Browsing by Author "Sobrino, Ignacio"
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- Are we ready to implement a discard ban in the gulf of Cádiz? Stakeholders' perceptionsPublication . Gamaza, MariAngeles; Torres, Maria Angeles; Acosta, Juan Jose; Erzini, Karim; Sobrino, IgnacioThe European Union Regulation No 1380/2013 revising the Common Fisheries Policy (CFP) aims at addressing the by-catch and discarding problem in commercial fisheries by implementing the "Landing Obligation" of the regulated species by 2019. At present, the gulf of Cadiz (GoC) landing ports are not ready to comply with this regulation; a number of key issues identified need addressing. Within this framework, the present study focuses on the challenges of finding relevant and efficient management solutions, considering opinions from all relevant stakeholders involved in the trawl fishery. The approach taken in this study involves participatory meetings, questionnaire surveys and interviews with stakeholders, including fishers, local fishery managers, government administrators, national inspectors, non-governmental organizations (NGOs) and scientists. Furthermore, we visited the main fish auctions in the GoC and talked personally to animal sub-products companies regarding their interest in new opportunities based on resources discarded by the trawl fishery. To achieve the goal of improving the management of this specific fishery and to bring it in line with the requirements of the CFP, we conclude that an effective participation of the fishing industry at all stages is of vital importance. Indeed, we advocate that fisheries research efforts should be directed towards management strategies proposed by all relevant actors within the fishery.
- Discard practices in the gulf of Cadiz multispecies trawl fishery. Implications for the EU 'landing obligation'Publication . Gamaza-Marquez, Maria Angeles; Grazia Pennino, Maria; Angeles Torres, Maria; Jose Acosta, Juan; Erzini, Karim; Sobrino, IgnacioDiscarding has been a common practice in multispecies trawl fisheries since the first trawlers were used. To date there have been no studies reporting an integrated analysis of discarding in the gulf of Cadiz (SW Spain, GoC) to evaluate and support the latest fisheries policies, specifically the Landing Obligation (European Union Regulation 1380/2013). In this study we provide estimates of discard ratios, species composition, reasons for discarding, along with the identification of high-density discard areas (hotspots) over the last decade in the GoC area. The analysis was based on data collected by the Spanish onboard sampling program, involving commercial trawling vessels from 2006 to 2016. In particular, data on catches and discards were analyzed by applying Multivariate Regression Trees (MRTs) to assess the species dominance within the discarded and retained portions of the total catch. Temporal and spatial variability in discard ratios were also explored together with the identification of high-density discard areas (hotspots) modelled using Hierarchical Bayesian Spatial Models (H-BSM). A discard ratio relative to the total catch (i.e. both commercial and by-catch) of 34% in weight was estimated, corresponding to an average at about 3500 t discarded annually by the GoC trawl fleet. Non-commercial by-catch species accounted for more than half of the discarded biomass in weight (59.4%). Finally, our study focuses on research efforts towards relevant and efficient management solutions under the discard ban policy. Recommendations aiming to contribute to the establishment of alternative management strategies for this fishery are further discussed.
- Length-weight relationships for 22 crustaceans and cephalopods from the Gulf of Cadiz (SW Spain)Publication . Angeles Torres, Maria; Vila, Yolanda; Silva, Luis; Jose Acosta, Juan; Ramos, Fernando; Palomares, Maria Lourdes D.; Sobrino, IgnacioLife history traits are available for many fish species in different regions, but less so for invertebrates such as cephalopods and crustaceans, though, they are increasingly needed for implementing an ecosystem-based approach. Recent food web modelling in the Gulf of Cadiz has identified invertebrates as keystone groups. However, information on life history traits of such groups remains incomplete in this region. To fill this knowledge gap, we report length-weight relationships for 12 cephalopods and 10 crustaceans collected in the Gulf of Cadiz from 2009 to 2013. This study reports, for the first time, life history traits of nine species in the area (Chlorotocus crassicornis, Pasiphaea sivado, Plesionika heterocarpus, Plesionika martia, Processa canaliculata, Solenocera membranacea, Allotheutis media, Sepia orbignyana and Sepietta oweniana). For each species, length-weight relationships, minimum and maximum lengths, mean weights, and depth ranges are presented. Overall, the results revealed that all species showed negative allometric growth (hypoallometry), except P. sivado, the only species showing an isometric growth pattern. We expect that this study will contribute to link sustainable fisheries with biodiversity conservation goals enabling the implementation of operational ecosystem-based management in the Gulf of Cadiz.
