Mud clouds, twine stretching and uncounted fish mortality: The complex world of commercial fishing gear

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Two dozen staff members from NOAA’s Greater Atlantic Regional Fisheries Office (GARFO) based in Gloucester, Mass., recently made their way to New Hampshire’s coast to learn about the complexities of fishing gear from those who know it best: commercial fishermen.

The workshop provided an opportunity for the managers who implement commercial fishing regulations in New England to interact with the fishermen who deal with a host of challenges affecting how their gear works — real-life complexities, like the natural stretching of fishing net twine and chains over time affecting gear performance, that are important for the managers to keep in mind.

The three-day workshop — organized by Gabby Bradt, NHSG/UNHCE fisheries specialist, and Ryan Silva, research coordinator with the Sustainable Fisheries Division of NOAA GARFO — took place on Sept. 26-28, 2016 at the Seacoast Science Center and aboard four N.H. fishing vessels. N.H. fishermen David Goethel and Tom Lyons, along with Henry Milliken from NOAA Fisheries, provided background information about fishing gear and fish behaviors. A variety of fishing nets — some to scale, some full-sized — were laid out for closer examination on the first day of the workshop.

“It’s definitely helpful to attend a workshop like this to see the basic gear design, see the scale of the gear and discuss how it works in different conditions,” Silva said. “We won’t be experts after this because it’s so complicated, but we’ll have a better understanding of what factors affect the gear selectivity for fish species,” he explained.

men stand around fishing net spread out on ground.

Above: Workshop attendees listen to N.H. fisherman David Goethel (left) discuss net components.

As a fisherman, Goethel said it is immensely helpful for him to have a math background in order to calculate his gear dimensions and determine how the nets will perform underwater. He spoke about how his trawl doors create vortices in the water behind them that pull a bit of mud off the bottom and create “mud clouds” that impact how the gear fishes — any changes to the doors, their orientation or the speed of the fishing vessel can change the mud cloud, thus affecting how many fish are caught. The size of the net’s mesh, the angle of the gear in the water, the tide cycle, and a host of other seemingly minor differences can add up to major changes that should be thought about when managers implement regulations, he said.    

The workshop’s open forum style allowed for NOAA staff to ask plenty of questions and for the fishermen to pose questions of their own. “How should regulations deal with the possibility of uncounted fish mortality?” Goethel asked, citing the possibility of fish that may incur scale or fin damage from nets that may cause eventual mortality, but because the fish aren’t captured there’s no real way of knowing their survival rates.

People look at small model of fishing net.

Above: Small models of different fishing nets help workshop attendees to see shape of net as it would look underwater.

Overall, the workshop allowed a space for positive dialogue to occur between all parties.

“Fishermen, scientists and fisheries managers often exist in different realms, but it’s important for them to come together to share their knowledge and ideas,” said Erik Chapman, acting director for N.H. Sea Grant who helped to set the stage for the discussion. “This workshop is a partnership between Sea Grant, NOAA Fisheries and fishermen that will help to move everyone forward and provide an impactful hands-on learning experience,” he added.

N.H. Sea Grant promotes the wise use, conservation and sustainable development of marine and coastal resources in the state, the region and beyond. Located at the University of New Hampshire, NHSG is part of a national network of programs located in our coastal and Great Lakes states as well as in Puerto Rico and Guam.   

Rebecca Zeiber, N.H. Sea Grant Science Writer