Conservation

Seagrasses are vital ecosystem engineers and habitat architects in coastal environments, with Posidonia oceanica in the Mediterranean playing a crucial role as an indicator of ecological health. As an endemic and vulnerable species, P. oceanica meadows are highly susceptible to environmental degradation, underscoring the importance of non-destructive monitoring techniques. Traditional SCUBA-based surveys are accurate but resource-intensive and difficult to scale, especially for estimating shoot density and leaf length. This study applies a conservative acoustic-based approach to assess Posidonia oceanica biometrics, habitat characteristics, and ecological status along the Turkish Levant coast. The method offers a non-destructive alternative to SCUBA surveys and addresses a regional knowledge gap in Mediterranean seagrass monitoring. Acoustic data collected during winter and summer 2019 along the Turkish Levant coast were analyzed to estimate seagrass biometrics and derive ecological indicators, with validation via SCUBA observations. Results show that acoustic methods can reliably estimate shoot density, leaf area index, and canopy height. They provide broad-scale coverage and efficiency, though further refinement is required to improve calibration across depths and substrates. While acoustic methods provide broad, non-invasive coverage, they are affected by spatial and temporal variability that SCUBA surveys capture more reliably. Calibration of the POSIBIOM (vers 1.1) algorithm was based on specimens collected at 15 m depth on rocky substrates. While this provided consistent regression relationships, it may limit accuracy when extrapolated to habitats such as sand, mud, or matte. This study represents the first high-resolution, spatiotemporal mapping of P. oceanica meadows and benthic habitats along a significant portion of the Turkish Levant coast using acoustics alone. Overall, the study highlights the potential of acoustics as a scalable, non-invasive tool for seagrass monitoring. This approach contributes to ecosystem-based management and conservation strategies in the Mediterranean. Future work will focus on refining models to address bottom type- and depth-dependent acoustic responses and improve biometric accuracy. Full article

The knowledge base for many small vertebrate species remains limited, largely because traditional manual data collection methods often overlook less charismatic species, such as reptiles. To address this, our pilot study harnesses open-source deep learning and markerless pose estimation technologies to evaluate the technical feasibility of tracking the spatial use and activity profiles of captive ectotherms. Specifically, we tracked these patterns over two months in a dynamically modified environment for Australian barking geckos (Underwoodisaurus milii). Our findings reveal descriptive changes in spatial occupancy and proximity across varying structural layouts. The system achieved a high raw detection accuracy (96.4%) and spatial categorization accuracy (91.7%) when validated against manual ground-truth data, confirming its robust technical performance and precision. Additionally, we automatically evaluated spatial proxies such as activity time budget, velocity, acceleration, and height usage, standardizing the analysis of extensive video recordings for nocturnal species. This pilot test introduces a simple, cost-effective method for rapid data extraction, offering a reliable, scalable monitoring solution for the management of understudied species. Full article

The Carpathian Mountains are an important hotspot of European biodiversity, where geological history, climatic diversity, and altitudinal heterogeneity have determined a great diversity and endemism of vascular plants. The study was conducted in the national park of Piatra Craiului, a distinctive limestone massif in the Southern Carpathians. The dataset included 731 vascular plant species from the study area, of which 35 taxa are endemic to the Carpathians (of the 47 reported in this area), and 18 are classified as species of conservation interest in the Management Plan of the National Park (MP). The distribution of endemic species showed different habitat and altitudinal specificity across 15 vegetation types, including 14 Natura 2000 habitats and one outside the EUR 28 classification. The endemic species showed a bell-shaped altitudinal distribution, peaking at 1600–1700 m and concentrated in high-altitude open habitats rather than forested mid-elevations. The PCA separates endemic species along a main gradient from open, disturbed, light-rich habitats to stable, nutrient- and moisture-rich forest environments, and a secondary gradient related to temperature and soil reaction linked to altitude. Endemic species are predominantly associated with calcareous rocky and grassland habitats and are almost absent from mesophilic and hygrophilous habitats. A positive association between endemic species frequency and the total number of species of conservation interest per plot was detected. We concluded that species of conservation interest (such endemic species) are unevenly distributed among habitat types in the Carpathians, with the greatest diversity and abundance in subalpine rocky and grassland habitats, shaped by altitude and isolation. Although the threatened endemic species are not officially listed by national law, they are indirectly protected by management zonation. In Piatra Craiului the richest habitats in endemic species are included in the designated zones of the national park with the highest protection regime, according to the National Park’s Management Plan. Moreover, this territory is included in a Natura 2000 site (ROSAC0194 Piatra Craiului) ensuring an additional level of protection for the habitats where endemic species are found. Full article

