Climate change is “long-term shifts in temperatures and weather patterns”. These shifts may be natural, or a result of human activities, which have been the main driver of climate change, for many decades. These activities produce heat-trapping gases, leading to global warming. Climate change brings cumulative impacts on environmental issues, including aquaculture activities.
The expected major impacts of climate change on aquaculture include direct impacts, indirect impacts, and uncertainty and inaccessibility of food/feed input supplies. Direct impacts affect the behavioral and physiological functions and the nutritional requirements and feed metabolism of framed aquatic animals. Indirect effects on the surrounding environments, include alteration of wind and water circulation, affecting the water’s primary and secondary productivity, changing the structure of the ecosystems, affecting the production and prices of landing crops and input supplies, and posing socio-economic impacts, which can indirectly affect aquaculture practices. Concerning uncertainty and inaccessibility of food/feed input supplies, fish meal (FM) and fish oil (FO) have traditionally been used as major nutritional inputs in aquaculture. However, the supply of FM and FO has been declining in recent years, due to the decline in forage fish landings. Consequently, the competition for FM and FO with human consumption is increasing. As a result, the use of FM and FO in fish feeds has dramatically decreased and will continue to decline, while the dependence on plant proteins and oil sources in aquafeeds has been accelerating. However, land plant crops are also affected by climate change. Climate change, including snow melt, rainfall variability, the availability of irrigation, droughts and floods, soil erosion, and the decline in arable areas will impact land crops.
The following interventions have been suggested to tackle these impacts and ensure aquaculture sustainability: a) searching for novel alternatives; b) production of renewable, nutritional resources; and c) on-farm feeding and feed management. Insect and worm meals (such as black soldier fly (BSF), housefly, blowfly, and mealworm beetle), micro and macro algae, single-cell proteins, and aquatic macrophytes have great potential as alternative aquafeed ingredients. The production of renewable, nutritional resources through recycling renewable biological resources can also be value-added, sustainable aquaculture inputs. The best on-farm feeding and feed management practices (BMP) can also reduce feed consumption and cost, improve feed utilization and fish yield, and reduce environmental impacts. Strategic planning, investment, and concrete-building measures should also be adopted to reduce greenhouse gas (GHG) emissions and aquaculture’s vulnerability to climate change.