Biology and Life Sciences

Abstract: Puntius sophore, a small indigenous fish species, has significance to the nutritional and livelihood security of rural communities in India. This study presents baseline data on the population dynamics, length-weight relationships (LWRs), and condition factors of P. sophore in two major rivers, the Ganga and Punpun in India, while assessing multi-decadal (1990-2023) land use and land cover (LULC) changes. Fish samples (506) were collected monthly from each of three landing sites from the river Ganga and Punpun. The results revealed that populations in both rivers have positive allometric growth, with length-weight relationship (LWR) equations of W = 0.0129 L^3.023 (Ganga) and W = 0.0079 L^3.169 (Punpun). The condition factors (Kc, Kn, Ka) were significantly higher (p < 0.05) than 1 in the Punpun River, indicating a favorable environment, while values < 1 in the Ganga showed higher ecological stress. The growth aspects (L∞ = 134.60 mm, K = 0.71 yr⁻¹ for Ganga; L∞ = 133.42 mm, K = 0.735 yr⁻¹ for Punpun) were analyzed by TropFish-R, showing a fast-growing species. Total mortality (Z) was higher in the Ganga (1.822 yr-1) in comparison to the Punpun (1.797 yr-1), though, exploitation rates (E < 0.5) confirmed under-exploitation. Length-based spawning potential ratio (LB-SPR) analysis revealed recruitment overfishing (SL < Lm), with a sustainable SPR of 0.40 in the Punpun and a depleting SPR of 0.32 in the Ganga. Although current fishing pressure is adequate, spatiotemporal LULC indicated that rapid urbanization and habitat fragmentation exhibit a substantial "squeeze" effect that adversely impacts aquatic ecosystems and poses a significant risk to spawning and feeding grounds of that ecosystem. Effective management approaches, including the execution of seasonal fishing bans during monsoon recruitment and the implementation of strict mesh-size standards, are essential for the conservation of wild populations and the protection of regional food supplies.

Abstract: Research into molecular machinery of eukaryotic unicellular organisms (protists) gives a unique opportunity to unveil mechanisms of intricate cellular processes and complete life cycles at the level of a single cell as a whole organism. Knowledge of protistan molecular biology and life cycle shifts as adaptations to varying physical-chemical features of the environment helps resolve important issues like evaluation of the balance between external abiotic triggers and internal molecular drivers of cells development. Understanding molecular mechanisms of these processes is crucial for prognostic modeling of population growth of the ecologically and economically important protists like toxic species forming harmful algal blooms (HABs) that currently expand worldwide. Here, we review basic features of bloom-forming mixotrophic dinoflagellates as drivers of their excess proliferation and HABs. We unveil key components of molecular machinery involved in life cycle regulation of dinoflagellates and highlight the deficiency/redundancy of nitrogen- and phosphorus-containing substrates as modulators of life cycles, diversity and nutrition strategies, including mixotrophy and kleptoplasty. We discuss linkages between cellular and molecular biology, omics and ecological modeling, since merging research approaches of these disciplines is a promising perspective for future progress of molecular biology within the framework of translational aquatic ecology.

Abstract: This paper is a literature study supplemented with self-collected data on fish density, age and growth of smelt (Osmerus eperlanus) in Lake Mjøsa over the last 40 – 50 years. Smelt is an important prey fish for piscivorus brown trout, and the development of the brown trout population is illuminated by catch reports. The smelt abundance in Lake Mjøsa declined in the period 1980 to 1990 but increased sharply in 2018 and 2023. Re-cruitment to the smelt population is positively correlated with air temperature in May and July. Increased smelt abundance is a possible reason why the population of large grown brown trout also appears to have increased, while smelt has shown reduced in-dividual growth in recent years. The brown trout population does not appear to have a decisive effect on the smelt stock but may have contributed to increased mortality in smelt in the material from 2006 - 2022 as compared to 1980. The effect of brown trout stocking, conducted for the last time in 2021, is uncertain, but future catch reporting will provide a better answer to this.

