Aquatic Ecology最新文献

Aquaculture is a rapidly growing industry that plays a crucial role in meeting the global demand for seafood. However, intensive aquacultural farming practices present significant challenges, including disease outbreaks, environmental pollution, and the development of antibiotic resistance. In recent years, the use of plant-derived bioactive compounds has emerged as a promising alternative approach to address these challenges. Plant bioactive compounds demonstrate diverse therapeutic and regulatory properties that make them particularly suitable for aquaculture applications. This review article aims to provide a comprehensive overview of the potential and application of plant bioactive compounds in aquaculture. It categorizes major classes of these compounds and evaluates their benefits in enhancing fish health, growth performance, and water quality. The review also discusses the challenges and limitations associated with the use of plant bioactive compounds in aquaculture while identifying critical knowledge gaps that require further investigation. By summarizing existing research and identifying future research directions, this article provides essential guidance for researchers, aquaculture professionals, and stakeholders pursuing the sustainable and innovative use of plant-based solutions in aquaculture farming practices.

The Allis shad (Alosa alosa L.) is a diadromous fish distributed along the coastal areas from Germany to Portugal. After approximately five years at sea, adults migrate upstream for hundreds of kilometres to reach spawning grounds in the middle and upper sections of river catchments, where they reproduce. Photoperiod is a key environmental factor, known to influence fish reproduction in temperate regions. This study examines the influence of photoperiod on the nocturnal spawning of Allis shad in the Loire River catchment (France). Results reveal a consistent spawning dynamic across the locations where it occurs in the study area, with activity beginning 1 h and 45 min before the start of dark night, peaking at 2 h after the start of dark night, and ending at 6 h after the start of dark night, with a total activity duration of 7 h and 45 min. However, variations in spawning dynamics were observed throughout the spawning season, with significant differences between long and short nights. Specifically, spawning dynamic was shorter and more intense during short nights, while it was longer and more moderate during long nights. These findings highlight the role of photoperiod in regulating the spawning dynamics of Allis shad.

Studies on large branchiopods, crustaceans that inhabit temporary waters in Bosnia and Herzegovina, are relatively rare. Recently published data from the Ramsar site “Bardača Wetland” and the neighboring area of Donja Dolina revealed the presence of nine species. The nine-year study included the investigation of environmental gradients in regularly flooded and non-flooded areas where species occur, including 28 ephemeral sites. The ordination of environmental factors, species and samples on the space defining the first two CCA axes, as well as post-hoc test analyses, confirmed a significant influence of inundation. Conductivity, temperature and oxygen are the most important factors for species distribution. The temperature and oxygen values were independent of each other in the ordination. The position of species on the CCA axes revealed different patterns and in some cases was dominated by a single variable—conductivity (e.g. Lepidurus apus, and Cyzicus sp.), while most of branchiopod taxa occupied a lower portion in the ordination. Cluster analysis of the different taxa and localities revealed a complex pattern. In most cases, there was no clear subdivision between sites and species in terms of flooding. However, some species were clearly dependent on rainfall and groundwater (Eubranchipus. (S.) grubii, Linderiella sp. and Triops cancriformis), others exclusively on flood waters (L. apus).

Larger host body size can lead to larger parasites, as more energy is available for parasite growth. However, this size-matching correlation can also be influenced by additional host and environmental factors. Here, we utilized a long-term dataset of cymothoid isopods parasitizing palaemonid prawns to investigate whether there is evidence supporting a relationship between host and parasite body traits (i.e., length, sex, weight), while accounting for the effects of season (i.e., dry and wet) and year. We also tested whether prawn body condition (i.e., Scaled Mass Index—SMI) is affected by parasitism. We compared parasitized and non-parasitized prawns by sex. Prawns were sampled seasonally over 4 years in a tropical stream in southeastern Brazil. Our analysis showed that isopod body length and weight were positively associated with host length and weight. This relationship was independent of host sex and seasonal variation, but was influenced by interannual variability. Host length and weight explained most of the variation, while environmental variability accounted for the remainder. We also showed that the SMI was reduced in parasitized individuals of both sexes, compared to non-parasitized prawns. Moreover, we found a significant difference in SMI between sexes and years, but not between seasons, when considering only parasitized hosts. The findings suggest that interannual variability and parasitism may jointly affect host energetics, shaping the dynamics of the ‘host-parasite-environment’ triad. Future research should consider interannual variability as a potentially key driver of host-parasite interactions in freshwater ecosystems.

