PURPOSE: The titled fibers, consisting of sheath-core type conjugate fibers constituted of a sheath layer of polyethylene resin and a resin, containing dispersed powder of the specific gravity, and having compatibility with the above-mentioned resin of the sheath layer in a specific proportion, having a high specific gravity and strength, and suitable for fisheries materials, e.g. fishing nets.

CONSTITUTION: Fibers which are sheath-core type conjugate fibers, formed from (A) a sheath layer consisting of polyethylene resin and a core layer consisting of (C) a resin, e.g. ethylene-vinyl acetate copolymer, containing dispersed (B) powder of high specific gravity, e.g. trilead tetroxide, the resin (C) of the core layer having compatibility with the resin (A) of the above-mentioned sheath layer and a lower softening point than the resin (A) of the sheath layer, the powder (B) of high specific gravity having ≤10μ average particle diameter, and satisfying the following relations; (C/B)≥1.5 and 0.6≤A/(A+B+C)≤0.85 [(A), (B) and (C) are volumes of the resin (A), powder (B) and resin (C)].