Reconstructing discards profiles of unreported catches

In Portugal it has been estimated that unreported catches represent one third of total catches. Herein, information on landings and total unreported catches (discards) by commercial métier were disaggregated into high taxonomic detail using published scientific studies. Fish accounted for 93.5% (115493 t) of overall unreported catches per year, followed by cephalopods (2345 t, 1.9%) and crustaceans (1754 t, 1.4%). Sharks accounted for 1.3% of total unreported catches in weight (1638 t/y). Unreported taxa consisted mostly of the commercial landed fish species: Scomber colias, Boops boops, Trachurus picturatus, T. trachurus, Merluccius merluccius, Sardina pilchardus, Liza aurata and Micromesistius poutassou, which together accounted for 70% of the unreported discarded catches. The number of unreported/discarded species was highest in artisanal fisheries, followed by trawl and purse seine. In artisanal fisheries, L. aurata, S. colias, S. pilchardus, Trachinus draco and B. boops accounted for 76.4% of the unreported discards. B. boops, S. colias and S. pilchardus were also among the most discarded purse seine species, together with Belone belone accounting for 79% of the unreported catches. In trawl fisheries, T. picturatus (16%), M. merluccius (13%), S. colias (13%) and M. poutassou (13%) accounted for 55% of the trawl discarded unreported catches. The discarded species that most contribute to overall unreported catches are those that are most frequently landed and that most contribute to overall landings in weight.SFRH/BD/104209/2014 and SFRH/ BPD/108949/2015). This work received national funds through the Foundation for Science and Technology (FCT) through project UID/Multi/04326/2013. Karim Erzini was supported by funding from the European Commission’s Horizon 2020 Research and Innovation Programme under Grant Agreement No. 634495 for the project Science, Technology, and Society Initiative to minimize Unwanted Catches in European Fisheries (MINOUW)info:eu-repo/semantics/publishedVersio

An assessment of scup (Stenotomus chrysops) and black sea bass (Centropristas striata) discards in the directed otter trawl fisheries in the Mid-Atlantic Bight

This study was undertaken to re-assess the level of scup (Stenotomus chrysops) discards by weight and to evaluate the effect of various codend mesh sizes on the level of scup discards in the winter-trawl scup fishery. Scup discards were high in directed scup tows regardless of codend mesh — typically one to five times the weight of landings. The weight of scup discards in the present study did not differ significantly from that recorded in scup-targeted tows in the NMFS observer database. Most discards were required as such by the 22.86 cm TL (total length) fish-size limit for catches. Mesh sizes ≤12.7 cm, including the current legal mesh size (11.43 cm) did not adequately filter out scup smaller than 22.86 cm. The median length of scup discards was about 19.83 cm TL. Lowering the legal size for scup from 22.86 to 19.83 cm TL would greatly reduce discard mortality. Scup discards were a small fraction (0.4%) of black sea bass (Centropristis striata) landings in blacksea-bass−targeted tows. The black sea bass fishery is currently regulated under the small-mesh fishery gearrestricted area plan in which fishing is prohibited in some areas to reduce scup mortality. Our study found no evidence to support the efficacy of this management approach. The expectations that discarding would increase disproportionately as the trip limit (limit [in kilograms] on catch for a species) was reached towards the end of the trip and that discards would increase when the trip limit was reduced from 4536 kg to 454 kg at the end of the directed fishing season were not supported. Trip limits did not significantly affect discard mortality

Overlooked impacts and challenges of the new European discard ban

Discards are the portion of animal and plant material in the catch that is dumped back at sea. The Common Fisheries Policy plan proposed by the European Commission for 2014-2020 presents a controversial goal: to enforce the landing of fishing discards as a measure to encourage their reduction. This historical and political decision will shape the future of the fishing exploitation in European Seas. Discards generated by European fleets are not negligible, and its reduction is an ecological, socioeconomical and moral imperative. However, it must be achieved through the reduction in discards at source and the promotion of selective and non-destructive gears. We argue it is doubtful that this discard ban will result in an effective reduction of discards. The proposed measure may, in fact, negatively affect ecosystems at all levels of biological hierarchy by disregarding the Ecosystem-Based Approach to Fisheries and the Precautionary Principle. It could negatively impact several species by increasing fishing mortality, also commercial species if discards are not accounted in the total allowable catch. Communities preying on discards will likely be affected. The role discards currently play in the energy turnover of current ecosystems will be modified and should be fully evaluated. The landing of discards will likely generate new markets of fishmeal due to the growing demands for marine living resources. The ban will require substantial public investment to deal with technical problems on board and to control and enforce. Therefore, this measure should be only implemented after rigorous scientific and technical studies have been developed