- Natural geochemical markers reveal environmental history and population connectivity of common cuttlefish in the Atlantic Ocean and Mediterranean SeaPublication . Rooker, Jay R.; Wells, R. J. David; Addis, Piero; Arrizabalaga, Haritz; Baptista, Miguel; Bearzi, Giovanni; Dance, Michael A.; Fraile, Igaratza; Lacoue-Labarthe, Thomas; Lee, Jessica M.; Megalofonou, Persefoni; Rosa, Rui; Sobrino, Ignacio; Sykes, António; Villanueva, RogerNatural markers (delta C-13 and delta O-18 stable isotopes) in the cuttlebones of the European common cuttlefish (Sepia officinalis) were determined for individuals collected across a substantial portion of their range in the Northeast Atlantic Ocean (NEAO) and Mediterranean Sea. Cuttlebone delta C-13 and delta O-18 were quantified for core and edge material to characterize geochemical signatures associated with early (juvenile) and recent (sub-adult/adult) life-history periods, respectively. Regional shifts in cuttlebone delta C-13 and delta O-18 values were detected across the 12 sites investigated. Individuals collected from sites in the NEAO displayed more enriched delta C-13 and delta O-18 values relative to sites in the Mediterranean Sea, with the latter also showing salient differences in both markers among western, central and eastern collection areas. Classification success based on cuttlebone delta C-13 and delta O-18 values to four geographical regions (NEAO, western, central and eastern Mediterranean Sea) was relatively high, suggesting that environmental conditions in each region were distinct and produced area-specific geochemical signatures on the cuttlebones ofS. officinalis. A modified delta C-13 and delta O-18 baseline was developed from sites proximal to the Strait of Gibraltar in both the NEAO and Mediterranean Sea to assess potential mixing through this corridor. Nearly, all (95%) of delta C-13 and delta O-18 signatures ofS. officinaliscollected in the area of the NEAO closest to the Strait of Gibraltar (Gulf of Cadiz) matched the signatures of specimens collected in the western Mediterranean, signifying potential movement and mixing of individuals through this passageway. This study extends the current application of these geochemical markers for assessing the natal origin and population connectivity of this species and potentially other taxa that inhabit this geographical area.
- One device does not fit all: limited results of using a Sort-X grid in the multi-species trawl fishery in the Gulf of CádizPublication . Gamaza, MariÁngeles; Fonseca, Paulo; Campos, Aida; Erzini, Karim; Sobrino, IgnacioA Sort-X grid device with four different bar-spacing grids (25, 30, 40 and 50 mm) was tested in the Gulf of Cádiz (GoC) on-board commercial trawlers. A total of 83 fish, five crustacean and nine cephalopods species were sampled in 282 hauls. Most of the target and commercial bycatch species were sorted out by the grid with the exception of hake. Merluccius merluccius (L.). Additionally, common pandora, Pagellus erythrinus (L.), sardine, Sardina pilchardus (Walbaum), octopus, Octopus vulgaris Lamark, and cuttlefish, Sepia officinalis L., also showed a sizeable retention for some of the grid bar spacing. Statistical modelling of selectivity at length for hake found influence of depth on the selection parameters. Lengths at 50% retention for hake were estimated to be 27.4, 30.3, 36.3 and 42.3 cm TL for 25–50 mm bar spacing, respectively, all above the minimum conservation reference size (MCRS) in the GoC. The probability of hake contacting the grid was estimated as 0.95. Overall, although the selective device showed a good performance for hake, it is not appropriate for improving the fishing pattern of a multi-species trawl fishery such as that of the GoC.
- Regional patterns of δ13C and δ15N for European common cuttlefish (Sepia officinalis) throughout the Northeast Atlantic Ocean and Mediterranean SeaPublication . David Wells, R. J.; Rooker, Jay R.; Addis, Piero; Arrizabalaga, Haritz; Baptista, Miguel; Bearzi, Giovanni; Fraile, Igaratza; Lacoue-Labarthe, Thomas; Meese, Emily N.; Megalofonou, Persefoni; Rosa, Rui; Sobrino, Ignacio; Sykes, Antonio V.; Villanueva, RogerThe European common cuttlefish, Sepia officinalis Linnaeus, 1758 is a coastal nektobenthic species ranging from the Shetland Islands through the Northeast Atlantic Ocean and Northwest Africa into the Mediterranean Sea [1]. This species constitutes one of the most economically valuable cephalopod resources in the Northeast Atlantic Ocean, supporting an important fishery resource [2,3]. Sepia officinalis has a relatively short lifespan of 1–2 years, early sexual maturity and an extended spawning season laying eggs on the seafloor with direct benthic, large hatchlings [4,5]. Given this species geographical distribution combined with limited dispersal, it has been a targeted model species to examine connectivity throughout the Northeast Atlantic Ocean and Mediterranean Sea (hereafter NEAO-MS) [6]. Natural biomarkers such as stable isotopes are commonly used to examine food web structure and ecosystem connectivity in marine environments [7,8]. Stable isotopes of carbon (δ13C) and nitrogen (δ15N) are particularly useful tracers due to their natural abundance being influenced by the environment and ease of measurement in body tissues without having to track individuals in a population. δ13C is traditionally used to trace carbon pathways because little fractionation occurs between predator and prey, and different primary producers (energy sources) often have unique δ13C values [9]. δ13C values of consumers are a product of the primary producers’ composition and influenced by the dissolved inorganic carbon (DIC) pool, as well as local abiotic factors including sea surface temperature, and can differ across ocean basins [10] and region-specific freshwater to marine gradients [9]. δ15N becomes enriched with increasing trophic level and is used to infer trophic position [7], but can also differ at the base of the food web. Depending upon the types of nutrients available to stimulate growth, δ15N values can be used to track energy flow in high-nutrient (nitrate) and low-nutrient (N2 fixation) ecosystems as well as new nitrogen (upwelled nitrate) versus regenerated nitrogen (ammonia, urea). Combining both δ13C and δ15N offers the potential to study the connectivity and population structure of species because longitudinal and latitudinal gradients exist throughout marine ecosystems [11,12], including the NEAO-MS [8,13].
