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•Herein, we present a comprehensive list of fishes in the Red River basin.•We verify the use of two fish fauna analyses to identify characteristic taxa.•The TFFA and VFFP methods were ...compared; the TFFA reflected the main fish taxa.•The VFFP results indicated the taxa representative of the Red River basin.•Data from fish fauna analyses should be used as indicators to plan fish preserves.
The composition of fish fauna in the Red River basin was analyzed based on 288 fish species belonging to 138 genera, 53 families (subfamilies), and 14 orders, using the Traditional Fish Fauna Analysis (TFFA) and the Value of Fish Fauna Presence (VFFP) methods. The TFFA and VFFP methods allow for a ranking of the taxa according to commonality and uniqueness of the taxa to the river basin; however, both methods provide different, complimentary results. Based on the results from the TFFA method, 15 families (subfamilies), including 85 genera and 219 species, were identified as the main fish taxa in the Red River basin. Based on the results of the VFFP method, 17 families (subfamilies), including 89 species and 52 genera, were highlighted as representative families (subfamilies) and genera in the Red River basin. Overall, Cypriniformes was the most abundant order, followed by Siluriformes and Gobiiformes. Although the Red River basin is geographically situated in Southeast Asia, it had obvious characteristics of East Asian fish fauna rather than Southeast Asian fish fauna. Therefore, the Red River fish fauna can be considered the boundary between the fish fauna of Southeast Asia and East Asia. This paper further detailed the indexes and calculations of the TFFA and VFFP methods. The authors proposed using the results of the TFFA and VFFP methods as indicators for planning fish preserves as well as discussed the specific methods related to using these indicators to plan and establish fish preserves.
Revised Checklist of Fishes of Sagami Bay, Japan Honda, Kosuke; Senou, Hiroshi; Wada, Hidetoshi
Bulletin of the Kanagawa Prefectural Museum (Natural Science),
2024/03/22, Volume:
2024, Issue:
53
Journal Article
Open access
A previous checklist of the fishes of Sagami Bay, Japan, which included 1517 species belonging to 249 families (45 orders) recorded up to 2006, was revised using the following resources: fish ...collections of the Kanagawa Prefectural Museum of National History (KPM), the fish image database in KPM and literature records. The survey revealed 1934 species belonging to 284 families (43 orders) in the study area. Many of the species newly recorded in Sagami Bay are distributed mainly in waters south of the bay, which is likely to be closely linked to the transport of fishes by the Kuroshio Current. In addition, the recent rise in seawater temperatures in and around Sagami Bay due to global warming and other factors, may have allowed normally southern fish species to overwinter in Sagami Bay, thus leading to the significant increase in the number of species recorded over a relatively short period.
Aim The present study investigated the social impacts caused by the construction of a large hydropower dam (Lajeado Dam) on artisanal fishers in the Middle Tocantins River, evaluating how the ...impoundment affected fishing techniques (locations, transport and gears), operation (income, effort and costs), and fisher’s well-being. Methods The study interviewed 30 artisanal fishers (Colony Z-04, Porto Nacional, TO) between August and October 2018 with the application of a structured questionnaire. Results Results indicated that fishing is socially important as a source of income and occupation, carried out essentially by men with low levels of formal education. Fishers reported, however, significant changes in the fishery system after the impoundment of the Tocantins River. The main fishing area was maintained, but fishers abandoned some sites. There were significant changes in fishing equipment, with an increase in the use of aluminum boats and outboard engines, and a reduction in the use of various gears, replaced by the use of gillnets. Almost all fishers (96.6%) declared that fishing effort and the financial costs increased after damming. Many also reported an increase in financial income (70%), but part reported a decrease, no change or could not say. The majority reported that the impoundment damaged the fishing activity (80%) and their well-being (individual and their families; 83.3%); dissatisfaction with the profession also increased. Conclusions Results indicated that the impoundment created by Lajeado Dam impacted several aspects of artisanal fisheries in the Middle Tocantins, with a wide perception of damage, which indicates that working conditions of fishers have declined. This information is relevant and can support fisheries management in the Tocantins River Basin, in order to balance societal demands with sustainability goals and fisher’s needs.
