scholarly journals The demersal fish assemblages of the infra and circalittoral coastal rocky bottoms of the Aeolian Archipelago (Central Mediterranean Sea) studied by Remotely Operated Vehicle (ROV)

2020 ◽  
Author(s):  
IVAN CONSALVO ◽  
GABRIELE La MESA ◽  
SIMONEPIETRO CANESE ◽  
MICHELA GIUSTI ◽  
EVA SALVATI ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Fish Assemblages ◽  
Demersal Fish ◽  
Total Density ◽  
Depth Range ◽  
Remotely Operated Vehicle ◽  
Depth Ranges ◽  
Aeolian Archipelago ◽  
Rocky Bottoms

Demersal fish assemblages on the rocky bottoms of the Aeolian Archipelago were investigated using a Remotely Operated Vehicle (ROV) within the framework of research activities aimed at drawing up the zoning proposal of a new Italian national marine protected area. Visual assessments were conducted around the seven main islands by means of a total of 36 ROV transects. Video material was divided into 3 parts belonging to 3 Archipelago sectors (Western, Central and Eastern) and into 3 depth ranges (20-50, 51-120, 121-190). Thirty taxa of teleosts (29 species and 1 genus) belonging to 16 families were recorded. The assemblages were numerically dominated by some schooling fishes, such as Anthias anthias, Callanthias ruber and Chromis chromis, which exhibited a depth related partitioning of space, and three non-gregarious species, i.e. Serranus cabrilla, Coris julis and Lappanella fasciata. In terms of species composition, the assemblages observed in the sectors of the Archipelago largely overlapped. No significant sector-related differences were detected in fish species richness, diversity and total density. Species composition and the investigated assemblage parameters were significantly affected by depth. The pattern of variation in species richness among depth ranges changed depending on the archipelago sectors. No significant interaction between the factors depth range and sector was observed for species diversity and total density. Diversity values at 20-50 and 121-190 m depth were similar and significantly higher than that at 51-120 m depth. Fish total density showed a clear decreasing trend with increasing depth, though significant differences were detected between the 20-50 and 51-120 depth layers and the deepest one. Overall, the demersal fish assemblage of the Aeolian Archipelago was poorly diversified and depleted, most likely due to overfishing. This information highlighted the importance of the adoption of specific measures aimed at the recovery of overexploited resources and the restoration of the whole marine ecosystems.

scholarly journals Assessment of coastal fish assemblages before the establishment of a new marine protected area in central Mediterranean: its role in formulating zoning proposal

2017 ◽  
Vol 18 (1) ◽  
pp. 11 ◽  
Author(s):  
G. LA MESA ◽  
E. SALVATI ◽  
S. AGNESI ◽  
L. TUNESI
Keyword(s):  
Species Composition ◽  
Protected Area ◽  
Fish Assemblages ◽  
Marine Protected Area ◽  
Scuba Diving ◽  
Northwestern Part ◽  
Total Density ◽  
Central Mediterranean ◽  
Italian Law ◽  
Depth Ranges

The fish assemblages of the coastal area of the promontory of Cape Milazzo (Italy, Central Mediterranean), which has been recently designated by the Italian Law to become a national marine protected area (MPA), were characterized by visual censuses carried out over different habitats (rocky algal reef, Posidonia oceanica meadow and soft bottom) and depth ranges (0-3, 4-7, 12-16 and 24-30 m) to identify areas of major concern for the MPA zoning. The study area was divided into 6 sectors to assess spatial-related differences in the assemblage parameters, such as species composition and richness, and the size structure of species of recreational (e.g. SCUBA diving) interest. Fifty-eight taxa (56 species and 2 genera) and 20 families of fishes were totally recorded. Species composition was significantly affected by habitat and depth, whereas no significant changes were detected among sectors. Conversely, species richness and total density of fish showed no significant differences among sectors, habitat types and depth ranges. The majority of species of recreational value was recorded only off the northwestern part of the promontory. The implementation of fishing ban in such an area, characterized by the presence of a rocky bank, would contribute to the recovery of populations of some emblematic species (e.g. groupers and other large predator) and to the enhancement of environmentally sustainable activities such as scuba diving. Throughout the investigated area and, especially, in the eastern and southwestern coasts of the promontory, several species were almost exclusively represented by small and medium sized individuals, a likely consequence of an intense fishing pressure.

