Northeast Trawl Advisory Panel Trawl Door Testing
Researchers fitted a trawl net used in research surveys with different door types to better understand net spread.
Consistent performance of research survey gear is critical to maintaining a time series of data. By testing different types of doors—the part of the gear most involved in keeping the net open when it is being towed—researchers can learn more about what influences net spread when the gear is in use.
What type of trawl door can provide the most consistent optimal net spread of 13 meters over a range of depths?
The goal is to find a trawl door that achieves a target net spread of 13 meters and provides consistent wingspread performance over the range of depths sampled in the Northeast Fisheries Science Center (NEFSC) bottom trawl survey.
The Ecosystem Survey Branch is working with Northeast Trawl Advisory Panel members to test the performance of different types of doors on the NEFSC bottom trawl survey aboard the NOAA Ship Henry B. Bigelow. The trawl doors currently used have variable wingspread performance. Optimal wingspread is 13 meters, but the net fishes at wingspreads from 9 to 16 meters (narrower in shallow sites and wider in deeper sites). The goal is to find a door that achieves the optimal target net spread of 13 meters and provides consistent wingspread performance over the range of depths sampled in the survey.
In August 2019, we evaluated the performance of three door types:
- 1.5 square meter Thyboron Type 21 flipper
- 66 inch Thyboron Type IV (used in the NEAMAP survey)
- Bison 9
The doors were evaluated on NOAA Ship Henry B. Bigelow during two legs. The first leg focused on deep water and the second leg focused on shallow water. A fourth door type, Bison 8, has been rigged and is ready for testing when sea days are available.
- Both the Bison 9 and Thyboron Type IV doors achieved stable target spread in shallow water, but overspread in deep water
- Thyboron Type 21 flipper doors were generally unstable at all depths and were underspread in shallow water and overspread in deep water
- No door tested consistently achieved the target spread in deep water
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.
- Terry Alexander, NEFMC member
- Vincent Balzano, NEFMC member
- Tony DiLernia, MAFMC member
- Wendy Gabriel, NEFSC scientist
- James Gartland, MAFMC scientist
- William Gerencer, NEFMC stakeholder
- Vito Giacalone, NEFMC stakeholder
- David Goethel, NEFMC stakeholder
- Dustin Gregg, MAFMC scientist
- Pingguo He, NEFMC scientist
- Michael Luisi, MAFMC member
- Anna Mercer, NEFSC scientist
- Timothy Miller, NEFSC scientist
- Frank Mirarchi, NEFMC stakeholder
- Christopher Parkins, ASMFC representative
- Michael Pol, NEFMC scientist
- Philip Politis, NEFSC scientist
- Christopher Roebuck, MAFMC stakeholder
- Robert Ruhle, ASMFC representative
- Michael Sissenwine, NEFMC scientist
Northeast Trawl Advisory Panel
NEFSC Ecosystems Survey Branch
Contact Phil Politis