Abstract: Environmental DNA (eDNA) metabarcoding is a valuable, non-invasive approach for assessing fish biodiversity in freshwater ecosystems. This study characterized fish-associated diversity across four freshwater locations in Indiana, including upstream and downstream sites of the White River, Shadyside Lake, and Trail Creek, and examined contemporary White River fish communities in the context of recovery following the historical 1999 chemical spill. Water samples were analyzed using high-throughput sequencing targeting the mitochondrial 12S rRNA gene, and fish-associated exact sequence variants (ESVs) were evaluated using richness, diversity, and community composition analyses. A total of 87 unique fish-associated ESVs were detected. White River downstream exhibited the highest ESV richness (60), followed by White River upstream (27), Shadyside Lake (22), and Trail Creek (7), and also had the highest Shannon diversity (H′ = 2.30). Community analyses revealed substantial overlap between the two White River sites and greater similarity between them than with Shadyside Lake or Trail Creek. The relatively high richness and diversity detected downstream are consistent with previous biological assessments documenting substantial recovery of White River fish communities following the 1999 spill. Overall, these findings support eDNA metabarcoding as a useful complement to conventional fish monitoring for assessing freshwater biodiversity and long-term ecological change.

Abstract: The cytochrome P450 (CYP) system is a superfamily of heme-containing monooxygenases essential for the metabolism of endogenous compounds and xenobiotics. In fish, CYP enzymes process diverse pollutants and contribute to adaptation to chemical stress. Their activity depends on NADPH-cytochrome P450 reductase (CYPOR), which provides electrons for CYP-mediated reactions. Two aspects remain insufficiently understood: the mechanisms underlying species-specific CYPOR reactivity in relation to ecological niche and the potential of CYPOR dynamics as a biomarker of bioremediation effectiveness. This review-hypothetical study aims to formulate and substantiate hypotheses linking CYPOR species specificity with ecological niche and to establish a conceptual framework for using CYPOR in bioremediation monitoring. Scientific literature published from 1980 to 2026 was searched in PubMed, Scopus, Web of Science, and Google Scholar. The proposed hypotheses form an integrated model in which species-specific CYPOR reactivity is considered an evolutionarily fixed trait reflecting ecological adaptation, while CYPOR dynamics may serve as an integrated indicator of pollution and remediation efficiency. The central concept is CYPOR as a common elec-tron donor system whose activity reflects the cumulative induction of CYP isoforms and responds to changes in toxicant exposure. This framework provides a basis for interpreting CYPOR variability in fish populations and developing future biomonitoring approaches.

Abstract: Microplastics (MPs) (1 μm - 5 mm-) are now ubiquitous in the environment. They exhibit a variety of different shapes and compositions and accumulate in organs of virtually every organism. Recently, biomedical researchers have focused on nanoplastics (NP) (1 nm -1 μm ) because of their potential to enter organisms, cross cell barriers, and impact biological processes. Taken together, micro- and nano-plastics (MNP) are increasingly considered a contaminant of concern in freshwater systems such as the Laurentian Great Lakes in North America, which provide drinking water for 40 million people in the United States and Canada. We review here the current knowledge and challenges to overcome for evaluating the long-term consequences of MNP exposure in freshwater ecosystems and their aquatic vertebrates. We demonstrate how the use of a novel animal model in the amphibian Xenopus within the context of a transdisciplinary research center has the potential to rapidly advance knowledge about key biological mechanisms and potential health impacts of environmentally-relevant MNPs.

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Probiotics, especially Bacillus species, have gained attention for their potential to improve growth and strengthen disease resistance in cultured shrimp. This study evaluated the effects of native Bacillus strains on growth performance, disease resistance and gut microbiota of Penaeus vannamei through the rearing water. The shrimp were reared in water supplemented with different treatments: (a) a negative control (no bacterial addition), (b) a commercial Bacillus spp.® product (positive control), (c) B. subtilis and (d) B. cereus, every 7 days over a period of 21 days. Shrimp reared with B. cereus showed significantly increased specific growth rate (SGR) and average daily gain (ADG) among treatments as compared to the control group (p < 0.05). There was no significant difference in final body weight and feed conversion ratio among groups (p > 0.05). After Vibrio parahaemolyticus challenge, the cumulative mortality was lowest in the B. cereus treated group, showing the highest disease resistance. Alpha diversity of gut microbiota was not significantly different among groups, but beta diversity analyses showed significant differences of gut microbial community structure and LEfSe identified the genus Bacillus as a significant biomarker of the B. cereus-treated group, confirming its colonization in shrimp gut. The results suggest that supplementation of water with a native B. cereus strain enhances growth efficiency and disease resistance and leads to a stable colonization of Bacillus in shrimp gut, offering a practical probiotic approach for intensive shrimp aquaculture.

