Review of Remote Sensing Techniques for the Visualization of Mangroves, Reefs, Fishing Grounds, and Molluscan Settling Areas in Tropical Waters

Globally there has been tremendous progress in space technology especially in the field of satellite remote sensing applications during the past five decades. Satellite based sensors provide a repetitive and synoptic coverage of inaccessible / larger areas which generated a time series database useful in identification and mapping of environment and resources. These databases form a scientific tool for various stakeholders to device suitable strategies for management of coastal and marine resources. This chapter analyses the various applications of satellite remote sensing and numerical modelling on identification and mapping of mangroves, coral reefs, fishing and molluscan grounds in the coastal marine ecosystems with relevant case studies and illustrations. The mapping methods for mangroves explains the classification protocols, advantages in using different remote sensing techniques and the comparison of different mapping techniques. In case of reef mapping, the vulnerability mapping of reefs due to extreme events is also discussed. Fish movement in a dynamic environment and the mapping of these movements with the help of proxy indicators are also detailed. Molluscan mapping is done based on the biomass differences during different seasons and their physical attributes

Evaluation of Ecosystem services of Villorita cyprinoides in Vembanad

Vembanad Lake, a wetland of international importance, famous for waterfowl habitat was designated a Ramsar site, for conservation and sustainable utilisation of the ecosystem. Millennium ecosystem assessment (2005) emphasises that the various services provided by the ecosystem benefitting human population needs to be identified and evaluated for judicious utilisation of the resources. Villorita cyprinoides is a major species contributing to the molluscan fishery of Vembanad lake. The study involving Villorita sp. was taken up with the objectives of development of a conceptual framework encompassing the different ecosystem services provided by the clam resources, estimation of the values of selected ecosystem services using appropriate proxies and analysis of the trade-offs between anthropogenic activities like dredging vis-a-vis clam resources utilizations following the principles of MEA (2005). The study identified that the clam fisheries in the lake is most acknowledged for its provisioning ecosystem services. Apart from the regulating services such as water quality maintenance and carbon sequestration, the cultural and the linking services provided by clam fisheries to human are also identified. In spite of the identification of the various services, the non-realisation of the value of the services provided by clam fisheries has prompted the destruction of the resource knowingly or unknowingly by our activities. One of the anthropogenic activities affecting the clam fisheries is the dredging of sub fossil deposits of clamshell or white clams which are good sources of calcium carbonate for cement manufacturers. Identifying the lacunae of non-realisation of the services of clam resources, the paper has judiciously attempted not only to evaluate the services of the ecosystem service provider but also to externalize the internalities in the ecosystem services evaluation process by considering the various social costs and benefits associated with the resource

Identification and evaluation of ecosystem services provided by clam (Villorita cyprinoides) fisheries in wetland

Black clam (Villorita cyprinoides), constitute a major molluscan based subsistence level fishery in Vembanadlake providing a variety of ecosystem services to the dependent populations of the ecosystem. The non-realization of the values of the services provided by clams coupled with the anthropogenic activities like dredging aggravated the non-sustainable harvest of the resource. The paper attempts to evaluate the provisioning and cultural services provided by clams in-order to highlight the importance of the management of this ecosystem service provider and various tradeoffs between anthropogenic activities and clam resource utilizations

Ecosystem Responses in the Distribution of Black Clam (Villorita cyprinoides) Beds in Vembanad Estuary during Environmental Changes Using GIS and RS

The biomass and distribution of black clam (Villorita cyprinoides) in Vembanad, a tropical estuary located along the southwest coast of India varied significantly. Sampling was done in freshwater-dominated zone in the south (distal) and brackish water zone in the north (proximal), during pre and post monsoon seasons. Clam biomass was estimated from samples, collected from different stations during the study period. Water transparency and temperature were measured at the sample sites. Water samples were collected and analysed for salinity, dissolved oxygen (DO), pH and hardness. There was a significant difference in the clam biomass during the two seasons in the distal zone, and those collected from the distal and proximal zones during premonsoon season. The data were further analysed to determine the factors affecting the clam biomass distribution in the two zones and seasons. Factor analyses, comparing the distal zone during two seasons and zonal variations were similar to earlier observations. Step wise regression analyses found that dissolved oxygen (adjusted R2 = 0.3) is the only variable affecting clam survival during pre-monsoon period in the distal and proximal zones. A geographic map of the region obtained from the Indian satellite sensor LISS (Linear Image Self Scanner) was used along with in situ data to map the results using inverse distance weightage model

Length-weight relationship and condition factor of Dawkinsia filamentosa (Valenciennes, 1844) in different aquatic habitats

The growth rate of a species in any aquatic environment is an indicator of the water quality of the system. In the current study, the Length-weight relationship (LWR) and the condition factor of Dawkinsia filamentosa from various aquatic ecosystems especially lotic, lentic and brackish lentic systems were compared. It was observed that growth rate of the fish was more in brackish lentic systems. The study showed that already reported growth rate (b) of the species in brackish lentic systems is around 3.273 indicating proximity towards the isometric growth pattern as compared to the growth rate in reservoirs (2.3184) and that in lentic systems (3.116) obtained from present study. Similar studies supplemented with environmental variables can be used to study the health status of the ecosystem. The best system suitable for the adaptive growth of the species can be ascertained only after a holistic approach involving environmental variables

