Previous Page Table of Contents Next Page

4. Issues

4.1 What is “the discard problem”?

The expression “the discard problem” embraces several issues or subproblems, which go to the foundations of fisheries management philosophy and practice. Several subsidiary problems and issues can be identified (Hall, 1994).

4.2 Policy issues

4.2.1 International instruments and guidance

The international community has recognized both ethical concerns and policy regarding discards, related biodiversity and endangered species in several international instruments and statements, including United Nations resolutions,[79] multilateral agreements and plans of action (see Box 1).

The initial UN resolution (49/118) invited international organizations to:

Subsequent resolutions 50/25 and 51/36 of 1996 called for states and regional fisheries organizations to: adopt policies, apply measures, collect and exchange data and develop fishing techniques to reduce bycatches and fish discards; place “discards” on the United Nations General Assembly (UNGA) Law of the Sea (LOS) agenda; provide assistance to developing countries to collect and exchange data and develop techniques to reduce bycatches and fish discards; and requested the Secretary-General to submit biennial reports to UNGA relating to the implementation of the resolutions.

Resolution 52/29 of 1997 recalled that the Agreement relating to the Conservation and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks provides in its general principles that states shall minimize discards and reaffirmed the previous UN resolutions.

Selected multilateral initiatives

Agreement for the Implementation of the Provisions of the United Nations Convention on the Law of the Sea (UNCLOS) relating to the Conservation and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks (United Nations Implementing Agreement [UNIA])

... minimize... discards,..., catch of non-target species, both fish and non-fish species, and impacts on associated or dependent species, in particular endangered species...

The Rome Consensus on World Fisheries adopted by the FAO Ministerial Conference on Fisheries, Rome, 14-15 March 1995

... reduce bycatches, fish discards ...

CCRF has numerous references1 to discards

... collect information on discards...;... take account of discards (in the precautionary approach)...;... take appropriate measures to minimize waste, discards...;... develop technologies that minimize discards...; use of selective gear to minimize discards; ...

International Plan of Action (IPOA) on sharks

Minimize waste and encourage full use of dead sharks

IPOA on seabirds

Prevention of seabird capture and release of seabirds

Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)

Under CITES, marine mammals, turtles and seabirds and some fish species are listed under Appendix I (species threatened with extinction that are or may be affected by trade), and Appendix II (species threatened with extinction unless trade is subject to strict regulations). CITES listing may have a significant effect on fisheries that catch such species

Convention on Migratory Species (CMS)

The Convention has provided a forum for the development of legally binding regional agreements on marine mammals and turtles (e.g. ACCOBAMS and ASCOBANS)

Convention on Biological Diversity (CBD)

Discards affect biodiversity2 along at least three axes: species numbers, species densities and species dispersion. These impacts are not well understood, particularly with regard to benthos

1 For a discussion of the references to discards in the CCRF, see Clucas, 1997.

2 The role of discards in terms of broader ecosystem change, e.g. supporting seabird populations in the North Sea, has been well documented.

Resolution 53/33 of 1998 recognized the progress in the preparation of draft plans of action in relation to shark fisheries and the incidental catch of seabirds and drew further attention to incidental losses of sharks and seabirds.

Resolution 55/8 of 2000 expressed concern about the significant level of bycatch and discards in several of the world’s commercial fisheries; recognized the importance of the development and use of selective, environmentally safe and cost-effective fishing gear and techniques for reducing bycatch and discards; acknowledged the value of FAO, UNEP and GEF initiatives; and urged further action to reduce discards.

Resolution 57/142 of 2002 urged action to reduce or eliminate bycatch and fish discards and drew attention to a range of appropriate measures.[80]

4.2.2 Ethics of discards

Many societies and religions adhere to the principle that human beings have a moral obligation to make best use of natural resources and minimize wastage. In others (Tucker, 1998), nature is seen as intrinsically valuable. Islam and many other religions support the concept of stewardship (Afrasiabi, 1995), or that humans hold nature in trust and are accountable to god for the use or misuse of nature. Buddhist “environmentalism” is also based on an underlying belief in causal relationships between living beings and human beings with an individual and general responsibility for the state of nature. Shinto purification is performed to restore the balance between humans, nature and the deities (Bernard, 1998). These themes are repeated in Judeo-Christian beliefs and echoed in the saying “waste not, want not” and in several Biblical ethical models (Bratton, 2000):

Throughout many of these belief systems there is an underlying theme that technology alone cannot resolve the issues of human beings’ relationship with nature, but that greater harmony and balance in the use of natural resources depend on values, their application through governance[81] systems and lifestyles, and the distinction between wants and needs (Tamari, no date).

Good and bad discards[82]

The notion that discards are wasteful is closely linked to the assumption that most, if not all, discards are either already dead or subsequently die as a result of the fishing activity. However, many discarded animals survive, and live release of captured animals may make a significant contribution to the sustainable use of fisheries resources. Guidelines and criteria can be developed to identify “responsible” discarding. Examples of “good” discards may include:

“Bad” discards may include all dead discards that had a potential commercial value when alive, including juveniles of commercial species and endangered or threatened species, which indicate undesirable fishing practices.

As discard practices also impact on biodiversity and energy transfers within ecosystems, assessing the impact of discards in simple positive and negative terms may prove difficult. It may be of more practical value to prepare additional guidelines on best practices with regard to bycatch management on a fishery-by-fishery basis.

There are major differences in discard policies and practices between regions, between countries within a region and between fisheries within a country. National policies and objectives (e.g. prioritizing food supply), markets, food preferences, fishery economics and moral orientations all influence discard practices. In very broad terms, countries can be classified into four groups, those that:

Acceptable level of discards

Assuming that discards are unavoidable, the question of an acceptable level of discards has a moral dimension in addition to the more obvious biological and economic criteria. No-discard policies are consistent with the ethical orientations cited above and are addressed in more detail in Section 4.3.1. In the United States bycatch plan (see Section 4.4.2), “concerns” regarding bycatch and discards are considered under four indicators: (i) population concerns where discards contribute significantly to the status of the fish population; (ii) social and economic concerns; (iii) ecological concerns; and (iv) public concerns that are of particular relevance in the case of seals, marine mammals, seabirds and other marine animals of an aesthetically high profile. In practice, “acceptable” levels of discards are negotiated between interest groups with little reference to morality.

4.2.3 Incidental catch and discards of charismatic and endangered species

The incidental catch of most of these species is discarded, either because of a legal requirement or because of lack of commercial value. Endangered species are those threatened with local or global extinction. Several species or species groups are considered “charismatic” since certain societies accord their existence an additional value for numerous reasons. There are long-standing cultural and religious ties with some species such as dolphins and seabirds.[83] Many feature in children’s stories or are used in advertising, films and cartoons, which contribute to their enhanced status in society.

