Report of the 4th Workshop on Age Reading of horse mackerel, Mediterranean horse mackerel and blue jack mackerel (Trachurus trachurus, T. mediterraneus and T. picturatus) (WKARHOM)

Based on the previous work from WKARHOM3 (ICES, 2018), the Working Group on Biological Parameters (ICES, 2020) identified the need for a new otolith exchange followed by an age read-ing Workshop. The Workshop on Age reading of Horse Mackerel, Mediterranean Horse Macke-rel and Blue Jack Mackerel (Trachurus trachurus, T. mediterraneus and T. picturatus) (WKAR-HOM4) had several main objectives; to review the current protocols of ageing Trachurus species, to update the advances in the validation of the ageing criteria (i.e. the annual deposition of one annulus, coherency of the interpretation), to evaluate the new precision of ageing data of Tra-churus species and to update guidelines, common ageing criteria and reference collections of otoliths. An online otolith exchange was performed using SmartDots during 2021 and 2022, and results including the three Trachurus species were published in advance of the meeting, showing a low Percentage of Agreement (PA) both when considering all the readers (44-55%) and the advanced readers only (52-54%) (Massaro and Jurado-Ruzafa, 2022). For T. trachurus the Coef-ficient of Variation (CV) was lower for the sliced samples (22-18%) than for whole otoliths sam-ples (44-38%). Readers participating in the exchange, following discussion during the WKAR-HOM4 meeting, agreed that the main cause of age determination error for T. trachurus was due to the different otolith preparation techniques (whole/sliced). These differences reflect the stunted growth and compactness of the annuli in older specimens (from the 4th-5th annuli on-wards). Anyway, for the three Trachurus species, there are several difficulties in age determina-tion: identification of the first growth annulus, presence of many false rings (mainly in the first and second annuli) and the interpretation and identification of the edge characteristics (opaque/translucent). The second reading exercise was performed during the workshop orga-nized in four different events (i.e. Trachurus trachurus whole otoliths -135 images-, T. trachurus sliced otoliths -95 images- T. mediterraneus whole otoliths -150 images- and T. picturatus whole otoliths –121 images). For T. trachurus no enhancement among readers’ precision was observed in all cases, in terms of PA and CV. Conversely, for T. mediterraneus and T. picturatus a notice-able improvement in terms of PA and decrease of CV occurred compared to the pre-workshop exchange. Finally, this group updated the ageing guidelines and a reference collection of images for all the species, with the aim to employ these tools for all laboratories.ICESN

Digging for historical data on the occurrence of benthic macrofaunal species in the southeastern Mediterranean

The benthic macrofaunal biodiversity of the southeastern Mediterranean is considerably understudied compared to other Mediterranean regions. Monitoring biodiversity in this area is crucial as this region is particularly susceptible to biological invasions and temperature alteration. Historical biodiversity data could provide a useful baseline for monitoring potential changes and provide informarion to support a better understanding of the possible effects of anthropogenic activities on marine benthic communities. In this study, performed under the LifeWatchGreece Research Infrastructure, we present historical benthic occurrence data obtained from the sampling expedition carried out in 1933 by Adolf Steuer in the coastal area around Alexandria, Egypt, eastern Mediterranean. The occurrences were geo-referenced to more than 170 stations, mostly located in the area of Alexandria, and the nearby coasts and lakes. All records were digitized and species names were cross-checked and taxonomically updated using the World Register of Marine Species. The outcome clearly shows that such initiatives can reveal an unexpected amount of highly valuable biodiversity information for "data-poor" regions

EMODnet Workshop on mechanisms and guidelines to mobilise historical data into biogeographic databases

The objective of Workpackage 4 of the European Marine Observation and Data network (EMODnet) is to fill spatial and temporal gaps in European marine species occurrence data availability by carrying out data archaeology and rescue activities. To this end, a workshop was organised in the Hellenic Center for Marine Research Crete (HCMR), Heraklion Crete, (8–9 June 2015) to assess possible mechanisms and guidelines to mobilise legacy biodiversity data. Workshop participants were data managers who actually implement data archaeology and rescue activities, as well as external experts in data mobilisation and data publication. In particular, current problems associated with manual extraction of occurrence data from legacy literature were reviewed, tools and mechanisms which could support a semi-automated process of data extraction were explored and the re-publication of the data, including incentives for data curators and scientists were reflected upon