Marine Food Research Articles

Mapping phenoregions and phytoplankton seasonality in Northeast Pacific marine coastal ecosystems via a satellite-based approach

Phytoplankton phenology describes yearly algal growth cycles and characterises the timing, duration, and magnitude of bloom occurrences. This study used satellite chlorophyll-a data from 1998 to 2020 and the Hierarchical Agglomerative Clustering method to define phenoregions based on phytoplankton phenology spatial patterns over the British Columbia and Southeast Alaska coastal oceans. The defined phenoregions were used to simplify the spatial complexity of the heterogenous study region and thus better describe phytoplankton seasonality across the target area. The cluster analysis allowed the delineation of four coherent regions: two coastal regions and northern and southern shelf/offshore regions. Results showed that each phenoregion had distinguishable phytoplankton phenological characteristics, likely due to different physical forcings acting in these areas. Moreover, the interannual variability of the spring bloom initiation was evaluated considering interactions between sea surface temperature (SST) anomalies and the El Niño Southern Oscillation Index (ENSO). Early spring blooms were associated with positive SST anomalies and El Niño conditions; conversely, average or late spring blooms occurred in years with negative SST anomalies and La Niña conditions, with the strongest relationship occurring in the southern shelf/offshore phenoregion. This study provided new insights into the regionalisation of the British Columbia and Southeast Alaska coastal oceans based on phytoplankton phenology patterns. Given the critical role of phytoplankton as the base of the marine food web, such phenoregions have implications for regional zooplankton biomass and fish production. The link between phytoplankton phenology and climate drivers points to the importance of environmental change in phytoplankton bloom dynamics. Further research into the connection between phytoplankton bloom indices and zooplankton community structure and production would be an important step towards using these indices for ecosystem monitoring and fisheries management.

Trophic transfer of dechloranes in marine food webs in Dalian Bay, China

Dechloranes, including dechlorane 602 (Dec 602), dechlorane 603 (Dec 603), dechlorane 604 (Dec 604), dechlorane plus (DP, including syn- and anti-DP) and mirex, were determined in marine food web from Dalian Bay, Northeast China to investigate their occurrence andtrophic transfer. In all organisms, the detection rates were Dec 602 (99%) > mirex (95%) > Dec 603 (92%) > anti-DP (91%) > syn-DP (82%) > Dec 604 (9.6%). The concentrations were 0.92–16 ng/g lipid weight (lw) for mirex, 0.53–2.3 ng/g lw for syn-DP, 1.1–4.5 ng/g lw for anti-DP, 0.19–5.0 ng/g lw for Dec 602, 0.26–1.9 ng/g lw for Dec 603 and 0.020–0.33 ng/g lw for Dec 604. Significant positive relationships (p < 0.0001) were observed between lipid normalized concentrations and trophic levels for mirex (R2 = 0.80) and Dec602 (R2 = 0.82) in food webs, with the calculated TMFs values of 3.09 and 3.39, respectively, indicating the trophic magnification potential of these compounds. For syn-DP, anti-DP, Dec 603 and Dec 604, the similar significant relationships were not found, suggesting that these chemicals do not trophic magnification nor trophic dilution in the food web. With low log KOW values for mirex (7.01) and Dec 602 (8.05), these two compounds have the highest magnifications potentials, while the magnification potential of Dec 603, Dec 604 and DP dramatically decreased because of their extremely big log KOW values (higher than 10). The observed fractional abundance of anti-DP (fanti) ranged of 0.58–0.69, closing to the one in Chinese industrial products, indicating DP isomers had not undergone significant differences of physicochemical or biological process in the studied food web.

Development of food and gastronomy in the sub-Antarctic end of the world

Regional food and gastronomy flourish worldwide driven by unique local foods, the remembrance of old culinary traditions, and the visitors’ desire to taste memorable dishes in an environment evoking cultural heritage and geographical uniqueness. The sub-Antarctic Magellan region of Chile is the southernmost zone of the planet and is unique in centenary food and culinary practices. A detailed description of marine and terrestrial local food sources and biocultural traditions is documented. This article presents a PCF to develop local food and gastronomy in this region. Collection and analysis of bibliometric data led to three pillars supporting the FPC: the nutritional value and uniqueness of local foods and culinary traditions; a booming sustainable tourism that drives the development of gastronomic endeavors, and; lessons from past experiences in other remote places. The proposed PCF may be adapted to different regions worldwide. Recent gastronomic initiatives to implement this PCF at the Cape Horn International Center in Puerto Williams (Chile) are also described.

