scholarly journals Winter and summer differences in probability of fish encounter (spatial overlap) with MHK devices

2018 ◽  
Vol 1 (1 (Aug)) ◽  
pp. 9-18 ◽  
Author(s):  
H. Viehman ◽  
T. Boucher ◽  
A. Redden
Keyword(s):  
Tidal Energy ◽  
Test Site ◽  
Energy Development ◽  
Bay Of Fundy ◽  
Natural Distribution ◽  
Spatial Overlap ◽  
Vertical Distributions ◽  
The Vertical Distribution ◽  
Distribution Of Fish ◽  
Tidal Stage

The likelihood of fish encountering an MHK device, and therefore the risk posed to fish, depends largely on the natural distribution of fish at tidal energy development sites. In temperate locations, such as the Bay of Fundy, seasonal changes in the environment and fish assemblage may alter the likelihood of fish encounters with MHK devices. We examined two one-month hydroacoustic datasets collected in winter 2015 and summer 2016 by an upward-facing echosounder deployed at the Fundy Ocean Research Center for Energy test site in the Minas Passage. Fish density was higher and less variable in winter than in summer, likely due to the presence of migratory vs. overwintering fish. The vertical distribution of fish varied with sample period, diel stage, and tidal stage. The proportion of fish at MHK device depth was greater, but more variable, in summer than in winter. Encounter probability, or potential for spatial overlap of fish with an MHK device, was < 0.002 for winter and summer vertical distributions. More information on the distribution of fish (horizontal and vertical), species present, fish sensory and locomotory abilities, and nearfield behaviours in response to MHK devices is needed to improve our understanding of likely device effects on fish.

scholarly journals The impacts of tidal energy development and sea-level rise in the Gulf of Maine

Energy ◽  
2019 ◽  
Vol 187 ◽  
pp. 115942 ◽  
Author(s):  
Boma Kresning ◽  
M. Reza Hashemi ◽  
Simon P. Neill ◽  
J. A. Mattias Green ◽  
Huijie Xue
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Gulf Of Maine ◽  
Tidal Energy ◽  
Energy Development ◽  
And Sea Level

Spatial distribution of the intertidal snail Ilyanassa obsoleta in relation to parasitism by two species of trematodes

2000 ◽  
Vol 78 (7) ◽  
pp. 1137-1143 ◽  
Author(s):  
Dean G McCurdy ◽  
J Sherman Boates ◽  
Mark R Forbes
Keyword(s):  
Spatial Distribution ◽  
Intertidal Zone ◽  
Bay Of Fundy ◽  
Spatial Distributions ◽  
Ilyanassa Obsoleta ◽  
Intermediate Hosts ◽  
Corophium Volutator ◽  
Vertical Distributions ◽  
Second Intermediate Host ◽  
Intertidal Snail

We studied the spatial distributions of mud snails (Ilyanassa obsoleta) infected by two trematodes, Lepocreadium setiferoides and Gynaecotyla adunca, on a macrotidal mudflat in the Minas Basin, Bay of Fundy. Snails, as first intermediate hosts, were castrated by both parasites, and we found no evidence of sex differences in parasitism. Similar to previous work, prevalence of L. setiferoides in I. obsoleta increased exponentially with host size (and age). Unexpectedly, prevalence of G. adunca decreased over the largest size classes of snails, a result that may be due to several causes. Distributions of both parasites across the intertidal zone differed from previous accounts in that snails infected with L. setiferoides were found only in the middle of the intertidal zone, whereas prevalence of G. adunca increased exponentially moving seaward. Several species of polychaetes could be infected by L. setiferoides in the laboratory and may act as appropriate second intermediate hosts, whereas only the amphipod Corophium volutator served as a second intermediate host for G. adunca. Finally, the vertical distributions of I. obsoleta infected by either species of trematode overlap with distributions of apparent or known second intermediate hosts.

