The study established a method for assessing discards at the global level by creating a fishery-by-fishery database of landings and discards. The estimate can be checked or updated through change to individual records of the fisheries. This database is supplemented by a searchable bibliographic database and electronic archive of many of the reference materials used in the study. It should be recalled that the sample excludes a number of important fisheries, notably those in the Russian Far East, the Democratic Republic of Korea, the Republic of Korea, New Zealand and in United States non-Federal fisheries. No allowances are made for illegal, unreported and unregulated (IUU) catches.
The assessment is based on a number of assumptions. A linear relationship between discards and total landings was assumed. The total quantity of discards was derived by raising the discard rates obtained from studies by total landings of these fisheries. Based on expert opinion, fisheries in some countries (notably South and East Asia) were assigned zero discard rates. Similarly, artisanal and subsistence fisheries in many countries were assumed to have low or negligible discards, while fisheries harvesting small pelagics for fishmeal were generally considered to have negligible discards. It has not been possible to eliminate double counting entirely, particularly with regard to the tuna fisheries, since the discard assessment for these fisheries used data from the international tuna management organizations rather than from national sources.
The current estimate of the global level of discards is concluded to be substantially lower than the 1994 estimate. The aggregate landings matching the discard data in the database total 78.4 million tonnes or 94 percent of the average global nominal marine catch of 83.8 million tonnes. The corresponding discards total 6.8 million tonnes, giving a weighted discard rate of 8.0 percent for the sample. Applying this sample discard rate to the average global nominal catch gives an estimated annual total of 7.3 million tonnes of discards for the 1992-2001 period.
In geographical terms, the Northeast Atlantic (1.4 million tonnes), the Northwest Pacific (1.3 million tonnes) and the Western Central Atlantic (0.8 million tonnes) generate the highest discards. Differences in discard rates between developed and developing fishing nations are not readily apparent except in the case of Southeast Asia where discards are generally negligible because of almost full utilization of the catch. The global values conceal a wide range of discard rates. Trawl fisheries and shrimp fisheries account for 55 and 27 percent of the recorded discards respectively.
No coherent time series of discard rates is available at the global level. However, from case studies of a wide range of fisheries, it is apparent that the global level of discards has decreased in recent years. This is a result of both bycatch reduction and increased bycatch utilization. Bycatch reduction has occurred not only in Organisation for Economic Co-operation and Development (OECD) countries (e.g. Northwest Pacific, Gulf of Mexico, Gulf of Carpentaria, NAFO area) but also in other countries that have introduced bycatch reduction measures (e.g. Argentina and other Latin American countries).
Increased bycatch utilization has been widespread in Asia, Africa and South and Central America. Increasing human consumption, improvements in technology (e.g. surimi products) and the expanding market for aquaculture and animal feeds have also contributed to this increase.
Incidental catch and discard of charismatic species are creating increased difficulties for trawl, longline, gillnet and purse-seine fisheries. Additional mitigation and trade measures may reduce the economic performance of such fisheries. The development of technologies and enforcement of measures for bycatch reduction and incidental catch mitigation continue to offset possible further restrictions and declines in these fisheries.
5.3.1 Fishery management issues
Quantifying discards poses a range of difficulties in sampling, raising and making effective use of results. Observer programmes appear to be essential for accurate quantification of discards in most fisheries. The impacts of discards are not easily quantified and the methods for such impact assessment require further development, with particular reference to physical accounting and valuation of the broader ecological impacts.
The United Nations General Assembly (UNGA) resolutions, the Code of Conduct for Responsible Fisheries (CCRF) and the International Plans of Action (IPOAs) are valuable starting-points for public policy on discards. The range of policy options is determined by both the biological characteristics of the fishery and the social and economic environment. Best practice in bycatch reduction is illustrated by a number of OECD countries, while East and Southeast Asian countries provide valuable experiences in utilization of bycatch.
A no-discards approach to fisheries management holds the high moral ground and is in conformity with UNGA resolutions and the CCRF. However, the comparative ecological and social benefits of such an approach need further assessment and its application in some fisheries may not be practical, at least in the medium term. A range of complementary measures is required to support an effective no-discards regime.
Each fishery or management unit is likely to require a specific suite of measures to optimize bycatch and discard management. Such measures may best be structured through a bycatch strategy and action plan formulated as an integral part of a fishery management plan. In overexploited fisheries, effort reduction is likely to be an essential approach to decreasing discards. Effort reduction may be neglected if efforts to promote bycatch reduction devices or other technical measures take a central role. Economic measures can make an important contribution to discard reduction and bycatch management.