scholarly journals The influence of offshore windpower on demersal fish

2006 ◽  
Vol 63 (5) ◽  
pp. 775-784 ◽  
Author(s):  
Dan Wilhelmsson ◽  
Torleif Malm ◽  
Marcus C. Öhman
Keyword(s):  
Species Richness ◽  
Power Plants ◽  
Fish Assemblages ◽  
Demersal Fish ◽  
Fish Abundance ◽  
Artificial Reefs ◽  
Fish Community Structure ◽  
Blue Mussels ◽  
Fish Aggregation ◽  
Surrounding Areas

Abstract A significant expansion of offshore windpower is expected in northwestern Europe in the near future. Little is known about the impacts it may have on the marine environment. Here, we investigate the potential for wind turbines to function as artificial reefs and fish aggregation devices (FADs), i.e. whether they would locally increase fish densities or alter fish assemblages. Fish communities and habitat composition were investigated using visual transects at two windpower farms off the southeastern coast of Sweden, central Baltic Sea. Fish abundance was greater in the vicinity of the turbines than in surrounding areas, while species richness and Shannon–Wiener diversity (H′) were similar. On the monopiles of the turbines, fish community structure was different, and total fish abundance was greater, while species richness and diversity (H′) were lower than on the surrounding seabed. Blue mussels and barnacles covered most of the submerged parts of the turbines. On the seabed, more blue mussels and a lesser cover of red algae were recorded around the power plants than elsewhere. Results from this study suggest that offshore windfarms may function as combined artificial reefs and fish aggregation devices for small demersal fish.

scholarly journals A review of the spatial extent of fishery effects and species vulnerability of the deep-sea demersal fish assemblage of the Porcupine Seabight, Northeast Atlantic Ocean (ICES Subarea VII)

2010 ◽  
Vol 68 (2) ◽  
pp. 281-289 ◽  
Author(s):  
Imants G. Priede ◽  
Jasmin A. Godbold ◽  
Tomasz Niedzielski ◽  
Martin A. Collins ◽  
David M. Bailey ◽  
...  
Keyword(s):  
Fish Assemblage ◽  
Deep Sea ◽  
Demersal Fish ◽  
Commercial Fishing ◽  
Depth Range ◽  
Northeast Atlantic ◽  
Porcupine Seabight ◽  
Species Vulnerability ◽  
Northeast Atlantic Ocean ◽  
Depth Ranges

Abstract Priede, I. G., Godbold, J. A., Niedzielski, T., Collins, M. A., Bailey, D. M., Gordon, J. D. M., and Zuur, A. F. 2011. A review of the spatial extent of fishery effects and species vulnerability of the deep-sea demersal fish assemblage of the Porcupine Seabight, Northeast Atlantic Ocean (ICES Subarea VII). – ICES Journal of Marine Science, 68: 281–289. We review information from scientific trawl surveys carried out between 1977 and 2002 in the Porcupine Seabight and Abyssal Plain area of the Northeast Atlantic (240–4865 m water depth). Since the late 1980s, commercial bottom-trawl fisheries targeting mainly roundnose grenadier (Coryphaenoides rupestris), black scabbardfish (Aphanopus carbo), and orange roughy (Hoplostethus atlanticus) have been operating at depths of 500–1500 m, intersecting the depth ranges of 77 demersal fish species that would therefore be vulnerable to fishery effects. Comparisons of trawls pre-1989 and post-1997 indicate a significant decrease in total abundance of demersal fish down to 2500 m. Detailed analyses of the 15 most-abundant species showed that nine species with depth ranges within the commercial fishing depth have decreased in abundance. Other species were either not affected (Bathypterois dubius) or only affected at the shallow end of their range (Coryphaenoides guentheri). Species with a minimum depth of occurrence >1500 m (Coryphaenoides armatus and Coryphaenoides leptolepis) increased in abundance over part of their depth range. Decreases in abundance are probably caused by commercial fishing activities, an effect that is transmitted downslope by removal of fish at the shallow end of their depth range, resulting in declines at the deeper end of the depth range. The estimated fishery area is ca. 52 000 km2, but the potential impact probably extends to ca. 142 000 km2 and to many non-target species.

scholarly journals Effect of environmental and spatial factors on small-sized fish assemblages in a tropical river

2021 ◽  
Vol 51 (2) ◽  
pp. 129-138
Author(s):  
Izaias Médice FERNANDES ◽  
Katiele de Jesus SACOMAN ◽  
José Paulo de FARIAS-NETO ◽  
Hugmar Pains da SILVA ◽  
Jhony VENDRUSCOLO ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Species Richness ◽  
Species Composition ◽  
Environmental Variables ◽  
Fish Assemblages ◽  
Negative Relationship ◽  
Dispersal Limitation ◽  
River Continuum ◽  
Spatial Factors ◽  
Water Characteristics

