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Trawling is one of the most common fishing methods used by small vessels. This method requires the vessel to operate at a constant low speed because the depth of the trawl must be kept constant. In addition, the operation is often conducted by a small number of people, who must simultaneously maneuver the vessel and fish, making automation desirable. To develop this device, a mathematical model of the vessel was created based on data collected from actual operation of the vessel, and simulations were conducted to determine what type of control system would be suitable. As a result, it was possible to grasp effective control methods, effects of disturbances such as tides and waves, and how to deal with effective parts to improve response.

Fisheries discards have become a source of concern for the perennation of marine resources. To reduce discards, the European Union adopted a Landing Obligation under the reform of its Common Fisheries Policy. However, food web consequences of reducing discards remain uncertain since their degree and pathway of reintegration are understudied. We used multi-marker DNA metabarcoding of gut contents and an ecological network approach to quantify marine fauna reliance on discarded fish and functional importance of discard consumers in coastal fishing grounds. We show that potential discard consumption is widespread across fish and invertebrates, but particularly important for decapods, which were also pinpointed as functionally important. Potential discard consumption may represent up to 66% of all interactions involving fish prey in the reconstructed network. We highlight that discard reliance may be more important than previously assessed in some fishing areas and support functionally important taxa. While reducing discarding remains a conservation priority, it is crucial to understand discards reintegration in marine food webs to anticipate changes in the context of an ecosystem approach to fisheries management.

Background. Atlantic horse mackerel, Trachurus trachurus (Linnaeus, 1758), is among bento-pelagic species subject to discard within deep-water rose shrimp fisheries, and how such species would react to light wavelength is therefore important, to be consistent with the Common Fishery Policy (CFP). Despite the existing literature currently available, there is still paucity of relevant information about how artificial light wavelengths affects the behaviour of T. trachurus juveniles. In this context, the effects of different artificial light wavelengths on some behavioural features of juvenile T. trachurus were investigated. Materials and methods. Maintained in a fish tank, the juveniles of Atlantic horse mackerel, after acclimatization, were subject to six different light wavelengths, representing the following colours: white, violet, blue, green, yellow, and red. Subsequently, behavioural features, specifically phototaxis (degree of attraction or repulsion toward the light source) were tested. Results. By phototaxis per light wavelength, the studied juvenile individuals produced statistical differences in the presence frequency (P < 0.05) revealed by blue that noticeably attracted some, relative to the white light that repulsed others. Yet, violet and red lights produced much less but no significant attraction of these juveniles (P > 0.05). Conclusion. The presently reported study has provided additional information about ecological knowledge and understanding specific to juvenile T. trachurus individuals, which can further the development of (selective) light fishing techniques, aimed at reducing unwanted catches of commercial pelagic fisheries

Under the individual vessel quota regulations, the expected economic return of a multi species fishery is influenced by an array of a multi-component choice such as targeted species, landings per haul, harvesting time and its location. The components of effort allocation decisions are further complicated by changes in the market conditions and the constant movements of fish between spawning and feeding habitats. Migratory behavior influences the dispersal of species, relative availability of fish and its composition, and the bycatch likelihood across different locations over the course of a fishing year. The objective of this article is to investigate the optimal allocation of fishing effort in the Norwegian bottom-trawl fleet within economically important species; cod, saithe, and haddock across three heavily trawled areas—including southern and northern parts of the west coast of Norway, and the high sea areas of the Arctic—to achieve maximum expected economic return, with respect to the individual vessel quota constraints and bycatch considerations. The results from a mixed integer non-linear optimization problem evidence that the spawning migration of Northeast Arctic cod along the northwest coast, effort allocation behavior of coastal fleet, together with institutional regulations necessitate the substitution of fishing effort across different fishing locations within the fishing season to maximize expected return. The results of our study further reveal that the Arctic region to target cod is the biggest contributor to annual fishing revenue. By contrast, conducting saithe fishery in the southwest of the Norwegian coast has the lowest economic contribution. The results from Monte Carlo simulation demonstrate that the proposed model is effective and applicable for effort allocation decision analysis.

