Latest Articles from Nature Conservation Latest 8 Articles from Nature Conservation https://natureconservation.pensoft.net/ Thu, 28 Mar 2024 18:08:02 +0200 Pensoft FeedCreator https://natureconservation.pensoft.net/i/logo.jpg Latest Articles from Nature Conservation https://natureconservation.pensoft.net/ Effects of anthropogenic and environmental stressors on the current status of red mullet (Mullus barbatus L., 1758) populations inhabiting the Bulgarian Black Sea waters https://natureconservation.pensoft.net/article/103758/ Nature Conservation 54: 55-79

DOI: 10.3897/natureconservation.54.103758

Authors: Ivelina Zlateva, Violin Raykov, Albena Alexandrova, Petya Ivanova, Nesho Chipev, Kremena Stefanova, Nina Dzhembekova, Valentina Doncheva, Violeta Slabakova, Elitsa Stefanova, Svetlana Mihova, Nadezhda Valcheva, Ognyana Hristova, Boryana Dzhurova, Dimitar Dimitrov, Almira Georgieva, Elina Tsvetanova, Madlena Andreeva, Ivan Popov, Mariya Yankova, Yordan Raev, Konstantin Petrov

Abstract: The red mullet (Mullus barbatus Linnaeus, 1758) is a keynote species for the Bulgarian Black Sea ecosystem and fisheries; nevertheless, existing knowledge on population status is very scarce. The present study was intended to assess the health status and adaptive potential of M. barbatus populations inhabiting the Bulgarian waters of the Black Sea. Our findings revealed that populations of M. barbatus are exposed to a variety of anthropogenic and environmental stressors. The species’ status was assessed using representative genetic, morphological, biochemical and chemical biomarkers from specimens obtained in the research area’s northern and southern regions. Based on mtDNA markers, genetic analysis revealed low haplotype and nucleotide diversity, typically observed in overexploited or “threatened” populations. Examining the morphology of the specimens revealed no discernible pattern of differentiation. Except for aluminium and chrome, metal and PAH concentrations in fish were below the regulatory thresholds. The specimens from the southern region ingested more microplastics than those from the northern region. The majority of specimens collected from the southern region also exhibited elevated levels of oxidative stress and decreased antioxidant defence, which can be interpreted as an early indication that they had reached the limits of their adaptive potential. Further research on the composite effects of the stressogenic environment on the Black Sea biota are critically needed, as well as the introduction of new indicators and thresholds at molecular and cellular levels for adequate monitoring of both the ecological state of the marine environment and its biota.

HTML

XML

PDF

]]>
Research Article Tue, 5 Dec 2023 10:22:16 +0200
Morphological and genetic characteristics of garfish Belone belone (L., 1760) (Belonidae, Teleostei) population from the southern Bulgarian Black Sea coast https://natureconservation.pensoft.net/article/113071/ Nature Conservation 54: 1-12

DOI: 10.3897/natureconservation.54.113071

Authors: Maria Yankova, Violin Raykov, Petya Ivanova, Nina Dzhembekova, Cemal Turan, Yordan Raev

Abstract: This study was conducted to investigate genetic and some morphometric and meristic characteristics of garfish Belone belone from Nesebar in the Bulgarian Black Sea coast. Twelve morphometric characters were measured, and six meristic characters were counted for each individual. Based on both sexes’ morphological and meristic analyses, no statistically significant sexual differences were observed. Additionally, DNA barcoding was done. The fragment of the cytochrome oxidase subunit I (COI) gene of mitochondrial DNA was sequenced to supplement the species identification and population diversity study. Two haplotypes were found out of 39 sequences, indicating a low level of haplotype diversity (0.146±0.072). Nucleotide diversity was also found to be low (0.00023±0.00011). The Nesebar population of B. belone requires conservation efforts, due to the highly decreased mtDNA genetic diversity.