Variations of the Local Failure Pressure With Depth Through First-Year and Multi-Year Ice

1988 ◽  
Vol 110 (2) ◽  
pp. 159-168 ◽  
Author(s):  
D. Blanchet
Keyword(s):  
Ice Thickness ◽  
First Year ◽  
Strain Rates ◽  
Failure Pressure ◽  
Pressure Profiles ◽  
Vertical Distributions ◽  
Pressure Area ◽  
Ice Floes ◽  
Ice Pressure ◽  
The Vertical Distribution

Typical vertical distributions of the failure pressure in an ice sheet are presented. The distributions, derived for intermediate strain rates, are a function of many parameters, namely, the salinity, the temperature, the type of ice, the location of the ice pressure area through the ice thickness, the thickness of ice, the density, and the crack and flaw distributions. Two combinations of these parameters lead to “representative” summer and winter vertical ice pressure profiles for 8 and 2-m thick ice floes. The importance of the vertical distribution of the failure pressure inside an ice cover is fundamental for two reasons. The change in the eccentricity of the resultant of the load induces changes in failure mode and load transmission to the structure. This nonuniform distribution will create nonsimultaneous failure and the ice pressure on the structure will not be hydrostatically distributed over a given area.

Bottom hypoxia alters the spatial distribution of pelagic intermediate consumers and their prey

2020 ◽  
Author(s):  
Rebecca A. Dillon ◽  
Joseph D. Conroy ◽  
Kathryn J. Lang ◽  
Kevin L Pangle ◽  
Stuart A. Ludsin
Keyword(s):  
Food Webs ◽  
Pelagic Fish ◽  
Spatial Overlap ◽  
Natural Lakes ◽  
Coastal Marine ◽  
Midwestern Usa ◽  
Vertical Distributions ◽  
Pelagic Food Webs ◽  
Coastal Marine Ecosystems ◽  
Bottom Hypoxia

While recent research has shed insight into how bottom hypoxia affects pelagic food webs in coastal marine ecosystems and natural lakes, its effects on man-made lake (reservoir) food webs remains more incomplete. To address this gap, we conducted a study in two Midwestern USA reservoirs to examine how the spatial overlap and vertical distributions of dominant zooplanktivores (i.e., pelagic fish, the bentho-pelagic macroinvertebrate Chaoborus) and their prey vary between periods of normoxia and hypoxia. Surprisingly, we found high levels of spatial overlap between zooplankton and both intermediate consumers (pelagic fish and Chaoborus) during both normoxia and hypoxia, though the extent of spatial overlap was higher during hypoxia at night relative to day. As expected, pelagic fish and zooplankton avoided hypoxic waters, and Chaoborus moved from hypoxic waters during the day to the well-oxygenated surface waters at night. Using our findings, we discuss the potential influence of bottom hypoxia and Chaoborus on the function and structure of north-temperate reservoir food webs.

Fish, finances, and feasibility: Concerns about tidal energy development in the United States

2019 ◽  
Vol 53 ◽  
pp. 126-136
Author(s):  
Stacia J. Dreyer ◽  
Ezra Beaver ◽  
Hilary J. Polis ◽  
Lekelia D. Jenkins
Keyword(s):  
United States ◽  
Tidal Energy ◽  
The United States ◽  
Energy Development

scholarly journals A HOLISTIC METHOD TO SELECT TIDAL STREAM ENERGY HOTSPOTS

2017 ◽  
pp. 5
Author(s):  
Angela Vazquez ◽  
Gregorio Iglesias
Keyword(s):  
Ad Hoc ◽  
Holistic Approach ◽  
Tidal Energy ◽  
Energy Development ◽  
Potential Conflict ◽  
Cost Of Energy ◽  
Tidal Turbine ◽  
Tidal Stream ◽  
Tidal Stream Energy