Seabirds interaction with trawl fishing gear was observed aboard the large freezing-processing trawler «Moskovskaya Olimpiada» during the pollock fishery in the Okhotsk Sea in January-April, 2015. In total, 579 observation rounds were realized including 105 ones during the trawl setting, 116 ones during hauling, and 358 ones during trawling, with total duration of 280.7 hours. In the observations, 1443 contacts of birds with the fishing gear were recorded. Light contact of a flying gull with the trawl net was observed in one case only; all other contacts were collisions with the wires. The warps and the depth sounder cable were the greatest hazard for birds. Collisions with the sounder cable during the trawling were the most frequent, with approximately 5 times higher frequency than with the same cable during the trawl setting or hauling. Almost all strikes with the wires were registered for northern fulmars (97.5 %) and the rest of the strikes — for large gulls. Gulls had only light contacts with the depth sounder cable (2 contacts afloat and 34 contacts in flight). Fulmars had contacts both with the depth sounder cable and warps. Flying birds of this species contacted with the depth sounder cable more frequently (75.5 %) than those sitting on the water. On the contrary, majority of fulmars (61.6 %) contacted with the warps being afloat in the process of their feeding. Several cases only (0.6 %) of direct interactions with the fishing gear caused the bird’s death. All these cases occurred with the fulmars drowned when they fell under the depth sounder cable (7 ind.) or under the warp (1 ind.). Frequency of the bird collisions with the wires differed prominently by the fishery districts, with the maximum in the Kamchatka-Kuril subzone (8.35 contacts/hour for fulmars and 0.22 contacts/hour for gulls). These spatial differences are related to the birds abundance near the ship that depends on distribution patterns of certain bird species in the Okhotsk Sea in winter. General frequency of the contacts depends credibly on intensity of the waste discharges after fish processing and on wind direction relative to the ship course.

17 pages, 7 figures, 2 tables, supplementary material https://doi.org/10.3389/fmars.2021.610241.-- Data Availability Statement: The datasets presented in this article are not readily available because some of the original raw data are protected by confidentiality. Requests to access the datasets should be directed to GM, giacomo.milisenda@szn, The recent establishment of the “landing obligation” under the reformed EU Common Fishery Policy has the twofold objective of reducing the excessive practice of discarding unwanted catch at sea and encouraging more selective and sustainable fisheries. Within this context, the awareness of the spatial distribution of potential unwanted catches is important for devising management measures aimed to decrease discards. This study analyzed the distribution of Hot Spot density areas of demersal fish and crustaceans below the Minimum Conservation Reference Size (MCRS) in four different southern European seas: continental Portuguese coast, Catalan Sea, South of Sicily, Liguria and northern Tyrrhenian Seas using both bottom trawl survey data and information on the spatial distribution of commercial fisheries. Critical areas for discarding were identified as zones where the highest densities of individuals below MCRS were consistently recorded throughout a series of years. Results clearly showed a patchy distribution of undersized individuals in each investigated area, highlighting the overlap between high density patches of both discards and fishing effort. The present findings provide a relevant knowledge for supporting the application of spatial-based management actions, such as the designation of Fisheries Restricted Areas (FRAs), in order to minimize the by-catch of undersized specimens and improve the sustainability of demersal fisheries, This work was funded by the European Commission’s Horizon 2020 Research and Innovation Program under Grant Agreement No. 634495 for the project Science, Technology, and Society Initiative to minimize Unwanted Catches in European Fisheries (MINOUW). This study received Portuguese national funds from FCT-Foundation for Science and Technology through project UIDB/04326/2020, With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

The behavior of the Argentine shortfin squid (Illex argentinus) in reaction to a trawl net is reported from images obtained during one fishing tow operated by a commercial trawler in May 2015 in slope grounds off southern Brazil (depth 370-361 m; 33°37’S, 50°49’W). Video analysis utilized criteria to classify the horizontal and vertical distribution of squid in the field of view of the camera, posture (pitch and yaw), squid color patterns, escape reaction, swimming time and use of the tail fin. The monitored bottom trawl operation intercepted dense and patchily distributed schools of I. argentinus that could be observed for brief periods of time swimming ahead of the mouth of the trawl. Individuals were evenly distributed in the water column but concentrated on the center and right sectors of the trawl mouth. Most squids in the path of a trawl tended to swim by jet-propulsion for 10-20 s, tail-first and with regularly spaced fin flaps. Estimated speed (1.24 m s-1) was higher than cruise speed recorded for other ommastrephid squids in nature (0.3 m s-1), possibly reflecting an emergency escape reaction. After a period of sustained swimming ahead of the trawl, squid reacted in different ways including: a) slowing down and swimming into the net tunnel, b) shifting directions to escape through the trawl mouth sides, and c) swimming up, trying to escape over the top trawl panel, sometimes turning around pointing the tail towards the trawl mouth.