HTML

XML

PDF

]]>
Research Article Tue, 5 Dec 2023 10:03:31 +0200
Coastal beaver, Chinook, coho, chum salmon and trout response to nearshore changes resulting from diking and large-scale dam removals: synergistic ecosystem engineering and restoration in the coastal zone https://natureconservation.pensoft.net/article/85421/ Nature Conservation 53: 61-83

DOI: 10.3897/natureconservation.53.85421

Authors: J. Anne Shaffer, Dave Parks, Katrina Campbell, Anna Moragne, Bligh Hueske, Pamela Adams, Jenise M. Bauman

Abstract: In this paper we assess long-term trends and habitat changes to understand the relationships between coastal beaver (Castor canadensis), salmon, shoreline alterations, large-scale dam removals and nearshore ecological restoration. From this work we conclude that the removal of two large scale dams in the Elwha River has benefited beaver use of the coastal zone through water quality changes that allow beaver to re-establish high-quality zones and the expansion of riparian zones that provide extensive new food resources to beaver. However, the lower river hydrodynamic processes continue to be disrupted by a 200-meter earthen dike installed by local government and landowners for flood protection in the Elwha coastal zone in the 1960’s. The dike acts as a driver of lower river geomorphology and has resulted in the formation of a large and persistent lateral bar along the lower river channel. Associated disrupted hydrodynamics are causing a critical coastal zone of the unimpounded lower river side channels to fill in. This channel habitat has decreased by 23%, with an annual average shrinkage rate of 13%, from pre-dam removal size, resulting in a decrease in both quality and quantity of nursery function for juvenile wild fish in a coastal zone that was historically documented to be the highest functioning for endangered juvenile salmon and trout. Inversely, physical changes including improved water quality in the adjacent impounded west side channel and continued expansion of riparian vegetation along the west delta lateral bar benefitted coastal beaver that recolonized the west delta after dam removals. The newly colonized coastal beaver may provide ecological engineering services to offset side channel loss as well as promote continued fish access. However recreational use was found to negatively impact beaver use of the area. We therefore recommend a series of additional ecosystem restoration actions that incorporate beaver as an ecosystem restoration component of the coastal zone. These actions include a public outreach program to encourage passive recreation measures to prevent negative impacts to beaver, and legacy, ecosystem scale restoration projects that reconnect the hydrodynamics of the west delta to complete Elwha ecosystem restoration. Together, these steps, if implemented, will result in a synergistic ecosystem restoration throughout the watershed to the benefit of the coastal ecosystem, including both beaver and salmon, as intended by the large-scale dam removal project.

HTML

XML

PDF

]]>
Research Article Tue, 18 Jul 2023 18:07:55 +0300
First insight into freshwater fish assemblages in the western part of the Endau-Rompin landscape, Malaysia https://natureconservation.pensoft.net/article/86090/ Nature Conservation 50: 265-281

DOI: 10.3897/natureconservation.50.86090

Authors: Munian Kaviarasu, Farah Farhana Ramli, Lokman Mohd Ilham Norhakim, Nursyuhada Othman, Nur Aina Amira Mahyuddin, Hidayah Haris, Nur Hartini Sariyati, Mohd Faudzir Najmuddin, Salim Aman, Salman Faris Zaharin, Muhammad Abu Bakar Abdul-Latiff

Abstract: In Malaysia, our knowledge of freshwater ecosystem and its aquatic inhabitants, particularly freshwater fish, remains inadequate, even in protected regions. It is essential to understand the composition of freshwater fish, their distribution along river gradients, and their interactions between environmental variables to develop and strategize effective conservation and management plans. Consequently, an investigation into freshwater fish assemblages in three rivers draining off from the western part of Endau-Rompin Landscape was conducted in 12 established substations. Sampling sessions were conducted from September to December 2021 in the Labis district of Johor, using multiple sampling methods along 200 meters for each substation. The environmental variables were measured using water quality parameters. A total of 66 species were collected. The family Cyprinidae presented the highest species diversity (17 species), constituting 52% of total capture. Crossocheilus obscurus was the most dominant species, and the highest species richness was recorded in the Segamat River (45 species), followed by Juaseh (36 species) and Labis River (34 species). It was discerned that the composition of fish varied between the substations. The knowledge presented here is the first documentation on the freshwater fish from these rivers. It would serve as a baseline information for key authorities and stakeholders to conserve the biodiversity inhabiting freshwater ecosystems in Malaysia.

