A NOVEL INDEX OF ABUNDANCE OF JUVENILE YELLOWFIN TUNA IN THE ATLANTIC OCEAN DERIVED FROM ECHOSOUNDER BUOYS

The collaboration with the Spanish vessel-owners associations and the buoy-providers companies, has made it possible the recovery of the information recorded by the satellite linked GPS tracking echosounder buoys used by the Spanish tropical tuna purse seiners and associated fleet in the Atlantic since 2010. These instrumental buoys inform fishers remotely in real-time about the accurate geolocation of the FAD and the presence and abundance of fish aggregations underneath them. Apart from its unquestionable impact in the conception of a reliable CPUE index from the tropical purse seine tuna fisheries fishing on FADs, echosounder buoys have also the potential of being a privileged observation platform to evaluate abundances of tunas and accompanying species using catch-independent data. Current echosounder buoys provide a single acoustic value without discriminating species or size composition of the fish underneath the FAD. Therefore, it has been necessary to combine the echosounder buoys data with fishery data, species composition and average size, to obtain a specific indicator. This paper presents a novel index of abundance of juvenile yellowfin tuna in the Atlantic Ocean derived from echosounder buoys for the period 2010-2018

ICES. 2020. Working Group on Acoustic and Egg Surveys for Sardine and Anchovy in ICES areas 7, 8 and 9

he Working Group on Acoustic and Egg Surveys (WGACEGG) coordinates pelagic surveys for a number of stocks and provides monitoring for the two major sardine and anchovy stocks in ICES areas 6, 7, 8, and 9. The group evaluated small pelagic fish biomass indices derived from acoustic and Daily Egg Production Method (DEPM) surveys in ICES areas 6, 7, 8 and 9. These indices have been provided to the ICES Working Group on Southern Horse Mackerel, Anchovy and Sardine (WGHANSA), the Working Group on Widely Distributed Stocks (WGWIDE) and the Herring Assessment Working Group for the Area South of 62ºN (HAWG) stock assessment group, to serve as fishery-independent input for analytical assessment purposes. DEPM and acoustic indices were derived based on data collected using independent methods. Acoustic- and DEPM-derived biomass indices from quasi-synoptic surveys conducted in the Bay of Biscay in spring were compared, to assess the presence of potential bias and to improve the precision of fish stock biomass estimates. The DEPM-based anchovy biomass index was 22% higher than the acoustic index in 2019. Unusual concentrations of anchovy in Eastern Cantabrian Sea, an area not covered by the acoustic survey, and the presence near the sea surface of actively spawning individuals possibly under-sampled by acoustics in central Bay of Bay had been postulated as potential causes of this discrepancy. No significant difference was found between sardine biomass indices derived from DEPM and acoustics in 2019. The group has updated its database of standard gridded maps covering the European Atlantic area. This initiative continues to inform on the spatial dynamics of various parameters collected during the surveys coordinated under the auspices of the group (fish acoustic densities, anchovy and sardine egg abundance, surface temperature and salinity). Results of an analysis of the time series of gridded maps (anchovy and sardine acoustic density, surface salinity and temperature) showed quantitative changes in the spatial and temporal distribution of anchovy and sardine over the last 15 years, and further define their habitats in European Atlantic waters in spring. The timing and spatial coverage of DEPM and acoustic surveys that will be conducted by group members in 2020 were planned to optimise the monitoring of anchovy and sardine populations and their pelagic environment in the European Atlantic area. The synoptic nature of the survey components has been assessed for each target species. A manual describing the protocols used during the DEPM surveys coordinated by the WGACEGG group was reviewed, and writing of a manual of WGACEGG acoustic surveys continued. Both manuals will be available in 2020. The final results of the 2017 sardine DEPM assessment were endorsed by the group

Preliminary results from the ECOCADIZ 2020-07 Spanish acoustic survey (01 – 14 August 2020)

