Abstract
The present study was carried out at the Thycattussery area in Vembanad lake and assessed the ichthyo-diversity, variability in climatic variables, the exploited status of predominant ...small-scale sector fisheries (SSFs) and impact of climatic variables upon an existing SSF. Fish, as well as clam specimens collected from the study area, were identified. Diversity indices and dominance curves helped to identify monsoon (June–September) as the diverse season in the wetland. SIMPER (similarity percentage) analysis indicated that Villorita cyprinoides (clam) was the predominant species in the wetland with a mean relative abundance of 16.1%. Canonical correspondence analysis (CCA) of variables with clam production identified calcium hardness and rainfall with axis loadings of –0.56 and 0.50 respectively as the variables predominantly contributing to clam production. Stepwise regression indicated that temperature and rainfall were the determinants of clam production. A decrease in rainfall and an increase in temperature at an annual rate of 0.02 and 0.8%, respectively, decreased the clam production by 5.37%/year in the study area. Further, the generalized linear model (GLM) indicated stagnancy in clam production until 2035 below 400,000 kg per year. The study introduced diversification of livelihood systems using clam culture in climate resilient pen structures (CRPS) as an adaptation strategy.
This paper overviews the role of exotic fishes in providing ecosystem services such as employment, economy, efficiency, exchange and equity using various case studies in the Indian subcontinent in a ...socio-economic perspective. Case study I identified that the culture period of exotics especially Tilapia species (i.e., 180–200 days) created a total labour requirement of 840 labour days compared to agricultural labour. Case study II identified a 20% increase in contribution of share of the fisheries sector during 2010–2019 to the country’s national Gross Value Added (GVA) due to exotics. Case III found that the fisheries export earnings of exotics in fiscal year 2019–20 increased to over 6678.69 million USD from 2132.84 million USD in 2009–2010. Case study IV identified greater involvement of women in fish farming activities, especially 2% in intensive aquaculture and 50% in extensive aquaculture. The current systematic review attempted to highlight that exotic fishes have a productive role in steering the regional economy through providing basic tangible ecosystem services that may be identified in monetary terms. The identification and evaluation of aquaculture-based ecosystem services provided by exotic fishes often leads to a dilemma whether to ban or promote the culture of such exotic fish species. Previous studies revealed that the economic impacts of aquatic exotic species are significantly positively correlated with their ecological impacts. Unfortunately, assessment of ecological impacts required evaluation of losses due to exotics or ecosystem services offered by exotics, which was greatly lacking across globe. This review summarizes the positive effects of exotics taking ecosystem services into account, despite the need for controlling invasive species for the ecology.
•The paper highlights the trade-offs in banning exotic fishes by considering the socio-ecological consequences.•Exotic aquaculture helped in identifying the employment opportunities further ensuring the betterment of family income.•The study remarked that exotic fishes helped to increase the current foreign exchange drastically.•The introduction of exotics in aquaculture helped in improving the technical and performance efficiency of farming systems.•The study considers the positive ecosystem services of exotics as the species ensures better nutrition and livelihood to the poorest community.
Tropical inland capture fisheries are susceptible to a series of vulnerabilities such as habitat destruction, biodiversity loss, pollution, overfishing, invasive species and anthropogenic climate ...change. A comprehensive review of the impact of climatic uncertainties on Indian inland fisheries has not been adequately attempted yet. Recent approaches emphasizing ecosystem-based management in a regional context, specific to inland fisheries for combating climatic changes, have not been reported to date. The paper presents a critical bibliometric review of the climatic vulnerabilities faced by Indian inland fishery resources and various adaptive and mitigation strategies put forward by the country for the sustainability of the resources. In this communication, a systematic review of the impact of climate change and other stressors on various inland ecosystems of the subcontinent and the ecosystem-based management strategies adopted in India is presented and discussed.