The Anatolian Diagonal is a major mountain system in Türkiye, yet its community-level structuring effect on mammalian assemblages remains understudied. This study provides a comprehensive inventory of the mammal fauna in Ağrı Province and evaluates the biogeographical role of the Diagonal by comparing 14 provinces. Field surveys in Ağrı (2014–2015) across 228 localities identified 16 medium- and large-sized mammal species (705 individuals), including Felis silvestris as a new provincial record. Community structure followed a lognormal distribution (AIC: 95.29). Regional patterns were analysed using presence–absence data on medium- and large-sized mammals using alpha and beta diversity indices, PERMANOVA, and Partial Canonical Correspondence Analysis (PCCA). PERMANOVA revealed significant differences in mammal assemblages between the western and eastern sides of the Diagonal (F = 3.08, R² = 0.19, p = 0.007). Beta diversity was driven predominantly by species turnover (83.8%) rather than by nestedness (16.2%). Notably, PCCA confirmed that biogeographical position significantly influenced community variation independently of habitat, elevation, and slope. These findings support a biogeographical filtering effect associated with the Anatolian Diagonal, where species replacement drives diversity patterns. The results emphasize the necessity of trans-regional conservation strategies that account for the distinct faunal compositions across this evolutionary boundary. Full article

Spain is the world’s leading producer and exporter of olive oil, with Andalusia being the autonomous community with the largest cultivated area. In recent decades, agricultural practices have followed a trend toward maximizing production without adequately considering ecosystem contamination. Olive groves are, in fact, complex agroecosystems in which thousands of plant species and numerous plant communities have been documented, supporting a rich diversity of vertebrate and invertebrate fauna. Intensive and unsustainable practices have led to a decline in floral diversity and, consequently, in faunal diversity. The aim of this research is to demonstrate the loss of floristic diversity associated with herbicide use. To this end, a comparative analysis of floristic diversity was conducted across 117 plots, contrasting data collected in 2007 with that from the same plots in 2021. From a methodological perspective, an inquiry-based approach was implemented involving students from the Master’s program in Olive Growing, Olive Oil, and Health. Abundance–dominance indices were compared, and the Importance Value Index (IVI) was calculated to assess changes in plant community composition. For instance, Hordeum leporinum exhibited an IVI > 70 in 2007, decreasing in 2021 to values ranging between 11 and 31.58. Similarly, Sinapis alba subsp. mairei showed a decline in IVI from 81.06 to 26.35. A notable result is the greater floristic change observed in plots located on basic substrates where herbicides were applied, compared to plots on siliceous substrates designated for grazing. This issue clearly highlights a lack of knowledge regarding appropriate cultivation techniques that promote sustainable development and social awareness. It underscores the need for educational interventions that foster learning at all levels about agricultural practices, sustainability, and ecosystem services. Full article

Kenya has a long history of both legal and illegal wildlife trade, functioning as a source, consumer, and transit hub within global wildlife markets. Yet, despite its increasing prominence, the scale and composition of Kenya’s captive-bred and ranched wildlife trade sectors remain poorly characterized, particularly following the enactment of the Wildlife Conservation and Management Act (WCMA) in 2013. This study addresses this gap by analyzing Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) annual report data from 2013 to 2023 to: (1) identify trends in the volume and taxonomic composition of CITES-listed species exported as captive-bred or ranched from Kenya; (2) quantify the number of specimens and individuals traded; (3) assess their conservation status and legal classification; and (4) identify key export destinations. Between 2013 and 2023, Kenya reported 886 CITES export records involving captive-bred and ranched specimens from 28 vertebrate taxa across nine orders. Reptiles dominated exports (81% of records), followed by birds (15%) and mammals (4%). Live animals accounted for 80% of records (with reptiles comprising 96.1% of all live animal export records), totaling more than 870,000 individuals traded over the study period. The annual number of export records more than doubled across the decade, while exports of individual live reptiles increased more than tenfold, from 8551 individuals in 2013 to 86,330 in 2023. Most exports were commercial (93%) with the United States, Germany, Spain, Taiwan, and the Republic of Korea identified as major importers. 77% of exported species have unknown or declining wild population trends, and seven species are internationally threatened, including the Critically Endangered pancake tortoise (Malacochersus tornieri). We highlight the animal welfare, conservation, and biosecurity implications of this rapidly expanding trade, as well as consistent discrepancies between exporter- and importer-reported quantities that indicate substantial monitoring and regulatory challenges. The findings provide timely evidence to inform national wildlife management and protection measures, and ongoing policy discussions including those surrounding the forthcoming Wildlife Conservation and Management Bill (2025) and the role of captive breeding in Kenya’s wildlife trade. Full article