Abstract: River–lake confluence zones are shaped by inflow hydrology, evaporative concentration, and water mixing, providing natural systems for examining phytoplankton responses to environmental gradients. Here, we investigated Siling Co and adjacent river–lake confluence zones at elevations above 4,500 m. We integrated genus-level phytoplankton cell-density and biomass data with 22 environmental variables from 14 sampling events at 10 sites, including seven Lake and seven River samples. Community diversity, composition, and community–environment associations were evaluated using ordination, permutation tests, correlation analyses, distance-based redundancy analysis, Mantel tests, and multi-method evidence integration. In total, 54 genera were recorded, with Bacillariophyta representing the dominant phylum. Lake and River samples overlapped in community composition, whereas sampling period explained more genus-level variation than water-body type. Major-ion and mineralization gradients were consistently associated with community turnover. pH and SiO₂ were associated with cell-density composition, whereas Cl⁻ was associated with biomass composition. Cyanobacterial relative biomass was positively correlated with total nitrogen and negatively correlated with SO₄²⁻. These findings indicate that phytoplankton community structure in the Siling Co river–lake confluence zone cannot be attributed simply to two discrete habitat types, namely lakes and rivers, and provide a new perspective on community assembly in extremely high-altitude river–lake confluence zones.

Abstract: The Siberian sturgeon (Acipenser baerii, Brandt, 1869) is a potamodromous freshwater species with major ecological and commercial importance. Natural populations across the main Siberian River basins have declined so severely that the species is now classified as Critically Endangered on the IUCN Red List. This narrative analysis synthesizes current scientific knowledge regarding the ecology, reproductive biology, conservation status, and nutritional value of products derived from A. baerii, with the aim of providing an integrated perspective on this species, which has recently been introduced into Romanian aquaculture and occupies the interface between biodiversity and human consumption needs. The species’ remarkable ecological and morphological plasticity, which underlies its wide natural distribution in the Ob, Irtysh, Yenisei, and Lena River basins, has also made it the dominant species in global sturgeon aquaculture, commercially farmed in Europe, Asia and South America. Reproductive management in farming systems relies on hormonal induction, non-invasive maturity assessment and controlled hatchery practices, while emerging no-kill technologies enable repeated caviar harvesting without sacrificing the female, improving both ethical standards and economic efficiency. From a nutritional standpoint, A. baerii yields two high-value products like caviar, a rich source of long-chain polyunsaturated fatty acids (EPA and DHA) with recognized cardiovascular and neurodevelopmental benefits and meat, characterized by high biological value protein, a favorable amino acid profile, and significant omega-3 content. By products such as skin, swim bladders, glands and cartilage contribute to the higher value utilization of the species within the circular bioeconomy. Still, notable gaps remain in genetics and sex determination methods, in early life behavioral ecology and in cryopreservation protocols. Future work should also look at more sustainable feed formulations and new value added proucts.

Abstract: Bigeye tuna (Thunnus obesus) are ecologically important pelagic predators in the eastern Pacific and support valuable international fisheries. Their distribution responds sensitively to the El Niño–Southern Oscillation (ENSO) and to multiscale changes in upper‑ocean structure. However, existing statistical or machine‑learning models often fail to distinguish between environmental suitability and advective redistribution, while complex ecosystem models often face parameter identifiability challenges. To bridge this gap we develop a Physics‑Guided Advection‑Diffusion‑Reaction (PhyG‑ADR) model. The model represents the time‑varying biomass density C(x,y,t) by a partial differential equation where advection describes large‑scale movement, diffusion represents mixing and sub‑mesoscale dispersion, and the reaction term implements environment‑dependent growth and density limitation. A non‑linear habitat selection function combines sea‑surface temperature, mixed‑layer depth, dissolved oxygen, and ocean‑heat content to provide physiological realism. To constrain poorly known parameters, we used a Bayesian inference framework and estimated posterior parameter distributions from a 19-year record of monthly catch-per-unit-effort (CPUE) indices (1994–2012) using Markov chain Monte Carlo (MCMC). The posterior analysis suggests that habitat selection dominates the formation of spatial aggregation, while climate‑driven advection plays a key role in inter‑annual shifts associated with ENSO. Parameter uncertainty is explicitly quantified, and sensitivity experiments demonstrate that the inferred habitat-preference structure of bigeye tuna is robust across carrying‑capacity scenarios. PhyG‑ADR therefore combines predictive skill with mechanistic insight and can inform dynamic fisheries management and spatial conservation planning.

