembled the small-scale megaripple bedforms. Contrary to the endobenthos communities that were unaffected by S. spinulosa, epifauna density and species richness were at least two times higher in S. spinulosa habitats compared to sandy habitats, resulting in different community compositions between the two habitat types. We showed that S. spinulosa persisted in the area for almost 2 years. Although the stability of individual patches remained unclear, we demonstrated that even patchy biogenic reefs may promote density and local biodiversity of mobile, epibenthic species, very likely as a result of increased habitat heterogeneity provided by reef habitat patches. This indicates that patchy biogenic reefs that occur in dynamic environments may also have high ecological value and their conservation status should be (re)considered to ensure their protection.

Comparison of 3D Coral Photogrammetry and Coral Video Transect for Coral Lifeform Analysis Using Low-cost Underwater Action Camera

This research analysed the use of 3D Coral Photogrammetry (CP) and Coral Video Transect (CVT) images collected from SCUBA divers using a low-cost underwater action camera to examine the coral lifeform. A comparison was made between data sets obtained using both methods on nine transects with different coral lifeform compositions and percentage cover within an area of 4 × 7 m. The comparison of the statistical analysis for CPCe revealed that there were no significant differences (p < 0.05) between CP and CVT photos where dead corals (p = 0.006), sand (p = 0.011), and unknown (p = 0.002) are present. Additionally, the coral value (p = 0.131) between CP and CVT was not significant. CP was capable of producing prominent branching, massive, and plate coral morphology results. This suggests that survey methods using low-cost action cameras for 3D Coral Photogrammetry would yield appropriate results in terms of coral lifeform detection. Hypothetically, by improving camera quality, it will yield a higher accuracy of 3D coral images that are suitable for use in scientific research and management. Other benefits of using CP include the possibilities for future studies with 3D coral surveys using remotely operated vehicles, less field time, and 3D coral seabed information.

Evidence of a biomass hotspot for targeted fish species within Namena Marine Reserve, Fiji

Namena is Fiji’s oldest and second largest no-take marine reserve, and has relatively high abundance and biomass of targeted fishes within its boundaries due to a high level of protection since its creation in 1997 (formalised in 2005). Following anecdotal reports of exceptionally high fish abundance at the Grand Central Station dive site within Namena, we conducted a 500-m meandering diver-operated video transect along the main reef formation, to obtain abundance, length and biomass estimates for fish species targeted by local fishers. Our census revealed extremely high diversity, abundance and biomass (11436kgha−1) of targeted fishes. While demersal reef fishes were present at higher densities than on typical fished reefs in the region, they were dwarfed by aggregations of reef-associated pelagics, namely the barracuda Sphyraena forsteri (5540kgha−1) and the trevally Caranx sexfasciatus (4448kgha−1). These estimates are comparable to those of historically unfished or ‘pristine’ locations, an unexpected finding given the historical fishing pressure within the reserve before its establishment and ongoing pressure in surrounding fished areas. This finding presents Grand Central Station as a useful reference site for ecologists and managers, and highlights the ability of protected coral reefs to support or attract very high densities of fish.

Species diversity and abundance of Euphylliidae (Cnidaria: Anthozoa: Scleractinia) corals in Tioman, Redang and Payar Islands, Peninsular Malaysia

The number of endangered coral species is increasing over the past decades due to multiple stresses and threats. Euphylliidae corals are among the species heavily targeted for the marine aquarium trade due to their colourful appearance and aesthetic importance. However, their distribution in Peninsular Malaysia has not been thoroughly investigated. Present study aims to investigate the diversity and abundance patterns of euphylliid species at 36 reef sites in Marine Protected Areas of Tioman, Redang and Payar Islands. Video transect surveyed a total of 671 euphylliids individuals belonging to six species from three genera. The diversity and evenness indices of euphylliids were significantly higher (P