ABSTRACT The river continuum concept predicts that gradual changes in river geomorphology and hydrology can drive longitudinal changes in aquatic community structure. Accordingly, we evaluated how environmental variables (electrical conductivity, pH, water transparency and water velocity), spatial factors (distance from headwaters and Moran’s eigen vector maps - MEMs), and the presence of dams affect small-sized fish assemblages along a 105-km stretch of the upper Branco River, a tributary in the Madeira River, Amazonas Basin, Brazil. Seine-net based collections were carried out at 15 sites up- and downriver from dams during the 2019 dry season. We captured a total of 4,330 individual fish belonging to three orders, nine families and 26 species (and a hybrid individual). Electrical conductivity and pH were affected by the presence of dams and the distance from headwaters. Species richness and abundance did not vary in response to environmental variables. While species richness showed no significant variation along the sampled river section, abundance showed a negative relationship with distance from headwaters. Species composition varied significantly in response to pH, linear spatial factors and the presence of dams. Our results suggest that change in species composition of small-sized fish assemblages in the upper Branco River occurs due to variation in water characteristics, inherent dispersal limitation, and in response to the presence of dams.

scholarly journals Demersal Fish Assemblages in NE Atlantic Seagrass and Kelp

Diversity ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 366
Author(s):  
Evie Furness ◽  
Richard K.F. Unsworth
Keyword(s):  
Species Richness ◽  
Fish Assemblages ◽  
Demersal Fish ◽  
Kelp Forests ◽  
Evidence Based ◽  
Ecological Value ◽  
Commercial Fish ◽  
Seagrass Meadows ◽  
The North ◽  
Commercial Species

Global fisheries are in decline, calling for urgent evidence-based action. One such action is the identification and protection of fishery-associated habitats such as seagrass meadows and kelp forests, both of which have suffered long-term loss and degradation in the North Atlantic region. Direct comparisons of the value of seagrass and kelp in supporting demersal fish assemblages are largely absent from the literature. Here, we address this knowledge gap. Demersal fish were sampled using a baited camera to test for differences between habitats in (1) the species composition of the fish assemblages, (2) the total abundance and species richness of fishes, and (3) the abundances of major commercial species. Seagrass and kelp-associated fish assemblages formed two significantly distinct groupings, which were driven by increased whiting (Merlangius merlangus) and dogfish (Scyliorhinus canicula) presence in seagrass and higher abundances of pollock (Pollachius pollachius) and goby (Gobiusculus flavescens) in kelp. The abundance, diversity, and species richness did not change significantly between the two habitats. We conclude that seagrass and kelp do support unique demersal fish assemblages, providing evidence that they have different ecological value through their differing support of commercial fish species. Thus, this study improves the foundation for evidence-based policy changes.

scholarly journals Delineating the habitat of demersal fish assemblages with acoustic seabed technologies

2011 ◽  
Vol 68 (9) ◽  
pp. 1973-1985 ◽  
Author(s):  
Jeroen van der Kooij ◽  
Sven Kupschus ◽  
Beth E. Scott
Keyword(s):  
Species Composition ◽  
Fish Assemblages ◽  
Demersal Fish ◽  
Single Beam ◽  
Explanatory Variables ◽  
Acoustic Data ◽  
Spatial Management ◽  
Fish Habitats ◽  
The Relationship ◽  
Demersal Species

Abstract van der Kooij, J., Kupschus, S., and Scott, B. E. 2011. Delineating the habitat of demersal fish assemblages with acoustic seabed technologies. – ICES Journal of Marine Science, 68: 1973–1985. Habitats influence species distribution and, although the seabed is an important habitat factor for demersal species, traditional sampling methods often provide no practical solution to investigating the seabed over large areas. The ability of a multivariate method that utilizes single-beam acoustic seabed data combined with species composition data to define demersal fish habitats was tested. The best model explained 19.4% of the variance observed in the species data and was robust between years. Ten biotopes were identified, each containing species that, either alone or in combination with others, were indicative of that biotope. Using unclassified acoustic seabed data as explanatory variables, discrepancies between the numbers of acoustically distinct classes and species assemblages, as previously reported in the literature, were avoided, while utilizing their relationship with community structure. The study focused on the relationship between simultaneously recorded species composition and seabed data from fishing stations, but because continuous acoustic data along the survey tracks were available between stations, the model could be used to predict the spatial extent of the biotopes. Although the method was developed with the eventual aim of providing a meaningful foundation to the spatial management of mixed fisheries, it could also contribute to applications in spatial planning.

