NMFS NUMBER: 95-NER-009
Near-Zero Mortality Trawl for Silver Hake
National Marine Fisheries Service, Northeast Region, One
Blackburn Drive, Gloucester, MA 01930-2298. PHONE:
Any mesh used
in New England to capture regulated species in the regulated
mesh area of the federal EEZ less than the present 6"
regulated minimum, must result in the capture of regulated
species not in excess of 5% of the total when measured
by weight. This requirement has rendered the use
of small mesh bottom trawls historically used to capture
silver hake (Merluccius bilinearis) illegal in
all but a small part of the regulated mesh zone.
To allow a fishery for silver hake to continue under the
new regulations, a stipulation permitting a modified small
mesh net was introduced, based on the proven success and
acceptance of the Nordmore grate in the Northern U.S.
shrimp fishery. It called for the use of the grate
with 40mm. spacing between the bars and the limited use
of ground gear between the net and doors this combination
held out some hope that a silver hake fishery could continue,
little use of the new configuration is taking place. The
difficulties encountered in correctly installing and using
the grate are problematic. It is more difficult
to use for a strong swimming fin fish like silver hake,
which actively seeks to escape from the net. Also,
the largest silver hake cannot be taken because the narrow
(40mm. or about 1 5/8") openings in the grate exclude
not only regulated species but larger silver hake from
capture in the codend. Goals of this project were
to develop a net and grate separation system which together
allow larger silver hake to be retained while maintaining
a <5% by-catch level, and to encourage pre-spawning
and less valuable small whiting minimal stress when escaping
the net. A 45mm grate opening was used and 15 fathoms
of ground gear were added to the 15 fathom leg system.
Square mesh was placed in varying configurations in the
body of the net and the codend to encourage easy escapement
for juvenile fish. Research results were presented
to various audiences. Videographic details of fish
behavior were recorded.