Whatever the reason, society values these species and is willing to pay a price for their preservation. These perceptions and values have a direct impact on fisheries, which incidentally catch and discard these species, through changes in fishing techniques (e.g. TEDs, Medina panels and pingers [acoustic deterrents]), and through trade (e.g. through CITES and unilateral measures such as tuna, shrimp and shark imports to the United States).

Assessing the impact of a fishery[84] on marine mammal, seabird or turtle populations poses several problems. There is a general shortage of information, e.g. in pelagic trawls where the incidence of cetacean bycatch may be higher than previously estimated (De Haan et al., 1998). Reliable information on incidental catches is generally only available through observers. It is also difficult to assess population size (particularly for marine mammals) and to assess the consequences of a relatively low and unpredictable incidental catch rate. While over 2 million dolphins may be encircled by tuna purse seiners in the Eastern Tropical Pacific, fewer than 3 000 are killed by the fishery as a result of strict application of release procedures monitored by observers. However, the failure of the dolphin stocks to recover may indicate additional indirect[85] mortalities caused by fishing activities and the effects of other factors are not well understood. Information on incidental catches of manatees and dugongs is particularly scarce and it is likely that these animals are consumed rather than discarded if caught by artisanal fishers.

A number of NGO reports[86] indicate that fishing activities cause substantial mortalities of sea turtles. In contrast, at a recent FAO meeting[87] representatives of certain Asian fishing nations contested the level of turtle mortality resulting from longlines, indicating that incidental turtle catches were rare and survival is apparently high since most turtles are released alive. Trials of mitigation measures to avoid or reduce hooking have not proved promising since the incidence of hooking is so low that field trials have encountered difficulties in achieving statistically significant results.

Reliable current compilations (Brothers, Cooper and Løkkeborg, 1999) of global information on the interaction between fisheries and charismatic species are relatively scarce. This absence of a recognized (Gillespie, 2002) global database on incidental catches of such species tends to result in argument and conflict over the impact of fisheries, the effectiveness of mitigation measures and the impact of other factors such as pollution or destruction of breeding grounds and nesting sites on endangered populations.

Mitigation and conservation measures

Comprehensive legislation (FAO/UNEP, 1986) and numerous action plans[88] for the conservation of charismatic species exist at national and international levels. The United States’ Marine Mammal Protection Act (MMPA) and Endangered Species Act (ESA), and Australian legislation provide good examples. Release of live rajids, bluefin tuna (United States and Canada) and other regulated species is mandatory in certain fisheries. The United States has a ban on shark finning and a similar ban is coming into force in the EU. Near real-time monitoring of discards and retention of incidental catches for monitoring purposes is obligatory in certain United States fisheries.

Recent amendments[89] to United States fisheries legislation calls for the Secretary of State, in cooperation with the Secretary of Commerce, to seek an international agreement to establish standards and measures for bycatch reduction that are comparable with United States standards in any fishery regulated under the Magnuson-Stevens Act for which an international agreement is necessary and appropriate.

A range of mitigation measures is in force throughout the world, for example:

Fishery managers, particularly those in developing countries, require: (i) a framework[95] for the introduction and acceptance of such measures by industry; (ii) more specifically, advice on the design, operation and financing of incidental catch monitoring; and (iii) assessments of the advantages and disadvantages of the different mitigation measures.

Trade and economic impact of incidental catch

The incidental catch of charismatic and endangered species is having a growing influence on fisheries and fish trade. Conservation activists and scientists have called for the cessation of tuna longline fishing to protect turtles and for trawl bans to protect corals and other benthos. Multinational companies are making purchases only from fisheries that implement mitigation measures, and ecolabels are intended to promote products from implementing fisheries. Trade disputes over mitigation measures regarding incidental catches of turtles and dolphins have disrupted trade in shrimp[96] and tuna respectively. Several important developments are likely to impact further on fisheries and fish trade:

The action of conservation organizations in the United States is of particular note in relation to bycatch and charismatic species and may be the precursor of other such activities. Oceana,[98] an NGO, requested the United States Department of Commerce to rule on the interpretation of fisheries legislation, specifically the legislation that requires the NMFS to “establish a program to count, cap and control bycatch in the nation’s fisheries”. Pursuant to a United States court finding the NMFS in violation of fisheries legislation (MSA), Oceana claimed that the NMFS had failed to apply national legislation. In a comprehensive response (Federal Register, 2003), the NMFS was effectively forced to set out such a programme and make financial and other provisions for its implementation. In a second case, a coalition of conservation NGOs led by the Earth Island Institute effectively blocked the United States administration’s attempts to change the “dolphin safe” designation of certain tuna products, thereby pressuring for a cessation in fishing for tuna on “dolphin schools”. Such trends are likely to expand to other fishing and fish-consuming nations.

4.3 Fishery management issues

The central “discard problem” for the fishery manager is to design a management regime that meets multiple social, economic and biological objectives, while limiting or preventing discarding (Hall, Alverson and Metuzals, 2000).

Impact of discards

Design of effective management regimes may require assessment of the biological, ecological and economic impacts of discards. A parallel study[99] has addressed this question in some detail. Just as the quantity of discards is difficult to assess, it is equally clear that it is even more difficult to assess their impact. Few relevant studies exist, and it is not easy to disentangle the relative impacts of bycatch and discards. The economic and social impacts are briefly discussed in Section 4.6.3. The causal diagrams of discarding are presented as a means of structuring further studies on discards and their impacts (see Annex C).

Management frameworks

The following sections address three different approaches to bycatch and discards:

4.3.1 The “no-discard” regime

A number of countries[100] pursue a “no-discard” policy[101] and several prohibit discards at sea under their legislation. A “no-discard” policy is consistent with best practice and is likely to minimize discards in conformity with UNGA resolutions and the CCRF.

The following key points are noted:

A “no-discard” policy changes the focus of management and fishery indicators from landings to gross catches and from production to total fishing mortality. This is exemplified in the contrasting Norwegian and EC legislation:[102]

This means that many of the Norwegian fisheries management measures are designed to ensure that unwanted fish is not caught. Thus, the choice is not between returning unwanted fish to the sea and obligatory landings for fishmeal or animal feed, but between catching and not catching unwanted fish. These complementary measures accompanying discard bans include:

In Iceland fishers are allowed to land a certain proportion of undersized fish, which is only partly deducted from quotas. Quotas are tradable, allowing fishers to purchase them to cover unanticipated landings. A similar system exists in Norway whereby fishers are allowed to substitute quotas in one species for quotas held in another in accordance with predetermined ratios (Kelleher, 2001). The ratios are partly based on the anticipated species composition ratios in the catch. This allows fishers to avoid discards when encountering a species composition that does not meet the species composition of their quota holdings.

