scholarly journals The importance of oceanic atoll lagoons for coral reef predators

2020 ◽  
Vol 167 (2) ◽  
Author(s):  
Christina Skinner ◽  
Aileen C. Mill ◽  
Steven P. Newman ◽  
S. Nadia Alsagoff ◽  
Nicholas V. C. Polunin
Keyword(s):  
Dominant Species ◽  
Outer Edge ◽  
Ecological Role ◽  
Underwater Video ◽  
Visual Census ◽  
Outer Reef ◽  
Underwater Visual Census ◽  
Body Sizes ◽  
Lagoonal Habitat ◽  
Depth And Complexity

AbstractPredators on coral reefs play an important ecological role structuring reef fish communities and are important fishery targets. It is thought that reef predator assemblages increase in density and diversity from inner lagoonal to outer edge reefs. Oceanic atolls may differ though, as nutrients are available throughout. Reef predator populations are declining, but there is little known about how their distributions may vary across oceanic atolls. Using a combination of underwater visual census and baited remote underwater video, this study aimed to compare reef predator populations between inner and outer reefs of North Malé Atoll (Maldives) and determine which reef metrics may drive any differences in assemblage structure. We found that predator assemblages were significantly different between inner and outer atoll. Body sizes of several predator families were consistently larger in the outer atoll, however, abundance, biomass and species richness were similar between outer edge reefs and inner lagoonal reefs suggesting atoll lagoons may be undervalued habitats. Depth and complexity were consistently important predictors of the predator assemblage. Inner atoll lagoonal habitat is equally as important for reef predator assemblages as outer reef slopes, although the dominant species differ. This study provides important information on reef predator populations in the Maldives, where detailed assessments of the reef predator assemblage are lacking but the reef fishery is thriving and annual catch will continue to increase.

scholarly journals Performance of a baited underwater video system vs. the underwater visual census technique in assessing the structure of fish assemblages in a Mediterranean marine protected area

2021 ◽  
Vol 22 (3) ◽  
pp. 480
Author(s):  
GABRIELLA LA MANNA ◽  
IVAN GUALA ◽  
DANIELE GRECH ◽  
FRANCESCO PERRETTI ◽  
FABIO RONCHETTI ◽  
...  
Keyword(s):  
Species Richness ◽  
Protected Area ◽  
Fish Assemblages ◽  
Marine Protected Area ◽  
Fish Fauna ◽  
Underwater Video ◽  
Visual Census ◽  
Underwater Visual Census ◽  
Species Richness And Abundance ◽  
High Level

Accurate, rapid and cost-effective fish assemblage monitoring is fundamental for marine protected area (MPA) management as a pivotal tool to verify whether and to what extent MPA conservation objectives have been achieved and to redefine these objectives in the framework of an adaptive management. Recently, there has been a sharp increase in the number of video-based methods to study fish fauna, such as baited remote underwater video (BRUV) systems, that, depending on the objectives of the monitoring, can provide complementary or additional data to the more commonly used underwater visual census (UVC). Even though BRUV systems have been widely used in a wide range of geographic contexts and habitats, their use in the Mediterranean basin is still sporadic and the evaluation of the efficiency of BRUV systems and whether they can be used to complement other techniques needs investigation. Thus, the objective of this study was to assess the performance of a BRUV system in a Mediterranean MPA and to evaluate its effectiveness in assessing the structure of fish assemblages (abundance and species richness) by comparing estimates with those obtained by the UVC technique. The fish fauna were monitored by BRUV and UVC in the Capo Caccia – Isola Piana Marine Protected Area (Sardinia, Italy), in July and October-November 2020, at four sampling sites and two areas, hundreds of meters apart, for each site. Overall, 46 taxa and a total of 3620 individuals were observed by BRUV, while 36 taxa and a total of 2995 individuals were observed by UVC. The species first observed in front of the camera’s field of view and able to reach the maximum abundance were the planktivores (Chromis chromis and Oblada melanura) followed by several carnivorous species belonging to the families Labridae, Serranidae and Sparidae, and lastly two carnivores (Mullus surmuletus and Mugilidae spp.) and some high-level predators (Dentex dentex, Seriola dumerili, Sphyraena viridensis, Dicentrarchus labrax). The maximum species richness and abundance were reached between 39 and 50 min. The cumulative species richness increased until around 30 min. Species richness was higher during the BRUV compared to the UVC monitoring. The consistency in findings between BRUV and UVC and a better performance of BRUV in detecting some species (mainly high-level predators), supports BRUV as an additional technique for describing and quantifying species richness and abundance also in the Mediterranean Sea. Based on the results of this study, the advantages/disadvantages, shortcomings, suggestions and resources needed for the two techniques are outlined.

