scholarly journals A comprehensive investigation of mesophotic coral ecosystems in the Hawaiian Archipelago

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2475 ◽  
Author(s):  
Richard L. Pyle ◽  
Raymond Boland ◽  
Holly Bolick ◽  
Brian W. Bowen ◽  
Christina J. Bradley ◽  
...  

Although the existence of coral-reef habitats at depths to 165 m in tropical regions has been known for decades, the richness, diversity, and ecological importance of mesophotic coral ecosystems (MCEs) has only recently become widely acknowledged. During an interdisciplinary effort spanning more than two decades, we characterized the most expansive MCEs ever recorded, with vast macroalgal communities and areas of 100% coral cover between depths of 50–90 m extending for tens of km2in the Hawaiian Archipelago. We used a variety of sensors and techniques to establish geophysical characteristics. Biodiversity patterns were established from visual and video observations and collected specimens obtained from submersible, remotely operated vehicles and mixed-gas SCUBA and rebreather dives. Population dynamics based on age, growth and fecundity estimates of selected fish species were obtained from laser-videogrammetry, specimens, and otolith preparations. Trophic dynamics were determined using carbon and nitrogen stable isotopic analyses on more than 750 reef fishes. MCEs are associated with clear water and suitable substrate. In comparison to shallow reefs in the Hawaiian Archipelago, inhabitants of MCEs have lower total diversity, harbor new and unique species, and have higher rates of endemism in fishes. Fish species present in shallow and mesophotic depths have similar population and trophic (except benthic invertivores) structures and high genetic connectivity with lower fecundity at mesophotic depths. MCEs in Hawai‘i are widespread but associated with specific geophysical characteristics. High genetic, ecological and trophic connectivity establish the potential for MCEs to serve as refugia for some species, but our results question the premise that MCEs are more resilient than shallow reefs. We found that endemism within MCEs increases with depth, and our results do not support suggestions of a global faunal break at 60 m. Our findings enhance the scientific foundations for conservation and management of MCEs, and provide a template for future interdisciplinary research on MCEs worldwide.

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Frederieke J. Kroon ◽  
Carine D. Lefèvre ◽  
Jason R. Doyle ◽  
Frances Patel ◽  
Grant Milton ◽  
...  

Abstract The corallivorous Crown-of-Thorns Starfish (CoTS, Acanthaster spp.) has been linked with the widespread loss of scleractinian coral cover on Indo-Pacific reefs during periodic population outbreaks. Here, we re-examine CoTS consumption by coral reef fish species by using new DNA technologies to detect Pacific Crown-of-Thorns Starfish (Acanthaster cf. solaris) in fish faecal and gut content samples. CoTS DNA was detected in samples from 18 different coral reef fish species collected on reefs at various stages of CoTS outbreaks in the Great Barrier Reef Marine Park, nine of which had not been previously reported to feed on CoTS. A comprehensive set of negative and positive control samples confirmed that our collection, processing and analysis procedures were robust, although food web transfer of CoTS DNA cannot be ruled out for some fish species. Our results, combined with the (i) presence of CoTS spines in some samples, (ii) reported predation on CoTS gametes, larvae and settled individuals, and (iii) known diet information for fish species examined, strongly indicate that direct fish predation on CoTS may well be more common than is currently appreciated. We provide recommendations for specific management approaches to enhance predation on CoTS by coral reef fishes, and to support the mitigation of CoTS outbreaks and reverse declines in hard coral cover.


2016 ◽  
Vol 8 (1) ◽  
Author(s):  
Fakhrizal Setiawan ◽  
Sonny Tasidjawa ◽  
Efra Wantah ◽  
Hendri Johanis