New techniques of fish tranport from fishing gears aboard is proposed for a case of mixed aggregations of chub mackerel and japanese sardine. These species resume their mass migration to the Russian waters since 2014. Submersible impeller pumps with hydraulic power drive are used usually for catch transport aboard in the world practice of purse seining of mackerel. However, this technique is unsuitable for mixed aggregations of mackerel and sardine because the impeller pump could damage the sardine. Applicability of the vacuum and waterjet pumps for this case is considered. The vacuum fish pump TransVac was designed in 1982, initially for transfer of damage-sensitive fish from fishing vessel to shore fish processing plant, and the waterjet fish pump SilkStream was designed in 1988 for transfer of alive fish and later was adapted for fish transport aboard from trawl and seine nets. Both types of fish pumps are recommended for the medium- and large-capacity fishing vessels working with the mixed aggregations of sardine and mackerel. Using of these pumps together with freezing equipment allows to avoid losses in quality of catch.

Special issue on Discards regulation vs Mediterranean fisheries sustainability.-- 10 pages, 6 figures, 7 tables, [EN] With the full implementation of the landing obligation on 1 January 2019, In European waters it will become mandatory for the trawling fleet to land at port all catches of certain species because, according to Article 15 of the new European Common Fisheries Policy, the species subject to the minimum conservation reference size (MCRS) cannot be discarded. Additionally, since 2005, trawlers over 15 m in length are required to carry an onboard vessel monitoring system (VMS), which generates information on fleet dynamics. The objective of this work was to provide a tool for avoiding unwanted catches by integrating the catch study of trawlers operating in the port of Blanes together with VMS data. To achieve this objective, the catches of 40 hauls were monitored, sampled and analysed together with VMS data for the years 2012-2014 integrated in a geographical information system. The results show that specimens below the MCRS were often captured in crinoid aggregation habitats, bottoms with maërl and muddy bottoms that were identified as nursery habitats of commercial species, e.g. Merluccius merluccius, Pagellus spp. and Mullus spp. VMS data showed considerable fishing pressure on areas with maërl and muddy habitats during the recruitment periods of these and other commercially relevant species. Implementing spatial or seasonal closures in habitats where species regulated by the MCRS are subject to catches could be a useful tool for preventing unwanted catches, [ES] Con la plena aplicación de la Obligación de desembarque a partir del 1 de enero de 2019, pasará a ser obligatorio para la flota de arrastre desembarcar en puerto todas las capturas de ciertas especies, que según el Artículo 15 de la nueva política pesquera común no pueden ser descartadas, ya que están sujetas a MCRS. Por otro lado, desde 2005, se requiere a los arrastreros de más de 15 m de longitud, llevar a bordo un VMS, que proporciona información acerca de la dinámica de la flota. El objetivo de este trabajo fue proporcionar una herramienta para evitar capturas no deseadas integrando el estudio de la captura de arrastreros que operan en el puerto de Blanes junto con datos VMS de la flota de arrastre. Para lograr dicho objetivo, las capturas de 40 lances fueron monitoreadas, muestreadas y analizadas junto con los datos VMS de los años 2012-2014 integrados en un Sistema de Información Geográfica. Los resultados muestran que se capturaron de forma notable especímenes por debajo de la MCRS en hábitats de agregación de crinoideos, fondos con presencia de maërl y fondos fangosos que fueron identificaron como hábitats de cría para especies como Merluccius merluccius, Pagellus spp. y Mullus spp. Los datos VMS mostraron una notable presión pesquera en hábitats fangosos y fondos con presencia de maërl durante los períodos de reclutamiento de estas y otras especies comerciales relevantes. El uso de cierres espaciales o temporales en hábitats sujetos a descarte de especies reguladas por MCRS podría ser una herramienta útil para evitar capturas no deseadas, This work was funded by the research project MINOUW (H2020-SFS-2014-2) from the European Commission (contract nº 634495). We also acknowledge the help of the vessels’ crew during sampling and the data provided by MAGRAMA, which were indispensable for meeting the objectives of this work

