FINAL REPORT FOR PHASE THREE OF THE ICCAT SHORT-TERM CONTRACT: SWORDFISH BIOLOGICAL SAMPLES COLLECTION FOR GROWTH, REPRODUCTION AND GENETICS STUDIES

This report details the third phase of biological sampling and associated analysis undertaken as part of an international swordfish biology program. The program was established in 2018 and sampling was conducted for swordfish in the North and South Atlantic and Mediterranean. Fish were sampled for size, sex, and maturity. Anal fin spines, otoliths, gonads, and tissues were obtained for ageing, growth, maturity and genetic analyses. These data will be used to inform ICCAT assessment and the ongoing management strategy evaluation process. In this report we examine sampling representativeness relative to spatial and temporal patterns in recent catch data. Samples were obtained from a broad temporal and spatial range, however, some improvements are required in spatial-temporal coverage.En prens

REPORT OF THE 2021 ICCAT SWORDFISH BIOLOGY WORKSHOP (Online, 22-26 March 2021)

“The results, conclusions and recommendations contained in this Report only reflect what was discussed by the Group of scientists that participated in the 2021 Swordfish Biology Workshop. Therefore, these should be considered preliminary until the Swordfish Species Group and the SCRS discuss and possibly adopts them at its annual Plenary meeting and the Commission revise them at its Annual meeting. Accordingly, ICCAT reserves the right to comment, object and endorse this Report, until it is finally adopted by the Commission.”En prens

Comment on "mechanisms for Pressure-Induced Isostructural Phase Transitions in EuO"

Authors thank the financial support from Projects PGC2018-101464-B-I00, PGC2018-097520-A-I00, and MALTA-Consolider Team RED2018-102612-T (Ministerio de Ciencia, Innovaci´on y Universidades) is acknowledged. V. Monteseguro acknowledges the “Beatriz Galindo” fellowship (BG20/000777) and the “Juan de la Cierva” fellowship (IJC2019-041586-I)

BRIEF UPDATE ON THE SATELLITE TAGGING OF ATLANTIC SWORDFISH

This paper provides a brief update of the study on habitat use for swordfish, developed within the working plan of the Swordfish Species Group of ICCAT. A total of 9 miniPAT tags have been deployed by observers on Portuguese and Spanish vessels and the Uruguayan research cruise in the North and South Atlantic. Data from eight tags/specimens are available, four specimens suffered from post-release mortality and one individual tag pop-up date has not occurred yet. These preliminary results showed swordfish moved in several directions, travelling considerable distances. Swordfish spent most of the daytime in deeper waters, being closer to the surface during night-time. The main plan for the next phase of the project is to continue the tag deployment during 2020 in several regions of the Atlantic Ocean and Mediterranean SeaEn prens

Phosphoglycerate Kinases Are Co-Regulated to Adjust Metabolism and to Optimize Growth

[EN] In plants, phosphoglycerate kinase (PGK) converts 1,3-bisphosphoglycerate into 3-phosphoglycerate in glycolysis but also participates in the reverse reaction in gluconeogenesis and the Calvin-Benson cycle. In the databases, we found three genes that encode putative PGKs. Arabidopsis (Arabidopsis thaliana) PGK1 was localized exclusively in the chloroplasts of photosynthetic tissues, while PGK2 was expressed in the chloroplast/plastid of photosynthetic and nonphotosynthetic cells. PGK3 was expressed ubiquitously in the cytosol of all studied cell types. Measurements of carbohydrate content and photosynthetic activities in PGK mutants and silenced lines corroborated that PGK1 was the photosynthetic isoform, while PGK2 and PGK3 were the plastidial and cytosolic glycolytic isoforms, respectively. The pgk1.1 knockdown mutant displayed reduced growth, lower photosynthetic capacity, and starch content. The pgk3.2 knockout mutant was characterized by reduced growth but higher starch levels than the wild type. The pgk1.1 pgk3.2 double mutant was bigger than pgk3.2 and displayed an intermediate phenotype between the two single mutants in all measured biochemical and physiological parameters. Expression studies in PGK mutants showed that PGK1 and PGK3 were down-regulated in pgk3.2 and pgk1.1, respectively. These results indicate that the down-regulation of photosynthetic activity could be a plant strategy when glycolysis is impaired to achieve metabolic adjustment and optimize growth. The double mutants of PGK3 and the triose-phosphate transporter (pgk3.2 tpt3) displayed a drastic growth phenotype, but they were viable. This implies that other enzymes or nonspecific chloroplast transporters could provide 3-phosphoglycerate to the cytosol. Our results highlight both the complexity and the plasticity of the plant primary metabolic network.This work has been funded by the Spanish Government and the European Union: FEDER/ BFU2012-31519 and FEDER/ BFU2015-64204R, FPI fellowship to S.R.-T., and the Valencian Regional Government: PROMETEO II/2014/052.Rosa-Tellez, S.; Anoman, A.; Flores-Tornero, M.; Toujani, W.; Alseek, S.; Fernie, A.; Nebauer, SG.... (2018). Phosphoglycerate Kinases Are Co-Regulated to Adjust Metabolism and to Optimize Growth. PLANT PHYSIOLOGY. 176(2):1182-1198. https://doi.org/10.1104/pp.17.01227S11821198176