Invertebrates possess an innate immune system that acts non-specifically against pathogens and is regulated by the circadian clock. Using the host–parasite system, Daphnia magna and its bacterial parasite Pasteuria ramosa, we investigated day–night differences in susceptibility. In an infection experiment where hosts were exposed to spores either during the day or night, infection was slightly higher during daytime exposure and in animals treated with exogenous melatonin. Daphnia exhibited rhythmic expression of five immune genes, with low daytime expression and a pronounced, synchronized peak immediately after the transition from day to night. This timing aligns with the documented increase in daytime susceptibility, which may benefit Pasteuria as encounter rates rise when Daphnia forage in sediment during diel vertical migration. Melatonin exposure altered immune gene expression and increased susceptibility both day and night. Melatonin can act as an immune suppressor and may also influence parasite spore maturation. Disruption of circadian rhythms and melatonin signaling by anthropogenic stressors alters the infection dynamics in this freshwater keystone organism, with consequences for population stability, ecosystem functioning, and the conservation of freshwater biodiversity. Our results spotlight the mechanisms underlying infection risk in host–pathogen systems, highlighting the importance of circadian regulation for disease dynamics in freshwater ecosystems. Full article

Soils contaminated with heavy metals including cadmium, lead, zinc, copper, and chromium continue to represent a significant environmental issue, particularly in areas affected by industrial activities. In this context, the present study aimed to assess the feasibility and efficiency of an integrated bioremediation technique that combines, in a synergistic approach, phytoremediation with the use of natural amendments in order to reduce soil pollution with heavy metals. In addition, the potential for heavy metal recovery was investigated. The experiments were conducted under field conditions in the vicinity of the CET II Holboca power plant, using two plant species, Trifolium repens and Brassica napus, as bioaccumulators, while biochar was applied as a natural amendment. The analyses focused on metal concentrations, translocation factors, the degree of heavy metal recovery, and morpho-structural characteristics. The results indicated a high accumulation of metals in plant roots, particularly in soils treated with higher doses of biochar (4905.93 mg/kg iron for B. napus), and a significant growth stimulation (root elongation increases of up to 78% in T. repens and up to 29% in B. napus). B. napus exhibited greater translocation of metals to the aerial parts (with values up to 0.83 for zinc), whereas T. repens predominantly retained metals within the root system. The highest recovery efficiency values were observed in the case of lead, reaching 224.7% in T. repens and 86.7% in B. napus in soil amended with increased amounts of biochar. Overall, biochar application stimulated plant growth and enhanced metal uptake efficiency, suggesting a viable and practically applicable method for the ecological reconversion of contaminated land. Full article

This scientometric review examines the evolution and scope of invasive (blood and tissue) and non-invasive (faeces, hair, and saliva) sampling in terrestrial mammal population genetics, with particular emphasis on the comparability of observed heterozygosity (Ho), expected heterozygosity (He), and the inbreeding coefficient (Fis) between studies published from 1985 to 2026. Searches in Web of Science and Scopus, filtered under PRISMA/PRISMA-S criteria, yielded a compendium of articles analysed with Bibliometrix and VOSviewer 1.6.20 to quantify temporal production, keyword evolution, collaborative networks, and publication outlets. Searches in Web of Science and Scopus, filtered under PRISMA/PRISMA-S criteria, yielded a broad corpus of 145 articles for general scientometric analyses, of which 85 met the eligibility criteria for the focused analysis of Ho, He, and Fis. The field shows steady growth (annual rate ≈ 6.1%), substantial authorship and international collaboration, and increasing thematic diversity. Adoption of non-invasive sampling has accelerated, broadening spatial and taxonomic coverage, but also increasing exposure to DNA degradation and genotyping error when laboratory quality control is insufficient. Across the literature, reporting of quality control practices (e.g., extraction blanks, negative PCR controls, multi-tube replication, and error-rate estimation) has improved over time but remains inconsistent. Comparisons indicate that differences in Ho, He, and Fis between invasive and non-invasive sampling are generally modest once marker system and species are taken into account. These findings indicate that quality control and transparency in reporting, rather than invasiveness per se, are the main factors determining comparability among studies. The scientometric patterns also reveal a methodological transition from microsatellites to SNP-based and reduced representation approaches, with implications for synthesis across marker types. Overall, this review identifies geographic and taxonomic biases in research effort and highlights the need for standardised reporting of DNA quality indicators, inclusion thresholds, and validation protocols to strengthen genetic monitoring in mammalian conservation. Full article

