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2019 Northeast Trawl Advisory Panel Flume Tank Demonstration
A trawl net was towed under different simulated conditions in a flume tank, while a group of fishermen and researchers live-streamed the demonstration in a classroom nearly 1,000 miles away.
The primary objective of this effort was to observe the 1:7 scale model of the standard Northeast Fisheries Science Center's survey bottom trawl in the flume tank and evaluate physical changes to the model as net spread changed.
Research Questions
How does the Northeast Fisheries Science Center survey trawl physically change as net spread varies?
How does tow speed affect gear performance?
Project Goals
Observe the 1:7 scale model of the NEFSC survey trawl in a flume tank at various net spreads, ranging from underspread to overspread
Evaluate physical changes to the model as net spread varies
Image
Observing net behavior in the flume tank at the Fisheries and Marine Institute of Memorial University of Newfoundland.
Project Description
In July 2019, a scale model of the Standard trawl used in the NEFSC bottom trawl survey was observed in the flume tank at Memorial University in St. John’s, Newfoundland. NTAP members gathered at the University of Massachusetts School of Marine Science and Technology in Dartmouth, Massachusetts to watch the deployment over a live video feed from the flume tank. Flume tank operators tested the model’s performance at the gear’s designed “optimal” spread of 13 meters, as well as at narrower- and wider-than-optimal spreads. They measured and recorded door spread, wingspread, headrope height, and water flow for each experimental treatment. Tank operators also captured photographs to get paired measurements and visualizations.
Study Methods
Still images were taken at each net spread and water speed from different locations around the model trawl: above, from the side, and into. Net spread, door spread and headrope height were measured. The first set of data were taken with the model net rigged as used during standard survey operations. The second set of data were taken with the 0.5 meter top-wing extension removed from the model and observed as “even.” During the final set of data, water speed was varied and the model was put back to the standard survey rig, with the 0.5 meter top wing extension.
The panel includes New England and Mid-Atlantic Fishery Management Council members, commercial trawl fishermen, academic and industry gear experts, leaders of other regional surveys, state scientists, and the Center staff assigned to work with this important panel.
View over the stern of the NOAA Ship Henry B. Bigelow, exiting the Cape Cod Canal headed east toward Provincetown, Mass. at the beginning of Leg 3 of the 2021 Northeast Fisheries Science Center fall bottom trawl survey. The two bridges spanning the canal are used by trains (background) and vehicle traffic (foreground). Credit: NOAA Fisheries/Katelyn Depot.
An oceanic whitetip shark swims near the surface of the water. Photo courtesy of John Carlson.
Dense beds of small Atlantic sea scallops photographed on the ocean floor in the Mid-Atlantic in 2015. Credit: NOAA Fisheries.
The Fishadelphia team. Credit: Dr. Talia Young.
View over the stern of the NOAA Ship Henry B. Bigelow, exiting the Cape Cod Canal headed east toward Provincetown, Mass. at the beginning of Leg 3 of the 2021 Northeast Fisheries Science Center fall bottom trawl survey. The two bridges spanning the canal are used by trains (background) and vehicle traffic (foreground). Credit: NOAA Fisheries/Katelyn Depot.