A “no-discard” policy is precautionary since the “default scenario” is a ban on discards. It is incumbent on a particular fishery to justify discards or show why they are unavoidable. The legislation may then make an allowance for such unavoidable discards, e.g. applied only to commercial species. The country’s development programme can examine means of reducing the unwanted bycatch, develop alternative fishing opportunities or finance the phasing out of such wasteful fishing technologies.

It is suggested that there is a fundamental difference between a “no-discard” approach and a “minimize discards” approach. “Minimize discards” often merely endorses the status quo by paying lip service to discard reduction. Policies and programmes that seek to minimize discards often do not determine the target minima and there is little consensus on how to determine an acceptable level of discards. Enforcement of discard regulations is likely to encounter the same practical problems whether the regulations are designed to prevent or to minimize discards. However, the ethical interpretation, management philosophy, regulatory framework and design and application of measures are substantially different in the “no-discard” approach. This approach would benefit from a detailed appraisal in terms of its impact on resources and broader application in other fisheries. For example, many fishers in the United Kingdom are opposed to a “no-discard” regime, regarding it as unworkable and claiming, with some justification, that discards are unavoidable (Agricultural Economics Research Institute, 2000). Further analysis of the rationale behind such views may be of value in seeking effective management approaches.

4.3.2 Implications of generic fishery regulations on discards

Many generic fishery regulations may promote discards or do little to minimize or eliminate them. As discard practices are determined by a wide range of factors, it is difficult to attribute changes in these practices to a given regulation or set of regulations. Fishery managers often face a regulatory dilemma since regulations designed to protect one species may increase bycatch or discards of another. The groundfish fisheries of Alaska provide a history of different regulatory approaches to discard practices.

Effort control

Overfishing often contributes to discards since declining average sizes tend to make the catch less marketable. A reduction of fishing effort (e.g. through fleet capacity reduction, closed seasons, days-at-sea programmes) can make a significant impact on discard practices.

Minimum landing size (MLS)

MLS regulations[104] almost invariably promote discards since MLS is difficult to harmonize with the selectivity of the fishing gear, particularly in multispecies fisheries. In these fisheries different sizes and shapes of fish are likely to have a wide range of MLS, often determined as a function of the size at first maturity of each species, rather than as a function of the gear selectivity. A recent change in MLS in the North Sea simply “legalized” the previous discards of juvenile plaice caught in the trawl fishery targeting sole. In fisheries where there is a high discard survival rate (e.g. lobster), MLS regulations are important. When increased recruitment results in large year classes of juvenile fish, discards may increase if MLS regulations are applied. MLS regulations are often applied only at landing sites and not at retail markets or restaurants (which, for example, commonly serve undersized fish, including fish larvae and lobster). MLS regulations may also conflict with obligations to land bycatch.

Minimum mesh size (MMS)

MMS is closely linked to MLS. Increasing MLS without accompanying increase in mesh size will only increase discards. Several countries show inconsistencies between MMS, MLS and size at first maturity of the target species. Mesh alone does not determine selectivity of the net and hanging parameters may be equally important. Rigging of the fishing gear, and trawl gear in particular, exerts a major impact on selectivity and can entirely undermine mesh size regulations. Many jurisdictions lack trawl rigging regulations to complement those of trawl mesh size. This demonstrates poor awareness of such impacts or possible difficulties in framing and enforcing appropriate regulations. Codend mesh size is difficult to enforce without observers and costly sea inspection. Regulations limiting a vessel to carrying nets of one mesh size may encounter strong opposition by fishers who target different species on different grounds during the same trip. An increased mesh size may not reduce discards since 100 percent of many species are discarded (Allain, Biseau and Kergoat, 2003) and selectivity of gear may be highly variable in relation to the discarded species. Square mesh panels are obligatory in many fisheries.

Composition of landings

Senegal requires shrimp trawlers to land a minimum of 15 percent shrimp to retain a shrimp licence, thereby creating an incentive to discard. French dredgers keep worthless species on board merely to comply with the percentage regulations. Such regulations may be difficult to enforce effectively, particularly when weights have to be calculated as live-weight equivalent, as set out in the EC regulation.[105] However, although such measures have an economic cost, in the case of obligations placed on tropical shrimp trawlers to land bycatch, there is some evidence that these regulations reduce discards. Local landings of bycatch from distant water fishing vessels licensed to fish in coastal state waters may be considered an import by the coastal state and subject to import tariffs that render bycatch landings unprofitable.

Seasonal closures and time restrictions

These are common and useful measures, which reduce mortalities and discards of juveniles (Adlerstein and Trumble, 1998). Several Australian prawn trawl fisheries only open when the prawns have reached a certain size (e.g. Spencer Gulf, South Australia). Time restrictions are applied in varying levels of detail. For example, if hake comprises more than 10 percent of landings in Argentine fisheries that do not target hake, then vessels are required to stay in port for 48-96 hours. Certain vessels are required to fish south of 48ºS and remain in harbour for 120 hours between trips.

Closed areas and area controls

These are usually general, rather than discard-specific measures. Closed areas are normally established to protect juveniles,[106] spawning grounds or areas of special biological interest (e.g. coral reefs, Posidonia beds). Area restrictions include the creation of marine parks, areas reserved for traditional fishing activities and areas where certain gears are prohibited (e.g. no-trawl areas). Closed areas are likely to be of particular use in countries that pursue a “full catch utilization” strategy (e.g. in Southeast Asia). Obligatory change of fishing area is a common complementary measure[107] under “no-discard” regimes.

High catches of unwanted fish may trigger area closures in some fisheries. Norway enforces an active closure scheme to protect juvenile cod in the Barents Sea, i.e. the closed areas change in relation to the distribution of the undesirable bycatch of juveniles. The closures are determined according to the percentage of juveniles in the catch, based on combined information from research cruises, observer reports and monitoring of chartered commercial trawlers. Australia’s northern prawn fishery provides another example of “active closures” to avoid catches of juvenile prawns, while the Gulf of Maine fisheries also make extensive use of area closures and “rolling closures” to protect juveniles or marine mammals. While these active closures have the advantage of responding to the current conditions on the fishing grounds, the costs of administering such regimes can be high. In the BSAI/GOA groundfish fisheries information on bycatch is rapidly collated and disseminated to enable vessels to avoid areas with high bycatch or, if necessary, close certain fishing grounds.

Fish handling

EU pelagic freezer vessels may be prohibited from installing graders or must install automatic sorting machinery so that fish “cannot be easily thrown back into the sea”. Under Australia’s Sub-Antarctic Fishery bycatch action plan, the discharge of dead fish, fish offal or by-products of fish processing is not permitted in order to minimize feed opportunities for seabirds and marine mammals. Offal and retained bycatch are turned into fishmeal and stored on board. The release of unwanted live fish, crabs, tagged live fish, skates and large sharks is permitted.

