Deposition of trawl web on an Alaska beach after implementation of MARPOL Annex V legislation

Abstract

Deposition rate, mesh size, and weight of trawl web fragments washed ashore near Yakutat, Alaska, were monitored from 1988 to 1992 to examine the effectiveness of 1988 MARPOL Annex V legislation to reduce the amount of fishing gear and other plastics discarded or lost from ships at sea. Eight 1 km beach sections were surveyed twice each year, in March or April and September. The same sections had been surveyed previously, from 1985 to 1987. The mean deposition rate of trawl web (no. of pieces km −1 yr −1) from 1988 to 1992 declined from 10.1 to 3.8, a 60% reduction. The yearly mean deposition rate of trawl web from 1985 to 1987 was nine pieces. The mesh size of trawl web also declined: about 20% of fragments washed ashore in 1988–1992 had mesh sizes > 15 cm compared to 33% in 1985–1987. Mean weight of trawl web fragments was similar when comparing 1985–1987 fragments and 1988–1992 fragments. Beach surveys in Alaska show that the disposal or loss of trawl web at sea has declined since the implementation of MARPOL.