Red snapper discards in Texas coastal waters : a fishery dependent onboard pilot survey of recreational headboat discards and landings

Prepared for Gulf & South Atlantic Fisheries Foundation, Inc.GASAFFI no. 70-06-21807/11165December, 1999This fishery dependent pilot study determined the quantity and characteristics of red snapper recreational headboat discards and landings from three ports (Galveston, Port Aransas, and Port Isabel) along the Texas coast during the months of August and early September 1999. Mean fishing depth during 42 trips was 23.7 fathoms (range, 7.3 -- 52.2, 11.3 s.d.). Reels sampled were 36.5% of reels in use. A total of 3,863 snapper were sampled during the study period. Snapper <18 inches made up 92.3% of snapper caught, those <15 inches made up 75.5% of the catch. When brought on board, 70.1 % of snapper appeared normal and 26.1 % had their stomach protruding. When discarded, 52.8% of snapper were released alive & swam down, 19.9% swam erratically, 13.2% floated, 1.3% were dead, and 12.9% were kept. Fish released either dead or floating were caught at greater depths than fish which swam down or erratically. Galveston had the largest discard:landing ratio (218:1), smallest mean weight per fish (1.5 pounds), and the smallest mean fish total length (13.2 inches). Port Aransas had the lowest discard: landing ratio (5.2: 1) along with the largest mean weight per fish (2.1 pounds), and mean total length per fish (15.2 inches, 2.5 s.d.).Marine Scienc

Discards monitoring in the Gillnet Sole Fishery

The Gillnet Sole Fishery Study Group started discards monitoring. Data were supposed to be collected in three different ways: Self-sampling, catch monitoring by means of onboard cameras (CCTV) and monitoring under the Data Collection Regulation

Mogelijke consequenties van reductie van de hoeveelheid discard voor N2000 instandhoudingdoelen

Discards zijn overboord gezette bijvangst van vissersschepen. Volgens de Nederlandse Visie op herziening van het Gemeenschappelijk Visserijbeleid (GVB) zouden discards uitgebannen moeten worden. Verschillende soorten zeevogels profiteren echter van discards als voedselbron. De vraag is wat de mogelijke gevolgen zijn van een reductie van of totale ban op de teruggooi van vis (discards) op Natura2000 instandhoudingsdoelen

On the Microeconomics of Quota Management in Fisheries

This paper compares the economic incentives created by transferable and non-transferable quotas in a fishery, in particular the incentives to discard fish of certain species or grades when quotas are enforced at the landing site. With a hypothetical efficient allocation of non-transferable quotas, the incentive structure is essentially the same as under transferable quotas. However, in the absence of the information provided by the quota price, outcomes may not be the same under all conditions. Inefficient allocations of non-transferable quotas will tend to reduce discards due to highgrading but increase discards in multispecies fisheries. The impact of discarding on the quota price in a transferable quota fishery is examined.fisheries management, quotas, ITQs, discards, Resource /Energy Economics and Policy, D21, D45, Q22,

Bio-Economies of Scope and the Discard Problem in Mulitple Species Fisheries

This paper considers the problem of multi-species fisheries management when targeting individual species is costly and at-sea discards of fish by fishermen are unobserved by the regulator. Stock conditions, ecosystem interaction, technological specification, and relative prices under which at sea discards are acute are identified. A dynamic model is developed to balance ecological interdependencies among multiple fish species, and scope economies implicit in a costly targeting technology. Three regulatory regimes, species-specific harvest quotas, landing taxes, and revenue quotas, are contrasted against a hypothetical sole owner problem. An optimal plan under all regimes precludes discarding. For both very low and very high levels of targeting costs, first best welfare is close to that achieved through any of the regulatory regimes. In general, however, landing taxes welfare dominate species-specific quota regulation; a revenue quota fares the worst.scope economies; multiple species fishery management; costly targeting; discarding