Operation of the gear

In addition to obligations to use TEDs and BRDs, gear restrictions include mesh size and hook size limits, specification of longlines hook type and leader material and requirements for escape panels in traps. Extensive and detailed records of gear alterations may be required in some fisheries. Regulations[108] governing the operation of gear may be difficult to enforce.

Quota regulation and discards

A number of studies[109] have addressed the issue of whether quotas, and individual transferable quotas (ITQs) in particular, foster discarding. The regulatory framework is but one factor determining discards and the quota regulations may not be the most important regulatory cause of discards in a given fishery (e.g. MLS regulations may be more important). Building flexibility[110] and allowing quota transfers may help reduce discards resulting from quotas. While many EU fisheries do not operate under formal ITQ systems, there is little doubt that the regulatory discards resulting from the EU’s quota system is a major cause of discards in many EU fisheries. Trip limits may also cause discards of legal-sized fish.

Bycatch quotas

Bycatch quotas[111] exist in many fisheries (e.g. South Africa, United States, New Zealand). Under the United States Sustainable Fisheries Act, allocations of regulatory discards may be transferred to individual fishing vessels as an incentive to reduce per vessel bycatch and bycatch rates in a fishery, provided that “(i) such allocations may not be transferred for monetary consideration and are made only on an annual basis; and (ii) any such conservation and management measures will... result in an actual reduction in regulatory discards in the fishery” (see Annex A.6.1 for further details of the Alaskan arrangements).

Observer programmes

Seagoing observers are crucial for monitoring discards. Observers normally have a range of monitoring functions (and possibly an enforcement role), and monitoring of discards may not be a priority function. Training and skills of observers vary widely, as do the quality of observer reports and the use made of them. The presence of observers may influence discarding practices, particularly if the observer role is to report infringements of regulations. The low cost of observers makes them an important tool for monitoring in developing countries. The EU has a particularly low level of observer coverage, while there is increasing public pressure for a high level of observer coverage in North American fisheries (e.g. the Oceana petition). Monitoring of discards is an essential observer function in the United States Northeast Pacific groundfish fisheries.

4.4 Bycatch and discard management frameworks

Comprehensive bycatch and discard management frameworks are in place in several countries and fisheries. In contrast to the bycatch/discard reduction strategies described below, fisheries development and management plans in Southeast Asia focus on bycatch utilization and value added.

Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR)

CCAMLR has adopted an ecosystem approach to fisheries management and provides a comprehensive framework of management measures, many of which address bycatch and discard issues. The measures (CCAMLR, 2002b) directly related to bycatch and discards can be grouped as follows: reporting, gear regulations, bycatch limits, area and time restrictions, and mitigation measures (primarily directed at reducing seabird mortalities). The comprehensive CCAMLR framework is reflected in several other fishery management regimes, in particular in those countries where incidental catches of endangered species have attracted a high level of public awareness. NAFO and ICCAT are among the other regional fisheries management organizations that have established discard databases.

Guiding principles in Australia’s bycatch policy

An overarching objective of the policy is to ensure that bycatch species and populations are maintained at sustainable levels. Within this are the following sub-objectives:

  • reduce bycatch;

  • improve protection for vulnerable/threatened species;

  • minimize adverse impacts of fishing on the aquatic environment.

All decisions and actions to address bycatch will:

  • foster stewardship of Australia’s aquatic resource, i.e. maintain and improve the quality, diversity and availability of fisheries resources, including fish habitats, and the integrity of the aquatic ecosystem into the future;

  • promote cooperative and transparent approaches involving all stakeholders for effective stewardship of our aquatic resources;

  • integrate short-term considerations with long-term goals in managing aquatic resources;

  • use robust and practical methods to assess bycatch so as to make decisions on management;

  • recognize the unique biological, economic, cultural and social nature of individual fisheries;

  • encourage cooperation in the development of complementary and effective arrangements among relevant authorities where stocks overlap, are split between jurisdictions or are migratory;

  • ensure the widest adoption of bycatch mitigation measures through collaboration between the commercial, recreational, charter and indigenous fishing sectors, research and research funding organizations, environment and nature conservation agencies and fisheries management agencies; and

  • apply a precautionary approach to the management of fish and aquatic resources.

Australian Fisheries Management Authority (AFMA)

4.4.1 Australia: bycatch policy and action plans

Discard problems are subsumed under Australia’s bycatch policy and action plans. Central to the policy is a recognition that bycatch is a resource, environmental, educational, engineering and economic issue and needs to be addressed strategically and in a focused, coordinated manner.

The policy recognizes that there will be different requirements for addressing the bycatch issue in different fisheries. AFMA coordinates the efforts of various interest groups to develop fishery-specific bycatch action plans by establishing bycatch action plan working groups consisting of scientific, industry, government and conservation members. All 21 Commonwealth fisheries are required to prepare bycatch action plans to reduce the impacts of fishing on non-target species. The plans are in various stages of preparation, approval and implementation and cover a wide variety of fisheries including shrimp trawl, fish trawl, scallop, longline and tuna fisheries.

Bycatch action plans identify the specific bycatch issues in a fishery and detail actions required to address these issues. The bycatch action plan is then integrated into the management arrangements for the fishery to enable the actions to be implemented. Once completed, bycatch action plans will be reviewed annually in line with Commonwealth policy.

United States - Managing the nation’s bycatch

“The fundamental national goal of NMFS’ bycatch-related activities is to implement conservation and management measures for living marine resources that will minimize, to the extent practicable, bycatch and the mortality of bycatch that cannot be avoided. Inherent in this goal is the need to avoid bycatch, rather than create new ways to use bycatch.”

To accomplish these objectives, the report on Managing the nation’s bycatch (NMFS/NOAA, 1998a) made recommendations in the following areas:

  • bycatch monitoring and data collection programmes;

  • research on the population, ecosystem and socio-economic effects of bycatch;

  • research to increase the selectivity of fishing gear and increase the survival of fish and protected species that are inadvertently encountered by fishing gear;

  • incentive programmes for fishers to improve bycatch performance;

  • analysis of the implications of conservation and management measures for bycatch; and

  • exchange of information and development of cooperative management approaches.

Steps to be taken:

  • determine the quality of information on the magnitude of bycatch;

  • evaluate the impacts of current bycatch practices on populations, fisheries and ecosystems;

  • evaluate the effectiveness of current bycatch management measures;

  • identify potential management alternatives;

  • evaluate the population, ecosystem and socio-economic effects of each alternative;

  • choose and implement an alternative; and

  • evaluate the effectiveness of the implemented measures.

