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Temporal variation in the structure, abundance, and composition of Laminaria hyperborea forests and their associated understorey assemblages over an intense storm season
Full text linkKelp species function as important foundation organisms in coastal marine ecosystems where they provide biogenic habitat and ameliorate environmental conditions, often facilitating the development of diverse understorey assemblages. The structure of kelp forests is influenced by a variety of environmental factors, changes in which can result in profound shifts in ecological structure and functioning. Intense storm-induced wave action in particular, can severely impact kelp forest ecosystems. Given that storms are anticipated to increase in frequency and intensity in response to anthropogenic climate change, it is critical to understand their potential impacts on kelp forest ecosystems. During the 2021/22 northeast Atlantic storm season, the United Kingdom (UK) was subject to several intense storms, of which the first and most severe was Storm Arwen. Due to the unusual northerly wind direction, the greatest impacts of Storm Arwen were felt along the northeast coast of the UK where wind gusts exceeded 90 km/h, and inshore significant wave heights of 7.2 m and wave periods of 9.3 s were recorded. Here, we investigated temporal and spatial variation in the structure of L. hyperborea forests and associated understorey assemblages along the northeast coast of the UK over the 2021/22 storm season. We found significant changes in the cover, density, length, biomass, and age structure of L. hyperborea populations and the composition of understorey assemblages following the storm season, particularly at our most north facing site. We suggest continuous monitoring of these systems to further our understanding of temporal variation and potential recovery trajectories, alongside enhanced management to promote resilience to future perturbations.publishedVersio
Batch-to batch variation in nutrient digestbility of black soldier fly larvae meals in rainbow trout
Full text linkThe aim of this study was to evaluate the apparent digestibility coefficients (ADCs) of four batches of black soldier fly (BSF) meal, named BSF1, BSF2, BSF3 and BSF3, produced by the same company over one year, in rainbow trout (Oncorhynchus mykiss). To assess nutrients and amino acids ADCs, each insect meal was mixed with a high-quality reference diet in a 30:70 ratio on as is basis, including celite as inert marker, and pelleted. The reference diet was also used as control. The ADCs were calculated based on the data collected and determined during an in vivo experiment. A total of 240 fish were randomly divided into 250-L cylindroconical tanks supplied in flow-through open and Choubert systems (3 replicates/treatment). Data were analysed by One-Way ANOVA (SPSS V20.0.0.; P≤0.05). Globally, the four BSF meals showed a high ADC value, between 82.6 and 100%. No statistically significant differences were observed in the ADCs of dry matter, crude protein, ether extract and gross energy, while some differences were observed in the amino acid profile (P0.05). Despite the good digestibility of nutrients for all the insect mealsthe implementation of standardized production is important to have a standardize BSF meal capable of meeting market demands.publishedVersio
Early life stages of fish under ocean alkalinity enhancement in coastal plankton communities
Full text linkOcean alkalinity enhancement (OAE) stands as a promising carbon dioxide removal technology. Yet, this solution to climate change entails shifts in environmental drivers with unknown consequences for marine fish that are critical to ecosystem health and food security. Fish and their supporting food webs may be stressed by the novel carbonate chemistry or the nutrients contained in the deployed minerals. With a mesocosm experiment on natural plankton communities, we studied early life stages of fish under alkalinity (+600 µmol kg−1) and silicate (+75 µmol L−1) addition. Larvae and young juveniles of temperate coastal species, including Atlantic herring (Clupea harengus) and cod (Gadus morhua), were exposed to direct physiological and indirect food-web-mediated effects of OAE for 49 d. Neither in the shorter nor in the longer term did we find an impairment of fish growth and survival. Alkalization even led to an increase in fish biomass.publishedVersio
A Latitudinal Cline in the Taxonomic Structure of Eelgrass Epifaunal Communities is Associated With Plant Genetic Diversity