Resumo: Objetivo O presente estudo investigou os impactos sociais causados pela construção de uma grande barragem hidrelétrica (barragem de Lajeado) sobre os pescadores artesanais que atuam no Médio Rio Tocantins, avaliando como o represamento do rio afetou as técnicas de pesca (locais, transporte e petrechos), sua condução (geração de renda, esforço e custos) e o bem-estar dos pescadores. Métodos O estudo entrevistou 30 pescadores artesanais (Colônia Z-04, Porto Nacional, TO) entre agosto e outubro de 2018 com a aplicação de um questionário estruturado. Resultados Os resultados indicaram que a pesca tem grande relevância social como fonte de renda e geração de emprego, exercida essencialmente por homens com baixo nível de escolaridade. No entanto, os pescadores relataram mudanças significativas na atividade pesqueira após o represamento do rio Tocantins. A principal área de pesca foi mantida, mas os pescadores abandonaram alguns locais. Houve mudança notável nos equipamentos de pesca, com aumento significativo no uso de barco de alumínio e motor, redução no uso de diversos petrechos, e aumento no emprego de malhadeiras. Quase todos os pescadores (96%) declararam aumento no tempo gasto com a pesca e no custo financeiro envolvido. A maioria também afirmou aumento da renda financeira (70%), embora parte tenha relatado diminuição, ausência de alteração ou não soube dizer. A grande maioria relatou que o represamento prejudicou a atividade pesqueira (80%) e seu bem estar (individual e de sua família; 83.3%); também houve aumento na insatisfação com a profissão. Conclusões Os resultados indicaram que o represamento da usina de Lajeado impactou diversos componentes da pesca artesanal no Médio Tocantins, com ampla percepção de prejuízo, o que indica piora nas condições de trabalho dos pescadores. Essas informações são relevantes para o ordenamento e gestão pesqueira na bacia do Rio Tocantins, no intuito de equilibrar as demandas da sociedade com metas de sustentabilidade e necessidades dos pescadores.
Small streams in rural areas are commonly known as habitats for freshwater fish, but have lacked attention from conservation sectors and local governments. We established 30 survey points in three ...tributaries (Kawamata, Ogawa, and Ujie) of a medium-sized river, the Koise River, that flows into Lake Kasumigaura, Ibaraki Prefecture, Japan. We captured fish using an electrofisher and recorded environmental features from 2010 to 2011, in winter, spring, summer, and autumn, once for each. A total of 119 surveys caught 27,086 fish of 18 species. Of these, Rhodeus ocellatus ocellatus, Gnathopogon elongatus, and Nipponocypris spp. were alien species. Conversely, six species, Lethenteron reissneri, Tachysurus tokiensis, Oryzias latipes, Tanakia lanceolata, Misgurnus anguillicaudatus, and Cotton pollux, were species of conservation concern listed on the Red List of the Ministry of the Environment, Japan. There were five seasonal weirs, which retain water only during the irrigation period, and four fixed weirs, which do not change shape throughout the year, in Kawamata; additionally, there were two seasonal weirs in Ogawa, and one seasonal and eight fixed weirs in Ujie. The density of weirs, the ratio of concrete bottoms, and the vegetation coverage all indicated that Ogawa had the best natural conditions and Ujie the worst. The number of species per survey and the Shannon-Wiener index of diversity for each survey point were highest in Ogawa, and lowest in Ujie. The numbers of Opsariichthys platypus, G. elongatus, T. tokiensis, and Pseudorasbora parva captured per survey were higher at survey points where there was no weir on the close downstream side than at those where there was a weir, especially a fixed weir. These results suggest that cross-river artificial structures, especially fixed weirs, have a negative impact on many freshwater fish species. When employing weirs to utilise water from small streams for irrigation in plains, their negative impacts on freshwater fish should be reduced by using, for example, a seasonal weir with a small gap.
