scholarly journals The influence of depth on the Mediterranean reef fish assemblage revealed by the new video on underwater scooter method

2020 ◽  
Vol 61 (2) ◽  
pp. 145-162
Author(s):  
Igor Glavičić ◽  
Marcelo Kovačić ◽  
Dejan Paliska ◽  
Dani Laslo
Keyword(s):  
Reef Fish ◽  
Fish Assemblage ◽  
Environmental Variables ◽  
Fish Assemblages ◽  
Average Density ◽  
Depth Range ◽  
Fish Assemblage Structure ◽  
Visual Census ◽  
Reef Fish Assemblage ◽  
Significant Difference

The new video on underwater scooter method in combination with rebreather diving techniques was introduced and applied for visual census of fish assemblages. The presently applied method facilitates deeper visual census studies below 40 m, where they have rarely been done before due to the increasing research challenges with depth. The video on underwater scooter method is also expected to be less disturbing and faster compared to swimming divers. The method was applied in visual census study of fish assemblages from 8 to 50 m depth conducted at two locations in the east Adriatic using 102 video transects. The environmental variables contributing to the variation of the reef fish community in the depth range of the infralittoral and upper circalittoral bottoms were also recorded. Thirty-one fish species were recorded on transects and 10.3% of all individuals were not identified to the species level. The average density on transects was 0.8 individuals/m², with C. chromis, C. julis and G. auratus being both the most abundant and the most frequent species. Three environmental variables, depth, bottom with zoocover and eastern orientation of the coast, were identified as highly significant for species occurrence. Abundance and species richness of fish assemblages showed no significant variation with depths, inclinations, orientations and sites. A significant difference in the fish assemblage structure was found among orientations, depths and inclinations with the gradient change of species composition with increasing depth and with increasing inclination.

scholarly journals Rocky reef fish assemblage structure in coastal islands of Southern Brazil

2015 ◽  
Vol 2 ◽  
Author(s):  
Daros Felippe ◽  
Bueno Leonardo ◽  
Soeth Marcelo ◽  
Bertoncini Athila ◽  
Hostim-Silva Mauricio ◽  
...  
Keyword(s):  
Reef Fish ◽  
Fish Assemblage ◽  
Assemblage Structure ◽  
Rocky Reef ◽  
Fish Assemblage Structure ◽  
Southern Brazil ◽  
Reef Fish Assemblage ◽  
Rocky Reef Fish

scholarly journals Fish Assemblage Structure Comparison between Freshwater and Estuarine Habitats in the Lower Nakdong River, South Korea

2020 ◽  
Vol 8 (7) ◽  
pp. 496
Author(s):  
Joo Myun Park ◽  
Ralf Riedel ◽  
Hyun Hee Ju ◽  
Hee Chan Choi
Keyword(s):  
Fish Assemblage ◽  
Fish Assemblages ◽  
Estuarine Fish ◽  
Freshwater Species ◽  
Fish Assemblage Structure ◽  
Nakdong River ◽  
Structure Comparison ◽  
Significant Difference ◽  
Freshwater Habitats ◽  
The Nakdong River

Variabilities of biological communities in lower reaches of urban river systems are highly influenced by artificial constructions, alterations of flow regimes and episodic weather events. Impacts of estuary weirs on fish assemblages are particularly distinct because the weirs are disturbed in linking between freshwater and estuarine fish communities, and migration successes for regional fish fauna. This study conducted fish sampling at the lower reaches of the Nakdong River to assess spatio-temporal variations in fish assemblages, and effects of estuary weir on structuring fish assemblage between freshwater and estuary habitats. In total, 20,386 specimens comprising 78 species and 41 families were collected. The numerical dominant fish species were Tachysurus nitidus (48.8% in total abundance), Hemibarbus labeo (10.7%) and Chanodichthys erythropterus (3.6%) in the freshwater region, and Engraulis japonicus (10.0%), Nuchequula nuchalis (7.7%) and Clupea pallasii (5.2%) in the estuarine site. The fish sampled were primarily small species or the juveniles of larger species at the estuary region, while all life stages of fishes were observed at the freshwater habitats. The diversity patterns of fish assemblages varied greatly according to study site and season, with higher trends at estuarine sites during the warm-rainy season. No significant difference in diversity between freshwater and estuarine sites during the cold-dry season were found. Multivariate analyses of fish assemblage showed spatial and seasonal differences of assemblage structures. Higher effects of between-site variability but not within seasonal variability at each site were observed. Variations in assemblage structures were due to different contributions of dominant species in each habitat. Common freshwater species characterized the fish assemblage in the freshwater region, while marine juveniles were significantly associated with the estuarine habitat. The results from the ecological guild analyses showed distinct ecological roles for freshwater and marine species, and overlapping roles for fish sampled at the fishways. The lower reaches of the Nakdong River are an important ecosystem for both freshwater and marine juveniles. Nakdong River estuarine residents and migrant fishes, however, have been negatively affected by the construction of the weir (gravity dam), due to the obstruction to migration from and to freshwater habitats. Conservation and management policies aimed at minimizing anthropogenic influences on estuary ecosystems should focus on evaluating ecological functions of estuary weirs.

scholarly journals Rocky reef fish assemblage structure in coastal islands of southern Brazil

2018 ◽  
Vol 46 (1) ◽  
pp. 197-211 ◽  
Author(s):  
Felippe Daros ◽  
Leonardo Bueno ◽  
Marcelo Soeth ◽  
Athila Bertoncini ◽  
Mauricio Hostim ◽  
...  
Keyword(s):  
Reef Fish ◽  
Fish Assemblage ◽  
Assemblage Structure ◽  
Rocky Reef ◽  
Fish Assemblage Structure ◽  
Southern Brazil ◽  
Reef Fish Assemblage ◽  
Rocky Reef Fish

Assessing reef fish assemblage structure: how do different stereo-video techniques compare?

