scholarly journals Underwater Visual Census of Deeper Vertical Rocky Reefs

2020 ◽  
Vol 20 (11) ◽  
pp. 785-794
Author(s):  
Alen Soldo ◽  
Igor Glavičić
Keyword(s):  
Fish Assemblages ◽  
Scuba Diving ◽  
Marine Biodiversity ◽  
Biodiversity Hotspots ◽  
Visual Census ◽  
Underwater Visual Census ◽  
Video Cameras ◽  
Rocky Reefs ◽  
Temperate Fish ◽  
Vertical Transect

Diver-based underwater visual census (UVC), particularly transect-based survey, is a widely used method for the study of tropical and temperate fish assemblages. However, due to logistical constraints associated with conventional SCUBA diving, deeper habitats, such as vertical rocky reefs, are rarely studied and poorly known. This paper describes the Deep Vertical Transect (DVT) method as a safe and effective method for assessing fish in waters up to 50 m of depth. It is based on sampling of vertical transects browsing within it (S-type transect) by divers using Full HD video cameras. The diving profile includes the use of deep decompression stops and Nitrox 50 as a decompression gas. Hence, the study yields information on fish assemblages associated with deeper vertical coralligenous reefs. The results of 51 recorded species, yielded 41 considered as reef-associated and 10 as occasional. This suggests that underwater steep coralligenous reefs are marine biodiversity hotspots. They may be considered to represent a distinctive marine subecosystem, possessing its own food chain, with the depth, in relation to temperature, as the most important factor responsible for the diversity of fish assemblages within this habitat.

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.

scholarly journals Beyond traditional biodiversity fish monitoring: environmental DNA metabarcoding and simultaneous underwater visual census detect different sets of a complex fish community at a marine biodiversity hotspot

2019 ◽  
Author(s):  
Tania Valdivia-Carrillo ◽  
Axayácatl Rocha-Olivares ◽  
Héctor Reyes-Bonilla ◽  
José Francisco Domínguez-Contreras ◽  
Adrian Munguia-Vega
Keyword(s):  
Gulf Of California ◽  
High Throughput Sequencing ◽  
Environmental Dna ◽  
Marine Ecology ◽  
Marine Biodiversity ◽  
Rocky Reef ◽  
Monitoring Methods ◽  
Visual Census ◽  
Traditional Methods ◽  
Underwater Visual Census

ABSTRACTSignificant advances in the study of marine fish communities have been achieved with traditional monitoring methods and recently with novel genetic approaches. eDNA metabarcoding is one of them and a powerful tool for the study of biodiversity still in continuous development. Its applicability in marine ecology and conservation studies may be gauged by comparing its results with those of traditional methods. In the present investigation, we compare results from the underwater visual census (UVC) with eDNA metabarcoding (eDNA) carried out simultaneously in 24 rocky reef sites along the Gulf of California. We developed a two-PCR library preparation protocol followed by high throughput sequencing aimed at teleost fish. Our results show that both methods had different detection capabilities, and each registered different sets of fish taxa from rocky reefs, with some overlap. In particular, eDNA identified taxa from pelagic, demersal, and estuarine habitats beyond the rocky reef itself, suggesting differences in detection mainly attributed to the transport and permanence time of the eDNA in the ocean. Overlap in the detection with both methods increased with taxonomic level. We argue that substantial gaps in sequence reference databases for teleost are at the root of major discrepancies. Our results also confirm that PCR-based eDNA metabarcoding of seawater samples does not reflect patterns in abundance and biomass of species estimated from traditional methods. We discuss how to reconcile the results of eDNA metabarcoding and traditional methods in marine hotspots.

scholarly journals Comparative analysis of tidepool fish species composition on tropical coastal rocky reefs at State of Ceará, Brazil

2008 ◽  
Vol 98 (3) ◽  
pp. 379-390 ◽  
Author(s):  
Edna A. Cunha ◽  
Roberto A. A. Carvalho ◽  
Cassiano Monteiro-Neto ◽  
Luiz Eduardo S. Moraes ◽  
Maria Elisabeth Araújo
Keyword(s):  
Fish Assemblages ◽  
Species Assemblages ◽  
Northeast Brazil ◽  
Environmental Complexity ◽  
Visual Census ◽  
Rocky Reefs ◽  
Census Techniques ◽  
Abundant Taxon ◽  
Fish Species Composition ◽  
Number Of Individuals

This study compared tidepool fish assemblages within and among habitats at Iparana and Pecém beaches, State of Ceará, Northeast Brazil, using visual census techniques. A total of 8,914 fishes, representing 25 families and 43 species were recorded. The most abundant taxon was Sparisoma spp, followed by Haemulon parra (Desmarest, 1823), Acanthurus chirurgus (Bloch, 1787) and Abudefduf saxatilis (Linnaeus, 1758). Haemulidae was the most abundant family in number of individuals, followed by Scaridae, Acanthuridae and Pomacentridae. Within- and between- site differences in species assemblages probably reflected environmental discontinuities and more localized features, such as pool isolation episodes, or environmental complexity, both acting isolated or interactively. The locality of Iparana was probably subjected to a greater fishing pressure and tourism than Pecém, a potential cause for the observed lowest fish abundance and biodiversity. We conclude that tidepool ichthyofauna may be quite variable between and within reef sites. Thus, observations taken from or damages caused on one area may not be generalized to or mitigated by the protection of adjacent sites.

scholarly journals Checklist of invertebrates and conspicuous fishes in rocky reefs and Sargassum beds in the North Pacific of Costa Rica

