Aquatic Conservation-Marine and Freshwater Ecosystems最新文献

The Sea of Marmara, connecting the Black Sea and the Aegean Sea, experiences a two-layer current system due to density disparities. Unfortunately, pollution has emerged as a significant problem, resulting in diseases and abnormalities in animals, particularly fish. Monitoring studies have uncovered a significant deterioration in the environmental conditions of the Sea of Marmara. This study presents a multidisciplinary assessment of the Sea of Marmara conducted between August 2021 and August 2022. In this study, the cases that develop after the massive mucilage phenomenon due to plankton blooms observed throughout the Sea of Marmara are discussed. The study identified predominant bacterial species in mucilage aggregate, seawater, sediment and fish samples, emphasising Vibrio spp., focusing on Merluccius merluccius and Trachurus trachurus. The examination involved a total of 7392 samples, with detailed analyses of length–weight relationships, condition factors, gonadosomatic and viscerosomatic indices and microbiological and ichthyopathologycal aspects. Non-alcoholic fatty liver disease (NAFLD) was observed at various stages in almost all of the species sampled within the scope of the study. Depending on this, T. trachurus exhibited negative allometric growth (b = 2.8288), with males (b = 2.7948) and females (b = 2.8538) following this trend. M. merluccius also showed negative allometric growth (b = 3.0696), with males (b = 2.9755) and females (b = 3.2829) displaying growth types. Pollution from various wastewater sources poses a substantial threat to the biodiversity and water quality of the Sea of Marmara. This situation has been further exacerbated by the occurrence of the massive mucilage phenomenon, which consists of organic components. Understanding the pathogenesis processes of marine organisms and their responses to external factors, such as pollution and changes in environmental conditions, is crucial for preserving biodiversity and ensuring the well-being of widely consumed species.

Mangrove ecosystems face increasing anthropogenic pressures, yet socio-ecological perspectives remain underrepresented in coastal research. While mangroves provide critical ecological services and support human livelihoods, studies have largely emphasised biophysical assessments, leaving governance and community dimensions insufficiently integrated. This study integrates the SoP framework with the DPSIR model to examine mangrove dynamics in Metinaro, Timor-Leste. Employing a mixed-methods design, it combined household surveys (n = 60) with participatory DPSIR mapping, enabling triangulation of quantitative indicators of place identity, dependence, attachment, policy support and participation with qualitative insights into ecological processes and governance responses. Findings revealed that place identity (mean = 4.10) and dependence (3.92) were the strongest SoP dimensions, while policy support (3.20) and participation (3.08) were weakest. Within DPSIR, pressures registered the highest mean (3.1), whereas other components clustered around 2.9. Correlation analyses showed strong interrelations among identity, dependence and attachment (r > 0.95), moderate positive links with drivers and state (r = 0.58–0.67), and negative associations with pressures (r = −0.32 to –0.37). Regression indicated that SoP significantly predicted drivers (Adj. R² = 0.478) and state (0.368), while ANOVA confirmed a gender effect (F = 5.34; p = 0.0244). The novelty of this study lies in the empirical integration of SoP with DPSIR, producing the first socio-ecological baseline for mangroves in Timor-Leste and advancing a transferable framework for small-island contexts. The study concludes that embedding cultural values and demographic factors into governance frameworks is essential for strengthening participatory management and ensuring the long-term sustainability of mangrove ecosystems.

Ottelia cordata (Wall.) Dandy, an endangered tropical aquatic macrophyte, exhibits obligate sexual reproduction for population persistence. However, the absence of empirical data on seed storage and germination hinders evidence-based conservation. This study focuses on the optimal seed storage methods, germination requirements and key factors enhancing germination for O. cordata seeds to advance both ex situ conservation and original habitat vegetation restoration efforts. The results showed that 4°C-Water storage of O. cordata seeds was optimal for maintaining seed viability (> 90% after 14 months). Germination occurred maximally at 25°C–30°C under photic conditions and exclusively on sediment surfaces. For the first time, we found that both a simple 12-h desiccation pretreatment and the natural fruit mucilage markedly enhanced seed germination, revealing two previously unrecognised factors promoting germination in aquatic macrophytes. Notably, we observed a positive density-dependent germination response: high-density sowing enhanced germination by 40%–75% relative to isolated seeds treatment—contrasting with the commonly reported negative density dependence in many terrestrial species. These findings suggest the following conservation strategies: (1) establish ex situ conservation collections via 4°C-Water storage, (2) precondition seeds using a 30°C desiccation treatment, (3) sow seeds at the sediment–water interface in photic zones during 25°C–30°C temperature regimes, and (4) apply clustered sowing or mucilage amendments to exploit density-dependent enhancement. This framework provides a scientific foundation for conserving the endangered aquatic plant O. cordata and restoring its populations in degraded aquatic ecosystems.