Nitrate retention in a semi-arid watershed was assessed in parallel with the vegetation cover change from 2003 to 2013. The Soil and Water Assessment Tool (SWAT) model was used for simulating hydrology and nitrate retention in the Khemis Basin (375 km² in NW Algeria). The normalized difference vegetation index (NDVI), derived from remote sensing satellite data, demonstrated a degradation of vegetation from 2003 to 2013. Nitrate retention varied between −0.98 and 0.03 and decreased with vegetation degradation due to the mobilization and leaching of nitrates available from fertilization. The results of the principal component analysis (PCA) and the correlations among water parameters, vegetation, and nitrates indicated that organic nitrate was mobilized into the water yield from surface runoff. Furthermore, organic nitrates decreased in soil water due to mineralization. Moreover, in the semi-arid basin, evapotranspiration contributes to water loss and plays an important role in reducing water yield, which can cause an increase in nitrate concentration in the water. Nitrate from the lateral flow of the basin was the main source of nitrate retained by vegetation, in contrast to surface nitrate, which is easily leached. Basin geomorphology can have an impact on nitrate retention, especially in flatter landscapes, which tend to increase nitrate retention in the soil. According to the correlations and the simulated nitrate balance, agricultural fertilization was the main source of anthropogenic nitrates in the Khemis Basin.

To better understand the genetic diversity of local Indonesian horseshoe crab and its population structure, this is the first study to elucidate the genetic diversity and population structure of horseshoe crabs in Banyuasin estuarine waters near the Sembilang National Park based on 11 microsatellite markers. Asian horseshoe crabs (Carcinoscorpius rotundicauda, Tachypleus gigas and Tachypleus tridentatus) from three localities (Banyuasin River Estuarine (BRE), Carat Cape and Makarti Jaya) in South Sumatra, Indonesian. Our results revealed a moderate level of genetic diversity (PIC = 0.35–0.65; He = 0.36–0.69; Ho = 0–0.65) and a significant and moderate level of genetic differentiation of three localities (Fst = 0.068, P < 0.001). The population from Carat Cape showed limited gene flows (Carat Cape-Makarti Jaya and Carat Cape-BRE) differing from BRE-Makarti Jaya. The genetic structure revealed the presence of two populations. It classified as the first population contained BRE, Carat Cape and Makarti Jaya that corresponded to C. rotundicauda (90%) and T. tridentatus (10%) and the second population contained from BRE, CC and MJ, corresponded to C. rotundicauda (75%) and T. gigas (25%). The genetic information from this study should be considered for implementing of management and efficient conservation strategies for this endangered species in Banyuasin estuarine waters, Indonesia.

Ecological floating beds are an economically sustainable green technology that can effectively improve water quality. This study investigated the species and functional diversity of planktonic ciliates communities within the ecological floating beds of Sesuvium portulacastrum. The results showed that the abundance of planktonic ciliates was higher in spring and summer but lower in autumn and winter, with the lowest diversity indices observed in spring. Salinity was identified as the most influential environmental factor affecting community structure and was significantly correlated with all diversity indices. Among community traits, the presence of lorica was the strongest predictor of community structure, followed by feeding type. Most species within the community exhibited positive correlations, while negative correlations were primarily observed between the dominant genera Tintinnopsis and Strombidium. These genera displayed opposing patterns in response to environmental factors. Different ciliate groups exhibited distinct responses to nutrient levels, further highlighting the potential of ciliates as ecological indicators.