The global distribution and climate resilience of marine heterotrophic prokaryotes

Heterotrophic Bacteria and Archaea (prokaryotes) are a major component of marine food webs and global biogeochemical cycles. Yet, there is limited understanding about how prokaryotes vary across global environmental gradients, and how their global abundance and metabolic activity (production and respiration) may be affected by climate change. Using global datasets of prokaryotic abundance, cell carbon and metabolic activity we reveal that mean prokaryotic biomass varies by just under 3-fold across the global surface ocean, while total prokaryotic metabolic activity increases by more than one order of magnitude from polar to tropical coastal and upwelling regions. Under climate change, global prokaryotic biomass in surface waters is projected to decline ~1.5% per °C of warming, while prokaryotic respiration will increase ~3.5% ( ~ 0.85 Pg C yr−1). The rate of prokaryotic biomass decline is one-third that of zooplankton and fish, while the rate of increase in prokaryotic respiration is double. This suggests that future, warmer oceans could be increasingly dominated by prokaryotes, diverting a growing proportion of primary production into microbial food webs and away from higher trophic levels as well as reducing the capacity of the deep ocean to sequester carbon, all else being equal.

Phytoplankton bloom detection and trends in satellite inherent optical properties over the last two decades in a heterogeneous Patagonian coastal system

ABSTRACT To effectively address ecosystem health risks, it is crucial to use detection methods that efficiently cover vast areas with good spatial resolution. These methods should enhance understanding of how phytoplankton blooms might evolve due to climate change. Satellite Ocean Color sensors are advantageous for detecting and monitoring phytoplankton blooms over time. This study uses the Inherent Optical Properties (IOP) index, which considers light absorption by phytoplankton (Ab_phy) and by detritus plus colored dissolved organic matter (Ab_adg), to detect phytoplankton blooms in six subareas within the San Matías Gulf (SMG; Patagonia, Argentina). The findings reveal a significant increase in bloom alerts over the last 20 years in the northwestern and southwestern subareas. Temporal changes in chlorophyll a (Chla) and sea surface temperature (SST) were observed, both showing an increase over the studied period. Environmental features like the diffusive attenuation coefficient (Kd_490) and Ab_phy also showed positive trends in four of the six subareas. The positive trends in SST and Kd_490 suggest a potential reduction in the euphotic zone depth. Additionally, the presence of phytoplankton biomass, indicated by Chla and Ab_phy, is linked to reduced light penetration in the water column due to absorption by the cells and self-shading. A decrease in Ab_adg was observed, while photosynthetically active radiation (PAR) showed no significant trend over the last two decades. These patterns could significantly impact the frequency and timing of phytoplankton blooms, altering their community composition and phenology. Such changes have profound implications for the entire marine food web and the ecosystem services within the SMG. The results underscore the importance of incorporating optical data for monitoring phytoplankton blooms across multiple areas.

The Food Sources in Western Diets Modulate Obesity Development, Insulin Sensitivity, and the Plasma and Cecal Metabolome in Mice.

Dietary constituents modulate development of obesity and type 2 diabetes. The metabolic impact from different food sources in western diets (WD) on obesity development is not fully elucidated. This study aims to identify dietary sources that differentially affect obesity development and the metabolic processes involved. Mice were fed isocaloric WDs with protein and fat from different food groups, including egg and dairy, terrestrial meat, game meat, marine, vegetarian, and a mixture of all. This study evaluates development of obesity, glucose tolerance, insulin sensitivity, and plasma and cecal metabolome. WD based on marine or vegetarian food sources protects male mice from obesity development and insulin resistance, whereas meat-based diets promote obesity. The intake of different food sources induces marked differences in the lipid-related plasma metabolome, particularly impacting phosphatidylcholines. Fifty-nine lipid-related plasma metabolites are positively associated with adiposity and a distinct cecal metabolome is found in mice fed a marine diet. This study demonstrates differences in obesity development between the food groups. Diet specific metabolomic signatures in plasma and cecum associated with adiposity, where a marine based diet modulates the level of plasma and cecal phosphatidylcholines in addition to preventing obesity development.

Path analysis reveals combined winter climate and pollution effects on the survival of a marine top predator.