4.4.2 United States: managing the nation’s bycatch

The Magnuson-Stevens Fisheries Conservation and Management Act (FCMA), which is the principal United States fisheries management instrument, requires that bycatch be avoided or, where it cannot be avoided, that mortality be minimized. There are some differences between this and other major laws. The Marine Mammal Protection Act (MMPA) and the Endangered Species Act (ESA) require zero mortality rates while the Magnuson-Stevens Act indicates a reduction in bycatch “to the extent practicable”.

Federal fisheries operate under fishery management plans (FMPs), which must contain management provisions to eliminate or reduce bycatch of all kinds. Under the Sustainable Fisheries Act (SFA) and as an integral part of each FMP, the fishery management councils (FMCs) were required to:

4.4.3 European Union: Community action plan to reduce discards of fish

By virtue of the heavy reliance on quota systems in the Common Fisheries Policy (CFP) on conservation, discards in the EU are relatively high. Declining quotas and stocks result in significant discards of commercially valuable fish as a result of highgrading and quota limits.

European Union - On a community action plan to reduce discards of fish

“... the Commission will come forward with regulatory measures to reduce catches of younger fish, bycatches in mixed fisheries and discards.1 Such measures will include:

  • the introduction of more selective fishing gear, such as nets with larger meshes;

  • square mesh panels, separator grids and changes in design and rigging of such gear in order to improve selectivity;

  • restrictions on fishing to protect juvenile fish, sensitive non-target species and habitats;

  • minimum landing sizes in line with the selectivity of the gear concerned;

  • ‘discard ban trials’ in which representative samples of fishing vessels would be encouraged by economic incentives to retain their entire catch;

  • the targeting of economic incentives for the use of more selective fishing practices;

  • a voluntary code of conduct intended to reduce discarding;

  • scientific and technical monitoring of fishing practices that result in discarding.”


1 Extracted from European Commission, 2002a. See also European Commission, 2002c.

There is widespread recognition of “the discards problem” among fishers and administrators. Numerous studies by the EC and ICES have not adequately quantified discards in the EU, partly because of weak discard sampling and observer coverage. Several closed areas or boxes exist to protect juveniles. Bycatch and discard reduction relies heavily on technical measures, which are difficult to enforce. The preparation of production plans by producer organizations as provided under the CFP’s markets policy may also provide an indirect entry point for discard management.

EU policy and practice on discards are substantially in arrears of the United States and Australia as illustrated by the preliminary nature of the recent “Communication from the Commission to the Council and the European Parliament” (European Commission, 2002a).

4.4.4 Private sector initiatives

Numerous authors have stressed the need for fisheries administration and researchers to work closely with the fishing industry (fishers, fishing companies, product developers, gear specialists) on bycatch and discard management. A variety of private sector initiatives exist. In Australia there has been close collaboration with industry in the gradual introduction of BRDs. Essentially similar approaches have been pursued in the New Zealand hoki fishery and the Alaska pollock fishery in the Northwest Pacific (see Annex A.6).

4.4.5 Planning framework

A comprehensive and structured approach to discards and bycatch is required. It implies a clear statement of policy with regard to discards, a description of strategies and an implementation plan. Ideally, the discard/bycatch plan(s) would be an integral component of fishery management plans. Southeast Asian countries have held discussions on discards and formulated an action plan to reduce unwanted catch in the region (SEAFDEC, 2003).

Monitoring of bycatch and discards needs to be an integral part of the fishery research component of the management plan. A clear understanding of discard patterns is required. Factors such as light intensity, tides, gear rigging and skipper habits all affect the discard pattern (Catchpole, Gray and Frid, 2002). Education and awareness have been shown to be an essential part of the discard management process. Similarly, stakeholder involvement is crucial (Lart, 2002), in particular with regard to initiatives to introduce gear modifications or regulatory measures. The effects of measures to reduce bycatch and discards must be clearly demonstrated and the costs of changes distributed equitably.

Generic framework for a bycatch/discard management plan

1. Acquire information on bycatch and discards.

  • Determine magnitude of discards - observer programmes are usually indispensable.

  • Assess impacts (biological, social and economic) with a focus on major undesirable impacts.

  • Establish the spatial and temporal patterns and particularly the capability of fishers to control levels of unwanted bycatch.

2. Formulate bycatch/discard management policies and objectives as an integral part of a fishery management plan.

  • Account for the imputed costs of discards in the economic management framework of the fishery.

3. Measures.

  • Review/evaluate effectiveness of existing measures.

  • Identify/evaluate alternative measures.

4. Decision framework and evaluation.

  • Create decision framework/criteria in association with stakeholders.

  • Decide/implement new measures. Monitor effectiveness and review impact.

4.5 Biological and ecological issues

The provision of scientific advice relies on an accurate understanding of the state of fish stocks. Discard information is included in few[112] stock assessments partly because of the lack of adequate discard information. This omission may lead to inaccurate conclusions or substantial differences between assessments (Casey, 1996). However, if large, highly diverse fishing fleets are being sampled by a small handful of observers faced with many practical difficulties, there is a risk that stock assessments will be made less, rather than more accurate by the addition of the resulting raised estimates of discards.[113] Questions associated with discard sampling and raising of discard estimates are addressed in Annex C.

4.5.1 Selective fishing, discards and the ecosystem approach

Promoting more selective fishing is one of two principal approaches to discard reduction. Fisher behaviour and fishing gears are by nature selective. Fishers do not want to catch fish that cannot be sold or that create sorting difficulties. Typically, demersal trawling is considered to be at the less selective end of a range of fishing activities while handlining is at the more selective end. Fishing activities such as trawling, which cause mortalities across many trophic levels, marine communities or species groups, are more likely to generate discards. However, selective fishing is more likely to alter the balance of species in the ecosystem and across the trophic levels. In the absence of an empirical framework for valuation of species and biodiversity, value judgements may be necessary to resolve apparent inconsistencies between advocating more selective fishing and the “ecosystem approach”.

4.5.2 Discard survival

Determination of the survival of discards is important:

A wide range of studies[114] have been made on discard survival and a number of clear relationships are well recognized.

4.5.3 Ecological impacts

Many of the ecological impacts[116] of discards remain unquantified. The combined impact of the trawl damage to benthos and of discards may have a positive impact on the growth of target species through an energy shunt along the food chain or fertilizing unproductive sea floor (Rijnsdorp and van Beek, 1991). Evidence suggests that benthic discards are rapidly reassimilated into the food chain (Groenewold and Fonds, 2000). The physical presence of decomposing discard materials, together with downcurrent odour trails, may lead to avoidance of the area and localized anaerobic conditions (Chapman, 1981).