<p align="center"><strong><em>ABSTRACT</em></strong></p><p><em>There are </em><em>some marine sanctuaries (DPL) which are managed together by its societies in North Minahasa regency. From 19 villages with DPL, we conducted surveys using point intercept transect in 14 villages both inside and outside DPL in the subdistrict West Likupang and East Likupang, North Minahasa. Result showed that l</em><em>ive coral cover was in general in moderate to excellent conditions both inside and outside DPL. Reef fish recorded in the study areas consisted of 267 reef fish species which categorized into 40 families. Bahoi village had the highest abundance and biomass within the DPL due to a very good condition of coral reef ecosystemn (&gt;75% coral cover) both inside and outside DPL. Biomass of reef fish outside DPL of Bahoi was small but its abundance was the highest. This conditions indicated that the size of reef fish outside of Bahoi DPL was small and this gave a positive perspective to supply fishes into the outside region of Bahoi DPL. Overall, marine sanctuary in North Minahasa contained reef fish community structure in good condition, moderate diversity, relatively labile of evenness index, and low dominance. </em><em>Grouping</em><em> by similarity, reef fish species were generally similar in all locations. The separation of DPL locations produced some different fishes group due to its different location, oceanographic conditions, and characters.</em><em></em></p><p> </p><p><strong><em>Keywords</em></strong><em>: Marine sanctuary, reef fish community, North Minahasa.</em></p>


2020 ◽  
Vol 26 (2) ◽  
pp. 75
Author(s):  
Ayuningtyas Indrawati ◽  
Isa Nagib Edrus ◽  
Tri Aryono Hadi

Perairan karang Taman Nasional Komodo merupakan wilayah penangkapan ikan dan daerah tujuan wisata laut. Kondisi tutupan karang pada umumnya sudah di bawah 50%, namun dampak yang akan muncul terhadap ikan karang belum diteliti dan hal ini dibutuhkan bagi pengelolaan kawasan tersebut. Tujuan penelitian adalah mendapatkan karakteristik struktur komunitas ikan karang, meliputi komposisi, sebaran, kepadatan stok, dan biomassa ikan. Penelitian dilakukan pada bulan Juni 2019 dengan mengunakan metode sensus bawah air pada transek garis permanen untuk masing-masing stasiun penelitian. Sensus visual mendapatkan 128 spesies ikan target dari 21 suku dan 30 spesies ikan indikator dari suku Chaetodontidae. Rata-rata kepadatan stok ikan target dan ikan indikator adalah masing-masing 182 ± 67 individu/350m2 dan 35 ± 15 individu/350m2. Ukuran panjang ikan terbanyak antara 15 cm – 30 cm. Biomassa ikan target sebesar 1.174 ± 617 kg/hektar. Ikan karang target dan ikan indikator yang memiliki sebaran luas masing-masing 13 spesies dan 2 spesies . Komposisi kehadiran jenis ikan target di lokasi penelitian hanya 3% yang berdistribusi sangat tinggi, 7% berdistribusi tinggi, 18% berdistribusi sedang, 21% berdistribusi rendah dan 51% berdistribusi sangat rendah. Sementara jenis-jenis ikan indikator yang intensitas distribusinya sangat tinggi dan tinggi hanya 7%, dan lainnya tergolong sedang (23%), rendah (40%) sampai sangat rendah (23%). Kondisi sebaran spesies diduga menyebabkan keanekaragaman ikan karang pada keseluruhan lokasi penelitian terhitung tinggi, tetapi rendah untuk masing-masing lokasi penelitian. Semua lokasi di dalam kawasan taman nasional maupun diluar taman diperlukan pemantauan dengan porsi yang sama dan dilakukan secara berkala.Coral Reef Waters of Komodo National Park are fishing grounds and marine tourism destinations. The last condition of coral cover percentages of the regions have sustained below of 50%, however, their future potential impacts on fishes have not been studied and these will be needed in other to manage the regions. The study aimed to update reef fishes data in terms of some features of a community reef fish structure including composition, distribution, density, and biomass. A study was carried out in June, 2019 by using an underwater census visual at a permanent transect belt in the respective study sites. A total of 128 target fish species were recorded belonging to 21 families and 30 indicator fish species of Cahetodontidae were succesfully identified. The density mean of target and indicator fishes are 182 ± 67 individual/350m2 and 35 ± 15 individual/350m2, respectively. Most of fish sizes ranged from 15 cm to 30 cm. The biomass mean of target fishes are 1,174 ± 617 kg/hectare. Only for 13 species of target fishes that have high distribution in overall the study sites and 2 species of indicator fishes, as well. Composition present of target reef fishes in the distribution area given were in levels of 3% very high, 7% high, 18% fair, 21% low,and 51% veri low. Meanwhile, those for indicator fishes were in levels of 7% very high and high, 23% fair, 40% low, and 23% veri low. There was mayor significant diversity of reef fishes for overall study sites, however those was minor for respective study sites.The whole locations weather in-side or out-side of Komodo National Park need the equal portion for priodical monitoring.