A high stability semiconductor laser system for a 88^{88}Sr-based optical lattice clock

We describe a frequency stabilized diode laser at 698 nm used for high resolution spectroscopy of the 1S0-3P0 strontium clock transition. For the laser stabilization we use state-of-the-art symmetrically suspended optical cavities optimized for very low thermal noise at room temperature. Two-stage frequency stabilization to high finesse optical cavities results in measured laser frequency noise about a factor of three above the cavity thermal noise between 2 Hz and 11 Hz. With this system, we demonstrate high resolution remote spectroscopy on the 88Sr clock transition by transferring the laser output over a phase-noise-compensated 200 m-long fiber link between two separated laboratories. Our dedicated fiber link ensures a transfer of the optical carrier with frequency stability of 7 \cdot 10^{-18} after 100 s integration time, which could enable the observation of the strontium clock transition with an atomic Q of 10^{14}. Furthermore, with an eye towards the development of transportable optical clocks, we investigate how the complete laser system (laser+optics+cavity) can be influenced by environmental disturbances in terms of both short- and long-term frequency stability.Comment: 9 pages, 9 figures, submitted to Appl. Phys.

UPDATE ON THE SATELLITE TAGGING OF ATLANTIC AND MEDITERRANEAN SWORDFISH

This paper provides an update of the study on habitat use for swordfish, developed within the working plan of the Swordfish Species Group of ICCAT. A total of 26 miniPAT tags have been deployed so far in the North (n=13) and South Atlantic (n=9) and the Mediterranean (n=4). Data from eight tags was analysed for horizontal and vertical habitat use. These preliminary results showed swordfish moved in several directions, travelling considerable distances in both the North and South stocks. Swordfish spent most of the daytime in deeper waters with a mean of 540.8 m, being closer to the surface during nighttime (mean=78.3 m). The deepest dive recorded was of 1480 m. Regarding temperature, swordfish inhabited waters with temperatures ranging from 3.9ºC to 30.5ºC with a mean of 11.3ºC during daytime and 21.7ºC during nighttime. The main plan for the next phase of the project is to continue the tag deployment during 2022 in several regions of the Atlantic Ocean and Mediterranean Sea. Currently 11 tags are with the participating CPCs and nine tags are still to be attributed.En prens

ASSESSING THE SPAWNING STOCK BIOMASS OF ALBACORE (THUNNUS ALALUNGA) IN THE WESTERN MEDITERRANEAN SEA FROM A NON-LINEAR LARVAL INDEX (2001-2019)

Larval abundance indices express retrocalculated abundances of larval densities at hatching time. They provide a proxy for assessing spawning stock biomass and are applied to assess population status of various species in the Gulf of Mexico and in the Balearic Sea. Recently, the methodological approach to calculate the indices was improved to accommodate for non-linear responses of environmental effects on catchability. This improved methodology is routinely applied in the Balearic Sea to assess the bluefin tuna (Thunnus thynnus) spawning stock biomass. Here we apply the same methodology to update the larval index of albacore (Thunnus alalunga) from surveys conducted from 2001 to 2019 in the Balearic Sea, the most relevant spawning ground of this species in the Western Mediterranean. Albacore larval abundances show a decreasing trend and significant lower abundances from 2013 onwards, despite a slight recovery between 2016 and 2017. This larval index, standardized for gears, sampling coverage, salinity, date and sea surface temperature, provides information on the dynamics of the western Mediterranean stock of albacore, which is considered a data poor stock.En prens

LARVAL HABITATS AND CATCHES OF SWORDFISH (XIPHIAS GLADIUS) IN THE BALEARIC ISLANDS (2001-2020): OCEANOGRAPHIC DRIVERS AND OPPORTUNITIES FOR RESEARCH

Since 2001, ichthyoplankton and hydrographic surveys directed to tuna species have been conducted in the Balearic Islands, a main tuna spawning ground in the Mediterranean. These campaigns provide today key information about the interannual changes on larval abundances for Bluefin tuna and albacore, also allowing the investigation of the early-life ecology of various species. The Balearic Islands have been identified as a prominent oceanographic retention area within the western Mediterranean as well as the main spawning area for tuna species. Hence, the regular ichthyoplankton surveys become an opportunity to increase the knowledge of those species whose pelagic early-life stages are encountered during the summer in this area. This is the case of swordfish (Xiphias gladius). Here we analyse the possibility of applying those surveys to investigate the early life ecology of the Mediterranean swordfish, exploring the interannual changes on larval abundances and the hydrographic preferences of larval habitatsEn prens