Locating faunal breaks in the nearshore fish assemblage of Victoria, Australia

2012 ◽  
Vol 63 (3) ◽  
pp. 218 ◽  
Author(s):  
Madhavi A. Colton ◽  
Stephen E. Swearer
Keyword(s):  
Global Climate ◽  
Range Shifts ◽  
Effective Management ◽  
Underwater Video ◽  
Visual Census ◽  
Underwater Visual Census ◽  
Study Region ◽  
Marine Communities ◽  
Eastern Australia ◽  
Distance Data

Marine communities are frequently biogeographically structured, despite the potential for dispersal. Previous research on a variety of marine taxa in south-eastern Australia has suggested that a biogeographic break occurs along the coastline of Victoria. However, little of this research has focussed on nearshore ichthyofauna and the location of the break remains debated. Using fish abundance measured by two methods: underwater visual census (UVC); and baited remote underwater video (BRUV) at six locations along the open coast of Victoria, we examined (1) whether there is sufficient concordance among species to indicate the presence of a faunal break; and if present (2) where any such breaks occur. Differences in assemblage composition between locations were tested with analyses of similarity and examination of residuals from regressions of pairwise dissimilarities against coastline distance. Data collected using UVC revealed two large faunal breaks co-located with a habitat discontinuity, the convergence of two currents and a thermal gradient. Data collected by BRUV revealed only a gradation of change across the study region. Greater understanding of the biogeographic structure of these communities will facilitate more effective management, especially in light of anticipated range shifts in response to global climate change.

Asosiasi ikan pada terumbu buatan di Teluk Tahuna Kabupaten Kepulauan Sangihe

2016 ◽  
Vol 2 (2) ◽  
Author(s):  
Wenseslaus Fransiscus Makawaehe ◽  
Lefrand Manoppo ◽  
Revols D.Ch. Pamikiran
Keyword(s):  
Visual Census ◽  
Underwater Visual Census ◽  
Scuba Divers

Minimnya pengetahuan tentang ekologi terumbu buatan merupakan inti masalah perdebatan penggunaannya dalam manajemen sumberdaya perikanan; dan membatasi aplikasi habitat buatan tersebut sebagai alat mitigasi pada berbagai kerusakan lingkungan. Pemahaman ekologi yang lebih baik akan menuntun pada pembuatan desain dan penggunaan struktur buatan secara lebih efektif dan efisien. Hal ini juga akan menjawab pertanyaan tentang manfaat konstruksi habitat buatan pada berbagai kondisi lingkungan. Asosiasi ikan di terumbu buatan bervariasi, namun perlu dilakukan perbandingan jenis ikan yang berasosiasi pada saat air pasang dan air surut. Oleh karena itu penelitian ini bertujuan untuk Membandingkan struktur asosiasi ikan di terumbu buatan pada saat air pasang naik dan pasang surut di perairan Teluk Tahuna. Penelitian ini dilakukan di perairan Teluk Tahuna, Kabupaten Kepulauan Sangihe pada bulan April–Juni 2015; yang didasarkan pada metode deskriptif. Asosiasi ikan di terumbu buatan diamati dengan teknik Underwater visual census (UVC) oleh dua orang SCUBA divers sebanyak 4 kali. Kelimpahan spesies ikan di terumbu buatan dianalisis dengan indeks keragaman dan indeks dominansi. Berdasarkan jumlah individu total ikan yang berasosiasi dengan terumbu buatan, maka nilai tertinggi terdapat pada bulan purnama saat pasang tertinggi (156 ekor), kemudian diikuti bulan kuartir pasang tertinggi (120 ekor), bulan purnama surut terendah (107 ekor) dan bulan kuartir surut terendah (103 ekor). Keanekaragaman spesies ikan, baik pada bulan kuartir maupun pada bulan purnama masih tergolong sedang dan dominansi spesies tergolong rendah

scholarly journals Complementarity of Rotating Video and Underwater Visual Census for Assessing Species Richness, Frequency and Density of Reef Fish on Coral Reef Slopes

PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e84344 ◽  
Author(s):  
Delphine Mallet ◽  
Laurent Wantiez ◽  
Soazig Lemouellic ◽  
Laurent Vigliola ◽  
Dominique Pelletier
Keyword(s):  
Species Richness ◽  
Coral Reef ◽  
Reef Fish ◽  
Visual Census ◽  
Underwater Visual Census

scholarly journals eDNA metabarcoding as a biomonitoring tool for marine protected areas

2020 ◽  
Author(s):  
Zachary Gold ◽  
Joshua Sprague ◽  
David J. Kushner ◽  
Erick Zerecero ◽  
Paul H. Barber
Keyword(s):  
Protected Areas ◽  
Fish Species ◽  
Marine Protected Areas ◽  
Marine Reserve ◽  
Marine Ecosystem ◽  
Site Occupancy ◽  
Visual Methods ◽  
Visual Census ◽  
Underwater Visual Census ◽  
Promising Alternative

AbstractMonitoring of marine protected areas (MPAs) is critical for marine ecosystem management, yet current protocols rely on SCUBA-based visual surveys that are costly and time consuming, limiting their scope and effectiveness. Environmental DNA (eDNA) metabarcoding is a promising alternative for marine ecosystem monitoring, but more direct comparisons to visual surveys are needed to understand the strengths and limitations of each approach. This study compares fish communities inside and outside the Scorpion State Marine Reserve off Santa Cruz Island, CA using eDNA metabarcoding and underwater visual census surveys. Results from eDNA captured 76% (19/25) of fish species and 95% (19/20) of fish genera observed during pairwise underwater visual census. Species missed by eDNA were due to the inability of MiFish 12S barcodes to differentiate species of rockfishes (Sebastes, n=4) or low site occupancy rates of crevice-dwelling Lythrypnus gobies. However, eDNA detected an additional 30 fish species not recorded in paired visual surveys, but previously reported from prior visual surveys, highlighting the sensitivity of eDNA. Significant variation in eDNA signatures by location (50m) and site (~1000m) demonstrates the sensitivity of eDNA to address key questions such as community composition inside and outside MPAs. Interestingly, eDNA results recorded higher species richness outside the MPA while visual surveys observed the opposite pattern. This result is likely caused by swamping effects of high fish abundance in MPAs that reduce detection probabilities of pelagic and intertidal taxa. Results demonstrate the utility of eDNA metabarcoding for monitoring marine ecosystems, providing an important complementary tool to visual methods.

scholarly journals ANALISIS KESESUAIAN PERAIRAN BAGI KEGIATAN WISATA BAHARI SNORKLING DAN SELAM DI PERAIRAN PULAU NUSALAUT KABUPATEN MALUKU TENGAH

2019 ◽  
Vol 11 (3) ◽  
pp. 653-666
Author(s):  
Terry Indrabudi ◽  
Arif Seno Adji ◽  
Widhya Nugroho Satrioajie ◽  
Robert Alik
Keyword(s):  
Life Form ◽  
Visual Census ◽  
Underwater Visual Census

Maluku memiliki sumberdaya laut yang sangat besar, baik sumberdaya hayati maupun nir-hayati termasuk potensi wisata bahari yang menjadi prioritas pemerintah untuk dikembangkan. Namun pada kenyataannya, perkembangan wisata bahari di Maluku masih menghadapi berbagai kendala, yaitu menentukan lokasi yang layak untuk dijadikan tujuan wisata. Penelitian ini bermaksud untuk melihat tingkat kesesuaian wisata khususnya wisata snorkling dan selam di perairan Pulau Nusalaut. Pengambilan sampel dilakukan pada tahun 2014 dan 2015 di 6 (enam) lokasi yang berbeda.  Pengambilan data karang menggunakan metoda LIT (Line Intecept Trancect) dan dianalisis menggunakan "Life Form Program". Pengamatan ikan karang dilakukan dengan Underwater Visual Census (UVC) dan transek. Parameter lingkungan diambil dengan cara pengukuran langsung dilapangan. Terumbu karang dikategorikan dalam kondisi ”Baik” dan ”Sangat Baik” dengan persentase tutupan karang antara 58,54-77%. Sebanyak 217 jenis karang batu yang termasuk ke dalam 52 genera dari 16 famili menempati rataan terumbu. Keanekaragaman ikan karang berada pada kondisi yang cukup baik dengan indeks keanekaragaman berkisar antara 3,05-4,09. Setidaknya terdapat 2.838 individu ikan karang dari 25 famili dan 170 jenis, terbagi dalam kelompok ikan indikator sebanyak 6%, ikan mayor 67% dan ikan target 27%. Kecerahan perairan berkisar antara 8-12 m dengan kecepatan arus antara 1,6-18,5 m/s. Berdasarkan hasil analisis kesesuaian wisata, seluruh lokasi penelitian dikategorikan “Sangat Sesuai” untuk dijadikan tujuan wisata snorkling maupun selam dengan Indeks Kesesuaian Wisata antara 81,25-95,83%.