Marine ecosystems are experiencing growing pressure from multiple threats caused by human activities, with far-reaching consequences for marine food webs. Determining the effects of multiple stressors is complex, in part, as they can affect different aspects of biological organisation (behaviour, individual traits and demographic rates). Determining the combined effects of stressors, through different biological pathways, is key to predict the consequences for the viability of populations threatened by global change. Due to their position in the food chain, top predators such as seabirds are considered more sensitive to environmental changes. Climate change is affecting the prey resources available for seabirds, through bottom-up effects, while organic pollutants can bioaccumulate in food chains with the greatest impacts on top predators. However, knowledge of their combined effects on population dynamics is scarce. Using a path analysis, we quantify the effects of climate change and pollution on the survival of adult great black-backed gulls, both directly and through effects of individuals' body mass. Warmer ocean temperatures in gulls' winter foraging areas in the North Sea were correlated with higher survival, potentially explained by shifts in prey availability associated with global climate change. We also found support for indirect negative effects of organochlorines, highly toxic pollutants to seabirds, on survival, which acted, in part, through a negative effect on body mass. The results from this path analysis highlight how, even for such long-lived species where variance in survival tends to be limited, two stressors still have had a marked influence on adult survival and illustrate the potential of path models to improve predictions of population variability under multiple stressors.

Sex-specific trade-off under marine heat wave and food limitation: Insights from bioenergetic and intestinal microbiome in mussels

Global warming, marine heat waves and subsequent food limitation are projected to be more frequent and intense under future climate change. Understanding the consequences for key marine species such as mussels is critical to ensure sustainability and guide adaptation options. Mussels are not only an economically important species but also considered excellent indicators of environmental changes. This study evaluates the sex-specific effects of marine heat waves and food limitation on the bioenergetics and intestinal flora of the digestive glands of mussels. Heat waves had a significant negative effect on cell energy homeostasis of the digestive gland in female mussels. Food limitation significantly decreased the total energy reserve in the digestive gland of both female and male mussels. Combined food limitation and heat wave led to sex-specific responses with significantly higher cellular energy allocation parameters observed in the digestive gland of female mussels as compared to males. Additionally, 16S rRNA sequencing showed that the intestinal flora of female mussels was more stable, as well as sex-specific differences in the relative abundance of various bacteria phyla. This study highlights the importance to consider sex in studies evaluating the impact of climate change in mussels, and the results can contribute to the development of strategies for sustainable bivalve aquaculture under the growing risks of warming, heatwaves and food limitations.

Exploring the Link between Seafood and Traditional Fish Sauces, and Blood Pressure: A Bandar Kong Cohort Study

Background: High blood pressure (BP) is a risk factor for various health conditions, and dietary factors have been linked to the development of high blood pressure. Scientific studies have shown that consuming marine food, particularly oily fish, can be beneficial in reducing blood pressure levels. This study aims to investigate the relationship between traditional fish sauces and seafood consumption, and blood pressure levels in Bandar Kong Cohort study. Methods: Cross-sectional analyses were performed using data from 2823 volunteers, collected through questionnaires and BP measurements following a standardized protocol. Age-adjusted and multivariate associations between BP and seafood consumption were estimated using multiple linear regressions. Three models of analysis were used: model 1, daily energy intake; model 2, daily energy intake along with age; and model 3, daily energy intake, age, education, body mass index (BMI), residence, occupation, marital status, using hookah, socio-economic status, physical activity, and family history of hypertension. Results: Among 2823 participants (age; 46.88±8.94 yrs.), 1138(40.3%) men and 1685(59.7%) women, 693 (24.5%) individuals had hypertension, (n=288) accounting for 25.3% men and (n=405) 24.0% women. After adjusting for covariates, the study found significant negative relationships between the consumption of salted fish-water, Mahyaveh and Suragh (traditional Iranian fish sauces), and BP. Conclusions: This study suggests that consuming traditional Iranian fish sauces, Mahyaveh and Suragh, is associated with lower BP levels. This study sheds light on potential benefits of traditional dietary choices for regulating blood pressure.

Short-term dietary changes are reflected in the cerebral content of adult ring-billed gulls.

