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by Chris Glass
MANOMET, MA - Fishing activities routinely result in the entrapment of nontarget species. In some cases, the amount of these bycatch species that can be landed are strictly limited by regulation and those taken in excess of the regulations must be discarded.
The small-mesh fisheries of the Mid-Atlantic, particularly the squid and whiting fisheries, pose management difficulties because the legal mesh size is substantially smaller than that required for other commercial species.
In certain cases, discarding in small-mesh fisheries accounts for a substantial portion of the total allowable catch for other commercial species.
One such species is scup, where high levels of discard in certain areas at certain times prompted the National Marine Fisheries Service (NMFS) in 2000 to impose gear restricted areas (GRAs) in an attempt to restrict small-mesh fisheries and therefore reduce discards. These GRAs have posed difficulties for fishermen, managers, and law enforcement agencies and, not surprisingly, have generated substantial controversy.
As reported in the last edition of Commercial Fisheries News (September 2001), the GRAs will likely be back in 2002. However, the Mid-Atlantic Fishery Management Council is recommending that fishermen have the opportunity to fish in the restricted areas if they use modified gear.
The issue of scup discard and the imposition of GRA regulations prompted the Mid-Atlantic council to commission conservation engineering studies.
These studies were conducted by the Manomet Center for Conservation Sciences and the Massachusetts Division of Marine Fisheries (DMF) to help develop modified fishing gears to reduce bycatch and discard of scup. The Mid-Atlantic council provided full funding for the program with an in-kind match provided by DMF.
Project staff members included Gregg Morris, Tim Feehan, Ben Sarno, and Yoshiki Matsushita from Manomet and Arne Carr and Mike Pol from DMF.
Nets tested
Project participants tested four different extension/codend configurations, as part of standard fishing gears. Each design was based either on ideas put forward by industry people or on earlier studies that were shown to be effective in reducing bycatch for scup or other species.
Five boats participated in trials between June 2000 and March 2001. The trials took place in Nantucket Sound, in the waters off Long Island, and in the approaches to Nantucket. Some additional sampling was conducted in deeper waters around Hudson Canyon.
The different nets tested were as follows.
> 4-1/2" diamond-mesh extension window, also known as the Lovgren Window (#1) This netting arrangement was based on a design by fisherman and Mid-Atlantic council member Jim Lovgren. A 4-1/2" diamond-mesh section was inserted in the top panel 100 meshes ahead of the codend. The bottom panel and codend were made of standard 1-7/8" small-mesh netting.
> 5-1/2" square-mesh extension section (#2) A section of 5-1/2" square mesh was inserted in the extension 50 meshes ahead of the codend. The square-mesh netting extended around the circumference of the extension, forming a square mesh section as opposed to a window. The remainder of the extension and codend were constructed with 1-7/8" small-mesh netting.
> Square-mesh extension/tunnel (#3) Netting arrangement #3 was identical to arrangement #2 with the addition of a black tunnel between the square-mesh extension and the codend. The black tunnel was designed to present a strong visual stimulus to fish passing along the extension and to encourage escapement through the square-mesh extension netting. This design has been employed successfully in other fisheries. The remainder of the extension and codend were constructed with standard 1-7/8" small-mesh netting.
> 5" diamond-mesh extension window (#4) This arrangement was identical to arrangement #1 except that the window was constructed with 5" diamond-mesh netting on the top panel of the extension. Experiments were conducted using a cover net over the window to capture fish passing through the window.
Results
All sea trials were conducted on commercial fishing vessels in NMFS statistical reporting areas 537, 538, 539, 632, and 626. Vessels ranged from 65' to 75' in overall length and between 340 and 550 horsepower.
Overall, the 5-1/2" square-mesh extension section configuration (#2) proved to be the most effective arrangement of the four tested for reducing discard of scup while maintaining target catch.
This configuration showed an overall reduction in scup discards of over 66%. The other nets either showed little difference from the standard small-mesh net in scup discards or lost significant quantities of squid.
Questions
One very obvious and significant outcome from this research is the demonstration that fishing nets can be redesigned in a simple and inexpensive way to reduce the bycatch and discard of scup.
However, we are aware that further testing and development will be required. Our research focused on smaller vessels within the fleet and in shallower water than many vessels fish.
Fishermen have expressed concerns and asked questions such as:
> What will be the effect in deeper water or when catches are significantly larger or when nets are of a much larger scale or where the water is either warmer or cooler?;
> Where is the most appropriate position for the escape panel in a large-scale net?; and
> What is the effect of towing speed?
These concerns are valid, but because the device is so simple and is based on differences in behavior between scup and squid, we feel confident that it can be tailored to be successfully deployed in the offshore fishery.
Opportunities
The GRAs will likely remain in effect in 2002, but the recent research quota set-aside initiative announced by the Mid-Atlantic council and NMFS provides a real opportunity for expanded testing in the GRAs and other offshore areas.
We hope this will allow fine-tuning of the scup-discard-reduction device and it should allow many more fishermen to see the device in operation first-hand.
Manomet Center for Conservation Sciences plans to conduct further trials on commercial fishing vessels in the Mid-Atlantic region to answer many of the remaining questions.
We welcome any suggestions or input to help develop discard-reduction strategies and are looking for fishermen and vessels to assist in sea trials. If interested in participating, please contact Chris Glass, Gregg Morris, or Arne Carr (see below).
One very important outcome of this research and the action taken by the Mid-Atlantic council is that it provides an option -- and opportunity -- for fishermen if they wish to access the GRAs.
Gear engineering
Although some question the need for conservation engineering research or the need to conduct discard-reduction studies, this study emphasizes the benefits that can be gained from directed programs.
Even though the solution we outline may not be the full or perfect answer to the problem of scup discard in small-mesh fisheries, it is one step forward and, if nothing else, should provide the impetus for others to develop alternate strategies or modified gears. The alternative is continued restriction of fishing opportunities.
While discard reduction alone will not solve the complex problems of local fisheries, it must be a key component of the solution, a perspective that is reflected in ongoing management regimes and interim plans.
Manomet Center for Conservation Sciences has a long history of working with the fishing industry and state and federal agencies to address problems in northwest Atlantic fisheries. It is currently working on bycatch reduction and conservation engineering programs on commercial fishing boats from Virginia to Iceland.
For more information on this or other programs, contact Chris Glass or Gregg Morris at Manomet: phone (508) 224-6521; fax (508) 224-9220; or e-mail . Or contact Arne Carr or Mike Pol at DMF: phone (508) 563-1779; or e-mail .
Chris Glass is director of the Manomet Center for Conservation Sciences' marine fisheries program. He specializes in the study of fish behavior and in applying that knowledge to the development of more selective fishing gears in order to reduce bycatch and discard in commercial fisheries.
Prior to joining Manomet in 1996, Glass worked for 14 years as senior fisheries scientist at the Marine Laboratory in Aberdeen, Scotland and has worked extensively on bycatch reduction and conservation engineering programs throughout Europe.
