National Innovations on Climate Resilient Agriculture - Marine Fisheries

(Central Marine Fisheries Research Institute)

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  • Capture Fisheries Research

  • Mariculture Research

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Background/problem in relation to identified activity under NICRA

The marine fish production in India has increased by six times in the last six decades. However, there are sustainability concerns such as production approaching the potential yield, overcapacity in the fishing sector, open access to the fishery, degradation of habitats and trade-related issues. Climate change exacerbates the situation.

Sea surface temperature has increased by 0.2 to 0.3o C along the Indian coast in the last 45 years, and is projected to increase by 2.0 to 3.5o C by 2099. The projected sea level rise is 30 cm in 50 years. During the southwest monsoon, the wind speed, coastal upwelling strength and chlorophyll concentration are also undergoing changes in the Indian Seas. These changes are likely to influence the structure and function of marine ecosystems, on which evidences are accumulating. Species response to elevated temperature is different, showing changes in composition and abundance at the base of the food web.

Among marine fish, the more mobile species should be able to adjust their ranges over time, but less mobile and sedentary species may not. Depending on the species, the area it occupies may expand, shrink or be relocated. This will induce increases, decreases and shifts in the distribution of marine fish, with some areas benefiting while others lose. The small pelagics such as the oil sardine and the Indian mackerel have extended their distributional boundary to northern and eastern latitudes contributing to fisheries in the last two decades. They have extended their distribution to midwaters as well. The threadfin breams are found to shift their spawning towards cooler months off Chennai. These distributional and phenological changes may have impact on nature and value of fisheries. If small-sized, low value fish species with rapid turnover of generations are able to cope up with changing climate, they may replace large-sized high value species, which are already showing declining trends due to fishing and other non-climatic factors.

In mariculture, elevated water temperature and changes in salinity and pH are likely to affect the spawning season, spawning strength and larval growth of candidate species. Seed and feed availability are also likely to be impacted due to climate change. Phytoplankton, which form food of larvae of culturable organisms, grow faster at elevated temperature, but the decay sets-in earlier. Generally, it is believed that elevated temperature may enhance spawning success and growth rate of culturable organisms. Hence there is scope for harnessing the benefits of elevated temperature.

Despite the uncertainties and potential negative impacts of climate change on fisheries and aquaculture, there are opportunities to reduce the vulnerability to climate-related impacts. As the first step, projections on fish distribution, abundance and catches need to be developed; and for mariculture, suitable candidate species, which would be benefited by elevated temperature, need to be identified for planning better management adaptations.

 

Copyright (C) 2012 Central Marine Fisheries Research Institute, Kochi