With the full implementation of the landing obligation on 1 January 2019, In European waters it will become mandatory for the trawling fleet to land at port all catches of certain species because, according to Article 15 of the new European Common Fisheries Policy, the species subject to the minimum conservation reference size (MCRS) cannot be discarded. Additionally, since 2005, trawlers over 15 m in length are required to carry an onboard vessel monitoring system (VMS), which generates information on fleet dynamics. The objective of this work was to provide a tool for avoiding unwanted catches by integrating the catch study of trawlers operating in the port of Blanes together with VMS data. To achieve this objective, the catches of 40 hauls were monitored, sampled and analysed together with VMS data for the years 2012-2014 integrated in a geographical information system. The results show that specimens below the MCRS were often captured in crinoid aggregation habitats, bottoms with maërl and muddy bottoms that were identified as nursery habitats of commercial species, e.g. Merluccius merluccius, Pagellus spp. and Mullus spp. VMS data showed considerable fishing pressure on areas with maërl and muddy habitats during the recruitment periods of these and other commercially relevant species. Implementing spatial or seasonal closures in habitats where species regulated by the MCRS are subject to catches could be a useful tool for preventing unwanted catches., Con la plena aplicación de la Obligación de desembarque a partir del 1 de enero de 2019, pasará a ser obligatorio para la flota de arrastre desembarcar en puerto todas las capturas de ciertas especies, que según el Artículo 15 de la nueva política pesquera común no pueden ser descartadas, ya que están sujetas a MCRS. Por otro lado, desde 2005, se requiere a los arrastreros de más de 15 m de longitud, llevar a bordo un VMS, que proporciona información acerca de la dinámica de la flota. El objetivo de este trabajo fue proporcionar una herramienta para evitar capturas no deseadas integrando el estudio de la captura de arrastreros que operan en el puerto de Blanes junto con datos VMS de la flota de arrastre. Para lograr dicho objetivo, las capturas de 40 lances fueron monitoreadas, muestreadas y analizadas junto con los datos VMS de los años 2012-2014 integrados en un Sistema de Información Geográfica. Los resultados muestran que se capturaron de forma notable especímenes por debajo de la MCRS en hábitats de agregación de crinoideos, fondos con presencia de maërl y fondos fangosos que fueron identificaron como hábitats de cría para especies como Merluccius merluccius, Pagellus spp. y Mullus spp. Los datos VMS mostraron una notable presión pesquera en hábitats fangosos y fondos con presencia de maërl durante los períodos de reclutamiento de estas y otras especies comerciales relevantes. El uso de cierres espaciales o temporales en hábitats sujetos a descarte de especies reguladas por MCRS podría ser una herramienta útil para evitar capturas no deseadas.

WOS: 000439087100034, The discard and its losses is an important issue with the principles of sustainable and responsible fishery for researchers and the fishing technology. In this study, discard fate, which is caught and released into the sea by discarding in the Iskenderun Bay trawl fishery, was investigated. Small individuals of Nemipterus randalli (N: 340), Sparus aurata (N: 236) and Pagellus erythrinus (N: 148) with low economic value were evaluated as discard fish in the commercial trawl fishery. In order to estimate survival rates, the three fish species individuals were taken to observation tanks on the fishing vessels and waited for 30 minutes after trawl was hauled. In addition to, barotrauma treatment experiments were carried out with a formed pressure tank which produces the pressure gradient at the depth where the species is caught. Barotrauma treatment has been providing a significant contribution to increase the discard survival rate. In particular, it was observed that barotrauma treatment significantly contributed to the survival rate of the N. randalli individuals. The discard survival rates of N. randalli, S. aurata and P. erythrinus were calculated 53.4%, 65%, 68.1% with barotrauma treatment and 12.9%, 41.8%, 59% with 1 atm respectively., MKU-BAP; TUBITAK [1150439]; BAP Foundation of Mustafa Kemal University [13484], This article is part of the first author's doctoral dissertation. The doctoral dissertation was supported by MKU-BAP and TUBITAK. Authors thanks to BAP Foundation of Mustafa Kemal University (Project No: 13484) and TUBITAK (Project No: 1150439) for their financial support. The authors would like to thank Dr. Yavuz MAZLUM from the Faculty of Marine Science and Technology Faculty Iskenderun Technical University for critical review of the manuscript.

