scholarly journals Seasonal changes in fish assemblage structure at a shallow seamount in the Gulf of California

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2357 ◽  
Author(s):  
Salvador J. Jorgensen ◽  
A. Peter Klimley ◽  
Arturo Muhlia-Melo ◽  
Steven G. Morgan
Keyword(s):  
Species Richness ◽  
Gulf Of California ◽  
Individual Species ◽  
Fish Assemblage Structure ◽  
Visual Census ◽  
Underwater Visual Census ◽  
Thermal Habitat ◽  
Definition Of ◽  
Surrounding Areas ◽  
Response To Temperature

Seamounts have generally been identified as locations that can promote elevated productivity, biomass and predator biodiversity. These properties attract seamount-associated fisheries where elevated harvests can be obtained relative to surrounding areas. There exists large variation in the geological and oceanographic environment among the thousands of locations that fall within the broad definition of seamount. Global seamount surveys have revealed that not all seamounts are hotspots of biodiversity, and there remains a strong need to understand the mechanisms that underlie variation in species richness observed. We examined the process of fish species assembly at El Bajo Espiritu Santo (EBES) seamount in the Gulf of California over a five-year study period. To effectively quantify the relative abundance of fast-moving and schooling fishes in a ‘blue water’ habitat, we developed a simplified underwater visual census (UVC) methodology and analysis framework suitable for this setting and applicable to future studies in similar environments. We found correlations between seasonally changing community structure and variability in oceanographic conditions. Individual species responses to thermal habitat at EBES revealed three distinct assemblages, a ‘fall assemblage’ tracking warmer overall temperature, a ‘spring assemblage’ correlated with cooler temperature, and a ‘year-round assemblage’ with no significant response to temperature. Species richness was greatest in spring, when cool and warm water masses stratified the water column and a greater number of species from all three assemblages co-occurred. We discuss our findings in the context of potential mechanisms that could account for predator biodiversity at shallow seamounts.

scholarly journals Seasonal changes in fish assemblage structure at a shallow seamount in the Gulf of California

2016 ◽  
Author(s):  
Salvador J Jorgensen ◽  
A. Peter Klimley ◽  
Arturo Muhlia-Melo ◽  
Steven G Morgan
Keyword(s):  
Species Richness ◽  
Gulf Of California ◽  
Individual Species ◽  
Fish Assemblage Structure ◽  
Visual Census ◽  
Underwater Visual Census ◽  
Thermal Habitat ◽  
Definition Of ◽  
Surrounding Areas ◽  
Response To Temperature

Seamounts have generally been identified as locations that can promote elevated productivity, biomass and predator biodiversity. These properties attract seamount-associated fisheries where elevated harvests can be obtained relative to surrounding areas. There exists large variation in the geological and oceanographic environment among the thousands of locations that fall within the broad definition of seamount. Global seamount surveys have revealed that not all seamounts are hotspots of biodiversity, and there remains a strong need to understand the mechanisms that underlie variation in species richness observed. We examined the process of fish species assembly at El Bajo Espiritu Santo (EBES) seamount in the Gulf of California over a five-year study period. To effectively quantify the relative abundance of fast-moving and schooling fishes in a ‘blue water’ habitat, we developed a simplified underwater visual census (UVC) methodology and analysis framework suitable for this setting and applicable to future studies in similar environments. We found correlations between seasonally changing community structure and variability in oceanographic conditions. Individual species responses to thermal habitat at EBES revealed three distinct assemblages, a ‘summer assemblage’ tracking warmer overall temperature, a ‘winter assemblage’ correlated with cooler temperature, and a ‘year-round assemblage’ with no significant response to temperature. Species richness was greatest in spring, when cool and warm water masses stratified the water column and a greater number of species from all three assemblages co-occurred. We discuss our findings in the context of potential mechanisms that could account for predator biodiversity at shallow seamounts.

scholarly journals Seasonal changes in fish assemblage structure at a shallow seamount in the Gulf of California

2016 ◽  
Author(s):  
Salvador J Jorgensen ◽  
A. Peter Klimley ◽  
Arturo Muhlia-Melo ◽  
Steven G Morgan
Keyword(s):  
Species Richness ◽  
Gulf Of California ◽  
Individual Species ◽  
Fish Assemblage Structure ◽  
Visual Census ◽  
Underwater Visual Census ◽  
Thermal Habitat ◽  
Definition Of ◽  
Surrounding Areas ◽  
Response To Temperature