2016 ◽  
Vol 8 (1) ◽  
pp. 57-71 ◽  
Author(s):  
Fakhrizal Setiawan ◽  
Sonny Tasidjawa ◽  
Efra Wantah ◽  
Hendri Johanis

ABSTRACTThere are some marine sanctuaries (DPL) which are managed together by its societies in North Minahasa regency. From 19 villages with DPL, we conducted surveys using point intercept transect in 14 villages both inside and outside DPL in the subdistrict West Likupang and East Likupang, North Minahasa. Result showed that live coral cover was in general in moderate to excellent conditions both inside and outside DPL. Reef fish recorded in the study areas consisted of 267 reef fish species which categorized into 40 families. Bahoi village had the highest abundance and biomass within the DPL due to a very good condition of coral reef ecosystemn (>75% coral cover) both inside and outside DPL. Biomass of reef fish outside DPL of Bahoi was small but its abundance was the highest. This conditions indicated that the size of reef fish outside of Bahoi DPL was small and this gave a positive perspective to supply fishes into the outside region of Bahoi DPL. Overall, marine sanctuary in North Minahasa contained reef fish community structure in good condition, moderate diversity, relatively labile of evenness index, and low dominance. Grouping by similarity, reef fish species were generally similar in all locations. The separation of DPL locations produced some different fishes group due to its different location, oceanographic conditions, and characters. Keywords: Marine sanctuary, reef fish community, North Minahasa.


2013 ◽  
Vol 1 (2) ◽  
pp. 117
Author(s):  
Fakhrizal Setiawan ◽  
Janny D Kusen ◽  
Georis JF Kaligis

In order to look at changes in coral and reef fish communities during the period of 2006 to 2013, this research was carried out at Bunaken National Park (BNP) with 26 observation sites. The existing data and information of reef fish communities in the park generally could not be used as representative for describing the whole region. Percentage of coral cover and fish abundance during the study period shows that Bunaken Island is more similar to other locations. Reef fish community structure as seen from ecological index (H' at all sites being categorized, E category labile and low category C) shows the condition of the reef fish community is still good. Changes in the structure of reef fish communities showed declining conditions compared to 2006, and coral cover continued to decrease compared to 1998 and 2007. Good overall reef fish and coral cover have decreased; it is thought to be related to the pressure in BNP. Some of the pressures in the region were (i) increasing numbers of domestic as well as foreign visitors, (ii) increasing number of residents in the region, as well as the burden of waste and trash from the Bay of Manado. Penelitian dilakukan di Taman Nasional Bunaken (Utara dan Selatan)   pada 26 lokasi  pengamatan untuk menganalisis perubahan struktur komunitas ikan karang melalui kajian dari suatu time series data dari beberapa penelitian sebelumnya. Data primer mengenai ikan-ikan karang diperoleh melalui visual sensus bawah air yang bersamaan dengan observasi terumbu karang menggunakan point intercept transect. Nilai persentase tutupan karang dan kelimpahan ikan menunjukkan bahwa pada lokasi pengamatan Pulau Bunaken paling baik dibandingan lokasi lainnya. Struktur komunitas ikan karang yang dianalisis dengan indeks ekologi menunjukkan indeks keanekaragaman (H’) di semua site masuk kategori sedang, indeks kesamaan (E) kategori labil dan indeks Dominansi (C) kategori rendah. Hasil penelitian ini menunjukkan bahwa kondisi komunitas ikan karang masih baik, sekalipun  perubahan struktur komunitas ikan karang menunjukkan kondisi yang menurun dibandingkan tahun 2006, begitu juga tutupan karang yang terus turun dibandingkan tahun 1998 dan 2007. Secara keseluruhan baik ikan karang maupun tutupan karang mengalami penurunan, hal ini diduga terkait dengan tekanan yang dialami kawasan TN. Bunaken. Salah satu tekanan terhadap kawasan adalah jumlah turis dari dalam maupun luar negeri yang semakin meningkat tiap tahunnya, penambahan jumlah penduduk di dalam kawasan, serta beban limbah dan sampah dari Teluk Manado.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Florentine Riquet ◽  
Christiane-Arnilda De Kuyper ◽  
Cécile Fauvelot ◽  
Laura Airoldi ◽  
Serge Planes ◽  
...  