Although periphyton-based aquaculture is gaining traction, key drivers affecting periphyton dynamics in aquaculture production systems are not well documented. The study investigated the effect of different substrates, seasonality and grazing by Oreochromis mossambicus on periphyton composition in aqua dams. Three experiments were conducted. In the first experiment, net, stone, and plastic were deployed in triplicates in aqua dams. The periphyton (mainly attached algae) biomass was high on the plastic (155.40 no./ml) and net (150.63 no./ml) substrate. The net substrate was subsequently used in the second experiment to determine the seasonal variation of periphyton in aqua dams. Periphyton was most abundant in summer and winter. The dominant phylum in winter was Bacillariophyta and in summer it was Chlorophyta (mainly Scenedesmus sp.). The network analysis produced a weak connection since a few genera dominated the periphyton biomass across seasons. Periphyton abundance in summer was influenced by DO, EC, temperature, nitrogen, salinity, and transparency, while in winter it was influenced by nitrate. The third experiment was conducted in fibreglass tanks to determine the effect of O. mossambicus grazing on periphyton. Stomach and faecal analysis showed that O. mossambicus were grazing mostly on Scenedesmus across different size groups. However, the Chesson selectivity index showed no evidence of food selection. Multivariate analysis showed that season and substrates are the main factors affecting periphyton dynamics in aqua dams. Deployment of net and plastic substrate in aqua dams is recommended in order to reduce feed costs.

The present study sought to determine the phytoplankton diversity, distribution, and abundance in the Tono Dam in the Upper East Region of Ghana. Three (3) different geographical strata (SI, SII, and SIII) of the dam were demarcated for sampling across four (4) hydrological seasons (dry, pre-wet, wet, and post-wet seasons). From January to December 2020, phytoplankton samples were collected using a 53 µm mesh net, towed by a nonmotorized canoe at a speed of 0.60 ms⁻¹ against the dam’s water current. Physicochemical properties of the dam water were also assessed. A total of 25 phytoplankton species across five classes – Chlorophyceae, Cyanophyceae, Bacillariophyceae, Dinophyceae, and Chrysophyceae – were identified, with Chlorophyceae being the most diverse class (40%). Ulothrix sp. and Planktothrix sp. were consistently present in all strata of all seasons, while species like Tetraedron sp. and Volvox sp. had a more restricted presence. The highest Shannon-Weiner diversity index (H′) occurred during the wet season (1.72), and the lowest in the dry season (1.37). Species richness (SR) was high except in the pre-wet season (0.03). The evenness index (J′) was high in the wet season (0.65) and low in the dry season (0.49). Water temperature and nutrient levels varied significantly across seasons, with temperature being lowest in the wet season (26.5 ± 0.4 °C) and highest in the dry season (33.7 ± 0.3 °C). Ammonium levels peaked during the wet season (0.066 ± 0.03 mg/L). Redundancy analysis revealed correlations between phytoplankton species and physicochemical parameters. For instance, ammonium levels were positively correlated with Oscillatoria sp., dissolved oxygen (DO) with Synedra sp., and conductivity with Microcystis sp. Overall, the study confirmed the Tono Dam maintains healthy productivity levels. Effective management necessitates monitoring nutrient levels, adapting to seasonal and spatial variations, promoting sustainable agriculture, and implementing conservation strategies. These measures are essential to sustaining water quality, biodiversity, and fisheries productivity while addressing climate change impacts.

Aquatic ecosystems worldwide are increasingly threatened by eutrophication and anthropogenic disturbances, resulting in biodiversity loss and functional degradation. East Taihu Lake, a typical shallow lake in China, has experienced severe ecological stress due to nutrient enrichment and habitat alteration. We investigated the spatiotemporal patterns of macroinvertebrate communities to assess the degree of disturbance to aquatic ecosystems. Seasonal sampling was conducted across five functional areas from 2020 to 2021, including measurements of physicochemical water parameters, aquatic vegetation, and macroinvertebrate assemblages. A total of 28 species were identified, with Bellamya purificata, Limnodrilus, and Tubifex as dominant taxa. Statistical analyses revealed that water depth and aquatic vegetation coverage were the key drivers shaping community composition and diversity. Mollusks dominated in shallow, vegetated areas with high transparency, while Oligochaetes and Chlamydia were more abundant in deeper waters, reflecting tolerance to low-oxygen and eutrophic conditions. This study highlights the ecological benefits of aquatic vegetation in enhancing habitat complexity, supporting macroinvertebrate diversity, and improving water quality. These findings provide valuable scientific support for adaptive management of shallow lakes, emphasizing the restoration of aquatic plants and regulation of hydrological conditions as effective strategies to promote benthic biodiversity and longterm ecosystem resilience.