National Initiative on Climate Resilient Agriculture - CIBA

Background information

Aquaculture is the fastest growing food-producing sector and has been growing at an annual rate of nearly seven percent worldwide. Aquatic foods have high nutritional quality, contributing 20 percent or more of average per capita animal protein intake for more than 2.8 billion people, mostly from developing countries. Freshwater carps and brackishwater shrimp are the dominant cultured aquatic organisms in India. The aquatic environment will respond to climate changes in ways that are as equally significant as the responses of the terrestrial and atmospheric environments. Aquaculture practices like other agricultural activities constitute a largely undefined source of green house gases (GHGs). The predictions of climate change in the country viz., increasing trends in annual mean temperature, more warming during post monsoon and winter, increase in extreme rains in north-west during summer monsoon in recent decades, lower number of rainy days along east coast, consequent droughts, increase in frequency of hot days and multiple-day heat wave has greater impact on aquaculture. There are very limited studies on impact of climate change on aquaculture and vice versa and the major issues of concern are:

 

·         Understanding of the impact of global climate change on aquaculture

Aquaculture is threatened by changes in temperature, precipitation, drought, storms/floods that affect infrastructure and livelihoods. Increased water temperatures leads to other associated physical changes in pond environment, such as shifts in dissolved oxygen levels. These have been linked to more frequent algal blooms and increase in the intensity and frequency of disease outbreaks.  The impacts on aquaculture from climate change will likely be both positive and negative arising from both direct and indirect impacts on major natural resources required for aquaculture such as water, land, seed, feed and energy. Positive effects such as longer growing seasons, lower natural winter mortality and faster growth rates in higher latitudes and opening up of new opportunities for brackishwater aquaculture (as in Andaman & Nicobar Islands) where agriculture may become non-viable due to saltwater intrusion may be offset by negative factors such as a changing climate that alters established reproductive patterns, migration routes, and ecosystem relationships. More focused studies are required for the increased understanding of the climate change impacts (positive or negative consequences) on aquaculture along with possible strategies to counter them. India is highly vulnerable to extreme climatic events such as storms, cyclones, floods and drought and these events could cause extensive damage to land based aquaculture in terms of structural damage, stock escapes and loss of livelihoods of aquaculture farmers. Response to gradual and abrupt climate change events require appropriate adaptation plans and strategies. This would entail investments in flexible technologies and opportunity for alternative livelihoods during critical periods. Climate change inclusive adaptation plans need to be developed for the country.

 

Aquaculture is essentially dependent on the availability of good quality water. In case of brackishwater aquaculture, the problem of water scarcity and higher salinity is very site-specific with wide variations depending on the tidal amplitude, water current and inflow of freshwater. Water availability for aquaculture is already become a serious constraint in several parts of Asia, and climatic shifts caused by climate changes are likely to exacerbate the impacts. During summer months, the low availability of water in the creeks leads to an increase in the salinity beyond the tolerable limits of the cultured organisms. Since climate change is expected to affect the availability of freshwater and the flow in rivers it is essential to address the water budgeting, lower water availability and quality, and zero water exchange farming system issues.

 

·         Carbon and green house gases emission in aquaculture supply chain

Data on GHGs emission from aquaculture fields is not available. As with other food sectors, distribution, packaging and other supply chain components also will contribute to the aquaculture sector’s carbon footprint. Carbon labeling places more emphasis on greenhouse gas emissions, issuing guidance and standards. There is very limited assessment of GHG emissions in aquaculture supply chain. Primary production (farming), and the energy consumption associated with activities such as acquiring raw materials, mode of transport, refrigeration etc. are the processes in the supply chain. Carbon sources associated with aquaculture includes direct use of fossil fuels in production activities, indirect fossil fuel use, conversion of natural ecosystems or agricultural land, stock respiration and waste decomposition. Organic certification schemes through carbon labeling data ensures that responsible producers are able to benefit directly from potential price premiums associated with adopting mitigation and adaptation through low-carbon products. However, such a strategy demands a standardised approach to auditing carbon budgets across the sector and between production types and individual farms for the entire lifecycle of the product.

 

·         Carbon sequestration and pond management interventions to mitigate green house gases

There are opportunities to mitigate the climate change through carbon sequestration and other pond management interventions minimizing carbon dioxide and nitrous oxide emissions from aquaculture sector. Aquaculture has a potential significance in the carbon cycle, fixing CO2 through phytoplankton. If carbon is sequestered in the soil and used to increase productivity, there will be reduction in atmospheric carbon levels. Sediment management in pond-based aquaculture systems can have a significant affect on the accumulation of carbon and release of GHGs. Exposure of pond sediments can result in a loss of soil carbon through microbial processes as carbon dioxide, and failure to manage sediments can result in the evolution of more GHGs, notably methane. Application of excavated sediments to degraded or agricultural land could contribute significantly to building soil organic matter and carbon stocks and raising nutrient levels. The capacity to sequestrate carbon in soil under no till aquaculture is not conclusively proven and comparison with other management systems need to be made. There is a need for search of alternative pond bottom management practices after harvesting the crop for carbon sequestration.

 

 Evaluation of other cleaner technology such as anaerobic ammonia oxidation (ANAMMOX) which emits no or less nitrous oxide is a potential area in decreasing nitrous oxide. Cultured shrimp are continuously exposed to variable environmental conditions that have been associated with abiotic stresses, primarily water salinity and temperature. Shrimp farming has typically been conducted in places with different source waters varying in salinity and ionic composition.