Abstract: Piscirickettsia salmonis, the etiological agent of piscirickettsiosis (or SRS), represents the most significant health challenge for salmon farming in Chile. While it is generally assumed that fish farms are the epicenter of the disease, the role of migratory wild fish in its ecology and dissemination remains an enigma. This study evaluates the prevalence and shedding routes of P. salmonis in the Chilean silverside (Odontesthes regia), a pelagic fish with extensive latitudinal migration from southern Chile to Peru. Liver, kidney, spleen, and fecal samples were analyzed using nested PCR in individuals captured across five zones of Chile: four in Los Lagos Region, characterized by a high density of salmon farms, with active outbreaks and one in the Maule Region, a pristine area without salmon farming concessions. Results revealed an overall P. salmonis prevalence of 71.6% in O. regia. Remarkably, the highest positivity rate (83%) was detected in the Maule Region, an ecosystem characterized by the absence of salmon farming activities, compared to the Los Lagos region (68.7%), where aquaculture is intensive. These findings suggest that the pathogen is endemic in wild silverside populations regardless of proximity to industrial salmonid cages. P. salmonis was detected in 71,6% of the total samples. The statistical analysis ruled out a significant association between silverside infection and proximity to salmon farms. The pathogen was primarily detected in feces, confirming an active shedding route into the marine environment. These findings challenge the current paradigm, demonstrating that P. salmonis has a broad endemic distribution independent of salmon farming activities. The high rate of fecal shedding, combined with the extensive migratory patterns of O. regia, positions it as a crucial vector capable of transporting the bacteria toward warmer marine ecosystems in the north. This represents a latent risk of horizontal transmission to new geographic areas and other species of aquaculture interest, necessitating a reassessment of biosecurity strategies at a macro-regional level.

Abstract: The freeze-thaw process in sperm cryopreservation generates reactive oxygen species (ROS) that impair motility, viability, and fertilizing capacity in fish, including the Javan barb (Systomus rubripinnis), an endemic Indonesian cyprinid of conservation concern. This study evaluated five natural antioxidants: basil leaf extract (BLE), noni fruit extract (NFE), moringa leaf extract (MLE), sambiloto leaf extract (SLE), and honey-egg yolk (HEY). Radical-scavenging capacity was measured by DPPH assay (IC₅₀: BLE 134.06, MLE 297.04, NFE 422.86, SLE 3010.46 ppm), and post-thaw motility, duration of motility, viability, abnormality, fertilization rate, and ATP bioluminescence were assessed. Optimum doses were 1% for BLE, NFE, and MLE, 1.25% for HEY, and 7% for SLE. BLE at 1% gave the best overall profile (motility 85.15 ± 0.88%; duration 7.14 ± 0.38 min; viability 82.21 ± 1.86%; abnormality 18.29 ± 0.16%), significantly exceeding the control (65.00 ± 2.31%; 4.56 ± 0.33 min; 68.00 ± 2.42%; 23.54 ± 0.28%; p < 0.05), whereas SLE sustained the longest motility. All extracts supported fertilization rates above 82% versus 70.08 ± 3.82% in the control, and 1% BLE preserved post-thaw luminescence equivalent to fresh sperm (165,217 vs. 164,087 RLU), interpreted comparatively. These plant-derived antioxidants are promising supplements for Javan barb germplasm conservation.

Abstract: Our current understanding of the early developmental characteristics and growth traits of the potato grouper (Epinephelus tukula) is limited but necessary for the development of large-scale aquaculture farming of this species. To investigate this, this study used artificially propagated E. tukula and systematically observed embryonic and morphological development processes of both larvae and juvenile fish and analyzed the growth characteristics during the young developmental stage. Under water temperature and salinity conditions of 23.9 ± 0.4°C and 28-30 ppt, respectively, the fertilized eggs completed embryonic development in 25 h 34 min, sequentially passing through seven typical stages: fertilization, cleavage, blastula, gastrula, neurula, organogenesis, and hatching. The newly hatched larvae had an average total length of 1.60 ± 0.17 mm. The yolk sac and oil globule were visible at 1 dph (days post-hatching); at 3 dph they began exogenous feeding; the prototype of the “trident” appeared at 9 dph; by 30 dph, the fins were almost fully developed and the fish entered the juvenile stage; by 35 dph, the second dorsal fin spine and pelvic fin spine began to shrink; by 55 dph, spots and scales covered the entire body, and the fish entered the young developmental stage. After 105 dph, average body weight increased from 34.134 ± 5.85 g to 135.28 ± 20.11 g, and average total length increased from 13.41 ± 0.81 cm to 21.29 ± 1.15 cm. The best-fit model between average total length (TL) and age was the quadratic function TL = -0.001t² + 0.283t - 11.018 (R² = 0.982). The results of this study showed that the E. tukula has a relatively fast embryonic development rate, typical morphological changes in larval and juvenile stages, and rapid early growth in the young developmental stage, while the specific growth rate decreased with prolonged culture time. This study provides relevant biological information for the artificial propagation, fry rearing, and selective breeding of this species.

