Fishery bulletin of the Fish and Wildlife Service - NOAA

WHITEFISH FISHERY OF LAKES HURON AND MICHIGAN 301
and depth of the lifting pot were: depth—18 to 47% feet; length—30 to 40 feet. The
lifting pot usually tapered from front to rear so that the width in a single net varied
from about 24 to 20 feet. Mesh sizes in the pots ranged from 3^ to 5 inches as manufactured
4 except that the front side of the net (the side through which the tunnel enters)
contained meshes measuring not more than 3% inches. In some nets this small mesh
was extended along the sides and bottom of the net, but for a distance of not more
than one third the length of the pot.
The lifting methods employed varied considerably, the most general method being
that in which the net was brought to the surface by means of a lifting line attached to
the "king" anchor line 75 to 150 feet from the back of the pot. When the net was
brought to the surface, the boat was pulled under the anchor line and worked forward
until it was under the pot of the net. The fish were shoaled on the front or tunnel
side of the net and removed through laced openings. After the fish were removed, the
boat was worked back to the point where the lifting line was attached, the lines were
allowed to slip into the water, and the net was permitted to settle to the bottom.
The average time required to lift a deep trap net was approximately one hour. Numerous
mechanical devices have been developed to reduce the amount of labor involved
and several types of power lifting machines are now in use. Some fishermen released
the tension on the back anchor line and handled the net alongside the boat in a way
similar to that employed for lifting pound nets.
4
The present minimum size of mesh permitted in the pote of deep trap nets operated in the Michigan waters of Lake Huron is 4И inches as found
in им se; provision is made for a section of netting the meshes of which may not be more than ЗИ inches on which the fish may be shoaled.