Long Lines for a Purse Seiner

Purse seining is well known as one of the most effective technologies for demersal fisheries. Today many nations support extensive fleets of 20 to 30-meter wood, steel, fiberglass or aluminum vessels working with nets that range of 500 to 1000 meters in length.

Throughout Malaysia and Thailand, even in the wooden boat fleet, these vessels are typically equipped with sonar and Puretic-style hydraulic power-blocks for hauling back the nets.

All of this was evidenced on a recent visit to the F.V. Sombatpomae owned by Khun Thayuth, who recently acquired it from a processor. The 20 by 7-m wood purse seiner was built 20 years ago in Mahachai on the Gulf of Thailand and brought around Singapore and through the Straits of Malacca to the Thai Andeman Sea port of Ranong.

The boat’s crew was busy working to splice what looked like short 18-in. ganglions into skates of half-inch ground line. Captain Mien Saeguay (known to the crew as Capt. Dum) quickly explained that these were not ground-lines and it would be coconut husks, not hooks that would be affixed to the gear.

The boat fishes mackerel and various small local tunas in waters of 30 to 70 meters. Species include plaa oh dum (tonggol tuna), plaa oh lai (Thai skipjack or euthynnus) and plaa ta toh (big eye). The lines, with a small forest of coconut husks attached, are deployed between bamboo-pole-marked floats at the surface and concrete-filled bucket anchors. They are arranged in a 10-m diameter circle of 15 lines. Several of these are set out in the day. They to attract feed that in tern brings the larger fish. After dark, a light boat is anchored about 20 meters from the coconut husk assemblage. The lights draw the fish from the coconut husks to clear water where the seine boat can set around them.

The boat typically makes four sets per night for a total catch of about 50 metric tons that is the boat’s capacity. On departing the dock, two of the boat’s nine insulated hold compartments are filled with ice and a third with water.

In spite of the F.V. Sombatpomae's 500 horsepower Cummins KTA19 main engine that is standard on these vessels, this is a labor intensive fishery with a 35-man crew on the seine boat and another three on the light boat.