Abstract: Dissolved iron and low pH are widespread stressors in streams draining iron-rich soils, wetlands and former lignite-mining areas. The biological effects of ferrous iron are difficult to assess from iron concentration alone, because toxicity depends on pH, exposure duration, chemical form and species sensitivity. This study examined the combined effects of dissolved ferrous iron (Fe²⁺) and pH on the survival of brown trout (Salmo trutta), common dace (Leuciscus leuciscus) and European eel (Anguilla anguilla) exposed in flow-through cages in Danish lowland streams.Groups of five fish were exposed under field conditions, and survival was recorded after approximately one week and one month. Mean Fe²⁺ concentration and mean pH during each exposure period were related to survival using observed Fe²⁺–pH distributions and binomial generalised linear models. The final dataset comprised 128 one-week and 102 one-month observations for brown trout, and 21 observations for each exposure period for common dace and European eel.Brown trout showed the clearest response. Survival decreased consistently with increasing Fe²⁺ concentration and decreasing pH after both one week and one month. Common dace showed a more variable response, with weaker statistical support, especially after one month. European eel was the most tolerant species, with high survival across much of the observed Fe²⁺–pH range, although mortality occurred under some low-pH and high-iron conditions.The results show that no single Fe²⁺ concentration can be used as a universal survival threshold. Assessment of iron-rich streams should consider Fe²⁺ concentration together with pH, exposure duration, species and life stage.

Abstract: This study integrates cohort number and biological production, food consumption, feeding ecology, growth and mortality of brown trout (Salmo trutta) in Danish lowland streams monitored over long-term periods. Increasing trout density reduced instantaneous growth rate and final body size of Age-0 brown trout while increasing within-cohort variability, demonstrating strong density-dependent growth regulation. Total cohort production and food consumption increased with recruit abundance, whereas production and consumption per recruit declined strongly with increasing density, indicating reduced individual performance under crowded conditions. Despite marked interannual variation in yearly production, total yearly consumption remained comparatively stable, suggesting an upper energetic constraint imposed by prey production and stream carrying capacity. Energetic P/C ratios differed markedly between streams, averaging approximately 0.068 in BRB and 0.142 in TJB, and declined strongly with increasing body mass. Natural mortality increased with population density but decreased strongly with body mass and consumption per individual, indicating that survival was closely linked to energetic status and cumulative growth history. Feeding analyses showed that trout in both streams fed mainly on aquatic invertebrates, and prey composition overlapped substantially between streams. Overall, the results demonstrate that production, consumption, growth and mortality are tightly interconnected through density-dependent and bioenergetic mechanisms operating simultaneously at cohort and individual levels.

Abstract: To systematically evaluate the growth heterosis and genetic characteristics of the hybrid offspring E. moara ♀ × E. tukula ♂, this study assessed the phenotypic growth pattern through a comparative breeding experiment and cytogenic and molecular genetic characteristics through integrated chromosomal karyotype and mitogenomic analyses. The results showed that at 9 months of age, the body weight of the hybrid offspring reached 137.08 ± 26.41 g, which was 1.50 times that of the maternal E. moara (91.60 ± 18.63 g), but significantly lower than that of the paternal E. tukula (178.19 ± 32.74 g), exhibiting a mid-parent growth heterosis (1.62%). The chromosome number of the hybrid offspring was 2n=48, with a karyotype formula of 2sm+1st+45t, NF=51, and an intermediate chromosomal composition between the parents. The mitochondrial genome was 16,405 bp, and its gene composition, arrangement order, base composition and codon usage preference were highly consistent with those of E. moara. A phylogenetic analysis further supported that its mitochondrial genome strictly followed maternal inheritance. This study provides a theoretical foundation for evaluating the breeding potential and germplasm characteristics of E. moara ♀ × E. tukula ♂ hybrids.

