The effects of solar radiation upon breaking strength and elongation of fishing nets

The effect of solar radiation upon netting twines maintained under ambient conditions was investigated. Netting twines examined during the study were polyamide (PA) continuous filaments. These included 40 untreated grey twines (controls), 40 that were coated with a coal tar film to reduce UV radiation penetration of the fibres (treated), and 40 untreated green coloured twines. The last acted as a secondary control group. All twines were exposed to 780 It of direct solar radiation after which each was examined for breaking strength and extensibility. Results indicated that exposure of netting twines to solar radiation decreased breaking strength over time (P < 0.05), with the rate of deterioration being three times higher for untreated twines. In addition, coal tar treatment reduced elongation for up to 5 weeks following exposure. (C) 2003 Elsevier Science B.V. All rights reserved.