Full text linkAim: Biogenic structural complexity increases mobile animal richness and abundance at local, regional and global scales, yet an-imal taxa vary in their response to complexity. When these taxa also vary functionally, habitat structures favouring certain taxamay have consequences for ecosystem function. We characterised global patterns of epifaunal invertebrates in eelgrass (Zosteramarina) beds that varied in structural and genetic composition.Location: North America, Europe and Asia.Time Period: 2014.Major Taxa Studied: Peracarid crustaceans and gastropod molluscs.Methods: We sampled epifaunal invertebrate communities in 49 eelgrass beds across 37° latitude in two ocean basins con-currently with measurements of eelgrass genetic diversity, structural complexity and other abiotic and biotic environmentalvariables. We examined how species richness, abundance and community composition varied with latitude and environmentalpredictors using a random forest approach. We also examined how functional trait composition varied along with communitystructure.Results: Total species richness decreased with latitude, but this was accompanied by a taxonomic shift in dominance from pera-carid crustaceans to gastropods, which exhibited different sets of functional traits. Greater eelgrass genetic diversity was stronglycorrelated with both richness and abundance of peracarids, but less so for gastropods.Main Conclusions: Our results add to a growing body of literature that suggests genetic variation in plant traits influences theirassociated faunal assemblages via habitat structure. Because peracarids and gastropods exhibited distinct functional traits, ourresults suggest a tentative indirect link between broad-scale variation in plant genetic diversity and ecosystem function.publishedVersio
Adaptation in landlocked Atlantic salmon links genetics in wild and farmed salmon to smoltification
Full text linkIncreased knowledge of heritable traits in Atlantic Salmon (Salmo salar) is important to overcome bottlenecks in salmonid aquaculture. Atlantic salmonid populations, both landlocked and anadromous, represent an interesting model to gain insight into anadromy related traits, most notably, the probability to smoltify. While a previous study has identified several genomic regions diverging between anadromous and landlocked populations across the species range, the present study explores these data further with the aim to uncover if some of these genomic regions are linked to beneficial genetic traits associated with smoltification. In this study 17 of these loci were monitored in 669 anadromous salmon originating from 36 full-sibling families that had been reared under common garden conditions. The Smolt Index was calculated, using multiple visual markers, and provided a means of assessing smoltification stage. One SNP, located in Ssa04, showed a significant association with probability to smoltify, where individuals homozygous for the landlocked variant (LL) displayed a decrease in probability of smoltifying after one winter when compared with the homozygous for the anadromous variant (AA). This effect was independent of individual fish size. A separate common garden study comprising 200 individuals from either anadromous or landlocked strains showed that expression levels of ncor1, a thyroid mediator hormone located on the same chromosomal region (Ssa04), were significantly reduced in landlocked individuals post smoltification but remained constant in their anadromous counterparts. This study therefore suggests that while size is still the most important trigger for the induction of smoltification, there may also be an additional genetic component or trigger that has been ‘lost’ during the years deprived of SW transfer. In conclusion, the LL genotype identified here could potentially be used by the industry to delay smoltification and may also represent one of the first clues to the genetic regulation of smoltification in Atlantic salmon.publishedVersio
The social science of offshore aquaculture: uncertainties, challenges and solution-oriented governance needs
Full text linkAquaculture technology is on the move, enabling production in more open and exposed ocean environments around the world. These new systems offer solutions to environmental challenges facing conventional aquaculture, yet new technologies also create new social challenges while potentially exacerbating, or at minimum recreating, others. Offshore aquaculture research and governance are still in early stages, as is our understanding of the social repercussions and challenges associated with development. This paper provides an evaluation and reflection on offshore aquaculture from a social science perspective and is based on findings from a modified World Café group discussion method including the thoughts and experiences of social science experts. Key challenges and uncertainties including a lack of an appropriate regulatory framework, societal perceptions of offshore aquaculture, and offshore aquaculture’s contribution to society were identified. The governance implications of these challenges are discussed as well as the need for social sciences to address these challenges through transformative and transdisciplinary approaches that bridge science and society.publishedVersio
Fish species authentication in commercial fish products using mass spectrometry and spectral library matching approach
