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Fishing Techniques

Drum seining

Main Components

Aquatic species

Target Species
SalmonTarget Species
Herring

Gear types: Purse seines

Purse seines

A purse seine is made of a long wall of netting framed with a lead line of equal or longer length than the float line.

Vessel types: Drum seiners

Drum seiner

Characteristics

Drum seiningDrawing of Drum seiner

Species EnvironmentSuch fishing technique is mostly seasonal, when fish are aggregated into large dense schools.Fishing GearA purse seine is made of a long wall of netting framed with floatline and leadline (usually, of equal or longer length than the former) and having purse rings hanging from the lower edge of the gear, through which runs a purse line made from steel wire or rope which allow the pursing of the net. A drum requires a specially built seine. Most regular purse seines are built so that the leadline is substantially shorter than purse line. Thus, when the net is hanging ideally in the water, the circle described by the corkline is larger in circumference than that described by the leadline and the opening at the bottom of the net through which fish may escape before pursing is small.Vessel OverviewDrum seining was developed mainly for small vessels fishing for salmon in river estuaries, bays and creeks on the coast of British Columbia and Alaska. These seiners have usually the bridge and accommodation placed forward. Echosounder and sonar are used to locate schools of target species. Drum and a seine skiff are used during the fishing operations. The drum is mounted on the stern of the vessel. Vessels fitted with drums range from 19 to 22 m in length.Fishery Production SystemsSemi-industrial.Fishing EnvironmentMarine coastal and high-sea waters.Fishing OperationsThe biggest advantage of the seine drum lies in the greatly reduced crew needed to man the vessel. Even with a power skiff, the operation can be handled by as few as four men, in contrast to the six or seven men needed for block seining (common purse seining with the net being stocked on the deck and hauled with a power block). In addition, the net drum can haul the net nearly twice as fast as power block, and the elimination of overhead handling increases crew safety and comfort. Drum seining has also the advantage that, when setting the gear, the operation can be stopped at any time when it seems suitable. This is much more difficult in block seining, where normally the whole gear has to be set before retrieving can begin. A disadvantage of drum seining is that the purse seine to be used with drum has to be of a special design and construction (while any kind of purse seine can, in principle, be used when the operations are carried out with power block).

Starting a set

1. Setting the netThe net is set with the help of a seine skiff or a drogue. The skiff starts to tow the net off the drum.

Encircling

2. EncirclingThe purse seiner describes a circle around the shoal of fish.

Pursing the net

3. Pursing the netOnce the circle has been completed the skiff takes the messenger rope to the vessel and pursing can be proceeded in the normal manner by pulling on both ends of the purse line and, if desired, the seine net can, at the same time, be hauled for reducing the size of the purse where fish is trapped from the bow end while the other end is being wrapped onto the drum.

Reeling in the net

4. Reeling in the netOnce the rings are up (while the purseline is still threaded through) they are put on the "hairpin" or on a ring stripper. Then, as the net is retrieved with the drum, the purseline (under tension) and the rings are wrapped up with the net. As the net is retrieved, the stern of the boat tends to swing around in a circle until the whole net is almost in. Towards the end of hauling, the drum can be used to dry up the fish, and if the bunt is properly tapered the fish can be brought up ready for the pump.

Fishery AreaDrum seining is mainly used on the USA and Canadian coast; in British Columbia and Alaska.IssuesDiscard The potential negative impact which may result from drum seining practices would reflect an insufficient selectivity of the net, in particular if the mesh sizes are small, but not the mode of operations with a drum.Source of information

Sainsbury, J.C. 1996 “Commercial fishing methods: an introduction to vessels and gears.” Fishing New Books 0-85238-217-0.



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