HTML

XML

PDF

]]>
Research Article Fri, 16 Dec 2022 15:16:46 +0200
Genetic diversity and morphological characterisation of three turbot (Scophthalmus maximus L., 1758) populations along the Bulgarian Black Sea coast https://natureconservation.pensoft.net/article/64195/ Nature Conservation 43: 123-146

DOI: 10.3897/natureconservation.43.64195

Authors: Petya Ivanova, Nina Dzhembekova, Ivan Atanassov, Krasimir Rusanov, Violin Raykov, Ivelina Zlateva, Maria Yankova, Yordan Raev, Galin Nikolov

Abstract: Turbot (Scophthalmus maximus L., 1758) is a valuable commercial fish species classified as endangered. The conservation and sustainability of the turbot populations require knowledge of the population’s genetic structure and constant monitoring of its biodiversity. The present study was performed to evaluate the population structure of turbot along the Bulgarian Black Sea coast using seven pairs of microsatellites, two mitochondrial DNA (COIII and CR) and 23 morphological (15 morphometric and 8 meristic) markers. A total of 72 specimens at three locations were genotyped and 59 alleles were identified. The observed number of alleles of microsatellites was more than the effective number of alleles. The overall mean values of observed (Ho) and expected heterogeneity (He) were 0.638 and 0.685. A high rate of migration between turbot populations (overall mean of Nm = 17.484), with the maximum value (19.498) between Shabla and Nesebar locations, was observed. This result corresponded to the low level of genetic differentiation amongst these populations (overall mean Fst = 0.014), but there was no correlation between genetic and geographical distance. A high level of genetic diversity in the populations was also observed. The average Garza-Williamson M index value for all populations was low (0.359), suggesting a reduction in genetic variation due to a founder effect or a genetic bottleneck. Concerning mitochondrial DNA, a total number of 17 haplotypes for COIII and 41 haplotypes for CR were identified. The mitochondrial DNA control region showed patterns with high haplotype diversity and very low nucleotide diversity, indicating a significant number of closely-related haplotypes and suggesting that this population may have undergone a recent expansion. Tajima’s D test and Fu’s FS test suggested recent population growth. Pairwise Fst values were very low. The admixture and lack of genetic structuring found pointed to the populations analysed probably belonging to the same genetic unit. Therefore, a proper understanding and a sound knowledge of the level and distribution of genetic diversity in turbot is an important prerequisite for successful sustainable development and conservation strategies to preserve their evolutionary potential.

HTML

XML

PDF

]]>
Research Article Fri, 16 Apr 2021 14:02:24 +0300
Predicting the effects of climate change on future freshwater fish diversity at global scale https://natureconservation.pensoft.net/article/58997/ Nature Conservation 43: 1-24

DOI: 10.3897/natureconservation.43.58997

Authors: Ana Manjarrés-Hernández, Cástor Guisande, Emilio García-Roselló, Juergen Heine, Patricia Pelayo-Villamil, Elisa Pérez-Costas, Luis González-Vilas, Jacinto González-Dacosta, Santiago R. Duque, Carlos Granado-Lorencio, Jorge M. Lobo

Abstract: The aim of the present study was to predict future changes in biodiversity attributes (richness, rarity, heterogeneity, evenness, functional diversity and taxonomic diversity) of freshwater fish species in river basins around the world, under different climate scenarios. To do this, we use a new methodological approach implemented within the ModestR software (NOO3D) which allows estimating simple species distribution predictions for future climatic scenarios. Data from 16,825 freshwater fish species were used, representing a total of 1,464,232 occurrence records. WorldClim 1.4 variables representing average climate variables for the 1960–1990 period, together with elevation measurements, were used as predictors in these distribution models, as well as in the selection of the most important variables that account for species distribution changes in two scenarios (Representative Concentration Pathways 4.5 and 6.0). The predictions produced suggest the extinction of almost half of current freshwater fish species in the coming decades, with a pronounced decline in tropical regions and a greater extinction likelihood for species with smaller body size and/or limited geographical ranges.

