1,721,549 research outputs found
Research activities carried out by IEO in the Canary Islands during intersession
Full text linkRegarding the research activities carried out by Oceanographic Centre of the Canary Islands (IEO-CSIC) during intersession, several studies on different topics were presented. Firstly, reproductive traits for the four main species have been analysed including all the data obtained since the monitoring system was launched in 2013. Although with some variations, the spawning season matched with winter and beginning spring for S. colias, T. picturatus and S. pilchardus. However, spawning individuals of S. aurita are present all year round. Sizes at first maturity (SFM) were also estimated, with slightly smaller sizes obtained for S. colias and T. picturatus (around 19 cm of total length) compared with the reference values (20 cm and 23 cm, respectively) (Jurado-Ruzafa and Santamaría, 2013; Lorenzo and Pajuelo, 1996). It seems that SFM remains stable for S. pilchardus (15 cm) (Méndez-Villamil et al., 1997). In the case of S. aurita, size at first maturity has been estimated for the first time in the Canary Islands, and has been recently published (Jurado-Ruzafa et al., 2022). Secondly, a first attempt to describe total catches of the Canary artisanal purse-seine fleet based on scientific observation shows that discards are more relevant than what was supposed, reaching the 25 percent of the total catches. The situation is even more concerning if only S. colias is considered, with discards around 40 percent of the total catches, mainly impacting on juveniles’ fraction, which is usually used as bait by commercial vessels but that are not officially reported. Finally, very preliminary results were shown to the working group about the potential adaptive plasticity in Scomber colias from the Canary Islands, based on otolith shape analyses. These results were obtained from analysing 748 otoliths extracted from August 2016 to December 2017. A DIvisive ANAlysis (DIANA) Clustering method using the fourth wavelet obtained from otolith contours resulted in the detection of five different morphotypes (or otolith phenotypes), with two of them representing 85 percent of the samples analysed, and whose individuals were slightly larger than for the other morphotypes. Further questions should be explored, addressing possible intraspecific variation in the growth rate among phenotypes; phenotypes proportions change in relation to seasonal variations; existence of different ecological strategies related to each phenotype and the presence of these otolith phenotypes in other geographical areas, as it has been described for T. picturatus (Tuset et al., 2019; Vasconcelos et al., 2021).
References
Jurado-Ruzafa, A. and M.T.G. Santamaría. 2013. Reproductive biology of the blue jack mackerel, Trachurus picturatus (Bowdich, 1825), off the Canary Islands. Journal of Applied Ichthyology, 29(3): 526–531.
Jurado-Ruzafa, A., B. Sotillo de Olano, Z. Santana Arocha, B. G. Mañé, C. Estil-las, E. Hernández, S. Jiménez, G. González-Lorenzo and C. Perales-Raya. 2022. Reproductive traits of the round sardinella in the Canary Islands (Spain, NW Africa). Journal of the Marine Biological Association of the UK, (early view) 1-7.
Lorenzo, J. M. and J.G. Pajuelo. 1996. Growth and reproductive biology of chub mackerel Scomber japonicus off the Canary Islands. South African Journal of Marine Science, 17(1): 275-280.
Méndez-Villamil, M., J.M. Lorenzo, J.M. González and R. Soto. 1997. Periodo reproductor y madurez sexual de la sardina Sardina pilchardus (Walbaum, 1792) en aguas de Gran Canaria (Islas Canarias). Boletín del Instituto Español de Oceanografía, 13(1-2): 47-55.
Tuset, V.M., A. Jurado-Ruzafa, J.L. Otero-Ferrer and M.T.G. Santamaría. 2019. Otolith phenotypic variability of the blue jack mackerel, Trachurus picturatus, from the Canary Islands (NE Atlantic): Implications in its population dynamic. Fisheries Research, 218: 48-58.