Seamounts have generally been identified as locations that can promote elevated productivity, biomass and predator biodiversity. These properties attract seamount-associated fisheries where elevated harvests can be obtained relative to surrounding areas. There exists large variation in the geological and oceanographic environment among the thousands of locations that fall within the broad definition of seamount. Global seamount surveys have revealed that not all seamounts are hotspots of biodiversity, and there remains a strong need to understand the mechanisms that underlie variation in species richness observed. We examined the process of fish species assembly at El Bajo Espiritu Santo (EBES) seamount in the Gulf of California over a five-year study period. To effectively quantify the relative abundance of fast-moving and schooling fishes in a ‘blue water’ habitat, we developed a simplified underwater visual census (UVC) methodology and analysis framework suitable for this setting and applicable to future studies in similar environments. We found correlations between seasonally changing community structure and variability in oceanographic conditions. Individual species responses to thermal habitat at EBES revealed three distinct assemblages, a ‘summer assemblage’ tracking warmer overall temperature, a ‘winter assemblage’ correlated with cooler temperature, and a ‘year-round assemblage’ with no significant response to temperature. Species richness was greatest in spring, when cool and warm water masses stratified the water column and a greater number of species from all three assemblages co-occurred. We discuss our findings in the context of potential mechanisms that could account for predator biodiversity at shallow seamounts.

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 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.

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

Response of dry grassland vegetation to fluctuations in weather conditions: a 9-year case study in Prague (Czech Republic)

Biologia ◽  
2011 ◽  
Vol 66 (5) ◽  
Author(s):  
Jiří Dostálek ◽  
Tomáš Frantík
Keyword(s):  
Species Richness ◽  
Czech Republic ◽  
Weather Conditions ◽  
Grass Species ◽  
Individual Species ◽  
Weather Variability ◽  
Grassland Vegetation ◽  
Dry Grassland ◽  
Local Climate ◽  
The Impact

AbstractThe extreme habitats of dry grasslands are suitable for investigations of the response of vegetation to local climate changes. The impact of weather variability on the dynamics of a plant community in a dry grassland was studied. Correlations were found between different functional groups of species and individual species and weather variability. During a 9-year study in five nature reserves in Prague (Czech Republic), the following responses of dry grassland vegetation to weather conditions were observed: (i) wetter conditions, especially in the winter, affected the dominance and species richness of perennial grass species and the decline of rosette plants; (ii) the year-to-year higher temperatures in the winter produced a decline in the dominance of short graminoids and creeping forbs; (iii) spring drought adversely impacted the overall abundance, especially the abundance of dicotyledonous species, and the species richness. However, these relationships may be manifested in different ways in different locations, and in some cases the vegetation of different locations may respond to weather conditions in opposite manners.

Diverse perennial crop mixtures sustain higher productivity over time based on ecological complementarity

2011 ◽  
Vol 26 (4) ◽  
pp. 317-327 ◽  
Author(s):  
Valentín D. Picasso ◽  
E. Charles Brummer ◽  
Matt Liebman ◽  
Philip M. Dixon ◽  
Brian J. Wilsey
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Biomass Production ◽  
Cropping Systems ◽  
Individual Species ◽  
Selection Effects ◽  
Complementarity Effect ◽  
Change Over Time ◽  
Diversity Effects ◽  
Over Time

AbstractCropping systems that rely on renewable energy and resources and are based on ecological principles could be more stable and productive into the future than current monoculture systems with serious unintended environmental consequences such as soil erosion and water pollution. In nonagricultural systems, communities with higher species diversity have higher productivity and provide other ecosystem services. However, communities of well-adapted crop species selected for biomass production may respond differently to increasing diversity. Diversity effects may be due to complementarity among species (complementary resource use and facilitative interactions) or positive selection effects (e.g., species with higher productivity dominate the mixture), and these effects may change over time or across environments. Our goal was to identify the ecological mechanisms causing diversity effects in a biodiversity experiment using agriculturally relevant species, and evaluate the implications for the design of sustainable cropping systems. We seeded seven perennial forage species in a replicated field experiment at two locations in Iowa, USA, and evaluated biomass productivity of monocultures and two- to six-species mixtures over 3 years after the establishment year under management systems of contrasting intensity: one or three harvests per year. Productivity increased with seeded species richness in all environments, and the positive relationship did not change over time. Polyculture overyielding was due to complementarity among species in the community rather than to selection effects of individual species. Complementarity increased as a log-linear function of species richness in all environments, and this trend was consistent across years. Legume–grass facilitation may explain much of this complementarity effect. Although individual species with high biomass production had a major effect on productivity of mixtures, the species producing the highest biomass in monoculture changed over the years in most environments. Furthermore, transgressive overyielding was observed and was more prevalent in later years, in some environments. We conclude that choosing a single well-adapted species for maximizing productivity may not be the best alternative over the long term and that high levels of species diversity should be included in the design of productive and ecologically sound agricultural systems.

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%.

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