Omega-3 long-chain polyunsaturated fatty acids (n3-LCPUFAs) are produced primarily in aquatic ecosystems and are considered essential nutrients for predators given their structural role in vertebrates' cerebral tissues. Alarmingly, with urbanization, many aquatic animals now rely on anthropogenic foods lacking n3-LCPUFAs. In this study undertaken in Newfoundland (Canada), we tested whether recent or longer term diet explains the cerebral fatty acid composition of ring-billed gulls (Larus delawarensis), a seabird that now thrives in cities. During the breeding season, cerebral levels of n3-LCPUFAs were significantly higher for gulls nesting in a natural habitat and foraging on marine food (mean ± s.d.: 32 ± 1% of total identified fatty acids) than for urban nesters exploiting rubbish (27 ± 1%). Stable isotope analysis of blood and feathers showed that urban and natural nesters shared similar diets in autumn and winter, suggesting that the difference in cerebral n3-LCPUFAs during the breeding season was owing to concomitant and transient differences in diet. We also experimentally manipulated gulls' diets throughout incubation by supplementing them with fish oil rich in n3-LCPUFAs, a caloric control lacking n3-LCPUFAs, or nothing, and found evidence that fish oil increased urban nesters' cerebral n3-LCPUFAs. These complementary analyses provide evidence that the brain of this seabird remains plastic during adulthood and responds to short-term dietary changes.

Diatom abundance in the polar oceans is predicted by genome size.

A principal goal in ecology is to identify the determinants of species abundances in nature. Body size has emerged as a fundamental and repeatable predictor of abundance, with smaller organisms occurring in greater numbers than larger ones. A biogeographic component, known as Bergmann's rule, describes the preponderance, across taxonomic groups, of larger-bodied organisms in colder areas. Although undeniably important, the extent to which body size is the key trait underlying these patterns is unclear. We explored these questions in diatoms, unicellular algae of global importance for their roles in carbon fixation and energy flow through marine food webs. Using a phylogenomic dataset from a single lineage with worldwide distribution, we found that body size (cell volume) was strongly correlated with genome size, which varied by 50-fold across species and was driven by differences in the amount of repetitive DNA. However, directional models identified temperature and genome size, not cell size, as having the greatest influence on maximum population growth rate. A global metabarcoding dataset further identified genome size as a strong predictor of species abundance in the ocean, but only in colder regions at high and low latitudes where diatoms with large genomes dominated, a pattern consistent with Bergmann's rule. Although species abundances are shaped by myriad interacting abiotic and biotic factors, genome size alone was a remarkably strong predictor of abundance. Taken together, these results highlight the cascading cellular and ecological consequences of macroevolutionary changes in an emergent trait, genome size, one of the most fundamental and irreducible properties of an organism.

Coccolithophore Assemblage Response to Indian Monsoon–ENSO Teleconnections During the Last Century

AbstractWe present a new, annually resolved coccolithophore relative abundance record (1889–1993 CE) from a laminated marine sediment core obtained from the northeastern Arabian Sea to document assemblage variations during the last century. Our analysis revealed that ∼80% of the assemblage is composed of the coccolithophore species Gephyrocapsa oceanica, Emiliania huxleyi, and Florisphaera profunda. Hierarchical clustering of the coccolithophore data delineates time intervals (1889–1909 CE, 1910–1959 CE, 1960–1993 CE) comparable to previously reported interdecadal changes of the El Niño–Southern Oscillation (ENSO)–Indian monsoon variance. We find that F. profunda (Fp%) is positively correlated with central Pacific ENSO (Niño 4 and Niño 3.4). Frequency analyses of Fp% match ENSO quasiperiodicity reported from instrumental data and proxy records and support the existence of previously described ENSO–Indian monsoon teleconnections. Furthermore, the increased variance of Fp% and associated decrease in marine primary productivity starting ∼1960 CE appears to be driven by decreased upward nutrient transport linked to increased surface water stratification due to surface ocean warming. With the predicted increases in frequency and strength of central Pacific El Niño as well as surface ocean warming and upper ocean stratification in the Indian Ocean over the coming century, our results imply further impacts on coccolithophores in the northeastern Arabian Sea that may have cascading effects on the marine food web and global biogeochemical cycles.

Impacts of the Early Eocene Climatic Optimum (EECO, ∼53‐49 Ma) on Planktic Foraminiferal Resilience

Plain Language SummaryThe Early Eocene Climatic Optimum (EECO) is an interval of prolonged warmth that occurred ∼53 to 49 million years ago. Planktic foraminifera are important (alongside coccolithophores) for understanding the carbon cycle and determining export production in the ocean. To understand how foraminifera can be impacted by extreme heat, we analyzed samples from the Pacific Ocean through measuring changes in (a) the relative abundance, that is, the count of different taxa in a sample, and (b) body (shell) size of planktic foraminifera. At the start of the EECO, the abundance of the genera Morozovella and Chiloguembelina decreased. Despite this decline, the number of foraminifera being buried and the size of the largest shells in a sample does not change. We attribute this to the increased abundance of the genus Acarinina. In general, the accumulation of foraminifera remains stable while the relative abundance of foraminifera to coccolithophores decreases. Together, this implies that coccolithophores are increasing in abundance, and/or mass. During the EECO, one group of foraminifera was able to counterbalance the decrease in abundance of other genera. This highlights the resilience of open‐ocean carbonate production and the base of the marine food web.