The present study taken up in two reservoirs in India namely Peechi and Pothundi reservoir assess the vulnerabilities and various management aspects adopted in two reservoirs. Peechi reservoir ...situated in Peechi-Vazhani wildlife sanctuary was prevented from all fishery enhancement programmes. Pothundi reservoir, a manmade tropical lake though encompassed in Western Ghats biosphere was regularly stocked with Indian Major Carps. Livelihood survey was carried out on the fishers of Peechi and Pothundi reservoirs with the help of a structured schedule. The survey encompassed demographic information, particulars on fisheries and details on economic and marketing aspects of respective reservoir fisheries. The marketing part of the schedule dealt with ranking of various problems faced by the fishermen in the reservoirs using Garrette ranking. Out of the various socio-ecological vulnerabilities of reservoir fisheries communities that was analysed in this study, varied stakeholder interest, human and wild life interference and irregular stocking of fish were identified as the major vulnerabilities faced by them. Relevance of various strategies suggested by fishers in Peechi and Pothundi reservoirs estimated using RFMI (Reservoir fisheries management index) concluded that regular and continuous fish stocking (technical driver) along with allowing gender equity in land based fish production centres (social driver) was suggested as the appropriate strategy to augment the fisher's income from Pothundi reservoir. The study suggested for a possible intervention by practicing fishing holidays in Peechi reservoir during lean months and substituting the lost income with alternative livelihood programmes. The RFMI values for Peechi and Pothundi reservoirs were 52.12 and 68.57 respectively. The study thus emphasized a bottom approach where in the importance of planning at primary stake holders level is ensured. The relevant research ensured adoption of these strategies in local scale along with policy window would definitely provide a better management of reservoir fisheries in tropical countries.
The present study assessed the occurrence and impact of heat waves on the ecology of two ecosystems namely Bhomra wetland and Ganga River stretch, India. The water samples collected from these ...ecosystems were analyzed for estimating the hydrological and biological variables during heat wave. The inland heat index (IHI) was derived from the climatic variables, relative humidity and temperature. The study indicated the predominant and periodic occurrence of inland heat waves (IHW) with indices ranging from 34.8 to 42.8 °C and 35.9 to 43.5 °C at the Bhomra and Ganga River stretch respectively during the summer months (March–June). The first two components of the principal component analysis of physico-chemical parameters and heat index explained 45.6% and 59% of the variation in the Bhomra and Ganga River stretch respectively. PCA showed a similar pattern in variation of IHWs and dissolved oxygen, nutrients, hardness and alkalinity, but a distinct pattern with conductivity and TDS in the wetland. IHW exhibited a similar pattern of variation with TDS, conductivity, dissolved oxygen, pH and hardness and distinct pattern with alkalinity, phosphate and nitrate in the river stretch. The first two components of PCA of IHI and plankton abundance explained 89% of the variation and IHI had a similar pattern of variation with the abundance of diatoms and a diverse pattern of variation with blue-green and green algae in the studied ecosystems which might affect the food availability of the associated fishes. The study suggests that IHW influences the water quality and primary producers and also summarizes the impact of IHW on ecosystem services and necessitates mitigation measures.
Kerala, the southern state of India, was severely hit by a massive flood in August 2018 affecting millions of people causing loss to the state exchequer. The aim of this paper was to study the ...impacts of this flood on mineralogy, geochemistry (grain size, and heavy metal content) and nutrient content (organic carbon, total and available nitrogen, and phosphorus) of sediment of flood affected Pampa river, Kerala. The study indicates that this large-scale flood results in a considerable reduction in the heavy metals and nutrient concentration of sediment. Frequency histograms for most of the sediment particle size showed unimodal distribution curve with the dominance of sand particles which may be due to wash of fine size fraction like silt and clay during flood. FTIR study indicates that Pampa river sediment is dominant with quartz, orthoclase and microcline feldspar, and kaolinite, along with other trace minerals. SEM study also indicates that quartz is the common occurring mineral and its shape varies from highland to downstream due to transportation. Ratio of carbon to nitrogen and phosphorus particularly at downstream stations indicates the considerable influence of macrophyte which leads to accumulation of terrestrial organic matter. The cluster analysis results indicate that there were some similarity in origin and migration behaviour among these metals and nutrients of the sediments.
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