Study Area and Methods

The Uttara Kannada district lies at 74⁰9' to 75⁰10' E and 13⁰55' to 15⁰31' N extending over an area of 10,291 sq.km in the mid-western part of Karnataka state, India (figure 3). It is surrounded by Belgaum district and Goa territory in the north, Dharwad in the east, Shimoga and parts of Daskshina Kannada in the south and the Arabian Sea to the west. Uttara Kannada district is one of the northernmost districts in Karnataka State (Ramachandra, et al. 2018a; 2018b; 2018c). The district consists of a narrow strip of the coastline with a spatial extent of 3300 sq.km, which is relatively flat and starts sloping gently upwards towards the east (Deepthi et al. 2017), comprising five taluks namely Karwar, Ankola, Kumta, Honnavar and Bhatkal (Ramachandra et al., 2018d; 2018e).

Fig. 3. Aghanashini estuary, Uttara Kannada district, Karnataka, India 🡪

Aghanashini Estuary - Aghanashini River running its course of about 121 km, winding through gorges flanked with evergreen forests and valleys lush with spice gardens and rice fields, the river widens into an estuary covering about 4801 ha before its confluence with the Arabian Sea in the west coast between the villages Aghanashini in the south and Tadadi in the north, lies between 14.391° to 14.585° N and 74.304° to 74.516° E of Kumta taluk (Deepthi et al. 2017) in the Uttara Kannada district of central west coast in the Karnataka State of India (Fig. 3). Villages (about 21) along the estuarine banks mainly are traditionally dependent on agriculture and fisheries.

2.2 Methods: The secondary data was obtained from various sources for assessing the resource availability and consumption scenarios in the five estuaries. Field survey were carried out regarding the fish resources, sand mining and salt production in the estuaries. This involved actual measurements (quantifications) and discussions with the local people. The secondary data regarding the ecological functions of the estuaries was collected from Central Marine Fisheries Research Institute (CMFRI) centres of Cochin and Karwar; Department of Marine Biology, Karnataka University, Karwar; Cochin University of Science and Technology, Biodiversity portal (Sahyadri 2018). The socio-economic data related to the coastal taluks including the villages around the estuaries were obtained from 2001 Census Report, Govt. of India; District Administrative Reports, Govt. of Karnataka. The data regarding the production of Gazani paddy and Coconut in the estuarine region was obtained from Karnataka State Horticulture Department. The direct and indirect values obtained from the estuaries were calculated.

Market valuation technique was employed for valuing the goods and services having direct market prices such as fishing, gazani (salt tolerant) paddy cultivation, timber and fodder obtained from the mangrove vegetation, aquaculture, sand and lime shell mining, navigation, ferry services and port activities. The market price values were assigned to these goods based on the interaction with the locals residing in that region. The gross revenues obtained from these resources were obtained as per the equation 1.

Net benefit from the fisheries = Total fish production in the estuary (tons) x Price per ton

Net income from mining/agriculture products = Σ (P Q) ……1

Where, P = price of the product; Q = quantity of the product

Besides providing the direct use value goods, the estuaries also provide various other important benefits such as climate regulation, shoreline stabilization, natural hazard mitigation, habitat and refugia for various organisms, nutrient circulation, recreation and aesthetic benefits, etc. CVM (Contingent Valuation Method) was adapted to survey indirect values obtained from an ecosystem which is based on the people’s Willingness to Pay (WTP) for it. For the current valuation study, the values for the indirect ecosystem services were adapted from the published literatures (Ramachandra et al. 2017a; Bann 2003; Barbier et al. 2011; Costanza et al. 1997; Costanza and Folke 1997; UNEP 2013; NEP/GEF 2007; TEEB 2011). The values were converted into Indian Rupees (INR) and are given in Table.1.

Table 1: Economic values assigned to different indirect ecosystem services

The direct, indirect and recreational benefits of the estuaries were aggregated to obtain the Total Economic Values (TEV). These economic values can be considered as underestimates as the natural ecosystems are much more worth in terms of the benefits they provide. The valuation of natural resources is useful for policy formulations and decision making.

3.0 RESULTS AND DISCUSSION

CONCLUSION

Ecological systems goods and services play a fundamental role in supporting life and sustaining the economy. Valuation of the ecosystem goods and services has become critical to formulate prudent policies for the sustenance of natural resources. The present study provides an account of the resource potential of Aghanashini estuary of Uttara Kannada district, Karnataka state, India. Aghanashini estuary is the highly productive ecosystem evident form the total economic valuation of estuarine ecosystem with the total value of 24.03 billion Rs/year and the annual productivity of 5 million Rs/hectare/year. Provisioning service makes up the 23% of the total value. Information service share is about 2%, while regulating and supporting services are respectively 37% and 39%.

This highlights that estuaries of Uttara Kannada have been sustaining the economy of the district in a significant manner with the job potential and people’s livelihood. Decline in the environmental quality of these ecosystems necessitates the concerted effort to conserve the estuary in a sustainable manner with the active participation of native people. This also emphasizes the need for green GDP (Gross domestic product) with the accounting of ecosystem goods and services to ensure the sustainability of natural resources (water, energy, land, etc.).