Using hydroacoustics to relate fluctuations in fish abundance to river restoration efforts and environmental conditions in the Penobscot River, Maine

2019 ◽  
Vol 36 (2) ◽  
pp. 234-246
Author(s):  
Constantin Scherelis ◽  
Gayle Barbin Zydlewski ◽  
Damian C. Brady
Keyword(s):  
Environmental Conditions ◽  
River Restoration ◽  
Fish Abundance ◽  
Penobscot River

Estimating fish abundance and biomass from eDNA concentrations: variability among capture methods and environmental conditions

2016 ◽  
Vol 16 (6) ◽  
pp. 1401-1414 ◽  
Author(s):  
Anaïs Lacoursière-Roussel ◽  
Maikel Rosabal ◽  
Louis Bernatchez
Keyword(s):  
Environmental Conditions ◽  
Fish Abundance

Initiation of migration and movement rates of Atlantic salmon smolts in fresh water

2015 ◽  
Vol 72 (9) ◽  
pp. 1339-1351 ◽  
Author(s):  
Daniel S. Stich ◽  
Michael T. Kinnison ◽  
John F. Kocik ◽  
Joseph D. Zydlewski
Keyword(s):  
Atlantic Salmon ◽  
Environmental Conditions ◽  
Management Practices ◽  
Movement Rate ◽  
Movement Rates ◽  
Trade Offs ◽  
Hydropower Dams ◽  
Before And After ◽  
Penobscot River ◽  
Migratory Period

Timing of ocean entry is critical for marine survival of both hatchery and wild Atlantic salmon (Salmo salar) smolts. Management practices and barriers to migration such as dams may constrain timing of smolt migrations resulting in suboptimal performance at saltwater entry. We modeled influences of stocking location, smolt development, and environmental conditions on (i) initiation of migration by hatchery-reared smolts and (ii) movement rate of hatchery- and wild-reared Atlantic salmon smolts in the Penobscot River, Maine, USA, from 2005 through 2014 using acoustic telemetry data. We also compared movement rates in free-flowing reaches with rates in reaches with hydropower dams and head ponds. We compared movement rates before and after (1) removal of two mainstem dams and (2) construction of new powerhouses. Initiation of movement by hatchery fish was influenced by smolt development, stocking location, and environmental conditions. Smolts with the greatest gill Na+, K+-ATPase (NKA) activity initiated migration 24 h sooner than fish with the lowest gill NKA activity. Fish with the greatest cumulative thermal experience initiated migration 5 days earlier than those with lowest cumulative thermal experience. Smolts released furthest from the ocean initiated migration earlier than those released downstream, but movement rate increased by fivefold closer to the ocean, indicating behavioral trade-offs between initiation and movement rate. Dams had a strong effect on movement rate. Movement rate increased from 2.8 to 5.4 km·h−1 in reaches where dams were removed, but decreased from 2.1 to 0.1 km·h−1 in reaches where new powerhouses were constructed. Movement rate varied throughout the migratory period and was inversely related to temperature. Fish moved slower at extreme high or low discharge. Responses in fish movement rates to dam removal indicate the potential scope of recovery for these activities.

Vibration Isolator System for Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 182-183
Author(s):  
K. Ohi ◽  
M. Mizuno ◽  
T. Kasai ◽  
Y. Ohkura ◽  
K. Mizuno ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Magnetic Fields ◽  
Environmental Conditions ◽  
Vibration Isolator ◽  
Air Conditioners ◽  
Vibration Isolators ◽  
Large Size ◽  
Electron Microscopes

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

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