Abstract: Adult crayfish P. leniusculus originating from wild stocks of northwestern Greece, Epirus County, were randomly allocated in indoor RAS aquaria, following two dietary protocols: a semi-purified diet by total substitution of fish oil and entire substitution of fishmeal with plant-derived materials, and a control diet consisting of fresh Pangasianodon spp. and mixed vegetables. The semi-purified diet had a P: E ratio of 22.74 mg Prot. kj-1, a Protein level of 38.68% and a Crude Lipid level of 9.51% (on a DM basis), while the control diet had a P: E ratio of 22.13 mg Prot. kj-1, a Protein level of 37% and a Crude Lipid level of 4.5% (on a DM basis). Despite the total substitution of corn oil by soy oil, the exclusion of fish oil and the entire substitution of fishmeal by other plant-derived materials, the semi-purified diet did not hinder growth throughout the experiment with acceptable survival rates. It has also been demonstrated that the signal crayfish P. leniusculus has limited dietary requirements for the PUFAs EPA & DHA and that dietary linoleic and linolenic acids are indispensable for the species. Finally, the ability of signal crayfish for bioconversion of EPA to DHA remains questionable.

Abstract: Tenacibaculosis, caused by Tenacibaculum maritimum, remains a major bacterial disases affecting marine aquaculture, particularly European seabass farming. This study evaluated the immune response and efficacy of a formalin-inactivated T. maritimum vaccine administered by immersion or intraperitoneal (i.p.) injection in European seabass (Dicentrarchus labrax). Fish were challenged 36 days post-vaccination. Vaccine performance was assessed by relative percent survival (RPS), expression of immune markers (IL-1β, IL-10, IgT), and specific IgM production. Intraperitoneal vaccination provided significant protection, with 87% survival and an RPS of 67.5, accompanied by elevated serum IgM levels and strong systemic immune activation. Immersion vaccination resulted in complete survival under the experimental conditions; however, low mortality in the control group prevented reliable assessment of vaccine efficacy. Gene expression analysis revealed distinct immune profiles: immersion vaccination induced rapid but transient mucosal and systemic responses, whereas i.p. vaccination elicited stronger and more sustained systemic responses, particularly in innate and humoral pathways. Principal component analysis confirmed clear separation of immune responses according to vaccination route. Overall, i.p. vaccination induced stronger protective immunity, while optimization of immersion vaccination protocols is needed to improve protection against tenacibaculosis in European seabass.

Abstract: The taxonomic composition and zoogeographic characteristics of the malacofauna of the upper Konda River basin, a major left tributary of the Irtysh River within the taiga zone of Western Siberia, were identified. A total of 27 species of freshwater mollusks were recorded, including 19 bivalves and 8 gastropods. In terms of taxonomic structure and species composition, the malacofauna of the upper Konda differs significantly not only from most local freshwater mollusk faunas of Western Siberia but also from the middle reaches of the same river system. This indicates the impossibility of directly applying the River Continuum Concept in this case. The greatest genetic relationship between the populations of the studied species in the study area and populations from European Russia and Europe is demonstrated. Not all populations had similar haplotypes; in some cases, intrapopulation haplotypes differed significantly. The results of testing the a priori classification of water bodies based on the composition of malacocenoses indicate a lack of reliable support. A typology of freshwater mollusk habitats in the upper reaches of the Konda River basin is proposed, based on patterns of their distribution across environmental gradients.

Abstract: Invasive species are managed to mitigate ecosystem effects; however, unintended consequences from suppression may result. Investigating effects of management actions on lower trophic levels and nutrient dynamics can help avoid unintended consequences. Fish carcasses were deposited in the littoral zone in Yellowstone Lake, Wyoming, U.S.A. during autumn to suppress embryos of invasive trout at spawning sites. We studied the degree to which adding carcasses to the littoral spawning sites indirectly benefited invasive trout by altering food resources. We used carcasses as a natural isotopic tracer to estimate the degree to which carcasses were integrated into the food web. We compared basal resource and amphipod δ15N and δ13C signatures at reference and treatment sites. We also estimated the contribution of carcasses to amphipod diet, and the contribution of amphipods to invasive and native trout diets using stable isotope mixing models. Isotopic signatures of basal resources did not differ between treatment and reference sites. Amphipod isotopic signatures changed after treatment, but &lt; 3% of amphipod diet was carcass. Amphipods contributed &lt; 24% of estimated diet for invasive trout, but &gt; 55% of estimated diet for native trout. δ13C values of amphipods and phytoplankton increased at reference and treatment sites after autumn turnover suggesting carcass material was distributed throughout the lake. Unused carcasses from gillnetting discarded in the profundal zone since 1995 appeared to influence nutrient dynamics more than those added to the littoral zone. We demonstrate that investigating food web dynamics simultaneously with suppression to prevent unintended consequences can aid in developing effective management plans that minimally alter ecosystems.