Understanding variations in socio-economic vulnerabilities and the strategies adopted by small scale fishing communities of tropical reservoirs

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

काली सीपी (विलोरिता साईप्रीनोएड) का मात्स्यिकी में योगदान एक मूल्यांकन

भाकृअनुप-केंद्रीय मात्स्यिकी प्रौद्योगिकी संस्थान, कोचिन द्वारा ‘भारत की अर्थव्‍यवस्‍था में मात्स्यिकी के योगदान’ विषय पर हिंदी में आयोजित राष्ट्रीय वैज्ञानिक संगोष्ठी संपन्न हुआ। डॉ. रविशंकर सी. एन., निदेशक ने अपने अध्‍यक्षीय संबोधन में संस्‍थान और राजभाषा कार्यान्‍वयन की उपलब्धियों पर प्रकाश डाला। इस अवसर पर निदेशक ने सहाभगियों को शुभकामनाओं के साथ-साथ प्रमाण पत्र भी वितरित किया। डॉ. टी. के. श्रीनिवास गोपाल, पूर्व निदेशक, भाकृअनुप-केमाप्रौसं, कोचिन ने बतौर मुख्य अतिथि अर्थव्‍यवस्‍था और रोजगार प्रजनन में मात्स्यिकी के योगदान की भूमिका को प्रस्‍तुत किया। साथ ही, हिंदी भाषा में राष्ट्रीय वैज्ञानिक संगोष्ठी के आयोजन के लिए संस्‍थान के निदेशक एवं उप निदेशक (राजभाषा) को बधाई दी। इस अवसर पर प्रकाशित सारांश पुस्तिका का विमोचन मुख्‍य अतिथि द्वारा किया गया। डॉ. जे. रेणुका, उप निदेशक (राजभाषा) ने स्वागत संबोधन में कहा कि वैज्ञानिक उपलब्धियों को लक्ष्‍य समूह तक पहुँचाने में भाषाओं का अत्‍यधिक महत्त्व होता है। इस संगोष्‍ठी का उद्देश्य वैज्ञानिक विषयों को हिंदी में प्रस्‍तुत करना था

Assessing multi‑scale vulnerability of fisheries of Vembanad lake, Peninsular India, due to climate change: a stakeholders‑based approach , Environment, Development and Sustainability

Small-scale sector fisheries associated with tropical wetland were found to be highly vulnerable to various socio-economic, ecological and climatic factors. The present study conducted in Vembanad lake in India attempted to identify and assess vulnerabilities of wetland fishers to climate variability at spatial scale. One hundred and eighty fishers distributed across three villages (Vaikkom, Muhamma and Thycattussery) who were representative of marine, freshwater and brackish water fishers, respectively, were surveyed based on a structured schedule prepared by National Innovations for Climate Resilient Agriculture and ICAR-Central Inland Fisheries Research Institute. Potential indicators of vulnerability as perceived from survey were segregated under seven drivers such as health, livelihood, social, food, ecological, resource and resource user. These indicators which were represented by attributes were scored, based on fishers’ perception, and were used for identifying the highly contributing drivers of vulnerabilities. Kruskal–Wallis parametric test was used for analyzing the vulnerabilities statistically. The overall wetland vulnerability indices derived from various villages indicated that Thycattussery was highly vulnerable compared to Muhamma and Vaikkom. A transactional analysis across each sampling station indicated that in Vaikkom, fishers were less vulnerable to resource, food security and resource user vulnerabilities in a climate changing context. Poor status of livelihood, social and food related insecurities and resource user-based uncertainties were the factors attributing to fishers' vulnerability in Thycattussery. The fishers of Muhamma experienced greater ecological and resource-based vulnerabilities. The study suggested that a bottom-up approach involving the primary stakeholders (fishers) along with the community will adequately position them to climate change adaptation and mitigation

Dilemma on the ban on exotics in Indian subcontinent: A systematic review in a socio-economic perspective

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

Not Available

Not AvailableThe biomass and distribution of black clam (Villorita cyprinoides) in Vembanad, a tropical estuary located along the southwest coast of India varied significantly. Sampling was done in freshwater-dominated zone in the south (distal) and brackish water zone in the north (proximal), during pre and post monsoon seasons. Clam biomass was estimated from samples, collected from different stations during the study period. Water transparency and temperature were measured at the sample sites. Water samples were collected and analysed for salinity, dissolved oxygen (DO), pH and hardness. There was a significant difference in the clam biomass during the two seasons in the distal zone, and those collected from the distal and proximal zones during premonsoon season. The data were further analysed to determine the factors affecting the clam biomass distribution in the two zones and seasons. Factor analyses, comparing the distal zone during two seasons and zonal variations were similar to earlier observations. Step wise regression analyses found that dissolved oxygen (adjusted R2 = 0.3) is the only variable affecting clam survival during pre-monsoon period in the distal and proximal zones. A geographic map of the region obtained from the Indian satellite sensor LISS (Linear Image Self Scanner) was used along with in situ data to map the results using inverse distance weightage model.Not Availabl