A number of studies (Camphuysen et al., 1995) in European waters have shown that discards are a major food source for seabirds[117] (approximately 18 percent of 600 000 total food requirement were discards) in the North Sea. Overall consumption rates were estimated at 95 percent for offal, 80 percent for roundfish, 20 percent for flatfish and 6 percent for benthic invertebrates. The mass of discards eaten, including offal, was estimated to be more than the amount of live fish (265 000 tonnes) taken by seabirds. Thus the discards support substantial bird populations, which further prey on fish.

The impact of discards on biodiversity is not well understood. Isolating the effect of discarding from other effects of fishing is difficult (Lindeboom and de Groot, 1998; ICES, 2000d). The measurement of discards at the species level and quantification of survival of the species present problems. As previously noted, reports also tend to lump together the discards of unknown numbers of finfish[118] and invertebrates. In general, discarding is likely to favour scavengers.

4.6 Technical and economic issues

4.6.1 Bycatch utilization

Bycatch utilization has been addressed in a series of FAO reports, which make numerous recommendations that are not detailed in this publication (FAO, 1997; FAO/DFID, 1998; FAO/UNDP/Government of Madagascar, 1995).

Tropical shrimp trawl fisheries face a particular range of difficulties. Vessels are often small and have little room for bycatch.[119] Landing large volumes may undermine the price of bycatch and prices for artisanal producers. Collection at sea must be highly cost effective and processing and distribution must be simple and inexpensive to avail of limited purchasing power. Legal restrictions on transhipment must be removed. Collectors may require medical certificates (to comply with shrimp export requirements). Arrangements for crew compensation and avoidance of shrimp contamination are required. Creation of bycatch collector associations and codes of practice may be needed to avoid theft of shrimp and to conclude agreements with vessel owners. Radio communication systems may also be necessary.

Experiences from Latin America, India and Africa indicate that stable arrangements for at-sea collection of bycatch in tropical shrimp fisheries can be developed through broad-based commercial agreements between groups of bycatch collectors and the fishing companies; through provision of credit; and through support for processing, marketing and distribution facilities.

4.6.2 Gear technology and selectivity

Gear technology and selectivity are specialized subjects and are not addressed in any detail here. A wide range of developments continue to have a significant impact on bycatch and consequently on discarding.

Mesh size and minimum landing size1

In 2001 technical regulations in the heavily overfished Baltic cod fishery were revised by the IBSFC on the basis of scientifically solid international research. However, managers refused to follow the recommendations of “a one net rule”, likewise a harmonizing of selectivity and MLS. Thus the minimum landing size of 35 cm was maintained (subsequently increased to 38 cm) but the minimum mesh of traditional diamond mesh codend was increased from 120 to 130 mm and then to 140 mm in polyethylene codends and to 125 mm in polyamide codends.

The amendments of the fishing rules did not merely fail to meet their objectives. They made the situation even worse. The length distribution of annual landed trawl catch remained unchanged despite the increase in minimum mesh size until the MLS was increased in January 2003 to 38 cm. Because no change in the selectivity of the widely used traditional diamond mesh codend was made, all fish between 35 and 38 cm were now undersized and consequently discarded. Thus it was the MLS and not the mesh size that determined which part of the catch was landed, indicating that the objective of increased selectivity had gone terribly wrong.

Swedish fisheries observers on board estimated that in January 2003, on average, 34 percent of trawl catches consisted of undersized cod and in April 2003 this devastating waste of resources forced the EC to stop the trawl fishery in EU waters.

1 Adapted from Valentinsson and Tschernij, 2003.

The gear technology per se is not necessarily the limiting factor in discard and bycatch reduction. The economic consequences of introducing gear modifications[124] are possibly the single most important constraint. This further emphasizes the need for a close partnership with industry in the introduction of BRDs and more selective gears in a gradual and adaptive manner. Because of the steep slope of the selectivity curve of bottom trawl mesh, increases in mesh size are not likely to have major impacts on discard levels.

Studies[125] on BRDs for the Gulf of Mexico shrimp fishery (primarily intended to reduce mortality of juvenile snapper and related species), showed that an increase in finfish biomass as a result of the BRDs could result in an increase (up to 4 percent), or a decrease (up to 17 percent) in shrimp biomass. A linear relationship between predation and shrimp biomass was developed. The protocols developed for testing of TEDs and BRDs provide a useful model for such work in similar fisheries.

In some fisheries the introduction of BRDs including square mesh panels has been industry driven by the need to exclude jellyfish, reduce discards of target species, comply with trade practices regarding turtles or reduce the costs of sorting fish.

A BRD technology clearinghouse or network of expert resources would be of value. In addition to the technical aspects of BRDs associated fish behaviour studies, the clearinghouse could establish guidelines for the introduction and acceptance of BRDs by fishers. Advice on framing and application of the required regulations would also be valuable. FAO is currently preparing technical guidelines on bycatch reduction in shrimp trawl fisheries.

4.6.3 Economic issues

Two sets of economic issues arise in relation to discards:

Costs and benefits to fishers

At the level of the fisher, the act of discarding involves an economic decision, usually of a short-term nature (day/trip/season). The fisher weighs the costs and benefits of a wide range of factors such as the following:

Cost factors


Of particular interest are schemes for special compensation for crews regarding retention of species with marginal value, which might otherwise be discarded. Bycatch in tropical shrimp fisheries is often considered the “property” of the crew, although vessel operators may discourage bycatch retention because of loss of shrimp quality or fears of theft of shrimp through transhipment at sea.

Regulations on discards and incidental catch force fishers to adapt their fishing techniques and operations with possible loss of efficiency and returns. Discards have had a major economic impact in the Alaska groundfish fishery. Operators are obliged to discard Pacific halibut, which is managed under a separate regime (International Pacific Halibut Commission [IPHC]). When the halibut discard quota is filled, the fishery may close or move to less profitable fishing areas, resulting in major economic losses (Trumble, 1996). Fishers will assess the costs, potential losses[126] and possible benefits associated with the use of BRDs or other measures designed to reduce discards or bycatch, e.g. BRDs introduced in New South Wales resulted in a decline of 90 percent in discards and employment of one less crew per vessel. The economic impact of incidental catch and discards on trade has already been noted.

Costs to the administration

The costs of monitoring and control can be substantial. In the United States the costs associated with enforcement of the Marine Mammal Protection Act and Endangered Species Act alone account for over 10 percent of total monitoring, control and surveillance costs. Observer programmes and efforts to acquire discard information for stock assessment may also involve significant costs.

Costs to society

Few comprehensive studies have been carried out on the cost of discards to society and on who bears such costs. The costs to society of losses of charismatic species or of ecosystem change resulting from discards (which could be positive) have not been identified. Assessment of the costs of discarding and the costs and benefits of measures relating to bycatch and discards will help in designing appropriate management programmes.