Time-series of fishing position, landings, satellite-derived sea-surface temperature and chlorophyll a concentrations were used to relate the spatial-temporal distribution of the Argentine hake Merluccius hubbsi with seasonal oceanographic processes in San Matías Gulf. Also, the seasonal effect of fishing on the hake population structure was analysed. During summer the fleet was concentrated over the area of the frontal system, obtaining the best catch-per-unit-effort (CPUE) of hake in relatively deep waters. In autumn, the dispersion of the fleet due to a reduction in CPUE coincided with the dissipation of the front, suggesting that the distribution and shoaling of the Argentine hake is associated with seasonal thermal structures. In spring, the thermal structure of the waters and the chlorophyll a blooms seem to modulate the timing of spawning of hake, which occurs mainly in October-November. In addition, the fleet captured a higher proportion of females in the gonadal recovery stage during warm months (November-April). While winter catches (May-October) consisted mainly of males, the intense summer fishing may result in a high impact on the female population. This information is relevant to design of spatial management tools intended to provide biological sustainability to the hake fishery. Fil: Ocampo Reinaldo, Matías. Universidad Nacional del Comahue. Instituto de Biología Marina y Pesquera Almirante Storni; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Leibniz Centre for Tropical Marine Ecology; Alemania Fil: González, Raul Alberto Candido. Universidad Nacional del Comahue. Instituto de Biología Marina y Pesquera Almirante Storni; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Williams, Gabriela Noemí. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: Storero, Lorena Pia. Universidad Nacional del Comahue. Instituto de Biología Marina y Pesquera Almirante Storni; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Romero, Maria Alejandra. Universidad Nacional del Comahue. Instituto de Biología Marina y Pesquera Almirante Storni; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Narvarte, Maite Andrea. Universidad Nacional del Comahue. Instituto de Biología Marina y Pesquera Almirante Storni; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: Gagliardini, Domingo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina

10 pages, 6 figures, 2 tables, [EN] In this work we analysed the spatio-temporal variability of discards in the fishery of the deep-sea red shrimp Aristeus antennatus in the northwestern Mediterranean Sea. We sampled fishery discards in the fishing grounds of Palamós (the main harbour for this fishery on the Catalan margin), which are located in several areas of a submarine canyon. We found that the discard ratio in this fishery showed a marked seasonal variability, with a maximum in spring and a minimum in summer. Most of the discarded biomass (almost 96%) were of species with no commercial interest. Within these, the most represented group was elasmobranchs, making up to more than 50% of total discarded biomass. Our findings show that the landing obligation established by the EU will have a low impact in mitigating discards in this fishery, as the vast majority of discards are non-commercial species that are not specified in the regulation. Alternative management strategies, such as a temporary fishery closure in spring (when the discard ratio reaches its maximum), should be considered in order to preserve the vulnerable ecosystem hosted by the submarine canyon, [ES] En este estudio se analizó la variabilidad espacio-temporal de los descartes en la pesquería de la gamba roja de profundidad Aristeus antennatus en el mar Mediterráneo Noroccidental. Para ello se muestrearon las capturas obtenidas en los caladeros de Palamós (el mayor puerto para esta pesquería en Cataluña), que están localizados en diferentes áreas adyacentes a un cañón submarino. Nuestros resultados demuestran que la proporción de descartes en las capturas de esta pesquería presenta una marcada variabilidad estacional, con un máximo en primavera y un mínimo en verano. La mayoría de la biomasa de los descartes (casi el 96%) está constituida por especies sin ningún interés comercial. Entre éstas, el grupo más representado es el de los elasmobranquios, que constituye más del 50% de la biomasa total de los descartes. Nuestros resultados indican que la obligación de desembarcar las capturas establecida por la UE tendrá un impacto bajo en disminuir los descartes en esta pesquería, ya que la gran mayoría de los descartes está constituida por especies no comerciales que no están especificadas en la regulación. Medidas de gestión alternativas, como el establecimiento de una veda en primavera (cuando la proporción de descartes llega a su máximo) deberían considerarse para preservar el ecosistema vulnerable de este cañón submarino, Finally, the EC Programme Science in Society EC FP7 (grant agreements 266544-GAP2 and 287600-PERSEUS), the FPU grant of the Spanish Ministry of Education and the Marine Stewardship Council are acknowledged for their financial support