More selective fishing is advocated as a means of reducing discards. However, selective fishing is likely to alter ecosystem balance. Any inconsistency that may exist between promoting more selective fishing and the ecosystem approach requires attention from both theorists and practitioners in order to formulate best scientific advice. Small-scale fisheries tend to be regarded as being more selective than industrial-scale fishing. However, by virtue of their ability to exploit most habitats, niches and trophic levels, a range of small-scale fisheries may have a more damaging effect on the ecosystem.
A high survival rate may reduce the negative impacts of discards. Practices to foster discard survival can be further evaluated and promoted.
5.3.2 Technical and economic issues
Increased utilization of bycatch is an important approach to discard reduction. The extent to which promotion of ever-greater utilization of marine resources is consistent with sustainable and responsible fisheries may require attention. The transfer of improved utilization technologies between fisheries and countries may be of value in reducing discards and fostering fish food security.
Techniques and technologies for bycatch reduction and incidental catch mitigation continue to develop. A clearinghouse mechanism to establish the relative merits of different technologies and develop approaches to their successful introduction may be of value.
Incidental catch of charismatic and endangered species poses a threat to certain fisheries, as mitigation measures may restrict fishing operations and raise costs. In particular, trade in fish products may be disrupted. Since many charismatic species are migratory, internationally agreed measures may be required. Internationally accredited databases of such incidental catches may be necessary in order to evaluate the threats posed by fisheries and determine appropriate mitigation measures.
5.3.3 Possible FAO actions
Balancing reduction and utilization approaches
Many fisheries, particularly those in developing countries, are likely to seek a balance between bycatch/discard reduction and bycatch utilization strategies. Guidelines may be developed that assist the development of a balanced approach consistent with sustainability of the fishery, the CCRF and the ecosystem approach. Case studies on discards in particular fisheries may be of value in further identifying solutions to discard problems.
Expert advice may be synthesized to provide a catalogue of best practice with regard to discards and bycatch. The catalogue may include, inter alia: sampling and raising methodologies and use of observers; approaches to economic analysis of bycatch and discard issues; the use of discard information in stock assessments, TACs and fisheries agreements; evaluation of the impacts of discarding; development of appropriate policies, strategies and plans for bycatch and discard management; and means of building stakeholder awareness.
Through consultations at a technical level the regional fisheries organizations may also wish to strengthen their discard-related policies and programmes.
Discards and trade
The discard database may be expanded (or a parallel database established) to assemble available information on discards and/or incidental catches of charismatic and endangered species. Such an information base may serve as an accredited source of information on the interaction between fisheries and these species. Institutional arrangements may be established to assess mitigation measures and facilitate international consensus on best practice in such measures.
Guidance from COFI
Following appropriate discussion and review of the numerous issues relating to bycatch and discards, an action plan may be submitted for the consideration of COFI. Based on a consensus of FAO member countries, a programme may be established to address the most important discard issues.
The discard database - an evolving tool
In order to maintain the discard database as a means by which global discards can be periodically reassessed, landings and discard values should ideally be verified and updated by competent authorities at regional and national level. Available catch, bycatch and discard information may also be collated by fishery in a standardized manner at national level. Time series of discard information may be compiled for important fisheries. The merits of compiling global catch statistics on a fishery-by-fishery basis may be further explored. A link between the discard database and the FAO Global Fisheries Information System (FIGIS) database has already been established and the discard database will remain as a domain within FIGIS. Cross-linkages between Fishstat and fishery-by-fishery catch/landings information may also be created.
The discard database is potentially a powerful tool, not only for discard assessment but also as an initial contribution to a quantitative description of the worlds marine fisheries on a fishery-by-fishery basis. This database may be extended in several dimensions, in particular by completing the field on the status of exploitation of each fishery. Additional fields indicating the value of catches would allow basic economic analysis by fishery at a global level.
 As recorded by FAO
Fishstat for the 1992-2001 period and excluding plants and aquatic animals, i.e.
marine mammals and reptiles.|
 Funding for FAOs discard-related activities is provided under programme entity 233A1: Reduction of Discards and Environmental Impact from Fisheries (2002-2005) and planned under 233A6 Impact of Fishing on the Environment (2006-2011) (FAO, 2001c).