An Investigation on the Presence and Risk Assessment of Microplastics in Quilon Beach, South West Coast of India

Microplastics (MPs) are the most serious emerging pollutant around the globe. Anthropogenic activities are the major contributor of MPs in beach sediments. MPs are widely distributed along beaches and pose a serious threat to the marine food chain including human health. The present study aims to investigate, for the first time, the occurrence, quantification of abundance and risk assessment of MPs in Quilon beach, India and also identifies the potential sources along with the assessment of degree of MPs contamination using Pollution load index (PLI) and Pollution Hazard index (PHI) parameters. Sampling was conducted in dry season in the beach. A total of thirty-three samples were collected establishing a 20m grid pattern along the study area. MPs of size range 5mm - < 0.25mm were considered. The average abundance of MPs in the study area is 3145±2515 MPs/kg of sand. Polyester (PES), Acrylonitrile butadiene styrene (ABS) are the major polymer types in the study area. Fibre was the most dominant shapes. The frequent colours found were white and transparent. MPs of size <0.25mm were the most common of all the samples. Anthropogenic activities including sewage effluents, fishing and tourism activities might be the main sources of MPs pollution in this area.

Small pelagic fish: new frontiers in ecological research

Populations of small pelagic fish (SPF), such as sardines, anchovies and herrings, support some of the largest marine fisheries globally and are critical for trophic transfer in large marine ecosystems and food security, particularly in low- to medium-income countries. Marked changes in population size, shifts in distribution on multiple time scales, and impacts on their populations from other pressures (e.g. overfishing, climate change) pose large challenges to sustainably manage these resources to avoid the serious socioeconomic and ecological impacts of population collapses. The ecology and management of SPF was discussed in an international symposium in Lisbon, Portugal, attracting participants from 38 countries and 6 continents. This Theme Section includes 18 research contributions examining SPF from 6 different ecological regions alongside 3 global analyses. These studies, including a wide range of topics from parasitology, behavior and trophodynamics to growth and spawning, provide important new knowledge that will improve science-based advice and tools needed for sustainable, ecosystem-based management of these resources. This symposium was an important milestone for a global working group and sowed the seeds for continued, globally coordinated research efforts on the role of SPF in complex socio-ecological systems.

Metal exposure in the Greenlandic ACCEPT cohort: follow-up and comparison with other Arctic populations

ABSTRACT Humans are exposed to metals through diet and lifestyle e.g. smoking. Some metals are essential for physiologically body functions, while others are non-essential and can be toxic to humans. This study follows up on metal concentrations in the Greenlandic ACCEPT birth-cohort (mothers and fathers) and compares with other Arctic populations. The data from 2019 to 2020 include blood metal concentrations, lifestyle and food frequency questionnaires from 101 mothers and 76 fathers, 24–55 years, living in Nuuk, Sisimiut, and Ilulissat. A high percentage (25–45%) exceeded international guidance values for Hg. For the mothers, the metal concentrations changed significantly from inclusion at pregnancy to this follow-up 3–5 years after birth; some increased and others decreased. Most metals differed significantly between mothers and fathers, while few also differed between residential towns. Several metals correlated significantly with marine food intake and socio-economic factors, but the direction of the correlations varied. Traditional marine food intake was associated positively with Se, As and Hg. To the best of our knowledge, this study provides the most recent data on metal exposure of both men and women in Greenland, elucidating metal exposure sources among Arctic populations, and documents the need for continuing biomonitoring to follow the exceeding of guidance values for Hg.