The development of a deep-sea fishery for aristeid shrimps off Brazil is reviewed from its early days in 2002. Descriptive data were collected by observers on board 75 directed fishing trips conducted in the study period, with a total of over 15,000 monitored trawls. An incipient fishing phase took place between No-vember 2000 and October 2002, when aristeid shrimps were occasionally reported in the bycatch of operations mostly targeting the Argentine hake (Merluccius hubbsi). After that, a directed fishery was established for these resources. All nine vessels involved in this fishery (one national and eight chartered) concentrated on 11 limited grounds between 700 and 800 m deep and 18°S and 34°S. The main species caught between November 2002 and May 2007 was the "carabinero" Aristaeopsis edwardsiana (456,710 kg), followed by the "moruno" Aristaeomorpha foliácea (121,497 kg), and then the "alistado" Aristeus antillensis (27,919 kg). The trawlers operate in conjunction, such that the total area of each fishing ground was swept at least twice. This harvest pattern substantially reduced "carabinero" catch rates from 14 kg hour-1 in the first sampled trimester to 4 kg hour-1 in the last. Despite the inferred biomass reduction of this species, the fishery has continued without a formal management plan.

The daily variation of fishing effort and ex-vessel price was analysed to determine which day of the week is suitable to ban the fishery, as an alternative management measure to the one month seasonal closure. Thus, 10-years landings data were used from two representative trawling ports of the western Mediterranean: Dénia and La Vila Joiosa. Analysis of variance (ANOVA) was used to detect significant differences in fishing effort (total and by métier) and daily ex-vessel price of the main target species. Also, the economic loss produced by banning one day (the proposed measure) was compared to economic loss produced by the seasonal closure (the actual measure). Daily variation in the fishing effort was observed in La Vila Joiosa mainly due to higher effort at the end of the week devoted on crustacean métiers, while effort was similar among days in Dénia. The lowest mean prices for most target species were on Tuesday and Wednesday, and were higher on Monday and Friday. Banning one day per week (Tuesday or Wednesday), when market prices of target species are lower would reduce the double of effort than one month of seasonal closure, and likely without subsidies. However, the loss by banning all Wednesdays (approx. 50 days) was higher in both ports than one month, but lower than an equivalent two months closure. M. Samy-Kamal was supported by a grant of the Spanish Agency for International Cooperation for Development (AECID) MAEC-AECID (Nº0000593564).

In this work we analysed the spatio-temporal variability of discards in the fishery of the deep-sea red shrimp Aristeus antennatus in the northwestern Mediterranean Sea. We sampled fishery discards in the fishing grounds of Palamós (the main harbour for this fishery on the Catalan margin), which are located in several areas of a submarine canyon. We found that the discard ratio in this fishery showed a marked seasonal variability, with a maximum in spring and a minimum in summer. Most of the discarded biomass (almost 96%) were of species with no commercial interest. Within these, the most represented group was elasmobranchs, making up to more than 50% of total discarded biomass. Our findings show that the landing obligation established by the EU will have a low impact in mitigating discards in this fishery, as the vast majority of discards are non-commercial species that are not specified in the regulation. Alternative management strategies, such as a temporary fishery closure in spring (when the discard ratio reaches its maximum), should be considered in order to preserve the vulnerable ecosystem hosted by the submarine canyon. En este estudio se analizó la variabilidad espacio-temporal de los descartes en la pesquería de la gamba roja de profundidad Aristeus antennatus en el mar Mediterráneo Noroccidental. Para ello se muestrearon las capturas obtenidas en los caladeros de Palamós (el mayor puerto para esta pesquería en Cataluña), que están localizados en diferentes áreas adyacentes a un cañón submarino. Nuestros resultados demuestran que la proporción de descartes en las capturas de esta pesquería presenta una marcada variabilidad estacional, con un máximo en primavera y un mínimo en verano. La mayoría de la biomasa de los descartes (casi el 96%) está constituida por especies sin ningún interés comercial. Entre éstas, el grupo más representado es el de los elasmobranquios, que constituye más del 50% de la biomasa total de los descartes. Nuestros resultados indican que la obligación de desembarcar las capturas establecida por la UE tendrá un impacto bajo en disminuir los descartes en esta pesquería, ya que la gran mayoría de los descartes está constituida por especies no comerciales que no están especificadas en la regulación. Medidas de gestión alternativas, como el establecimiento de una veda en primavera (cuando la proporción de descartes llega a su máximo) deberían considerarse para preservar el ecosistema vulnerable de este cañón submarino.