Vasconcelos, J., A. Jurado-Ruzafa, J.L. Otero-Ferrer, A. Lombarte, R. Riera and V.M. Tuset. 2021. Thinking of Fish Population Discrimination: Population Average Phenotype vs. Population Phenotypes. Frontiers in Marine Science, 8(1489)
Length weight relationships for seven fish species caught off Northwest Africa
No full textLength weight relationships (LWR) were determined for Deania calceus, Deania profundorum, Merluccius polli, Merluccius senegalensis, Mora moro, Trachyscorpia echinata, and Zenopsis conchifer. Specimens were collected during scientific trawl surveys conducted along the edge of the continental shelf of Morocco and Western Sahara in November December 2005 and 2006. Fish were measured in relation to total length (TL, to 0.1 cm) and total weight (TW, to 1 g), and sexed when possible. All LWRs obtained for the pooled sexes gave close linear regressions (r2 ge; 0.93), and LWR parameter b ranged from 2.638 (Z. conchifer) to 3.172 (D. calceus). Data presented herein expand the knowledge base for these species in Northwest Africa, as they have limited or no LWR data publicly available.The present study was performed in the framework of a partnership programme between the Spanish Oceanographic Institute (IEO, CSIC) and the Moroccan ‘Institut National de Recherche Halieutique’ (INRH).Peer reviewe
Length-weight relalionships of 17 demersal fish species in the Canary Islands (Spain, CE Atlantic)
No full text[EN]
Ten scientific surveys were carried out at ‘Isla de La Palma’ and ‘La Graciosa e Islotes al Norte de
Lanzarote’ Marine Protected Areas (MPAs) between 2003 and 2010.
Length-Weight Relationships (LWR) were estimated for 17 fish species using individual fish records collected
by fish pots (half an inch mesh size), bottom horizontal longlines (hook size 3/0) and set gillnets (80 mm mesh size). Fish was measured fresh for the total length (to the lower 0.1 or 0.5 cm, depending on the scientific surveys design) and weighted for the total weight (TW, to the 0.1 g). Except for the Myliobatiformes species
(with b-values lower than 2.0), the b-value varied between 2.63 and 3.72. All LWRs were obtained from well adjusted linear regressions with R² ≥0.74. In addition, two new maximum lengths were recorded.
Data presented herein expand the knowledge base for these species in the Archipelago, where any status
assessment of the species affected by the operating fisheries has been possible so far, and remain as datapoor stocks.[ES]
Entre 2003 y 2010, se llevaron a cabo diez campañas científicas en las Áreas Marinas Protegidas (AMP) de la Isla de La Palma y La Graciosa e Islotes al Norte de Lanzarote. Se han estimado las relaciones talla-Peso (LWR) para 17 especies de peces utilizando los datos de peces capturados con nasas (malla de media pulgada), palangres horizontales de fondo (anzuelos de tamaño 3/0) y redes de enmalle fijas (malla de 80 mm). Se midió la longitud total (TL, redondeando al 0,1 o 0,5 cm inferior, dependiendo del diseño de las campañas científicas) y se registró el peso total (TW, hasta los 0,1 g) de todos los ejemplares en
fresco. A excepción de las especies de Myliobatiformes (con valores b inferiores a 2,0), el valor b varió
entre 2,63 y 3,72. Todas las LWR se obtuvieron a partir de regresiones lineales con elevados ajustes con
R² ≥0,74. Además, se registraron nuevas longitudes máximas para dos especies. Los datos presentados en
este documento amplían la base de conocimientos de estas especies en el archipiélago, donde hasta ahora
no ha sido posible evaluar el estado de las especies afectadas por las pesquerías, y siguen siendo stocks
pobres en datos.The present study was performed in the framework of Specific Collaboration Agreements between the IEO and Spain’s Fishery Office from 2003 to 2010 with the aid of European Maritime and Fisheries Funds (EMFF).Peer reviewe
Second Workshop on Atlantic Chub Mackerel (Scomber colias)
Full text linkThe Atlantic chub mackerel Scomber colias has become an increasingly important commercial species in the European Atlantic waters in the last 10–15 years, probably through an expansion process from NW African waters and due to market needs. However, at present there are no assessment or advice requirements. In the WK framework, available information of the species in the West Atlantic waters has been compiled in order to evaluate possible geographical differences and trends, and the feasibility to describe its population structure. Though the Atlantic chub mackerel is not routinely included among the target species in the acoustic surveys performed in the Atlantic Iberian waters and the Mediterranean Sea, a synoptic overview of the species is possible over all its West Atlantic distribution. Moreover, the data available have indicated latitudinal trends, mainly in the landings’ length composition, L50 and the spawning periods. Nevertheless, even if some degree of connectivity likely exists and migrations are occurring between adjacent areas, some subunits could be considered for management purposes. From the assessment models’ trials carried out, the results or reference points obtained for the European fisheries cannot be retained at present. Therefore, continuing collating information from fisheries and biological sampling of the species, obtaining reliable biomass estimations from scientific surveys and identifying management units seem the main priorities to address in future research work and in case of assessment requirements
La Palma Island and La Graciosa Island Canary Islands. Spain – Macaronesia: Mapping of marine protected areas and their associated fishing activities
No full text[Título]
Mapping of marine protected areas and their associated fishing activities (MAPAFISH).