Potential areas for tidal stream energy development are conventionally selected on the basis of resource assessments. For all the importance of the resource, there are other elements (technological, economic, spatial, etc.) that must be taken into account in this selection. The objective of the present work is to develop a new methodology to select tidal stream hotspots accounting for all these relevant elements, and to apply it to a case study, showing in the process how the potential for tidal energy development can be fundamentally altered by technological, economic and spatial constraints. The case study is conducted in the Bristol Channel and Severn Estuary (UK), one of the regions with the largest tidal resource in the world. First, the most energetic areas are identified by means of a hydrodynamics model, calibrated and validated with field data. Second, the method calculates the energy that can be harnessed in these areas by means of a geospatial Matlab-based program designed ad hoc, and on the basis of the power curve and dimensions of a specific tidal turbine. Third, the spatial distribution of the levelised cost of energy (LCOE) is calculated, and a number of locations are selected as potential tidal sites. The fourth element in the approach is the consideration of restrictions due to overlap with other marine uses, such as shipping. As a result, potential conflict-free areas for tidal stream energy exploitation at an economical cost are identified. Thus, the case study illustrates this holistic approach to selecting tidal stream sites and the importance of elements other than the resource, which – for all its relevance – is shown to not guarantee by itself the potential for tidal stream energy development.

Integration of insect sterility and insecticides for control of Glossina morsitans morsitans Westwood (Diptera: Glossinidae) in Tanzania. III. Test site characteristics and the natural distribution of tsetse flies

1983 ◽  
Vol 73 (3) ◽  
pp. 373-381 ◽  
Author(s):  
D. B. Gates ◽  
P. E. Cobb ◽  
D. L. Williamson ◽  
B. Bakuli ◽  
D. A. Dame ◽  
...  
Keyword(s):  
Release Site ◽  
Test Site ◽  
Glossina Morsitans Morsitans ◽  
Tsetse Flies ◽  
Detailed Data ◽  
Glossina Morsitans ◽  
Natural Distribution ◽  
Male Density ◽  
Site Characteristics ◽  
North Eastern

AbstractDetailed data from a preselected release site in Tanzania were collected preparatory to testing the insect sterility concept against Glossina morsitans morsitans Westw. The site was at Mkwaja Ranch, a north-eastern coastal cattle-ranching enterprise, in which about 195 km2 was encompassed by a 1-km-wide fly barrier constructed at an average cost of $37/ha. Weekly surveys of flyround transects spaced 1 km apart were conducted over a 14-month period. The estimated male density of G. m. morsitans in the release site was about 630/km2 and for G. pallidipes Aust., 255/km2. The only other species of tsetse found was G. brevipalpis Newst., which was restricted to drainage areas during periods of low rainfall.

scholarly journals Nitric acid and particulate matter measurements at Athens, Greece, in connection with corrosion studies

2009 ◽  
Vol 9 (21) ◽  
pp. 8309-8316 ◽  
Author(s):  
C. Tzanis ◽  
C. Varotsos ◽  
M. Ferm ◽  
J. Christodoulakis ◽  
M. N. Assimakopoulos ◽  
...  
Keyword(s):  
Test Site ◽  
Water Soluble ◽  
Passive Samplers ◽  
Field Exposure ◽  
Exposure Test ◽  
Corrosion Studies ◽  
Long Time ◽  
The University ◽  
The Vertical Distribution ◽  
The Eu

Abstract. For a long time, scientists have been concerned about the effects of air pollution on materials and especially on the monuments of the cultural heritage. The EU funded a project, entitled MULTI-ASSESS, to determine these effects and to develop dose-response functions appropriate for the new multi-pollutant environment. The University of Athens participated in this effort as a targeted field exposure test site. In the present paper, the measurements of the passive samplers, which were exposed during the same period with the samples for corrosion studies, at the Athens station, are presented. The results have shown that only 16.5% of the deposited mass was water soluble. The vertical distribution of passive particle collectors has led to the conclusion that the height of maximum deposition of each ion is different. In addition, a variation of the water-soluble mass to total deposited mass between 8% and 31% was observed.

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