One of the most detailed studies on the estimated costs of discards was carried out in the North Sea. The study estimated that approximately 15 000 tonnes of landings of plaice, sole, cod and whiting were foregone as a result of discards in the North Sea Crangon fishery (Revill et al., 1999). These foregone landings were valued at 25.7 million euros. The estimated annual cost of discarding in three EU case studies varied from approximately 70 percent of total annual landed value in the Netherlands case to 42 percent in the United Kingdom whitefish case and 43 percent in the French Nephrops case (Nautilus Consultants, 2001). These studies focused on costs related to commercial species and did not address the more complex questions of costs associated with the ecosystem impact of discards.

In 1994, all BSAI groundfish fisheries discarded an aggregate total of 162 161 tonnes of allocated groundfish species for which a total allowable catch had been set. The opportunity cost of these discards exceeded US$92 million. The total retained catch of all groundfish species in these fisheries was just over 1 699 500 tonnes with a value in excess of $925 million. Thus, the ratio of the value of retained catch to discards (retained/discard value ratio), weighted by fishery across all BSAI groundfish fisheries, was 10:1. That is, for each dollar of bycatch “opportunity cost” imposed, $10.10 of output was produced from retained catch. Individual rates varied from a high of $29.20 in the pollock target fishery, to a low of $2.40 in the “other” groundfish target fishery. Discarding was estimated to have a social cost of $25 million per annum in the southern New England yellowtail flounder trawl fishery (1998-1994 period).

In contrast, the use of BRDs to reduce mortalities in the red snapper fishery was estimated to incur losses of $117 million in the shrimp fishery (NMFS, 1998). The costs of discards may be shifted. The Gulf of Mexico shrimp fishery discarded significant quantities of juvenile snapper, thereby depleting snapper stocks. The shrimp fishery has had to absorb the costs of snapper bycatch reduction, although the costs to the shrimp fishery may surpass the economic value of the snapper fishery.


Discards are a common source of conflict between artisanal and industrial fishers, particularly when large quantities of discarded fish are seen floating at sea or rotting on beaches. Apart from the waste of resources perceived by artisanal fishers, a common complaint is that the “trawlers are polluting” the sea with dying fish and destroying juvenile stocks. Even when unwanted bycatch is landed, competition with artisanal fish production can be the cause of further conflict.

Economic incentives for reduction of discards

Several authors[127] address the economic aspects of discards. Many such studies model the theoretical economic impacts or social optima of different discard and bycatch-related measures based on assumptions regarding fishers’ behaviour. A range[128] of economic incentives for discard reduction can be built into a fisheries management regime. Taxes[129] can be imposed on discards or a charge based on the estimated value of the entire catch, including discards, may be applied[130] through royalty or licence fee payments. It is then up to vessel operators to make best use of the entire bycatch for which they are already being charged. Development of theory on discard regulation may draw on regulatory frameworks and models that consider discards to be a form of environmental damage (Segerson, 1988). Iceland has operated a “bycatch bank” to assist in commercializing unwanted fish. Quotas may be debited for failure to land in proportion to a predetermined length frequency distribution or charges[131] may be levied for failure to land bycatch. Subsidies leading to fleet overcapitalization and reduced profits may pressure vessel operators to land previously discarded bycatch (Bostock and Ryder, 1995).

Licence or other fees may be discounted for use of BRDs. As a result of a Congressional ban on ITQs, they were not considered as an option in the important United States shrimp fisheries (e.g. Gulf of Mexico) as part of the 1996 regulatory impact review. Obligatory use of BRDs was recommended as a least cost solution ($117 million/year for a 44 percent reduction in red snapper bycatch) in this fishery.

Placing a monetary value on discards raises fundamental theoretical problems of valuation of natural resources, e.g. the use of cost-benefit analysis in relation to environmental issues. Existence values associated with biodiversity or discards (mortalities) of charismatic species may be highly subjective, possibly because no objective valuation framework exists.