Baltic and North Seas, Atlantic EU western waters and outermost regions. Final report annex 5, Case studies[Executive summary]
The main aim of this work was to examine whether there have been changes in the spatial
strategy of fishing activities in response to the implementation of two marine protected
areas (MPAs) in the Canary Islands (Spain), namely the La Graciosa Island MPA and the
La Palma Island MPA. Based on available fishing effort quantitative and semi-quantitative
data, spatial fishing strategies and potential changes in habitat use were explored inside
and outside each MPA during the period 2008–2023.
Although this work was unable to utilise data from before designation of both MPAs, our
analysis has shown that the fishing restrictions within each MPA results in the abandonment
or disuse of small-scale fishing gears (e.g. traps and trammel nets) inside the MPA
restricted zone. In this respect, implementation of both MPAs has led to long-term
displacement of restricted fishing gears to the external boundary of each MPA, including
fishing being undertaken further offshore.
Although there has likely been displacement of fishing activities away from each MPA
following implementation, this has resulted in the overlap of fishing grounds and strategies
between the artisanal and industrial fleet in the external MPA boundaries. This scenario
leaves the small-scale fishery at a disadvantage in terms of catches that could be managed
with longline specific zonation rules (buffer areas) in the surroundings of La Graciosa Island
MPA. Importantly, such displacement (especially where coastal habitats are limited, e.g.
La Graciosa Island MPA) may mean that artisanal fishing boats may navigate longer
distances to reach suitable fishing grounds. Such changes to fishing behaviour are not
likely to have been accounted for in the implementation of the MPAs and has likely led to
increased fuel costs and lower returns on catches for this fleet. Further work will be needed
to understand the full repercussions of such displacement on the economic viability of
different fishing métiers.
Regarding the potential changes in habitat use, the EMODnet habitats data is not sufficient
in terms of specificity and resolution. There is need to incorporate the still ongoing
cartography studies in the IEO-CSIC of deeper habitats where longline professional fishing
activity and small-scale trapping activity have potential impacts on the seabed.
The impact of an MPA was found to be related to fishing gears restrictions. The likelihood
of change in fishing activities would likely be low following implementation of an MPA
covering a very small area, as was the case for the La Palma Island MPA, where fishermen
who decided to continue using restricted fishing gears (traps and trammel nets) continued
to fish near the MPA boundaries. Otherwise, a large area such as the La Graciosa Island
MPA meant a high likelihood of change in fishing activities. Only a few larger small-scale
fishing boats displaced their traditional fishing activity (traps) to waters outside the MPA
boundaries.