Studies on fish fauna should not only focus on fish composition and the comparison of fish composition among the study region and adjacent regions, but should also explore the origin and uniqueness ...of different taxa as well as the substitution of genera and species. In this study, the value of floristic presence method was modified and renamed the value of fish fauna presence (VFFP) method. The specific steps of the VFFP method and the traditional fish fauna analysis (TFFA) method were refined and standardized. Then, the VFFP and TFFA methods were applied to study the fish fauna of the upper and middle portions of the Mekong River basin. The results indicate that the TFFA method reflects the families (subfamilies) and genera that constitute the main body of fish in the studied river basin. The results of the VFFP method show which families (subfamilies) and genera are representative for the basin. Therefore, combining the TFFA and VFFP methods to analyze the composition of fish fauna can reflect the characteristics of fish fauna from different perspectives. The case study shows that the fish fauna of the Mekong River is a part of the fish fauna of Southeast Asia. Although it shows some similarities to the composition of South Asian fish fauna, it does not belong to the South Asian fish fauna as a whole, and is essentially different from the East Asian fish fauna. This study provides an objective, quantitative, and verifiable method for studying fish fauna.
This study provides an objective, quantitative, and verifiable method for studying fish fauna.
Dams change the hydrological dynamics, patterns of biological production and distribution of organisms in space and time. In contrast, tributary rivers can function as source areas in reservoirs, ...since they harbor spawning and early development grounds for native fish species. Here, we analyze a time series of the first 14 years after the impoundment of the Porto Primavera Reservoir, a large reservoir with free tributaries in southeastern Brazil. To evaluate the impact of damming on the fish assemblage, we evaluated the abundance (catch per unit effort, CPUE) and α (species richness and Shannon-Wiener index) and β (Sørensen dissimilarity and turnover) diversity of four sites distributed along the reservoir. Overall, there was no decreasing trend in the α diversity and no increasing trend in the β diversity relative to the initial year or among the sites over time. Despite the expected disturbance in the fish assemblage at the lacustrine site, the sites located near the tributary mouths presented resistant fish assemblages, compensating the results of the overall assessment. We attribute this unusual variation in the ecological attributes to source-sink demographic dynamics, with the undammed tributaries as the source and the reservoir as the sink for native species. We highlight that the presence of these rivers minimized the expected trend towards biotic homogenization, and the preservation of the tributaries is imperative since they contribute to diversity maintenance in areas that are already impacted by damming. The inclusion of this agenda in environmental management programs and new impoundment plans will allow a balance between the demand for electricity production and the conservation of fish diversity.
•Marine reserve was more effective in maintaining fish functional diversity.•Fish density declines were associated to natural and anthropogenic disturbances.•Loser and winner species at all MPA ...indicated that functional structure is dynamic.•The marine reserve showed resilience by maintaining species and functional diversity.•Analyses of continuous years are necessary to detect accurate patterns in diversity.
Conservation strategies, such as the establishment of Marine Protected Areas (MPAs), aim to safeguard biodiversity and to promote resilience of ecosystems by increasing their capacity to maintain key functions and processes following disturbance. However, the extent to which ecosystems in MPAs exhibit resilience remains debated. To address this question, we evaluated changes in reef fish species and functional diversity over time in relation to environmental and anthropogenic disturbances at multiple locations in the Gulf of California, Mexico. From 2005 to 2017, we assessed reef fish species richness and abundance in three MPAs: one no-take marine reserve (Cabo Pulmo) and two multi-use marine protected areas (MUMPAs: Espíritu Santo and Loreto). To examine change in functional diversity and composition, we calculated three functional diversity indices – functional richness, functional dispersion and functional originality – using six biological traits (size, mobility, period of activity, gregariousness, water column position, and diet). Species richness, density and functional diversity were maintained over time (resilience) in the no-take marine reserve. In contrast, MUMPAs showed temporal decline in species richness, which translated into decreases in functional richness and increases in functional dispersion. These differences were also observed at the species level: in Cabo Pulmo, only two ‘loser’ species declined in density, while Espíritu Santo and Loreto showed declines of 12 and 17 species, respectively. The two MUMPAs also shared 9 of the total 22 ‘loser’ species, which are generally abundant and common in the Gulf of California. Density declines were attributed to the combined effect of environmental (sea surface temperature and Chlorophyll-a anomalies) and anthropogenic (fishing, tourism and coastal population density) disturbances. Given the regional decline and the ecological importance of dominant species, long-term decreases in their populations can profoundly modify processes and reef ecosystem services in this region. Thus, local management strategies should be implemented to try to reverse the observed recent decline in fish diversity in MUMPAs.
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