By Govind Choudhary; Mayuri Nag; Shubham Varshney

Aquatic systems that sustain fisheries and aquaculture are undergoing significant changes as a result of global warming and projections indicate that these changes will be accentuated in the future. It is now widely accepted that climate change is no longer simply a potential threat, it is unavoidable; a consequence of 200 years of excessive greenhouse gas (GHG) emissions from fossil fuel combustion in energy generation, transport and industry, deforestation and intensive agriculture is realized.

Climate change is an additional pressure on the freshwater aquaculture and the impacts of climate change on freshwater aquaculture are more complex than those on terrestrial agriculture because it holds poikilothermic animals, which is highly sensitive to various kind of biotic and abiotic stress that directly affect the growth, reproduction, physiology and behavior of fishes. Climate changes affect the aquaculture directly by influencing fish stocks or indirectly alter the primary and secondary productivity, structure, and composition of the ecosystems, or by influencing fish prices or the cost of fish meal, fish oil and other goods and services required by fishers and fish farmers.

Primary production in the oceans has been projected to decrease by three percent to nine percent by 2100; in freshwater systems observations vary depending on the area, but overall, forecasts are highly uncertain for both marine and freshwater systems because primary production is an integrator of changes in light, temperature and nutrients.

Water temperature – There is a high confidence that rising water temperatures will lead to shifts in freshwater species’ distributions and exacerbate existing problems in water quality, especially in those systems experiencing high anthropogenic loading of nutrients (IPCC, 2014). Oxygen content-GHG- driven global warming is the likely ultimate cause of this ongoing deoxygenation in many parts of the open ocean (Breitburg et al., 2018). Ocean warming, which reduces the solubility of oxygen in water, is estimated to account for approximately 15 percent of current total global oxygen loss and more than 50 percent of the oxygen loss in the upper 1 000 m of the ocean.

Effective adaptation will be required across all scales and sectors of fisheries and aquaculture in order to strengthen and maintain productive and resilient aquatic ecosystems and the benefits derived from them, but particular attention needs to be given to the most vulnerable if the sector is to continue to contribute to meeting global goals of poverty reduction and food security. In addition, as their poverty and marginalization are primary causes of their vulnerability, the eradication of poverty and provision of food security for the world’s poor are fundamental to building their resilience to climate change.

Climate-Smart Aquaculture is aim to support food security taking into account the need for adaptation and the potential for mitigation. CSA addresses the challenges of building synergies between the related
objectives of climate change mitigation, adaptation and productivity and income increase, and minimizing their potential negative tradeoffs.

Climate-smart aquaculture will require the following:

  1. Improving efficiency in the use of natural resources to produce fish and aquatic foods.
  2. Maintaining the resilience aquatic systems and the communities that rely on them to allow the sector
    to continue contributing to sustainable development; and
  3. Gaining an understanding of the ways to reduce effectively the vulnerability of those most likely to be
    negatively impacted by climate change
    Examples of tactics for attaining CSA objectives in respect to fisheries include: the reduction of excess
    capacity and the implementation of fishing activities that are linked with improved fisheries
    management and healthy stocks; increased production efficiency through better integrated systems;
    improved feeding and reduced losses from disease in aquaculture; the reduction of postharvest and
    production losses; and the further development of regional trade.

The transition to CSA will need to take place at all levels (individual, business, community, national and regional) and time scales. All stakeholders from private and public sectors will need to be involved in the
development of context-specific options to ensure the fisheries and aquaculture sector is climate-smart.
To make the transition to CSA, it will be necessary to ensure that the most vulnerable states, production systems, communities and stakeholders have the potential to develop and apply CSA approaches. Markets and trade may help buffer the impact of changes in production that affect food security,
consumer prices and supply-demand gaps. However, the implications of climate change impacts and climate change policies on the entire supply and value chain need to be better understood. Appropriate
policy measures need to be defined and implemented.

We surveyed the fish farmers of five states, viz. Andhra Pradesh, Karnataka, Gujarat, Odisha and West Bengal of India for adaptation and mitigation strategies of climate change impact in freshwater aquaculture. In monsoon period especially when the cyclone occurred, overall 9% fish farmers responded regarding fish migration from one pond to another pond. Sometimes entire stocks washed out due to heavy floods.

In Andhra Pradesh, the farmers responded that most of the hatcheries are closed in Krishna delta due to lack of water availability and is shifted to Godavari basins. As freshwater availability is crucial for securing a sustainable, lower carbon future, there is a critical connection between water management and climate policies. Under a rapidly changing climate, it is more important than ever to estimate the degree of future water security and Aquaculture.
Adaptation strategies : • Addressing drivers of vulnerability ► Diversify sources of household income ► Participate in income stabilization programmes ► Introduce social protection initiatives ► Promote community based risk management measures to face production failure and price of product ► Develop innovative risk financing instruments and insurance schemes to reduce climate-related risks • Building response capacity ► Conservation of genetic resources ► Implement co-
management systems • Managing climate risk ► Disaster risk reduction ► Disaster risk management.

The farmers tried to mitigate some of the problems of climate change in aquaculture practices. 60 to 100% of farmers pump freshwater to cool down the temperature of fish culture ponds. Andhra Pradesh and West Bengal farmers use this practice. In these states, farmers exchange water to maintain the good water quality. This helps to cool down the temperature. The farmers of Andhra Pradesh also planted coconut trees along the bunds of fish ponds to avoid heat in summer months.
Mitigation strategies: • Reducing emission ► Adopting improved aquaculture management. • Avoiding or Displacing emission ► reducing post-harvest lost ► Use of fishing practices that adhere to principles of the code of conduct for responsible fisheries ► Removing emission ► Replanting mangroves in aquaculture area.

Climate change is a serious challenge for the continent of Africa Nigeria inclusive. Impact of climate change limited sustainable production of fisheries and aquaculture. There is need to adopt climate smart approach because it combines adaptation and mitigation in a way that enhance sustainable fisheries production in the face of climatic change. Also, awareness on the climate smart approach is relatively low. Increased awareness on climate smart approaches in fisheries sector have potentials
for enhancing food security and sustainable better livelihood for farmers.
From the above discussion, it is clear that climate change has a strong impact on aquaculture.
Different strategies are being used by the fish farmers and by doing so, they are getting benefit. The strategies are location specific. Among the three main problems, viz., drought, flood and temperature rising, drought is very much dangerous as without sufficient rainfall, the culture of freshwater aquaculture practices will be difficult. In this regard, more research is required by which ‘per drop more crops’ can be achieved.
Creation of easily accessed regional, national and local depositories for climate and allied data will be necessary so as to increase capacity in information technology and modeling of climate change data. Suitable adaptation and mitigation measures should be site specific to respond to anticipated changes in rainfall and temperature in Nigeria. Models for sustainable fisheries management and aquatic resources conservation would be required for regeneration of fish stocks, Aquaculture and ecosystems.