Despite relatively low total coverage, the designation and implementation of both MPAs
have affected fishing activities within both La Graciosa and La Palma. For example, the notake zone of La Graciosa Island MPA represents only 1.7 % of the total protected area (i.e.
of the MPA) in the Chinijo archipelago, while within the La Palma Island MPA only one
relatively small no-take area was designated, despite the original plans indicating that two
were planned. These relatively small no-take areas show that protection within the Canary
Islands is a viable management measure for fishing activities. Future updates of both MPAs
could entail increases in the coverage of no-take areas, which will only further increase the
utility of both MPAs in supporting regional fishing sustainability.Peer reviewe
Clarifying species identity in Aphanopus using wavelet-based otolith shape analysis
No full textAccurate species identification is crucial for effective fisheries management, particularly for cryptic species with overlapping ranges and similar morphologies. This study explores the coexistence and distribution of Aphanopus carbo and Aphanopus intermedius in the northeastern Atlantic over four decades using otolith contour analysis. Otolith samples were collected from Madeira and the African coast between 1990 and 2021 and analyzed using a wavelet-based method, which improves species discrimination by capturing finer morphological details. The analysis revealed stable species proportions over time, with A. carbo generally dominating the catches (55–60%), except in 2010 when a decline was observed. A higher presence of A. intermedius in offshore areas may be associated with increased salinity near Madeira Island during the spawning season (October–December). Environmental changes, including variations in temperature and salinity at depths greater than 800 m, and the progressive expansion of the drifting longline fishery to new grounds, likely influenced these patterns. This study demonstrates that combining otolith contour analysis with genetically identified reference specimens enhances species discrimination and provides valuable insights into population dynamics and habitat use. These findings contribute to more effective fisheries management and stock assessments for these economically important scabbardfish in the northeastern Atlantic.The first author (JV) was supported by the ‘Grants for the Viera y Clavijo training program for researchers’ of the Government of the Canary Islands (VIERA Y CLAVIJO-2022-CIENCIAS-1). This research was also funded by the Portuguese national funds through Fundação para a Ciência e a Tecnologia I.P. (FCT) [grant numbers UIDB/04292/2020, https://doi.org/10.54499/UIDB/04292/2020 and UIDP/04292/2020 https://doi.org/10.54499/UIDP/04292/2020; LA/P/0069/2020, https://doi.org/10.54499/LA/P/0069/2020], The funders had no role in study design, data collection and analysis, decision to publish,or preparation of the manuscript.: With funding form the Spanish government through the "Severa Ochoa Centre of Excellence" accreditation (CEX2019-000928-S).Peer reviewe
Workshops on Age reading of horse mackerel, Mediterranean horse mackerel and Blue jack mackerel (Trachurus trachurus, T. mediterraneus and T. picturatus). ICES WKARHOM Background
No full textA Comparative Analysis of Sparisoma cretense in Island Environments: Unraveling Metal Accumulation Differences in the Canary Islands (Spain, NW African Waters)
No full textThis study investigates the impact of varying environmental conditions on the metal composition within the tissues of Sparisoma cretense, contributing to the understanding necessary to offer scientifically sound advice regarding the health status of this species. This knowledge extends beyond fishery production, encompassing implications for food security. The data span the years 2022 and 2023, encompassing both cold and warm climatic seasons. The concentrations of various metals, such as Al, Zn, Cd, Pb, Fe, and Cu, exhibited noteworthy variations across the islands, with significant increases recorded in 2023, particularly during the warm season. The intricate interplay between multiple factors shaped the availability of the analyzed elements in S. cretense. Factors such as rising temperatures during the warm season increased biological activity in marine ecosystems, seasonal fluctuations in weather conditions, water quality, and anthropogenic influences, all contributing to the observed variations in metal concentrations. Additionally, the geological composition of each island and the patterns of marine currents and sediment transport play pivotal roles in these differences. Comprehensive scientific research, monitoring, and environmental surveillance are essential for a holistic understanding of this variability and providing valuable insights for the conservation and management of marine ecosystems in the Canary archipelago
Disseny i construcció d'un sistema de bobines de Helmholtz en tres dimensions per al laboratori de mesures magnètiques del Sincrotró ALBA