The Andean walnut (Juglans neotropica Diels), locally known as tocte, is a keystone tree species of major socio-ecological importance in South American mountain ecosystems, facing severe anthropogenic pressure associated with genetic erosion, habitat fragmentation, and unregulated selective logging. This article presents a case study applying a qualitative phenomenological approach to examine the power relations and institutional failures shaping the sustainable management of its value chain in Imbabura Province, Ecuador. Drawing on 21 in-depth semi-structured interviews with key actors (including woodcarvers, sawyers, traders, and environmental authorities) conducted between March and September 2025 until theoretical saturation was achieved, and supported by thematic analysis in ATLAS.ti, we identified five thematic categories revealing the tension between cultural valuation and market pressure. The findings confirm the existence of a value paradox, whereby high timber demand paradoxically accelerates resource depletion rather than incentivizing conservation, as premature harvesting of young trees undermines the viability of non-timber forest products such as nuts and accelerates the loss of local genetic resources. We conclude that the long-term conservation of the species requires a transition toward polycentric stewardship, community forestry enterprises, and integrated landscape management in which the standing tree is formally recognized as carrying greater ecological and economic value than harvested timber. Full article

Costa Rica is a small country in terms of land area, but it is rich in natural resources and home to between 5 and 6 percent of the world’s biodiversity. The country is a leader in the conservation and sustainable use of protected areas through tourism, which is considered a pillar of the national economy and has become one of the most important activities for generating revenue. However, like any other activity, it can exert pressure on the environment in which it takes place, making it essential to analyze and understand how protected areas are used to implement effective management strategies. This study evaluates the frequency of tourism-related use of Corcovado National Park, considering the implementation of three key elements: 1. the frequency with which companies use the park for their tourism activities, 2. visitor density per kilometer by ranger station, and 3. the frequency of trail use based on voluntary geographic information. The research enabled the collection, analysis, and visualization of data using GIS, which facilitated the identification of tourism usage patterns by highlighting the most visited areas and establishing correlations regarding visitor density within the protected area. Among the most significant findings are sites that may be experiencing increased tourism pressure, offering the possibility of managing usage restrictions in specific areas of each station. Spatial analysis has identified areas with lower visitor concentrations, which can be leveraged to promote new attractions and disperse tourist flow throughout the park, thereby reducing pressure on the ecosystem. Full article

Coastal beach–dune systems along the Western Black Sea Coast represent geomorphologically complex and ecologically valuable environments that have been increasingly affected by long-term urbanisation and recreational pressure. This study examines the geomorphological settings, sedimentary connectivity and associated Natura 2000 dune habitats within two urbanised beach–dune systems, Pobeda (Burgas) and Asparuhovo (Varna), to improve their cadastral documentation and support objective conservation assessment. The analysis is based on high-resolution UAS-LiDAR surveys, complemented by UAS photogrammetry and field observations, allowing detailed three-dimensional characterisation of dune landforms, surface morphology and habitat patterns. The results identify foredune-dominated system architectures in both study areas, with the Pobeda (Burgas) and Asparuhovo (Varna) beach–dune systems comprising embryonic dunes, established foredune ridges and low-relief foredune plains, variably developed and spatially fragmented as a result of long-term urbanisation and recreational pressure, and spatially associated with dune habitats. Despite substantial anthropogenic modification, these elements remain recognisable, although locally fragmented and morphologically degraded. Subtle topographic changes related to trampling, informal access routes and surface compaction were detected, particularly affecting foredune crests and foredune plains, with implications for sediment transport continuity and habitat stability. The study shows that conventional habitat inventories alone are insufficient for capturing such changes. Integrated geomorphological and habitat analysis based on UAS-LiDAR provides a reliable framework for accurate mapping, conservation status assessment and informed consideration of coastal dune systems within the Natura 2000 network and related protection schemes. Full article

