J. Michael Jech
National Oceanic and Atmospheric Administration
PhysicsBackscatterAcousticsAtlantic herringClupea
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Publications 39
#1J. Michael Jech (NOAA: National Oceanic and Atmospheric Administration)H-Index: 10
#2Gareth L. Lawson (WHOI: Woods Hole Oceanographic Institution)H-Index: 18
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#1Michael B. O’Malley (Marine Institute of Memorial University of Newfoundland)
#2Rory Saunders (NOAA: National Oceanic and Atmospheric Administration)H-Index: 2
Last. Timothy F. Sheehan (NOAA: National Oceanic and Atmospheric Administration)H-Index: 16
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AbstractTemperate estuaries are inherently variable and productive ecosystems that provide nursery habitat, migration pathways, and forage areas for diadromous, estuarine, and marine fish. We used multifrequency scientific echo sounders (SIMRAD EK60 split-beam, 38 and 120 kHz) to describe the distribution of pelagic fish in the Penobscot River estuary, Maine, in 2012 and 2013. Differences in responses between frequencies were used to distinguish fish from other biota. Acoustic area backscatter f...
Euphausiids are a key link between primary production and higher-level predators in the Gulf of Maine, but are not well sampled during standard fisheries surveys. Multifrequency acoustic data may provide useful estimates of euphausiid distribution and biomass, as long as automated classification of acoustic backscatter is reliable and robust. Estimates of euphausiid biomass in the Georges Bank region of the Gulf of Maine were derived from annual acoustic/midwater trawl surveys from 1999 through ...
The National Oceanic and Atmospheric Administration’s (NOAA) National Centers for Environmental Information (NCEI) has developed archives for the long-term stewardship of active and passive acoustic data. Water column sonar data have been collected for fisheries and habitat characterization over large spatial and temporal scales around the world, and archived at NCEI since 2013. Protocols for archiving passive acoustic data are currently being established in support of the NOAA Ocean Noise Refer...
#1J. Michael Jech (NOAA: National Oceanic and Atmospheric Administration)H-Index: 10
#2John K. HorneH-Index: 25
Last. Kouichi SawadaH-Index: 9
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Analytical and numerical scattering models with accompanying digital representations are used increasingly to predict acoustic backscatter by fish and zooplankton in research and ecosystem monitoring applications. Ten such models were applied to targets with simple geometric shapes and parameterized (e.g., size and material properties) to represent biological organisms such as zooplankton and fish, and their predictions of acoustic backscatter were compared to those from exact or approximate ana...
14 CitationsSource
An acoustic imaging microtome system (AIMS) was constructed to map the internalstructureof fish.Thesystemconsistsoftwo pairs ofhigh-frequency(4.5MHz) transmit-and-receive planar arrays, with one pair in the vertical plane and the other in the horizontal plane. AIMS provides a series of acoustic images, analogous to microtome slices, along the length of a fish by combining electronically controlled sequentialacoustictransmissionsandreceptionsover224channelsandacomputercontrolled mechanical device...
Two broadband active acoustic systems, in concert with traditional narrowband systems and nets, were used to study distributions of fish in three regions within the Gulf of Maine. The long-range multi-beam broadband system detected fish out to 15 km range and the downward-looking short-range broadband system detected fish throughout the water column close behind the ship. The multi-year (2007–2011) study revealed distinct spatial patterns of fish and corresponding echo statistics in each region—...
1 CitationsSource
#1Jason D. Stockwell (Gulf of Maine Research Institute)H-Index: 24
#2Thomas C. Weber (UNH: University of New Hampshire)H-Index: 17
Last. J. Michael Jech (NOAA: National Oceanic and Atmospheric Administration)H-Index: 10
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Small pelagic fish can play an important role in the structure and function of ecosystems, and there is increasing interest in their nonmarket value. At the scale of fish aggregations, however, the impact of fishing has received relatively little attention, with most effort devoted to impacts of vessel and gear avoidance on stock size estimates. We used concurrent deployment of a downwards-looking echosounder (Simrad ES60 system) and an omnidirectional sonar (Simrad SP90 system) during commercia...
6 CitationsSource
Fisheries resource management is in a state of transition from managing populations at the species level to managing living marine resources at the ecosystem level. This transition will require changes in the way data are collected, analyzed, integrated, and finally utilized in management decisions. C. S. Clay “Clay” was a pioneer in underwater acoustics, but my first experiences and interactions with him were as a graduate student biologist learning to observe and understand the underwater envi...
A towed commercial sub‐bottom profiler acoustic system has been adapted for studying fish with swimbladders. It contains broadband acoustic channels collectively spanning the frequency range 1.7–100 kHz, with some gaps. Using a pulse‐compression technique, the range resolution of the echoes can be significantly improved, allowing high‐resolution imaging of patches and resolving fish near the seafloor. Measuring the swimbladder resonance at the lower frequencies eliminates major ambiguities norma...