- Strong fisheries management and governance positively impact ecosystem statusPublication . Bundy, Alida; Chuenpagdee, Ratana; Boldt, Jennifer L.; Borges, Maria de Fatima; Camara, Mohamed Lamine; Coll, Marta; Diallo, Ibrahima; Fox, Clive; Fulton, Elizabeth A.; Gazihan, Ayse; Jarre, Astrid; Jouffre, Didier; Kleisner, Kristin M.; Knight, Ben; Link, Jason; Matiku, Patroba P.; Masski, Hicham; Moutopoulos, Dimitrios K.; Piroddi, Chiara; Raid, Tut; Sobrino, Ignacio; Tam, Jorge; Thiao, Djiga; Angeles Torres, Maria; Tsagarakis, Konstantinos; van der Meeren, Gro I.; Shin, Yunne-JaiFisheries have had major negative impacts on marine ecosystems, and effective fisheries management and governance are needed to achieve sustainable fisheries, biodiversity conservation goals and thus good ecosystem status. To date, the IndiSeas programme (Indicators for the Seas) has focussed on assessing the ecological impacts of fishing at the ecosystem scale using ecological indicators. Here, we explore fisheries Management Effectiveness' and Governance Quality' and relate this to ecosystem health and status. We developed a dedicated expert survey, focused at the ecosystem level, with a series of questions addressing aspects of management and governance, from an ecosystem-based perspective, using objective and evidence-based criteria. The survey was completed by ecosystem experts (managers and scientists) and results analysed using ranking and multivariate methods. Results were further examined for selected ecosystems, using expert knowledge, to explore the overall findings in greater depth. Higher scores for Management Effectiveness' and Governance Quality' were significantly and positively related to ecosystems with better ecological status. Key factors that point to success in delivering fisheries and conservation objectives were as follows: the use of reference points for management, frequent review of stock assessments, whether Illegal, Unreported and Unregulated (IUU) catches were being accounted for and addressed, and the inclusion of stakeholders. Additionally, we found that the implementation of a long-term management plan, including economic and social dimensions of fisheries in exploited ecosystems, was a key factor in successful, sustainable fisheries management. Our results support the thesis that good ecosystem-based management and governance, sustainable fisheries and healthy ecosystems go together.
- Testing Nordmore grids on the target and by-catch species of the commercial bottom trawl fishery in the Gulf of CadizPublication . Gamaza, MariÁngeles; Sobrino, Ignacio; Erzini, KarimSorting grids have been tested worldwide in trawl fisheries. Here we report upon the first trials performed using Nordmore sorting grids with four different bar spacings in the trawl fisheries of the Gulf of Cadiz targeting crustaceans as the main resource. A total of 288 valid hauls and 67 commercial species were caught. Escapement and escape size selectivity were evaluated for the most important target and by-catch species. A decrease in the percentage of biomass escape was recorded with increasing grid spacing for the two target species, deep-water rose shrimp (Parapenaeus longirostris) and Norway lobster (Nephrops norvegicus), from 24% to 8% for the former and from 86 to 9% for the latter, with a 15-mm and 30-mm grid respectively. In general, high escape rates were found for most finfish and cephalopods. For hake (Merluccius merluccius), as the main by-catch species, the results showed an escape rate decreasing from 96% to 71% as the bar spacing increased. Our findings suggest the 30-mm grid would be effective for the deep-water crustacean trawlers but different mitigation measures will be required for other metiers in the multispecies trawl fishery of the Gulf of Cadiz.