Over the past three decades, the ecosystem of the Caspian Sea (CS) has undergone serious changes, which are consequences of human activity, climate change, changes in sea level and the invasion of the ctenophore Mnemiopsis leidyi, which has disrupted trophic interactions and fisheries productivity. This study investigates long-term changes in the macrobenthic community structure of the CS for 25 years, looking especially at the impacts of exotic species and environmental variability. Fifty-three macrobenthic taxa belonging to 18 families and Oligochaeta were recorded in the following three sampling periods: 1996–1997, 2010–2011 and 2018–2019. Species richness and abundance declined markedly, with both indices reduced to less than one-third in the final period. The exotic polychaete Streblospio gynobranchiata became the dominant species in the second and third periods, replacing Hypaniola kowalewskii, which prevailed in the first. Diversity indices fluctuated strongly, with the highest values observed in 1996–1997. Multivariate analyses indicated that depth and environmental shifts (salinity, dissolved oxygen, pH, nutrients) contributed substantially to community changes, highlighting the multifactorial nature of ecosystem dynamics. PCA and dbRDA identified salinity as the primary driver in the community, followed by DO, pH and depth. The DisTLM model explained 76.9% of species variation, although changing the sampling design may introduce uncertainty. Findings suggest invasive species, combined with environmental stressors, have caused dramatic ecological reorganization of the benthic ecosystem. The study highlights the need for adaptive management strategies to mitigate biodiversity loss and preserve ecosystem function in the face of ongoing anthropogenic and climatic pressures.

The noble crayfish, Astacus astacus, is a globally threatened species experiencing population declines throughout Europe. Despite its conservation status, genetic diversity patterns remain poorly characterized across its distribution, particularly in Eastern Europe. Here, we address this knowledge gap through mitochondrial (16S rDNA and COI) and microsatellite (19 loci) analyses of Belarusian populations. Our results reveal that these populations belong to previously described mitochondrial lineages 1 and 2 sensu, identifying seven mtDNA haplotypes (five novel), with the highest diversity concentrated in the Neman River catchment. This catchment not only represents a regional biodiversity hotspot but also exhibits the highest mtDNA diversity recorded for A. astacus across the entire Baltic Sea watershed, suggesting its role as a post-glacial colonization corridor from the Black Sea basin refugium. This unique diversity now constitutes a priority for conservation. Microsatellite analyses demonstrated limited within-population diversity but strong differentiation among populations, indicating severe genetic erosion in isolated groups. Our analyses support a hierarchical conservation framework with two Evolutionarily Significant Units (ESUs) corresponding to the Baltic and Black Sea basins, and multiple Management Units (MUs) within river catchments, which has direct implications for conservation management. Populations from lotic environments exhibited significantly higher genetic diversity than lentic ones, highlighting the vulnerability of these lentic populations. We strongly recommend catchment-specific conservation strategies, particularly regarding translocations, to preserve A. astacus's unique local adaptations and genetic integrity, and to prevent genetic homogenisation. We also propose considering within-catchment genetic rescue efforts for small, inbred populations. These strategies are critical to preserving A. astacus's adaptive potential and preventing regional extinctions.

Marine Protected Areas (MPAs) are central to global biodiversity strategies, including Senegal's 30×30 commitment. The Cayar MPA, designated as IUCN Category VI and established over two decades ago, was intended to conserve biodiversity while supporting sustainable small-scale fisheries. However, its partial protection status, lack of enforced no-take zones, and weak ecological connectivity pose challenges to achieving these goals. This study assessed the long-term effectiveness of the Cayar MPA using a mixed-methods approach that combined analysis of official fisheries catch data (2007–2016) with field surveys of 400 artisanal fishers and in-depth interviews with 35 stakeholders. The findings revealed limited ecological and socioeconomic outcomes. Fish catches declined by 36.5%, accompanied by the disappearance of several commercial species. Despite existing regulations, destructive fishing practices persisted, and 68% of surveyed fishers reported no improvement in income. Moreover, 85.5% of respondents reported increased conflicts over fishing grounds, mainly between artisanal fishers and industrial processors. Many community members perceived the MPA as a constraint rather than a benefit. Three governance failures explained these outcomes: weak enforcement of regulations, insufficient action against illegal fishing, and limited community participation in decision-making processes. Consequently, the Cayar MPA has fallen short of its conservation and socioeconomic objectives. To enable MPAs in developing countries to balance biodiversity conservation and livelihoods, reforms are needed. These include greater integration of local communities in co-management, stronger alignment between fisheries and conservation policies, and the promotion of alternative livelihood programs. Without such changes, MPAs risk exacerbating socioeconomic tensions while failing to achieve ecological recovery.