What is the difference between bycatch and discard

Shrimp trawls usually catch five to 10 pounds of other sea creatures for every pound of shrimp. Once bycatch is caught and piled up on deck of a fishing boat, the fishers can either:.

In the mids discards were estimated at 26 million metric tons per year, or about one-quarter of the world catch at the time. In the s global discards were estimated at million metric tons, which is about one-tenth of current marine catches. The decline is thought to be due to more bycatch being retained to produce feed for use in fish farming, but this low estimate is contested. Most people not connected with fisheries feel that discarding perfectly edible fish in our age of widespread hunger and scarcity is unethical, and they are right, even if it is only million metric tons that are discarded.

It is believed that the total volume of world catches is much higher than the declared catch because many fisheries do not provide information about their discards; in other cases, many catches that are not commercially valuable are not even considered discards and, as such, are not registered at all. Oceana works in the EU to achieve the approval of specific legislation concerning bycatch and discards. The proportion of discards in European waters is putting the future of many fisheries at risk.

Oceana proposes the implementation of a set of measures that have been proven effective in other fisheries:. Oceana works to introduce these measures in Community legislation and ensure they are effectively implemented. Close Would you like to view our EU site? The system of restricting landings, as was true with the previous system used in EU fisheries, is one cause of discards.

Many EU fisheries catch a mix of species simultaneously, many of which are regulated by landing quotas. Typically, once the landing quota is fully utilized for one or more species, fishers will continue catching and discarding those species while targeting other species for which quota is available or unregulated species.

Consequently, landings quotas often fail to deliver their main function of restricting fishing mortality. Fishers' responses to landing quota restrictions have been identified as an important driver of discarding and can be the principal reason for discarding in some fisheries Catchpole et al.

Other important drivers of discarding include fish caught under the legal minimum landing size MLS , fish caught for which there is no market or an inconsistent market, fishers' responses to catch composition regulations, and damage to the catch Alverson et al. These advances in data availability, understanding the interactive behaviour of fish and fisheries, and exploring patterns of variation in discards can be used to develop mitigation programmes.

The anticipated change to discard management in the European CFP has influenced and was influenced by recent research. A reformed CFP was agreed upon in May , which includes a move to catch limits and an obligation to land all catches, i. Canada Clucas, The principle of these reforms is that all catches of restricted species shall be brought and retained on board fishing vessels and recorded and landed. European fisheries will come under the new obligation to land all catches in a phased approach between and Exceptions to the landing obligation will be made for species where high discard survival rates can be demonstrated.

Other exemptions may also apply if certain conditions are met, for example, if increases in selectivity are very difficult to achieve, or if the costs of handling unwanted catches are disproportionate Council of the European Union, The catch limit approach is, therefore, intended to directly prevent discarding practices driven by quota and MLS restrictions.

Catch limits come with the potential to increase the landings quota to a full catch quota, by including some or all the previously discarded catches, so that total fishing mortality does not increase. Consequently, there is an economic incentive for fishers to transfer to this system and the strength of this incentive will depend on the level of quota increase and enforcement. Fleet-specific factors will impact on the incentive structure of catch limits Condie et al. Creating incentives to encourage fishers to match their catch compositions with agreed target catch levels is a challenge for fishery managers.

An approach widely used is the provision of conditional access to those fishers using more selective fishing methods. This can be either in the form of providing spatial access to fishing grounds Macdonald et al. These measures are introduced on an ad hoc basis and are conventionally initiated as part of wider plans to rebuild overexploited fisheries. These conditional access agreements require changes to technical regulations, which suffer from low compliance, circumvention, or unintended impacts Tsagarakis et al.

In the EU, technical regulations that constrain many aspects of fishing operations have proliferated. Table 1. Key of fishery, area, and species codes pertaining to the world bycatch database.

Table 2. Total number and number of records in weight-based and numbers-based formats for each gear type in the NRC bycatch database. Table 3. Table 4. Estimated bycatch and discards from world shrimp fisheries derived from reported bycatch levels and estimated amount of bycatch retained.

Table 5. Discard weight by major world region. Table 6. Table 7a. Top twenty fisheries with the highest recorded discard ratios by weight discard weight per landed target catch weight. Table 7b.

Top twenty fisheries with the highest recorded discard ratios by number discard number per landed target catch number. Table 8a. The ten lowest observed weight-based discard ratios in fisheries other than shrimp discard weight per landed target catch weight. Table 8b. The ten lowest observed numbers-based discard ratios in fisheries other than shrimp discard number per landed target catch number. Table 9a. The top weight-based discard to landed target catch ratios by gear type.

Table 9b. The top numbers-based discard to landed target catch ratios by gear type. Table The highest discard to target catch ratios by region discard weight per landed target catch weight. Discards of young tuna and other pelagic fish species in the ETP tuna fishery number of fish.

Dolphin mortality and fishery production. Halibut discard mortality rates estimated by fishery. Trend in halibut discard mortality rates during through and recommendations for preseason rates. Reported crab bycatch mortality rates in North Pacific fisheries. Reported salmon mortality rates in North Pacific fisheries.

Table 17a. Percentage by weight of three taxonomic groups in a subset of discards fish, non-commercial crustaceans, and cephalopods from prawn trawls, the percentage of each group that floated, and the percentage of each group that was alive 12 hours after a minute exposure to air on deck. Table 17b. Percentage of animals surviving for 12 hours after exposure for 10 minutes on deck. Dab mortality from shrimp fishery bycatch. Mortality of selected fish species in the bycatch of the shrimp fishery after five days of maintenance.

Annual discard mortalities by species and the percent of total fishing mortality attributed to discards for fisheries in the Northeast Pacific Bering Sea. Total retained and discarded weight and number for four gear types and nine target fisheries in the Bering Sea. Discard ratio for Bering Sea crab fisheries, and Estimated fishing mortality rates for key species in the Bering Sea in resulting from discarding major commercial target species. Estimated king crab population, discard as a percentage of population size number landed per number landed , and discard mortality as a percentage of population size, — Incidental mortality number of fish of chinook salmon in West Coast and Alaska salmon purse seine fisheries.

Cumulative percent of top fourteen bycatch taxa by region. Impact of discards on retrospective results. Impact of discards on fishery predictions. Annual weights of haddock and whiting in human consumption landings, discards, and bycatches of the industrial fishery. The severity of bycatch problems in a number of North Sea fisheries. Fishing mortality by age for haddock and whiting generated by human consumption landings, discards, and bycatches of the industrial fishery for North Sea haddock and North Sea whiting.

Relationship between demersal fish biomass and catch of target species. Figure 1. Example records of the world bycatch database. Figure 2. FAO fishery statistical areas. Figure 3. Major discard families by region. Figure 4. Discard mortalities numbers of porpoise in the Eastern Tropical Pacific tuna purse seine fisheries, — Figure 5.