In silico investigation of lipid-based compounds implicated in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal, currently incurable neurodegenerative disease that progressively affects the upper motor neurons in the brain and lower motor neurons in the spinal cord. A significant portion of patients exhibit abnormalities in lipid metabolism, which appear to contribute to denervation and subsequent motor neuron degeneration. This study aimed to computationally identify lipid-based compounds associated with ALS and elucidate their pathological and therapeutic roles to facilitate effective ALS diagnosis and treatment. The methodologies employed encompassed rational database searches, pharmacokinetic and target predictions, as well as docking and molecular dynamics simulations (MDS). The findings from the disease-to-lipids analysis identified 20 lipid compounds correlated with ALS, primarily categorized as potential inhibitors within the functional classes of vitamins, antibiotics, organic acids, and phytochemicals. Pharmacokinetic predictions revealed that only four compounds exhibited permeability across the blood&amp;ndash;brain barrier, namely 4-hydroxynonenal, resveratrol, rotenone, and valproic acid. Docking simulations indicated the highest binding affinity for 4-hydroxynonenal with alkaline ceramidase 2 (&amp;minus;4.516 kcal/mol), resveratrol with carbonic anhydrase 6 (&amp;minus;7.070 kcal/mol), rotenone with cytochrome P450 2C19 (&amp;minus;7.378 kcal/mol), and valproic acid with glutamate carboxypeptidase 2 (&amp;minus;5.629 kcal/mol). Furthermore, MDS and molecular mechanics/generalized born surface area calculations demonstrated the stability and binding energies of the complexes under simulated physiological conditions. In summary, further investigation is warranted to explore the synergistic effects of resveratrol and valproic acid in ALS, the mechanisms underlying 4-hydroxynonenal adduct-assisted aggregate formation of certain enzymes in ALS, and the impact of prolonged human exposure to rotenone from marine food sources (such as fish) on the development of ALS.

Cuttlefish Bone-Derived Calcium Phosphate Bioceramics Have Enhanced Osteogenic Properties.

Cuttlefish bones are byproducts of cuttlefish processing and are readily available in the marine food industry. In this study, calcium phosphate bioceramics were prepared from cuttlefish bones using a two-stage hydrothermal calcination process. The results indicated that all bioceramics derived from cuttlefish bones had a higher degradation capacity, better bone-like apatite formation ability, and higher degree of osteogenic differentiation than commercially available hydroxyapatite. Notably, β-tricalcium phosphate, which had the highest degree of Ca2+ and Sr2+ dissolution among the bioceramics extracted, can significantly upregulate osteogenic markers (alkaline phosphatase, osteocalcin) and stimulate bone matrix mineralization. Thus, it is a promising bioceramic material for applications in bone regeneration.

Seasonal dynamics of polycyclic aromatic hydrocarbons in microplankton from Kaohsiung Harbor (Taiwan Strait, northeastern South China Sea)

The impact of polycyclic aromatic hydrocarbons (PAHs) on the marine food web is crucially understudied in the primary trophic system. We evaluated the seasonal dynamics of PAHs in microplankton in a polluted environment (Taiwan), northeastern South China Sea. Replicate size-fractionated microplankton (55–1000 μm) were freeze-dried, and PAHs were extracted with a 1:1 v/v ratio of acetone: n-hexane, then analyzed using GC–MS. Total PAHs ranged between 68 and 2548 ng/g dw in microplankton, greatest during spring (130–2548 ng/g), followed by autumn (135–772 ng/g) and summer (44–423 ng/g). Spatial distribution varied through seasons but was higher in the southern part (S6 > S4 > S5 > S2 > S3 > S1 > S7), dominated by higher-ring PAHs from mixed pyrogenic and petrogenic sources. PAHs are significantly correlated with environmental factors, especially in colder seasons and lower salinity areas. Suspended matter and plankton influenced PAH transport and partitioning seasonally. Plankton's PAHs seasonal changes and environmental influences are revealed in an anthropic environment.

Small pelagic fish in the shallow Wadden Sea show opportunistic feeding with a strong benthic link

Abstract Small pelagic fish (SPF) are crucial in marine food webs, transferring energy from plankton to higher trophic levels. This study focuses on herring (Clupea harengus) and sprat (Sprattus sprattus), addressing knowledge gaps in their feeding ecology in a nursery area, the Dutch Wadden Sea. We conducted a year-long, monthly survey, and used DNA metabarcoding to analyse zooplankton samples and stomach contents of two size classes of herring and sprat. Intra-, interspecific, and seasonal variations in fish condition, stomach fullness, and diet composition, along with selective feeding, were studied. Our study showed that condition and diet composition of herring and sprat, along with zooplankton density, exhibited a clear seasonal pattern. Juvenile herring and sprat displayed opportunistic feeding behaviour, rather than showing distinct prey selection. Besides copepods, we regularly observed (larvae of) benthic invertebrates in their diet. This emphasizes the crucial role of SPF as energy transfer agents, not solely between trophic levels, but also from benthic to pelagic habitats. Furthermore, fish post-larvae were part of the diet of larger herring (10–15 cm). Because of its unprecedented temporal and taxonomical detail, this study advances the understanding of seasonal dynamics of dominant components at the base of the Wadden Sea food web.