Assessing individual animal health is essential for detecting early ecological stress that may scale to population-level impacts. Yet, conventional capture-based methods are invasive and logistically challenging, particularly for large mammals. This study evaluates the accuracy of drone-based morphometric measurements as a non-invasive approach for estimating elephants’ Body Condition Index (BCI). Research was conducted in Way Kambas National Park, Sumatra, using a DJI Matrice 300 RTK equipped with a multisensor camera to acquire aerial imagery, primarily from a top-down perspective. Morphometric parameters were extracted through image preprocessing, segmentation, and edge detection using an OpenCV-based Canny algorithm, followed by coordinate and Euclidean distance analyses. Drone-derived measurements were validated against field-based morphometry in captive Sumatran elephants. Linear regression revealed strong agreement between methods, with R² values ranging from 0.91 to 0.97. Mid-body width showed the highest accuracy (R² = 0.97, MAPE = 2.66%, RMSE = 2.36), while other body dimensions also performed consistently well. BCI-related morphometric ratios exhibited minimal differences between drone and field measurements, confirming methodological reliability. As an exploratory extension, a preliminary allometric scaling framework was applied to estimate body condition proxies in free-ranging wild elephants except for mid-body width; however, these estimates are model-derived from total body length and should be interpreted as indicative rather than as direct morphometric assessments of body condition. These findings demonstrate that drone-based photogrammetry provides a validated, practical, and non-invasive method for morphometric measurement in captive elephants, with promising but as yet incompletely validated potential for application to wild populations. Full article

The urban trade in non-timber forest products (NTFPs) plays a key role in sustaining livelihoods in the Global South, while also suggesting potential pressure on resource supply systems. This study provides an integrated analysis of NTFP diversity, market structure, economic importance, and perceived drivers of resource decline in Kolwezi, a rapidly expanding mining city where such dynamics remain poorly documented. Data were collected through surveys conducted with 35 sellers across two major urban markets and 384 consumers from different neighbourhoods and analysed using descriptive and inferential statistics to examine patterns, associations, and socio-demographic influences. A total of 65 NTFP species were recorded, including 49 plant, 14 animal, and 2 fungal species, reflecting strong dependence on Miombo ecosystems. Medicinal (59.3%) and food uses dominate, with multifunctional species such as Bobgunnia madagascariensis (Desv.) J.H.Kirkbr. & Wiersama, Canarium schweinfurthii Engl., Terminalia mollis M.A.Lawson, Gardenia ternifolia subsp. jovis-tonantis (Welw.) Verdc., and Albizia antunesiana Harms, playing a central role in both household use and market supply. The trade is largely female-dominated (79.1%) and constitutes a major component of the informal urban economy, with monthly incomes ranging from USD 9 to 429.3, primarily driven by sales volume rather than unit price. However, the sector is constrained by structural and logistical limitations, including remoteness of supply areas, seasonality, and limited value addition. The perceived declining availability of high-use-value species, attributed by respondents to deforestation, mining expansion, and overexploitation, highlights perceived sustainability concerns. These pressures are perceived differently across socio-demographic groups, indicating heterogeneous understandings of environmental change. Overall, the results indicate a perceived mismatch between rising urban demand and declining resource availability, which may reflect an emerging socio-ecological imbalance between urban demand and perceived resource availability. Addressing these challenges requires integrated strategies that combine the domestication of priority species, the development of processing chains, improved infrastructure, and strengthened governance mechanisms. Such approaches are essential to reconcile livelihood support with the sustainable management of NTFPs in rapidly transforming urban landscapes. Full article

In vertebrates, corticosterone and cortisol are glucocorticoid (GC) steroid hormones central to the vertebrate stress response, but their relative contribution depends on context and life history. We used water-borne hormone sampling in lesser sirens, Siren intermedia, to examine whether corticosterone or cortisol predominates in stress responses and evaluated whether dermal secretions reliably track acute corticosterone changes. First, we measured corticosterone via dermal swabbing over a 2 h period following a hand-restraint stressor. Dermal corticosterone did not increase relative to pre-stressor baseline levels during the 2 h sampling period, suggesting that dermal measurements may not reflect acute circulating GC changes. We then measured cortisol and corticosterone across the GC profile (baseline, stressed, and recovery) using water-borne sampling techniques in juveniles. Cortisol release rates were significantly higher than corticosterone and were elevated during the recovery phase relative to baseline (p = 0.08), whereas stressed samples did not differ from baseline. Additionally, cortisol release rates were positively associated with temperature, while no effect of temperature was detected on corticosterone. Although cortisol and corticosterone were strongly correlated, cortisol responded to environmental temperatures and was repeatable, whereas corticosterone was not. Finally, we validated the use of water-borne sampling techniques to measure cortisol and corticosterone in S. intermedia. Cortisol was higher in juvenile sirens, highlighting that each GC may play functionally distinct roles across contexts. Together, these findings indicate that cortisol is the more environmentally responsive GC in juvenile S. intermedia and that water-borne sampling provides a more reliable method for assessing acute stress physiology in this species. Full article