scholarly journals HUBUNGAN ANTARA KOMPOSISI IKAN TARGET DAN PRESENTASE TUTUPAN KARANG HIDUP DI KEPULAUAN KEI KECIL, MALUKU

2020 ◽  
Vol 26 (3) ◽  
pp. 147
Author(s):  
Ana Faricha ◽  
Isa Nagib Edrus ◽  
Rizkie Satriya Utama ◽  
Ahmad R. Dzumalex ◽  
Abdullah Salatalohi ◽  
...  
Keyword(s):  
Coral Reef ◽  
Reef Fishes ◽  
Average Density ◽  
Species Variation ◽  
Live Coral ◽  
Visual Census ◽  
Underwater Visual Census ◽  
Ecological Values ◽  
Average Biomass ◽  
The Relationship

Ikan terumbu karang memiliki peranan penting baik secara ekonomi maupun ekologi, namun kondisi terumbu karang termasuk di perairan Indonesia yang menjadi habitat utama ikan karang mengalami degradasi. Penelitian ikan karang sudah banyak dilakukan, namun di Indonesia kondisi habitat ikan karang memiliki karakter yang berbeda-beda. Tujuan penelitian ini adalah untuk mengetahui hubungan antara komposisi ikan karang target dan tutupan karang hidup. Penelitian ini dilakukan pada bulan Oktober 2019 di Kepulauan Kei Kecil, Maluku. Metode yang digunakan adalah UVC (Underwater Visual Census) untuk data ikan karang dan UPT (Underwater Photo Transect) untuk mengkaji tutupan karang hidup. Hasil pengamatan menunjukkan bahwa terdapat 130 spesies ikan karang target yang mewakili 19 famili, dengan variasi jenis ikan target antar lokasi pengamatan berkisar antara 25-66 spesies. Kepadatan rata-rata ikan karang target sebesar 8.811 ± 4.107 Ind/ha, dan biomassa rata-rata 1.335 ± 899 Kg/ha. Komposisi ikan karang target yang memiliki kedekatan dengan tutupan karang hidup yaitu famili Siganidae, Serranidae, Lutjanidae, Holocentridae, dan Pomacentridae. Akan tetapi hubungan tersebut rendah, dan kemungkinan besar ada faktor lain yang mempengaruhi. Reef fishes have an important economic and ecological values. However, the coral reef of the globe including in the most of the Indonesian waters which is the vital habitat for reef fishes is degraded. Study on the reef fishes is an abundance, while the habitat characteristic of reef fishes in Indonesian waters has a differences. The aim of this study is to determine the relationship between the target reef fishes compositions and the percentage live coral covers. This study was carried out in October 2019 at the Kei Kecil islands, Maluku. The method used in this study is UVC (Underwater Visual Census) for collecting the reef fishes data, and the UPT (Underwater Photo Transect) for assessing the live coral coverage. The result shows that there are about 130 fishes, which representing 19 families, with species variation ranges from 25 to 66 species among the observation sites. The average density of target fishes was about 8.811 ± 4.107 Ind/ha, whereas the average biomass of target fishes was 1,335 ± 899 Kg/ha. The target reef fishes compositions that has relation with live coral covers is family Siganidae, Serranidae, Lutjanidae, Holocentridae, and Pomacentridae. However, this relationship is weak, and may influenced by other factors.

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