New red giants in NGC 6791 and NGC 6819 using Kepler superstamps

Context. Stars that are members of stellar clusters are assumed to be formed at the same time and place from material with the same initial chemical composition. These additional constraints on the ensemble of cluster stars make these stars suitable as benchmarks. Aims. We aimed 1) to identify previously unknown red giants in the open clusters NGC 6791 and NGC 6819, 2) to extract their asteroseismic parameters, and 3) to determine their cluster membership. Methods. We followed a dedicated method based on difference imaging to extract the light curves of potential red giants in NGC 6791 and NGC 6819 from Kepler superstamp data. We extracted the asteroseismic parameters of the stars that showed solar-like oscillations. We performed an asteroseismic membership study to identify which of these stars are likely to be cluster members. Results. We found 149 red giant stars within the Kepler superstamps, 93 of which are likely cluster members. We were able to find 29 red giants that are not primary targets of Kepler, and therefore, their light curves had not been released previously. Five of these previously unknown red giants have a cluster membership probability greater than 95%.Comment: 10 pages, 7 figures, to be published in Astronomy & Astrophysic

Atlantic mackerel daily spawning dynamics and implications for batch fecundity estimations

The present study contributes to a better understanding of the daily spawning dynamics of southern NEA mackerel (Scomber scombrus) with implications for the estimation of batch fecundity. It shows that there is a time window during the day, mainly in the afternoon, during which the advanced oocyte mode in imminent spawners separates from the remaining, smaller oocytes. This synchronicity in the separation of the spawning batch amongst imminent spawners corroborates evidence for the existence of daily spawning synchronicity in the population. This is particularly important for applications of the daily egg production method, DEPM, because such pattern facilitates both the ageing of eggs for the estimation of the daily egg production at sea and the ageing of postovulatory follicles for the estimation of spawning frequency. For NEA mackerel, batch fecundity could only be measured when a clear hiatus was established between the spawning batch and the smaller oocytes. Hydrated females that do not show such hiatus would not be valid for batch fecundity measurements suggesting that the “hydrated oocytes method” is not fully applicable for this stock. Knowing the time of day at which the batch is separated, will facilitate the sampling of valid females for the estimation of batch fecundity

Working Group on Mackerel and Horse Mackerel Egg Surveys (WGMEGS). 2021

WGMEG

Intramolecular excimer formation and sensing behavior of new fluorimetric probes and their interactions with metal cations and barbituric acids

A new family of compounds able to promote host-guest interactions with specific molecules (e.g., cyanuric and parabanic acids) and to coordinate metal ions, namely Zn(II) and Cu(II), has been synthesized and fully characterized. The new probes derive from the attachment of two methylaminopyrene units to the carbonyl precursor 2,6-bis(2-formylphenoxymethyl)pyridine.http://www.sciencedirect.com/science/article/B6THH-4HF5KD3-1/1/ef66847d1e019d05e2068bef93cfbd9

Calculation of mackerel adult parameters for the application of the DEPM in the western spawning area

The ICES Working Group on Mackerel and Horse Mackerel Egg Surveys (WGMEGS) coordinates the mackerel and horse mackerel egg survey in the Northeast Atlantic (NEA) and the mackerel egg survey in the North Sea. The working group plans and reports on these surveys, with recent attention focused on the execution of the surveys given the increasing demands related to covering the expanding survey area as well as balanced fecundity sampling. WGMEGS also addresses data quality assurance in macke-rel fecundity and total annual egg production estimation.Currently, there are 3 surveys in place which are carried out triennially and deliver standing stock bio-mass (SSB) indices: (1) the survey for the western and southern stock components of the NEA mackerel stock, as well as for the western horse mackerel stock, (2) the survey for the NEA mackerel North Sea stock component, and (3) the survey for the southern horse mackerel stock.For the North Sea component, the egg survey in 2017 revealed an estimated egg production of 201*1012, resulting in an SSB of 287*103 tons. This is a strong increase of more than 100*103 tons com-pared to 2015 (SSB = 170*103 tons). While peak spawning in the North Sea was covered, the coverage of the complete spawning season and area was insufficient to produce a reliable estimate of survey in-dices.In 2019, the application of an alternate transect survey design made it possible to survey the persis-tently expanding mackerel spawning area and season. Northern and northwestern spawning bounda-ries for mackerel during survey periods 5 (weeks 19 – 22) and 6 (weeks 23 – 26) were not fully deline-ated. Peak spawning was observed in period 4 (weeks 16 – 18). Subsequent analyses of survey results in conjunction with results from exploratory surveys in the inter-survey-years showed that the mackerel core spawning area was covered and a reliable estimate of mackerel annual egg production was deliv-ered. The estimate of total mackerel egg production was 1.64*1015, which is a decrease of 7.6% com-pared to that of 2016 (rev. 1.77*1015).Realized fecundity was estimated at 1147 per g female, revealing the SSB for the NEA mackerel stock in 2019 at 3.09 million tons indicating at 12 % decrease since the 2016 survey (SSB = 3.52 million tons). At only 1.78*1014 , total annual egg production (TAEP) in western horse mackerel was found to be lowest production reported in the time series since 1992. The spawning maximum was detected in the last pe-riod 7 (weeks 27 – 29). It can, thus, not be concluded that peak spawning and the entire temporal ex-tent of horse mackerel spawning had been sufficiently covered.To further improve the quality of the index time series, WGMEGS will continue to dedicate much of its work to survey design and quality assurance in mackerel egg production and fecundity estimation

Microplastics in the stomach contents of common dolphin (Delphinus delphis) stranded on the Galician coasts (NW Spain, 2005–2010)

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