Dana Morse of Maine Sea Grant collaborated with Boothbay Harbor fishermen Kelo Pinkham and Stanley Coffin in a Northeast Consortium-funded project to reduce undersized flatfish bycatch through the use of knotless cod end mesh. 

Although expensive compared to knotted twine, knotless twine has several advantages. It is stronger than knotted and generally holds its shape better when hung square in the cod end. During a tow, the cod end stretches and is pulled creating a decreased mesh selectivity over the course of the trawl. It was anticipated that the square hung knotless twine would maintain its selectivity over the haul, thus reducing the number of undersized flatfish caught. The researchers used low-light underwater video to observe the escape of undersized flatfish as well as other undersized groundfish and to better understand net dynamics. You can watch video excerpts by visiting the Maine Sea Grant web site.

The specific objective of the research was to compare the selectivity of knotless 6.5" and traditional knotted 6.5" mesh in the cod end of a bottom trawl in the groundfish fishery of the Gulf of Maine. The researchers did not observe dramatic differences in selectivity between the two mesh types for any of the groundfish species caught during the experimental tows. However, they did observe a trend for release of plaice just under the legal size. A research brief describing this project in more detail is currently in publication by Maine Sea Grant. Visit the Northeast Consortium and Maine Sea Grant for project reports and investigator contact information.

Control: 6.5" knotted mesh