The aim of the present paper is to study the relationships between some climatic indices and parental stock, recruitment and accessibility to trawl fishery of hake (Merluccius merluccius) and red shrimp (Aristeus antennatus) off Balearic Islands (western Mediterranean). Available annual catch per unit effort, recruitment and spawning stock biomass have been used as biological data. As environmental data, the meso-scale IDEA index and the large-scale North Atlantic Oscillation (NAO) and Mediterranean Oscillation (MO) indices have been used. To analyze possible links between these indices with the population dynamics of demersal resources, two non-linear approaches have been applied: (i) stock-recruitment relationships from Ricker and Beverton-Holt models, by sequentially incorporating environment factors; (ii) generalized additive modelling, both classical general and threshold non-additive models were considered. The latter simulate an abrupt change in explicative variables across different phases (time periods or climatic index values). The results have shown that two oceanographic scenarios around the Balearic Islands, associated with macro and meso-scale climate regimes, can influence the population dynamics of hake and red shrimp. This is especially true for recruitment, which seems to be enhanced during low NAO and IDEA indices periods. During these periods, colder-than-normal winters generate high amounts of cold Western Mediterranean Intermediate Waters (WIW) in the Gulf of Lions, which flow southwards and reach the Balearic Islands channels in spring, increasing the productivity in the area. This oceanographic scenario could also be favourable to the distribution of hake on the fishing grounds where the trawl fleet targets this species, increasing its accessibility to the fishery. Both spawning stock and abundance of red shrimp seems to be also enhanced by high MO index periods, which could reflect the increased presence of the saline and warm Levantine Intermediate Waters (LIW) in the study area, extending over the fishing grounds of this species. The proposed interactions can be useful to assess and manage these important demersal resources. © 2007 Elsevier B.V. All rights reserved., The IDEA project has been funded by the Spanish Ministry of Education and Science (Plan Nacional I+D+i 2000-2003, REN2002-04535-C01-02/MAR)

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:20:36Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:33:23Z : No. of bitstreams: 1 2-s2.0-23744486183.pdf: 280832 bytes, checksum: e5063a250882b4e115de7cbd61c8e187 (MD5) Made available in DSpace on 2014-05-27T11:20:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-01-01 Monthly collections of fishes using a trawl net were carried out from August 1996 to December 1997 with the objective of evaluating the composition and diversity of fish species in the littoral area of the transition zone between Veados Stream and Jurumirim Dam (Upper Paranapanema River, São Paulo State). Diversity and similarity indices of ichthyofauna at the sites were determined and correlated with abiotic factors such as dissolved oxygen, temperature, pluviometric precipitation and hydrological level. Twenty-six (26) fish species (the majority small-sized) of the family Characidae (Tetragonopterinae and Cheirodontinae) were registered. Representatives of the orders Siluformes, Gymnotiformes, Perciformes and Synbranchiformes occurred in lower abundance. Significant differences were found in the site diversity indices, but not in the abiotic factors. Significant correlations between the abundance of the ichthyofauna and the variations in the abiotic factors were not detected. The presence of fish larvae in the samples indicates the importance of the transition zone as a reproduction area of the fish species registered in this study. Instituto de Biociências Departamento de Morfologia Universidade Estadual Paulista (Unesp), Distrito Rubião Jr. s/n, 18618-000, Botucatu, São Paulo Instituto de Biociências Departamento de Morfologia Universidade Estadual Paulista (Unesp), Distrito Rubião Jr. s/n, 18618-000, Botucatu, São Paulo

Landing obligation (LO) has become a core element on the Common Fisheries Policy (CFP). In this work a bioeconomic simulation tool is used to anticipate the effects of LO in a particular fleet that by its nature is likely to be highly affected by its implementation. These effects are measured in terms of biologic, economic and fleet indicators. Results show how LO has a negative short term effect in the economic performance of the fleet (the bad). That the exemption and flexibilities foreseen in the CFP alleviate, in the short term, the effects of the choke species and the redistribution effects created (the good). Furthermore, results show that there are private incentives to improve the selectivity and to reduce the discard levels of the fleets. It is concluded how a breeding ground for a more sustainable and productive system is created (very good).