Browsing by Issue Date, starting with "2025-06-04"
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- Amino acid supplementation in fish nutrition and welfarePublication . Aragão, Cláudia; Engrola, Sofia; Costas, BenjamínAmino acids are not only the fundamental building blocks of proteins and, consequently, essential for animal growth, but they have also gained recognition in recent years for their critical roles in regulating key metabolic processes. In aquaculture, where the demand for more sustainable production systems continues to grow, nutrition remains a central pillar. Within this context, amino acids serve dual purposes: they are essential to balance the nutritional profiles of alternative protein sources, and they also act as functional ingredients that can enhance fish health, robustness, and resilience to stressors.
- Resolving the population structure and demographic history of the European anchovy in the northeast atlantic: tracking historical and contemporary environmental changesPublication . Martin Pujolar, José; Gardiner, Courtney E. C.; Heyden, Sophie von der; Robalo, Joana I.; Castilho, Rita; Lopes da Cunha, Regina; Henriques, Romina; Nielsen, Einar E.The spatial distribution of the European anchovy has expanded in the northern part of its range in the Northeast Atlantic in recent decades. However, whether this results from a northward range shift of southern conspecifics or the expansion of a local northern population is unknown. Using for the first time whole-genome sequencing, we explore current patterns of genetic diversity and population sub-structuring of European anchovy in the Northeast Atlantic, with special focus on recently expanded North Sea areas. Genomic data suggested three distinct groups: Northern (North Sea and Kattegat), Southern (Ireland and Central Portugal) and Cadis (South Portugal). Despite most of the genome being homogenised by high levels of gene flow characteristic of small pelagic fish, several large regions of high genetic differentiation were observed. This suggests that genomic population boundaries might be maintained by local adaptation within chromosome structural variants (inversions). Admixture analysis indicates that the ongoing northern range shift involves both migrants of southern origin and expansion of the local North Sea population. Historical demographic inference suggests that anchovies survived the last glacial period with small population sizes, followed by a split into the current Northern and Southern groups at the end of the last glacial maximum. The Southern group then expanded into the North Sea as the ice sheets retreated, in an expansion involving a large number of individuals, which is consistent with the retention of most of the genetic diversity. In comparison with other small pelagic fish, the genetic patterns found in anchovies (deeply divergent groups, no loss of genetic diversity during expansion, mixing between groups) align well with those found in European sprat, while sardines fit the pattern of expansion of a leading-edge population, with reduced genetic diversity and much shallower divergence between populations. This study contributes to a better understanding of population structure, range shifts and local adaptation in small pelagic fish under climate change, informing conservation and management efforts.
- A paradise for Maldane sarsi antarctica: preliminary characterization of the marine soft-bottom fauna of false bay (Livingston Island, South Shetland Islands, Antarctica)Publication . Bascur, Miguel; Prófumo, Andrea; Gonzalez-Pineda, Mariona; Monràs-Riera, Pere; Azcárate-García, Tomás; Aubach-Masip, Àlex; Llobet, Marina De; Molina-Vacas, Guillem; Tibiriçá, Yara; Ballesté, Elisenda; Gil, João; Avila, ConxitaSoft-bottom areas are among the least explored ecosystems in Antarctica. To improve our understanding of these environments, we performed a preliminary assessment of the marine macrobenthic fauna in False Bay, Livingston Island, near Huntress Glacier (South Shetland Islands, Antarctica). Fourteen Van Veen grabs (0.018 m(2) area) were deployed at two stations within the bay at depths of 174-210 m. The samples provided values up to 159 556 individuals m(-2) within 15 major taxonomic groups. Annelida Polychaeta was predominant (similar to 93%), followed by Ophiuroidea and Bivalvia at the external station and Bivalvia and Amphipoda at the internal site. Maldanid polychaetes, particularly Maldane sarsi antarctica, constituted 84.62-90.74% of the samples. Total biomass was 6673.25 grams of wet weight per square metre, mainly from Ascidiacea, Polychaeta, Holothuroidea and Ophiuroidea. Approximately 12% of the macrofauna inhabited the sediment (epifauna), while 88% lived into the sediments (infauna). Regarding feeding modes, specimens were detritivores (77.91-82.71%), suspension-feeders (7.59-13.37%) and, infrequently, predators (4.07-5.07%) and grazers (4.63-4.65%). According to the compilation of occurrence records in the Southern Ocean, M. sarsi antarctica has a circum-Antarctic distribution. Furthermore, the population of this species in False Bay appears to be stable and undisturbed with a normal distribution in size structure, with a higher proportion of individuals at intermediate sizes (2.85-4.26 cm). This study provides for the first time detailed descriptions of the macrofauna from the soft bottoms of False Bay, representing a preliminary effort to monitor ecological shifts in this critically important and understudied region, which is experiencing rapid environmental changes within Antarctic marine ecosystems.