SCLERACTINIAN CORAL RECRUITMENT DENSITY IN COASTAL WATER OF BALOK, PAHANG, MALAYSIA

Study on scleractinian coral recruitment is important in understanding the mechanisms that regulate their population and the resilience of coral reef communities to disturbance. This study aims to investigate temporal recruitment density of scleractinian coral at selected remote area in Balok, Pahang. Two types of settlement plates, which are terra-cotta tiles and artificial reef, were deployed at three stations to determine the recruitment density. The retrieval of the settlement plate was done at every three months interval started from March to September 2014. A total of 159 coral recruits were counted with mean recruitment densities on both terracotta tiles was 1.52 ± 0.65 and artificial reef plate was 4.37 ± 1.84 respectively. Recruitment was dominated by Platygyra (36%) followed by Porites (32%), Fungia (17%), Turbinaria (7%), Acropora (2%), Stylopora (2%), Montipora (1%), Leptoria (1%), Favites (1%) and Echinophyllia (1%). Kruskal - Wallis ANOVA test shown that recruitment densities varied significantly with plate’s orientation (p < 0.05), but not with sampling stations, type of substrates and month retrieval. Artificial reef plate has better recruitment densities compared to terra-cotta tiles. Coral spat settlement and recruitment patterns were consistent with adult coral distributions. The percentage cover of adult coral varied within the three stations. A total of 33 coral genera from 13 families were recorded during coral video transect survey with Station 3 showed the highest H’ (2.35). Meanwhile, Station 2 showed higher EH’ indexes with 0.82. Therefore, results of this study is important because coral recruitment pattern reflect its adult coral population, and if it closely monitored and harvested sustainably, the survival of parent population could be increased for successful breeding.

Colonization of Coral Communities in the Krakatau Islands Strict Marine Nature Reserve, Indonesia (Kolonisasi Komunitas Karang di Kepulanan Krakatau)

Pulau-pulau Krakatau memiliki dinamika secara geomorfologi, dan berbagai perubahan fisik yang berlangsung memberikan dampak terhadap biota, termasuk pada proses dan tingkat pergantian suksesi komunitasnya. Tujuan penelitian ini untuk menjelaskan kondisi terkini dan proses kolonisasi komunitas karang, termasuk status kerusakan komunitas karang dan disturbansi lingkungan yang mempengaruhinya. Line intercept transect dilakukan di enam stasiun pada dua kedalaman yang berbeda yakni 5 dan 10m. Sedangkan observasi terhadap komunitas koral dilakukan dengan perekaman video. Hasil penelitian ini menunjukkan bahwa suksesi atau perkembangan komunitas (i.e. kolonisasi) karang yang dijumpai di Pulau Anak Krakatau masih mengindikasikan tahap awal kolonisasi, berbeda dengan komunitas karang yang dijumpai di Pulau Rakata dan Panjang. Diversifikasi komunitas karang di kedua pulau tersebut, menunjukkan dominansi spesies oportunis dan pioner (i.e. Pocillopora dan Seriatopora) yang umum dijumpai di Anak Krakatau sudah tergantikan. Dominansi dari beberapa spesies karang telah mengindikasikan terjadinya proses eksklusi kompetitif di antara komunitas karang. Tiga tipe komunitas karang yang dijumpai dapat dibedakan menurut karakteristik masing-masing kawasan, yaitu komunitas kawasan terpapar, semi terpapar/terlindung, dan terlindung. Kerusakan komunitas karang di Krakatau berdasarkan kriteria indeks kerusakan karang (CDI) sudah termasuk kedalam kategori wilayah “hot spot”, dimana sangat memerlukan perhatian, pengawasan, pengamatan atau restorasi komunitas karang. Hasil penelitian ini memberikan gambaran bahwa terjadinya kolonisasi dan tingkat kerusakan komunitas karang perlu menjadi acuan dalam pengelolaan kawasan terumbu karang di Cagar Alam Laut Krakatau. Kata kunci: kolonisasi, suksesi; komunitas karang; pengelolaan; Krakatau Krakatau Islands diversity is geomorphologically dynamic, and these physical changes influence on organisms including community successional. The purposes of this research were to determine the condition and describe the recent colonization development of coral communities in the Krakatau Islands after sterilization. Transects were done at six stations at two different depth (i.e. 5 and 10 m) using line intercept transect. While observations of coral communities were done with video transect. This study showed that succession or development of coral communities (i.e. colonization) that found in Anak Krakatau indicated earlier stage of colonization. It has different coral communities compared with those that found in Rakata and Panjang island. The diversification of coral communities on both islands, showed that opportunistic and pioneer species (i.e. Pocillopora and Seriatopora) that generally found in Anak Krakatau has been replaced. There are indications of dominance may already take place through competitive exclusion in the coral communities. Three community types were distinguished based on characteristics for each sites, as follows: communities of wave-exposed habitats, communities of semi- exposed to sheltered habitats, and communities of sheltered habitats. The extent of coral damage covered all six sites based on coral damage index (CDI). This suggests that of the all transects were "hot spots'' that required management action. These results indicate that colonization and the level of coral damage have to be taken into account on the manegement of coral ecosystem in the region. Keywords: colonization; succession; coral communities; management; Krakatau