AbstractCystoseira sensu lato (Class Phaeophyceae, Order Fucales, Family Sargassaceae) forests play a central role in marine Mediterranean ecosystems. Over the last decades, Cystoseira s.l. suffered from a severe loss as a result of multiple anthropogenic stressors. In particular, Gongolaria barbata has faced multiple human-induced threats, and, despite its ecological importance in structuring rocky communities and hosting a large number of species, the natural recovery of G. barbata depleted populations is uncertain. Here, we used nine microsatellite loci specifically developed for G. barbata to assess the genetic diversity of this species and its genetic connectivity among fifteen sites located in the Ionian, the Adriatic and the Black Seas. In line with strong and significant heterozygosity deficiencies across loci, likely explained by Wahlund effect, high genetic structure was observed among the three seas (ENA corrected FST = 0.355, IC = [0.283, 0.440]), with an estimated dispersal distance per generation smaller than 600 m, both in the Adriatic and Black Sea. This strong genetic structure likely results from restricted gene flow driven by geographic distances and limited dispersal abilities, along with genetic drift within isolated populations. The presence of genetically disconnected populations at small spatial scales (< 10 km) has important implications for the identification of relevant conservation and management measures for G. barbata: each population should be considered as separated evolutionary units with dedicated conservation efforts.


Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 119
Author(s):  
Antonio Fidel Santos-Hernández ◽  
Alejandro Ismael Monterroso-Rivas ◽  
Diódoro Granados-Sánchez ◽  
Antonio Villanueva-Morales ◽  
Malinali Santacruz-Carrillo

The tropical rainforest is one of the lushest and most important plant communities in Mexico’s tropical regions, yet its potential distribution has not been studied in current and future climate conditions. The aim of this paper was to propose priority areas for conservation based on ecological niche and species distribution modeling of 22 species with the greatest ecological importance at the climax stage. Geographic records were correlated with bioclimatic temperature and precipitation variables using Maxent and Kuenm software for each species. The best Maxent models were chosen based on statistical significance, complexity and predictive power, and current potential distributions were obtained from these models. Future potential distributions were projected with two climate change scenarios: HADGEM2_ES and GFDL_CM3 models and RCP 8.5 W/m2 by 2075–2099. All potential distributions for each scenario were then assembled for further analysis. We found that 14 tropical rainforest species have the potential for distribution in 97.4% of the landscape currently occupied by climax vegetation (0.6% of the country). Both climate change scenarios showed a 3.5% reduction in their potential distribution and possible displacement to higher elevation regions. Areas are proposed for tropical rainforest conservation where suitable bioclimatic conditions are expected to prevail.


Coral Reefs ◽  
2006 ◽  
Vol 25 (3) ◽  
pp. 461-472 ◽  
Author(s):  
Michelle J. Paddack ◽  
Robert K. Cowen ◽  
Su Sponaugle

Author(s):  
Paulo S. Pompeu ◽  
Débora R. de Carvalho ◽  
Cecília G. Leal ◽  
Rafael P. Leitão ◽  
Carlos Bernardo M. Alves ◽  
...  

Diversity ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 411
Author(s):  
Gal Eyal ◽  
Hudson T. Pinheiro

Mesophotic ecosystems (MEs) are characterized by the presence of light-dependent organisms, found at depths ranging from ~30 to 150 m in temperate, subtropical and tropical regions. These communities occasionally create massive reef structures with diverse but characteristic morphologies, which serve as the framework builders of those ecosystems. In many localities, MEs are physically linked with shallow and deep-sea habitats, and while taxa from both environments share this space, a unique and endemic biodiversity is also found. The main MEs studied to date are the mesophotic coral ecosystems (MCEs) and the temperate mesophotic ecosystems (TMEs), which have received increased attention during the last decade. As shallow coral reef ecosystems are among the most threatened habitats on Earth, the potential of MEs to act as refugia and contribute to the resilience of the whole ecosystem has been a subject of scrutiny. New technologies and methods have become more available to study these deeper parts of the reef ecosystems, yielding many new discoveries. However, basic gaps in knowledge remain in our scientific understanding of the global diversity of MEs, limiting our ability to recognize biogeographic patterns and to make educated decisions for the management and conservation of these ecosystems.


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