[79] The resolutions are A/RES/49/118 (1994); A/RES/50/25 (1996); A/RES/51/36 (1996); A/RES/52/29(1997); A/RES/53/33 (1998); A/RES/55/8 (2000); and A/RES/57/142 (2002).
[80] “... technical measures related to fish size, mesh size or gear, discards, closed seasons and areas and zones reserved for selected fisheries, particularly artisanal fisheries, the establishment of mechanisms for communicating information on areas of high concentration of juvenile fish,.... and support for studies and research that will minimize bycatch of juvenile fish”.
[81] A broader analysis of these issues is provided in FAO, 2001b.
[82] “Again, the kingdom of heaven is like unto a net, that was cast into the sea, and gathered of every kind: Which, when it was full, they drew to shore, and sat down, and gathered the good into vessels, but cast the bad away”. Matthew 13: 47-48.
[83] For example, the poem, “The Rime of the Ancient Mariner” by Samuel Taylor Coleridge (1789); frigate birds on amulets in the Solomon Islands.
[84] See Northridge, 1991; Perrin, Donovan and Barlow, 1994; and also the technical documents prepared for recent International Whaling Commission (IWC) meetings.
[85] Southwest Fisheries Science Center, 2002. Note that disease may also play a role in reducing some dolphin populations in the Eastern Tropical Pacific.
[86] Prepared for IUCN, the World Wide Fund for Nature (WWF), Pew Charitable Trusts and others.
[87] FAO file note on informal meeting held during the Committee on Fisheries (COFI) XXV, Rome, 2003.
[88] The Global Plan of Action for the Conservation, Management and Utilization of Marine Mammals was developed between 1978 and 1983 jointly by UNEP and FAO and was endorsed by UNGA. UNEP is to retool the Marine Mammal Action Plan in consultation with CMS, CITES, CBD, the regional seas conventions and action plans and relevant partner organizations, including IUCN.
[89] Magnuson-Stevens Fisheries Conservation and Management Act, Section 202 (h)(1), signed into law on 11 October 1996.
[90] See, for example, ASCOBANS Jastarnia Plan (Baltic harbour porpoise), ASCOBANS, 2002.
[91] Concern has been expressed over the effects of pingers in: (i) excluding marine mammals from certain habitats or zones; (ii) interference with migratory pathways; or (iii) long-term effects of aquatic noise.
[92] ASCOBANS and ACCOBAMS were both adopted under the auspices of the 1979 Convention for the Conservation of Migratory Species of Wild Animals (the “Bonn Convention”). There are similar arrangements in other regional seas conventions. Annex II of the Barcelona Convention Protocol Concerning Specially Protected Areas and Biological Diversity in the Mediterranean lists several marine mammal species as “endangered or threatened” and, as such, they are given special protection.
[93] EC Habitats Directive (92/43/EEC). The network of Special Areas of Conservation (SAC) is called Natura 2000.
[94] For example, the EC ban on the use of driftnets longer than 2.5 km, adopted by the Community in conformity with the UN resolution prohibiting the use of large pelagic driftnets (Council Regulation [EEC], No. 345/92 of 27 January 1992), and the prohibition of “dolphin sets” (Council Regulation [EEC], No. 3034/92 of 23 October 1992).
[95] A description of such a framework is given by Broadhurst, 2000.
[96] For example, World Trade Organization, 2001. The decision of the Appellate Body conditions market access on the adoption of a programme... comparable in effectiveness [with that of the United States].
[97] For example, the EU’s tracefish project and the introduction of radio-frequency identification device (RFID) tags in numerous products.
[99] Poseidon Aquatic Resource Management Ltd, 2003. See also Horsten and Kirkegaard, 2002.
[100] British Virgin Islands, Canada, the Comoros, Ecuador, Equatorial Guinea, Faeroe Islands, Iceland, the Islamic Republic of Iran, Indonesia, India, Lithuania, Namibia, Nicaragua, Nigeria, Norway, Peru, South Africa, Seychelles, United States and the United Republic of Tanzania.
[101] Known as a “full retention policy” in the United States.
[102] “Last year a Danish skipper was caught with more than 40 percent of illegal fish in the hatch. To the media the skipper says: ‘I was in the Norwegian zone and because of their discard ban, I had to keep the fish on board’. As a reply, the Danish Ministry argues to us: ‘the skipper has no excuse for having illegal catch onboard - he has to sail in Danish waters and dump the catch there’.” - K. B. Christensen, Chairman of The Danish Society for a Living Sea (Web site).
[103] The EU regulation prohibits “retention on board of fish which does not comply with the regulations”. The EU may propose a legal ban on discarding from 2006 (European Commission, 2002a).
[104] “... the only practicable method of checking the depletion of the North Sea fishing grounds and enabling the fish supply to recover is by legislation based on the principle of the size limit” (Holt, 1895).
[105] It is illegal to land more than a certain percentage of cod and haddock when using a mesh size <100 mm (Council Regulation [EC], 1998).
[106] In European waters the Norway pout Box protects juvenile haddock to the east of Shetland; the Plaice Box restricts fishing to smaller vessels and is intended to protect juvenile plaice and sole. In the Mackerel Box, purse seining is prohibited to protect juvenile mackerel.
[107] For example, the Australia Sub-Antarctic Bycatch Action Plan (BCAP): where any haul contains more than 100 kg of mackerel ice-fish, and more than 10 percent of the ice-fish by number are smaller than 240 mm total length, the fishing vessel shall move to another fishing location at least five nautical miles distant. The fishing vessel shall not return to any point within five nautical miles of the location where the catch of small ice-fish exceeded 10 percent for a period of five days. If, in the course of fishing, the bycatch in any one haul of any species for which bycatch limitations apply is equal to or greater than two tonnes, the fishing vessel shall not fish using that method of fishing at any point within five nautical miles of the location where the bycatch exceeded two tonnes for a period of at least five days (Australian Fisheries Management Authority, 2003). Similar regulations apply in the NAFO area. See NAFO/FC Document 02/9, Serial No. 4624.
[108] For example, in the Northeast Pacific midwater trawls must be kept off the bottom when the bottom trawl fishery is closed.
[109] Numerous studies have addressed this issue, inter alia: Copes, 1986b; Arnason, 1995, 1996; Pascoe, 1997.
[110] For example, some Norwegian fisheries allow individual fishers to substitute their quota in species A with quota in species B at predetermined ratios of substitution.
[111] The PFMC sets the discard rate at 16 percent for major species (range 5-20 percent). See the NPFMC Web site for regulations concerning numerous other bycatch reduction measures.
[112] Baltic stocks, North Sea haddock, northern hake (ICES) and some United States stocks are examples.
[113] ICES, 2002. See also ICES, 1985. There is a difference between short- and long-term stock assessments particularly if discarding is variable. If age-based stock assessment is not carried out then discard information may be of little or no value for stock assessment.
[114] For example, a study on the Great Barrier Reef showed that 98 percent of discarded finfish and cephalopods die. Approximately 12 percent of crabs, bivalves and echinoderms survived, thereby considerably altering the proportions of the phyla and species in the benthic biomass. There was a tenfold increase in crested tern populations caused by scavenging on the floating discards (Hill and Wassenberg, 2000). For further details see ICES, 2000c; Davis, 2002; Mesnil, 1996.
[115] Survival of fish passing through square mesh panels on top of the net is up to 65 and 90 percent for Scottish Nephrops and demersal fishing respectively.
[116] A separate FAO study addresses the ecological aspects of discarding (Poseidon Aquatic Resource Management Ltd, 2003). See also FAO, 2001a.
[117] “When seagulls follow trawlers, it is because they know sardines will be thrown into the sea.” Eric Cantona cited by Cook, 2001.
[118] Sharks and seahorses are among the exceptions.
[119] See Kungsuwan, no date, for a discussion of vessel design.
[120] “Small hooks catch a large proportion of large fish, and large hooks a considerable proportion of small fish.” Cunningham, 1896.
[121] In order to distinguish between small pelagics (some are low quota) that look identical on shipboard electronics (Triple Nine, an Esbjerg [Denmark] fishmeal company).
[122] Using eight trawls on five warps bycatch of cod was “practically none” in the North Sea prawn trawls (Fishing News International, 42, of 9 September 2003).
[123] The use of grids in shrimp trawl fisheries is relatively widespread. Their use in finfish trawl fisheries is less common but used inter alia in Argentina, the Faeroe Islands, Greenland, Canada, Iceland, Norway, the Russian Federation and Sweden (data from 1998).
[124] Gear definitions can be problematic. “... shall be prohibited to use any demersals trawl ...or towed gear ..., gillnet or similar static gear incorporating hooks ...”. Council Regulation (EC), 2002.
[125] Modelling studies tested several predator/prey relationship scenarios. For a summary see NMFS/NOAA, 1998b; Robins, Campbell and McGilvray, 1999.
[126] Substantial financial losses can be incurred by the introduction of square mesh panels. See Rommel and Napier, 1999.
[127] For example, Copes, 1986a; Arnason, 1994; Boyce, 1995.
[128] For a comprehensive discussion see Pascoe, 1997. For a discussion of deemed values and other options see Baulch and Pascoe, 1992; Willmann, 1996.
[129] For a theoretical model of such a scheme see Jensen and Vestergaard, 2000.
[130] This procedure is followed in Eritrea with respect to foreign vessels. The catch is monitored by 100 percent observer coverage.
[131] This is an option built into some fisheries access agreements, e.g. in Sierra Leone.

Previous Page Top of Page Next Page