HTML

XML

PDF

]]>
Research Article Fri, 22 Jan 2021 10:50:18 +0200
Applying bayesian population assessment models to artisanal, multispecies fisheries in the Northern Mokran Sea, Iran https://natureconservation.pensoft.net/article/25212/ Nature Conservation 28: 61-89

DOI: 10.3897/natureconservation.28.25212

Authors: Abdul Rashid Jamnia, Ahmad Ali Keikha, Mahmoud Ahmadpour, Abdoul Ahad Cissé, Mohammad Rokouei

Abstract: Small-scale fisheries substantially contribute to the reduction of poverty, local economies and food safety in many countries. However, limited and low-quality catches and effort data for small-scale fisheries complicate the stock assessment and management. Bayesian modelling has been advocated when assessing fisheries with limited data. Specifically, Bayesian models can incorporate information of the multiple sources, improve precision in the stock assessments and provide specific levels of uncertainty for estimating the relevant parameters. In this study, therefore, the state-space Bayesian generalised surplus production models will be used in order to estimate the stock status of fourteen Demersal fish species targeted by small-scale fisheries in Sistan and Baluchestan, Iran. The model was estimated using Markov chain Monte Carlo (MCMC) and Gibbs Sampling. Model parameter estimates were evaluated by the formal convergence and stationarity diagnostic tests, indicating convergence and accuracy. They were also aligned with existing parameter estimates for fourteen species of the other locations. This suggests model reliability and demonstrates the utility of Bayesian models. According to estimated fisheries’ management reference points, all assessed fish stocks appear to be overfished. Overfishing considered, the current fisheries management strategies for the small-scale fisheries may need some adjustments to warrant the long-term viability of the fisheries.

HTML

XML

PDF

]]>
Research Article Mon, 13 Aug 2018 14:49:19 +0300
Natural habitats uncovered? – Genetic structure of known and newly found localities of the endangered bitterling Pseudorhodeus tanago (Cyprinidae) https://natureconservation.pensoft.net/article/10939/ Nature Conservation 17: 19-33

DOI: 10.3897/natureconservation.17.10939

Authors: Kenji Saitoh, Noriyasu Suzuki, Masumi Ozaki, Kazuhiro Ishii, Tetsuya Sado, Takahiro Morosawa, Takatoshi Tsunagawa, Masaru Tsuchiya

Abstract: Overuse of natural resources by humans is a major threat to biodiversity. Overuse often involves species of economic or esthetic value, and fish are a typical example for a group that is exploited both for economic reasons (for human consumption) and for esthetic reasons (e.g. by aquarists). Pseudorhodeus tanago (Tanaka, 1909) (formerly known as Tanakia tanago) is a small colorful but legally protected (fishing, keeping and transfer are banned) bitterling fish distributed around Tokyo, Japan. Whereas it is critically endangered and more and more habitat loss has occurred, at least four stocks have been newly found during the last decade. To explore whether emergence of these newly found habitats is a consequence of incomplete survey, we genotyped mitochondrial cytochrome b sequence of P. tanago from 17 localities and an illegal home aquarium. Populations known by the past extensive survey (13 localities) showed geographically structured population genetic characteristics. Population-specific haplotypes were common indicating past divergence and bottleneck events. Four (north, {center + west}, south_1, south_2) or five (north, center, west, south_1, south_2) geographic groups were detectable as for these known localities. On the other hand, newly found stocks were polymorphic and showed identical haplotypes from distant known localities. If we assume historical basis of distribution and genetic characteristics of these newly found stocks, it must be a series of unlikely geological events and haplotype sorting. We discuss potential issues posed by these questionable stocks.

HTML

XML

PDF

]]>
Research Article Thu, 9 Mar 2017 11:18:56 +0200