The present working document summarises a part of the main results obtained from the Spanish (pelagic ecosystem-) acoustic survey conducted by IEO between 01st and 14th August 2020 in the Portuguese and Spanish shelf waters (20-200 m isobaths) off the Gulf of Cadiz (GoC) onboard the R/V Miguel Oliver. The 21 foreseen acoustic transects were sampled. A total of 26 valid fishing hauls were carried out for echo-trace ground-truthing purposes. Four additional night trawls were conducted to collect anchovy hydrated females (DEPM). This working document only provides abundance and biomass estimates for anchovy, sardine and chub mackerel, which are presented without age structure. The distribution of all the mid-sized and small pelagic fish species susceptible of being acoustically assessed is also shown from the mapping of their back-scattering energies. GoC anchovy acoustic estimates in summer 2020 were of 5153 million fish and 44 877 tones, with the bulk of the population occurring in the Spanish waters. The current biomass estimate becomes in the second historical maximum within the time-series. The estimates of sardine abundance and biomass in summer 2020 were 1923 million fish and 50 721 t, estimates close to the historical average, but lower than the values estimated last year and the most recent maxima reached in 2018. A total of 32 854 t and 448 million fish were estimated for Chub mackerel, estimates similar to the most recent ones and very close to the time-series average

Target strength of skipjack tuna (Katsuwanus pelamis) associated with fish aggregating devices (FADs)

[EN] This paper presents measures of target strength (TS; dB re 1 m(2)) and models of TS vs. fork length (L; cm), i.e. TS = 20log(L) + b(20), for skip-jack tuna associated with fish aggregating devices (FADs) in the Central Pacific Ocean. Measurements were made using 38-, 120-, and 200-kHz split-beam echosounders on a purse-seine workboat during fishing operations. To mitigate potential bias due to unresolved targets, TS measurements were rejected if they were not simultaneously detected with multiple echosounder frequencies in approximately the same location. The filtered TS and concomitantly sampled L data were used to estimate b(20) = -76, -71, and -70.5 dB for 38, 120, and 200 kHz, respectively, using the method of least squares. For comparison, quasi-independent estimates of TS and b(20) were calculated from acoustic echo-integration and catch data representing entire aggregations around the FADs. The results differed by <= 1 dB for all three frequencies. The sensitivities of these results to variations in fish morphology and behaviour were explored using a simulation of TS for fish without swimbladders. The utility of the results on acoustic properties of skipjack tuna and next research steps to achieve selective fishing at FADs are discussed.We thank the following organizations and people for their support of this work: the governments of Kiribati, Tuvalu, and Tokelau which permitted this research in their EEZs; Albacora for allowing this work aboard F/V ALBATUN TRES; Fishing Master Euken Mujika; the captain and crew; the scientists and divers J. Filmalter and F. Forget are thanked for invaluable insight about fish behaviour, vertical stratification and non-target species composition at FADs; Hector Pena for providing instruction on the sonar setup and analysis; Yolanda Lacalle for the illustration in Figure 2; and Andres Uriarte for advice concerning transmission of statistical errors. The research reported in the present document was funded by the International Seafood Sustainability Foundation (ISSF) and conducted independently by the authors. The report and its results, professional opinions and conclusions are solely the work of the authors. This paper is contribution 843 from AZTI (Marine or Food Research).Boyra, G..; Moreno, G.; Sobradillo, B.; Pérez Arjona, I.; Sancristóbal, I.; Demer, D. (2018). Target strength of skipjack tuna (Katsuwanus pelamis) associated with fish aggregating devices (FADs). ICES Journal of Marine Science. 75(5):1790-1802. https://doi.org/10.1093/icesjms/fsy041S1790180275

Robust control of UPFC for MV distribution grid for interconnection under unbalanced conditions

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Estudi de l'Agenda 21 Local de Lloret de Mar i dels seus reptes de futur

This article is based on a research devoloped during the academic year 2009-2010 by Carla Alexandra Ackermann, Anna Martínez Moles and Alba Vendrell Torres. The research was conducted under the supervision of Professor Josep Boyra, PhD from TSI - Turismo Sant Ignasi, Ramon Llull University. The aim of the article is to divulge the contents of the research and its main results regarding the positive eff ects of Local Agenda 21 in the tourism industry of Lloret de Mar.L’article és fruit d’un treball de final de carrera realitzat per les estudiants Carla Alexandra Ackermann, Anna Martínez Moles i Alba Vendrell Torres durant el curs 2009/2010. Aquest treball de recerca va ser tutoritzat per Josep Boyra, [email protected], doctor en Geografia, i professor de l’àrea de ciències socials de TSI - Turismo Sant Ignasi, Universitat Ramon Llull, Barcelona. L’objectiu d’aquest article és divulgar la recerca feta i al mateix temps fer una síntesi de les seves principals aportacions, entre les que destaquem l’anàlisi de L’Agenda 21 Local de Lloret de Mar i el seu grau d’assoliment respecte dels reptes de futur per tal d’aconseguir ser una destinació turística competitiva i sostenible al llarg del temps