2010 ◽  
Vol 157 (6) ◽  
pp. 1237-1250 ◽  
Author(s):  
Dianne L. Watson ◽  
Euan S. Harvey ◽  
Ben M. Fitzpatrick ◽  
Timothy J. Langlois ◽  
George Shedrawi
Keyword(s):  
Reef Fish ◽  
Fish Assemblage ◽  
Assemblage Structure ◽  
Fish Assemblage Structure ◽  
Reef Fish Assemblage ◽  
Stereo Video

scholarly journals Correlations Between Fish Assemblage Structure and Environmental Variables of Taruwa Pond in Nawalparasi District, Province No. 4, Nepal

2021 ◽  
Vol 11 (1) ◽  
pp. 1-8
Author(s):  
JASH HANG LIMBU ◽  
KESHI CHAUDHARY
Keyword(s):  
Temporal Variation ◽  
Fish Assemblage ◽  
Environmental Variables ◽  
Fish Assemblages ◽  
Mesh Size ◽  
Assemblage Structure ◽  
Fish Assemblage Structure ◽  
Fish Community Structure ◽  
Water Parameters ◽  
Analysis Of Similarity

The correlations between fisheries diversity and environmental variables of Nepal’s Pond are poorly understood. This study aims to investigate temporal variation of fish assemblage at Taruwa Pond in Nawalparasi district, Province no. 4, Nepal from October 2018 to April 2019. For the fish agglomeration, cast net of 4 kg in weight and 3.80 m in length and 22.5 m breadth with 12 mm mesh size was used. In total, 579 individuals representing 16 fish species, 10 families, and 12 genera were recorded. According to similarity percentage analysis, the most contributory species were Puntius ticto (27.92%) followed by Danio devario (12.06%), Puntius terio (9.76%), Badis badis (7.31%), Lepidocephalichthys guntea (5.57%) and Puntius sophore (5.57%). Analysis of similarity suggested that fish community structure was significantly different in temporal variation (R = 0.321, p<0.01). Based on the cluster analysis, fish assemblages were isolated into two distinct groups at Bray-curtis similarity. The Canonical Correspondence Analysis distinctly indicated that the water parameters of dissolved oxygen, carbon-dioxide, depth, and water temperature play an important role in influencing the fish assemblage structure of Taruwa Pond.

scholarly journals Fish Community Structure and Environmental Correlates in Nepal’s Andhi Khola, Province No. 4, Syangja

2020 ◽  
Vol 10 (2) ◽  
pp. 85-92
Author(s):  
Jash hang Limbu ◽  
BISHNU BHURTEL ◽  
ASHIM ADHIKARI ◽  
PUNAM GC ◽  
MANIKA MAHARJAN ◽  
...  
Keyword(s):  
Community Structure ◽  
Spatial Variation ◽  
Fish Assemblage ◽  
Environmental Variables ◽  
Fish Community ◽  
Mesh Size ◽  
Fish Diversity ◽  
Fish Assemblage Structure ◽  
Fish Community Structure ◽  
Significant Difference

The study of correlations between fish diversity, environmental variables and fish habitat aspects at different space and time scales of Nepal’s rivers and streams is scanty. This study investigated spatial and temporal patterns of fish assemblage structure in Nepal’s Andhi Khola. The field survey was conducted from September 2018 to May 2019 and the fishes were sampled from three sites using a medium size cast net of mesh size ranging from 1.5 to 2.5 cm and gill net having 2-3 cm mesh size, 30-35 feet length and 3-4 feet width, with the help of local fisher man. A total of 907 individuals representing 15 species belonged to four orders, six families and 11 genera were recorded during the study time. To detect the feasible relationships between fish community structure and environmental variables, we executed a Canonical Correspondence Analysis (CCA). Based on similarity percentage (SIMPER) analysis, the major contributing species are Barilius barila (26.15%), Barilius vagra (20.48%), Mastacembelus armatus (8.04%), Puntius terio (6.64%), and Barilius bendelisis (5.94%). One-way analysis similarity (ANOSIM) tried out for both time and space variations in fish community structure suggested that there was a significant difference in temporal variation (R = 0.794, P = 0.0037) but no significant difference in spatial variation (R = -0.18, P = 0.923). Results from the Canonical Correspondence Analysis (CCA) vindicated that dissolved oxygen, free carbon-dioxide and total hardness were the principle physio-chemical correlates of fish assemblage structure. One-way analysis of similarity (ANOSIM) on the Non-metric Multidimensional Scaling (NMDS) showed significant difference between spring, autumn and winter season but no significant difference was found in spatial variation. The extraction and transportation of boulders, cobbles, pebbles, sand mining, haphazard ongoing road development and dam construction for the irrigation without fish ladders were found to be existing threats to the fish diversity of Andhi Khola.   Keywords: Fish assemblage, multivariate analysis, rivers, spatio-temporal, streams

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