2021 ◽  
Vol 69 (Suppl.2) ◽  
pp. S180-S193
Author(s):  
Alvin Suárez ◽  
Rafael Riosmena-Rodríguez ◽  
Jorge Cortés
Keyword(s):  
Costa Rica ◽  
Fish Species ◽  
North Pacific ◽  
Field Work ◽  
Marine Ecosystems ◽  
Marine Biodiversity ◽  
Underwater Visual Census ◽  
The North ◽  
Rocky Reefs ◽  
The North Pacific

Introduction: The marine biodiversity is well known in some areas and for some marine ecosystems of the Pacific coast of Costa Rica. The marine sector of Área de Conservación Guanacaste, in the North Pacific of the country, is a priority area for conservation of marine and coastal biodiversity. Objective: Our aim was to increase the knowledge of marine biodiversity in a conservation priority site in Costa Rica and in poorly or scarcely studied marine ecosystems, such as rocky reefs and Sargassum beds, respectively. Methods: The study was conducted in Bahía Salinas and Golfo de Santa Elena in 2013. In January, four rocky reefs were visited; while in February three rocky reefs and one Sargassum bed were visited. We identified the macroinvertebrates and conspicuous fish species through underwater visual census methods (timed swim and band transects). The mean density of each species was estimated through band transects method. Results: A total of 25 invertebrates and 34 fish species were identified. We found a high number of species of invertebrates (23) and fish species (33) in rocky reefs, but few species on Sargassum beds (eight invertebrates and ten fish species). Species composition differed between marine ecosystems. Conclusions: Our study further evidence the limited knowledge of invertebrates and fish communities in these marine ecosystems in the North Pacific of Costa Rica. Considerably more surveys and field work are required to support management decisions that are backed by sound scientific knowledge.

scholarly journals Video transects as a complement to underwater visual census to study reserve effect on fish assemblages

2013 ◽  
Vol 18 (3) ◽  
pp. 229-241 ◽  
Author(s):  
A Tessier ◽  
J Pastor ◽  
P Francour ◽  
G Saragoni ◽  
R Crec’hriou ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Visual Census ◽  
Underwater Visual Census ◽  
Reserve Effect

scholarly journals A comparison of underwater visual distance estimates made by scuba divers and a stereo-video system: implications for underwater visual census of reef fish abundance

2004 ◽  
Vol 55 (6) ◽  
pp. 573 ◽  
Author(s):  
Euan Harvey ◽  
David Fletcher ◽  
Mark R. Shortis ◽  
Gary A. Kendrick
Keyword(s):  
Reef Fish ◽  
Relative Error ◽  
Fish Assemblages ◽  
Fish Abundance ◽  
Visual Census ◽  
Underwater Visual Census ◽  
Video System ◽  
Mean Relative Error ◽  
Scuba Divers ◽  
Stereo Video

Underwater visual census of reef fish by scuba divers is a widely used and useful technique for assessing the composition and abundance of reef fish assemblages, but suffers from several biases and errors. We compare the accuracy of underwater visual estimates of distance made by novice and experienced scientific divers and an underwater stereo-video system. We demonstrate the potential implications that distance errors may have on underwater visual census assessments of reef fish abundance. We also investigate how the accuracy and precision of scuba diver length estimates of fish is affected as distance increases. Distance was underestimated by both experienced (mean relative error = −11.7%, s.d. = 21.4%) and novice scientific divers (mean relative error = −5.0%, s.d. = 17.9%). For experienced scientific divers this error may potentially result in an 82% underestimate or 194% overestimate of the actual area censused, which will affect estimates of fish density. The stereo-video system also underestimated distance but to a much lesser degree (mean relative error = −0.9%, s.d. = 2.6%) and with less variability than the divers. There was no correlation between the relative error of length estimates and the distance of the fish away from the observer.

scholarly journals New Distributional Record of Twelve Scleractinian Corals From Saint Martin’s Island, Bangladesh

2021 ◽  
Vol 49 (1) ◽  
pp. 3-18
Author(s):  
Kazi Ahsan Habib ◽  
Md Jayedul Islam
Keyword(s):  
Scleractinian Coral ◽  
Coral Species ◽  
New Records ◽  
Scleractinian Corals ◽  
Marine Biodiversity ◽  
Biodiversity Monitoring ◽  
Visual Census ◽  
Underwater Visual Census ◽  
Coral Communities ◽  
First Time

Saint Martin's Island is the only island in Bangladesh where coral communities are found. An expedition on marine biodiversity monitoring of Saint Martin’s Island through underwater visual census method was carried out from December 2017 to March 2018. In this study, a total of 25 scleractinian coral species of 8 families and 14 genera were identified, of which 12 species, Dipsastraea lizardensis, Dipsastraea maritima, Dipsastraea veroni, Favites acuticollis, Favites melicerum, Favites pentagona, Goniastrea stelligera, Goniopora albiconus, Goniopora norfolkensis, Pavona clavus, Plesiastrea versipora, and Psammocora exesa were recorded for the first time in Bangladeshi marine water. These new records exemplify gaps in sampling and recording of coral species in Bangladesh, and suggest the need of extensive research on coral ecosystem in the country. Assessment of different valid reports and publications including the present study revealed that a total of 98 species of hard corals of 18 families and 37 genera have been reported until now in Saint Martin’s Island as well as Bangladesh. Bangladesh J. Zool. 49(1): 03-18, 2021

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

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