The critically endangered fan mussel Pinna nobilis is under strict protection in the Mediterranean waters and exhibited a documented fishing history in Greece dating back to 19th and early of 20th centuries. The present study examined historical documentary evidence from Greek archives, technical reports, and oral testimonies to reconstruct traditional fishing methods and their ecological implications. Historical records revealed the widespread use of specialized fishing tools called “pinologos”, a Y-shaped iron attached to a wooden poles, deployed primarily in shallow waters (2–7 m depth) across various Greek coastal regions in the Ionian and Aegean Seas. Two types of fishing gear existed, a simple Y-shaped tong and a scissor-type gear, both designed to encircle and extract individual fan mussels, through quarter-turn rotation. Fishers selectively targeted only large, established individuals of fan mussel, as small specimens with thin shells were unsuitable for this method. Historical fishing pressure on the species was spatially and size-limited, unlike current basin-wide mortality events. These findings demonstrate that structured populations persisted even under traditional exploitation, suggesting potential for recovery if contemporary threats are mitigated. Management strategies should reference historical population structures as restoration targets. Full article

Fibropapillomatosis, a disease associated with Scutavirus chelonidalpha5, commonly known as Chelonid alphaherpesvirus 5 (ChHV5), manifests as benign tumors that impair the motor, visual, and physiological functions of affected sea turtles. In this study, blood and tissue samples were collected from turtles exhibiting fibropapilloma-like lesions as well as from clinically healthy individuals. A nested PCR approach was employed to amplify the viral UL30 and UL28 genes for the detection and characterization of the virus variants. The mitochondrial control region was used to assess the relationship between the turtle population and the viral variant. Among the 19 turtles analyzed, six tested positive for ChHV5, including both symptomatic and asymptomatic turtles. Phylogenetic analysis revealed that three positive samples belonged to the Western Atlantic/Caribbean clade, whereas the other three grouped within the Atlantic clade. New oligonucleotides and probes were designed for ChHV5 qPCR detection, accounting for the globally accumulated genetic variability. The qPCR test parameters demonstrated an optimized assay with an efficiency of 101.4% and a detection limit of 2.4 genome copy equivalents (GCE)/μL. This study confirms the presence of two ChHV5 viral variants in rescued turtles from the Caribbean region of Colombia, including both clinically affected and asymptomatic individuals. Therefore, these results support the association between ChHV5 and fibropapillomatosis. Furthermore, analysis of the mitochondrial control region supports the hypothesis of horizontal transmission of the virus. A novel qPCR protocol with a synthetic control is proposed to improve early diagnosis and strengthen conservation and prevention strategies. Full article

The Round Goby Neogobius melanostomus, has been introduced and dispersed in North American waters, where it has adversely impacted native fishes. We must identify physical/chemical/biological parameters that will target the Round Goby but not have an adverse impact on native fishes if we are to control its further dispersal. Temperature is a quantifiable parameter influencing both the behavior and survival of fishes and may provide insights to predict their dispersal and survival. The temperature preference of the Round Goby was investigated in a horizontal thermal gradient. Fish were collected from LeBoeuf in Erie County, Pennsylvania, in August 2024. Round Gobies were acclimated to 5, 10, 15, 20, and 25 °C. The relationship between preference temperature and acclimation temperature was best explained by p = (0.91a) + 4.2. (R² = 0.83), where p = preferred temperature and a = acclimation temperature. When acclimated to 25 °C, three fish swam into water at 30 °C and immediately lost equilibrium. The final preferred temperature was estimated to be 26.5 °C. The difference between preferred temperature and acclimation temperature for most temperate fishes decreases as acclimation temperature increases. This trend was not observed for the Round Goby. Full article