scholarly journals Decommissioning impacts on biotic assemblages associated with shell mounds beneath southern California offshore oil and gas platforms

2019 ◽  
Vol 95 (4) ◽  
pp. 683-702 ◽  
Author(s):  
Erin L Meyer-Gutbrod ◽  
Milton S Love ◽  
Jeremy T Claisse ◽  
Henry M Page ◽  
Donna M Schroeder ◽  
...  
Keyword(s):  
Species Composition ◽  
Southern California ◽  
Oil And Gas ◽  
Fish Assemblages ◽  
Ecological Value ◽  
Remotely Operated Vehicle ◽  
Wide Range ◽  
Shell Mounds ◽  
Offshore Oil And Gas ◽  
Offshore Oil

The decommissioning of southern California offshore oil and gas platforms will create major economic, engineering, and environmental challenges in the next decade. Platform jackets, conductors, and shell mounds often host a diverse and productive marine community, and among the myriad considerations associated with decommissioning planning, platform operators and federal and state regulatory agencies will consider the ecological value of existing underwater structures as artificial reefs. In the event of partial removal of platform structure, fish assemblages on decommissioned platforms may remain unchanged in areas where structure is left intact. However, on the seafloor beneath the platforms, a mound of debris often called the shell mound will likely change over time if the supply of falling mussels and other organisms from the productive surface part of the structure is removed. In this study, we review shell mound research relevant to decommissioning, including mound formation, contaminant loads, associated biological communities, and transitions following the removal of platform structures at four sites. To address the gap in knowledge of shell mound fish community structure, we used manned submersible and remotely operated vehicle surveys from 1997 to 2013 to estimate the biomass, density, species composition and similarity between shell mounds at 22 southern California platforms. We found a wide range of variability in fish density and shell mound areal extent. Species composition also varied among sites, with three significant community clusters primarily distinguished by species depth preferences. These results will help inform a comprehensive net environmental benefit analysis of southern California offshore platform decommissioning alternatives.

scholarly journals Analysis of demersal fish assemblages of the Tuscany and Latium coasts (north-western Mediterranean)

2002 ◽  
Vol 66 (S2) ◽  
pp. 233 ◽  
Author(s):  
Franco Biagi ◽  
Paolo Sartor ◽  
Gian Domenico Ardizzone ◽  
Paola Belcari ◽  
Andrea Belluscio ◽  
...  
Keyword(s):  
Species Composition ◽  
Continental Shelf ◽  
Fish Assemblages ◽  
Demersal Fish ◽  
Western Mediterranean ◽  
Similar Species ◽  
The European Union ◽  
The North ◽  
North Western ◽  
Trawl Surveys

A four-year time series (1994-1997) of groundfish trawl surveys performed within the European Union Project MEDITS (Mediterranean International Trawl Surveys), was analysed to identify and describe the fish assemblages along the continental shelf and slope of Tuscany and Latium (Italy), in the north-western Mediterranean. Cluster analysis was used to group samples with similar species composition in terms of abundance, biomass and frequency of occurrence. Results allowed the identification of four to five broad assemblages along the depth gradient: a strictly coastal group (< 50 m depth), two groups in the upper and lower part of the continental shelf (essentially 50-200 m), an epibathyal group (200-450 m) and a group derived from hauls made at depths greater than 450 m. Each assemblage corresponded to a faunistic association with relatively homogeneous and persistent species composition, biomass and density indices.

scholarly journals Assessing the impact of fisheries on demersal fish assemblages of the Mauritanian continental shelf, 1987–1999, using dominance curves

2005 ◽  
Vol 62 (3) ◽  
pp. 380-383 ◽  
Author(s):  
Didier Jouffre ◽  
Cheikh A. Inejih
Keyword(s):  
Species Composition ◽  
Continental Shelf ◽  
Fish Assemblages ◽  
Demersal Fish ◽  
Octopus Vulgaris ◽  
Taxonomic Information ◽  
Associated Species ◽  
The Impact ◽  
Trawl Surveys

Abstract The assemblages of demersal fish and associated species of the Mauritanian continental shelf are characterized on the basis of annual trawl surveys conducted during the period 1987–1999. Species composition is dominated by exploited species (Dentex spp., Pagellus bellottii, and Octopus vulgaris). Dominance curves (Abundance Biomass Comparison plots) were used to evaluate the impact of fisheries, which have increased in magnitude over several decades. The diagnosis of a “stressed” assemblage seems to converge with the results of a similar study conducted off Senegal, but here there was no trend in impact during the period of study. The sensitivity of the present results to the various ways of considering the available taxonomic information is also analysed.

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