Full text linkSeafood fraud has become a global issue, threatening food security and safety. Adulteration, substitution, dilution, and incorrect labeling of seafood products are fraudulent practices that violate consumer safety. In this context, developing sensitive, robust, and high-throughput molecular tools for food and feed authentication is becoming crucial for regulatory purposes. Analytical approaches such as proteomics mass spectrometry have shown promise in detecting incorrectly labeled products. For the application of these tools, genome information is crucial, but currently, for many marine species of commercial importance, such information is unavailable. However, when combining proteomic analysis with spectral library matching, commercially important fish species were successfully identified, differentiated, and quantified in pure muscle samples and mixtures, even when genome information was scarce. This study further tested the previously developed spectral library matching approach to differentiate between 29 fish species from the North Sea and examined samples including individual fish, laboratory-prepared mixtures and commercial products. For authenticating libraries generated from 29 fish species, fresh muscle samples from the fish samples were matched against the reference spectral libraries. Species of the fresh fish samples were correctly authenticated using the spectral library approach. The same result was obtained when evaluating the laboratory-prepared mixtures. Furthermore, processed commercial products containing mixtures of two or three fish species were matched against these reference spectral libraries to test the accuracy and robustness of this method for authentication of fish species. The results indicated that the method is suitable for the authentication of fish species from highly processed samples such as fish cakes and burgers. The study shows that current and future challenges in food and feed authentication can efficiently be tackled by reference spectral libraries method when prospecting new resources in the Arctic.publishedVersio
Limited Parallelism in Genetic Adaptation to Brackish Water Bodies in European Sprat and Atlantic Herring
Full text linkThe European sprat is a small plankton-feeding clupeid present in the northeastern Atlantic Ocean, in the Mediterranean Sea, and in the brackish Baltic Sea and Black Sea. This species is the target of a major fishery and, therefore, an accurate characterization of its genetic population structure is crucial to delineate proper stock assessments that aid ensuring the fishery's sustainability. Here, we present (i) a draft genome assembly, (ii) pooled whole genome sequencing of 19 population samples covering most of the species’ distribution range, and (iii) the design and test of a single nucleotide polymorphism (SNP)-chip resource and use this to validate the population structure inferred from pooled sequencing. These approaches revealed, using the populations sampled here, three major groups of European sprat: Oceanic, Coastal, and Brackish with limited differentiation within groups even over wide geographical stretches. Genetic structure is largely driven by six large putative inversions that differentiate Oceanic and Brackish sprats, while Coastal populations display intermediate frequencies of haplotypes at each locus. Interestingly, populations from the Baltic and the Black Seas share similar frequencies of haplotypes at these putative inversions despite their distant geographic location. The closely related clupeids European sprat and Atlantic herring both show genetic adaptation to the brackish Baltic Sea, providing an opportunity to explore the extent of genetic parallelism. This analysis revealed limited parallelism because out of 125 independent loci detected in the Atlantic herring, three showed sharp signals of selection that overlapped between the two species and contained single genes such as PRLRA, which encodes the receptor for prolactin, a freshwater-adapting hormone in euryhaline species, and THRB, a receptor for thyroid hormones, important both for metabolic regulation and the development of red cone photoreceptors.publishedVersio
The state of the ocean in the northeastern Atlantic and adjacent seas
Full text linkIn this paper, the Copernicus Ocean State Report offers detailed scientific analysis of the ocean under climate change, ocean variability, and ocean extremes in the northeastern Atlantic and adjacent seas. Major results show that the northeastern Atlantic Ocean and adjacent seas have experienced consistent warming, with sea surface temperatures increasing at a rate of 0.25 ± 0.03 °C per decade since 1982, doubling the global average trend. This warming is most pronounced in the Black Sea, Mediterranean Sea, and Baltic Sea. Sea levels have risen significantly over the past 30 years, particularly in the Baltic and Mediterranean seas. Ocean acidification has also increased, with pH decreasing at a rate of −0.017 ± 0.001 units per decade. Marine heatwaves have intensified and expanded, affecting over 60 % of the region in 2022 and 2023. Over the past 16 years, most extreme wind speeds exceeding 22 m s−1 prevailed in the central and subpolar North Atlantic and northern Mediterranean Sea. The region has also seen significant variability in ocean climate indicators and circulation patterns, including increased Atlantic Water transport to the Arctic Ocean through the Fram Strait and notable variations in the Mediterranean Sea's meridional overturning circulation. No major Baltic inflow occurred in winter 2022/23.publishedVersio
