This study provides an update of the quantity of discards in the worlds marine fisheries based on a fishery-by-fishery approach. The weighted discard rate is estimated at 8 percent (proportion of the catch discarded). Based on this discard rate, in the 1992-2001 period, yearly average discards are estimated to be 7.3 million tonnes. Because of the different method used in the current estimate, it is not directly comparable with the previous estimates of 27 million and 20 million tonnes.
Trawl fisheries for shrimp and demersal finfish account for over 50 percent of total estimated discards while representing approximately 22 percent of total landings recorded in the study. Tropical shrimp trawl fisheries have the highest discard rate and account for over 27 percent of total estimated discards. Demersal finfish trawls account for 36 percent of the estimated global discards. Most purse-seine, handline, jig, trap and pot fisheries have low discard rates. Small-scale fisheries generally have lower discard rates than industrial fisheries. The small-scale fisheries account for over 11 percent of the discard database landings and have a weighted discard rate of 3.7 percent.
Evidence is presented for a substantial reduction in discards in recent years. The major reasons for this are a reduction in unwanted bycatch and increased utilization of catches. Bycatch reduction is largely a result of the use of more selective fishing gears, introduction of bycatch and discard regulations, and improved enforcement of regulatory measures. Increased retention of bycatch for human or animal food results from improved processing technologies and expanding market opportunities for lower-value catch.
A number of policy issues are discussed. These include a no-discards approach to fisheries management; the need for balance between bycatch reduction and bycatch utilization initiatives; and concerns arising from incidental catches of marine mammals, birds and reptiles. The study advocates the development of more robust methods of estimating discards, allowance for discards in fishery management plans, development of bycatch management plans and promotion of best practices for bycatch reduction and mitigation of incidental catches. Global discard estimates could achieve greater precision through additional studies at national and regional levels.
Discards in the worlds marine fisheries. An update.
FAO Fisheries Technical Paper. No. 470. Rome, FAO. 2005. 131p.
Includes a CD-ROM.