No full text3D Hall probes designed and produced by ALBA Synchrotron are currently being used at ALBA magnetic measurements laboratory to carry out accurate magnetic characterization of magnets and insertion devices. In order to characterize the magnetic fields with great accuracy, it is essential to have measuring devices calibrated with a high degree of precision. In this thesis we present the design and construction of a system of 3D Helmholtz coils with the objective of generating a magnetic field in any direction in a controlled way. This system will be used to determine with detail the response of the 3D Hall probe when applying magnetic fields with different orientations. The system will generate magnetic fields of up to 50 G with an expected angular precision of 0.2 mrad.En el laboratorio de medidas magnéticas del Sincrotrón ALBA, con el fin de llevar a cabo una detallada caracterización magnética de los imanes y de los dispositivos de inserción, se utilizan sondas Hall 3D diseñadas y producidas en ALBA. Para caracterizar con exactitud los campos magnéticos es imprescindible disponer de dispositivos de medida calibrados con un alto grado de precisión. En este trabajo presentamos el diseño y la construcción de un sistema de bobinas de Helmholtz 3D con el objetivo de generar un campo magnético de manera controlada en cualquier dirección. Este sistema se utilizará para determinar con detalle la respuesta de las sondas Hall 3D al aplicar campos magnéticos con diferentes orientaciones. El sistema generará campos magnéticos de hasta 50 G con una precisión angular de 0.2 mrad.Al laboratori de mesures magnètiques del Sincrotró ALBA, per tal de dur a terme una detallada caracterització magnètica dels imants i dels dispositius d'inserció, s'utilitzen sondes Hall 3D dissenyades i produïdes a l'ALBA. Per caracteritzar amb exactitud els camps magnètics és imprescindible disposar de dispositius de mesura calibrats amb un alt grau de precisió. En aquest treball presentem el disseny i la construcció d'un sistema de bobines de Helmholtz 3D amb l'objectiu de generar un camp magnètic de manera controlada en qualsevol direcció. Aquest sistema s'utilitzarà per determinar amb detall la resposta de les sondes Hall 3D en aplicar camps magnètics amb diferents orientacions. El sistema generarà camps magnètics de fins a 50 G amb una precisió angular de 0.2 mrad
Disseny i construcció d'un sistema de bobines de Helmholtz en tres dimensions per al laboratori de mesures magnètiques del Sincrotró ALBA
No full text3D Hall probes designed and produced by ALBA Synchrotron are currently being used at ALBA magnetic measurements laboratory to carry out accurate magnetic characterization of magnets and insertion devices. In order to characterize the magnetic fields with great accuracy, it is essential to have measuring devices calibrated with a high degree of precision. In this thesis we present the design and construction of a system of 3D Helmholtz coils with the objective of generating a magnetic field in any direction in a controlled way. This system will be used to determine with detail the response of the 3D Hall probe when applying magnetic fields with different orientations. The system will generate magnetic fields of up to 50 G with an expected angular precision of 0.2 mrad.En el laboratorio de medidas magnéticas del Sincrotrón ALBA, con el fin de llevar a cabo una detallada caracterización magnética de los imanes y de los dispositivos de inserción, se utilizan sondas Hall 3D diseñadas y producidas en ALBA. Para caracterizar con exactitud los campos magnéticos es imprescindible disponer de dispositivos de medida calibrados con un alto grado de precisión. En este trabajo presentamos el diseño y la construcción de un sistema de bobinas de Helmholtz 3D con el objetivo de generar un campo magnético de manera controlada en cualquier dirección. Este sistema se utilizará para determinar con detalle la respuesta de las sondas Hall 3D al aplicar campos magnéticos con diferentes orientaciones. El sistema generará campos magnéticos de hasta 50 G con una precisión angular de 0.2 mrad.Al laboratori de mesures magnètiques del Sincrotró ALBA, per tal de dur a terme una detallada caracterització magnètica dels imants i dels dispositius d'inserció, s'utilitzen sondes Hall 3D dissenyades i produïdes a l'ALBA. Per caracteritzar amb exactitud els camps magnètics és imprescindible disposar de dispositius de mesura calibrats amb un alt grau de precisió. En aquest treball presentem el disseny i la construcció d'un sistema de bobines de Helmholtz 3D amb l'objectiu de generar un camp magnètic de manera controlada en qualsevol direcció. Aquest sistema s'utilitzarà per determinar amb detall la resposta de les sondes Hall 3D en aplicar camps magnètics amb diferents orientacions. El sistema generarà camps magnètics de fins a 50 G amb una precisió angular de 0.2 mrad
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