Report on the Second Experiment with Bottom Vertical Longline in the South China Sea

Abstract

The South China Sea is dotted with many fish banks of various shapes and sizes. The waters around fish banks are thought to constitute good fishing grounds for both pelagic and demersal species.

In 1982 the SEAFDEC Training Department conducted experimental fishing with the bottom vertical longline at the Vanguard Bank. As the results were encouraging, it was decided to continue with this project, in the course of fishing practice during a training cruise for the Regular Course trainees.

The second experiment with bottom vertical longline in the south China Sea was carried out on 2-4 Octoder 1984 near the Riflemen Bank, which is located at approximately Lat 7º45’N, Long 111º38’E. The shape of this bank is almost rectangular: it is 26 miles long in the north-south direction and 13 miles wide. It is one of the largest banks in the South China Sea. The depth of water at the edge of the bank is about 100 meters. There are many reefs on the bank; in the shallowest parts the water is only 2 meters deep.

We conducted the experiment with two purposes in mind: (i) to study the catching efficiency of the bottom vertical longline gear, and (ii) to survey the demersal resources in the Rifleman Bank area. The present report combines our findings on both points.