Agriculture on the islands
The majority of the small islands developing states are heavily dependent on agriculture. The table below shows the percentage of the population engaged in agriculture. The agricultural population is defined as all people that depend on agriculture, forestry, fishing, and hunting for their livelihoods. 
In 30 of the small island countries at least one fifth of the population is engaged in agriculture. Even where agriculture’s contribution to GDP is small, a substantial part of the population may still be involved. For instance, in the Bahamas and Antigua-Barbuda, agriculture makes about the same contribution to GDP, but as a percentage, Antigua-Barbuda has nine times as many people working in the agricultural sector as the Bahamas. In the Seychelles, agriculture makes a contribution of less than 2 % to GDP, yet almost three-quarters of the population is engaged in agriculture.
As the table below shows that in eight of the SIDS, the majority of the population are engaged in agriculture: Comoros, Guinea Bissau, Haiti, Papua New Guinea, Sao Tome and Principe, Seychelles, Solomon Islands, and Timor Leste.
It is also noticeable that in each of these countries the fraction of the population engaged in agriculture has decreased significantly over the period 2000 to 2010. However, in absolute terms, due to the growing populations on each island, the number of people engaged in agriculture may well have increased.
Globally, more than 70% of agriculture is rain fed. Agriculture is therefore very sensitive to changes in rainfall, and highly vulnerable to climate change impacts that will change patterns of precipitation and increase local temperatures, and to weather that becomes become increasingly variable and frequently extreme. However, the resilience of agriculture on the islands can be increased using conservation agriculture techniques and ‘climate-smart’ practice.
Millions of coastal people across the globe depend on fishing both for food and as a source of income. Often combined with other ways to make a little money: agriculture and commerce being foremost, the revenue from fishing is essential for many poorer families and particularly for those living on small islands where nearly all coastal communities regularly engage in fishing to some degree. The fishing, aquaculture, and fish production sector employs around 150 million people in developing countries; of this total 38 million are fishing full-time. The number of full-time fishers has been growing steadily since 1990 at a rate ten times higher than the increase in agriculture workers over the same period 
This growth in employment has been mainly in small scale fisheries in developing countries. Many coastal fishers are among the poorest sector of society. Fishing is a way of reducing the vulnerability of poor families by supplementing and diversifying their incomes. Fishing is often the last resort livelihood for the poor.
Climate change will seriously impact fisheries on small islands. It will change both the productivity of fishing areas and the distribution of fish in marine and inland waters.
Nutrition will almost certainly suffer. The importance of fish in terms of nutrition is particularly high in developing countries–where protein intake may otherwise be insufficient. In developing countries, fish provides more than 20 percent of animal protein consumed, compared to just eight percent in industrial countries. This percentage rises to more than 50 percent of total animal protein in small island developing States 
Traditionally, island coastal communities in the Pacific have had some of the highest rates of fish consumption in the world—3 or 4 times the global average—and they have relied on fish to provide 50 to 90% of their dietary animal protein. Much of this fish comes from subsistence coastal fisheries based on coral reefs. By 2035, population growth is projected to reduce the availability of fish to below the 35kg of fish per person per year recommended for good nutrition. In addition, the direct effects of ocean warming on fish metabolism and the indirect effects of ocean warming on the quality of coral reef habitats as a result of coral bleaching and ocean acidification are expected to reduce production by around 20% by 2050.
The table below shows the expected shortfall in coastal fisheries production based on coral reef area for four Pacific island nations 
The rich tuna resources of the pacific region offer a potential solution to this forecast deficit. But modelling of the effects of ocean warming on ocean warming on the most abundant tuna species in the region, skipjack tuna, indicates that there is likely to be an eastward shift in the relative abundance of this important species.
Over time, it should be easier for coastal communities in Kiribati, the Cook Islands and French Polynesia to catch tuna than it is for coastal communities in the western Pacific, e.g. Papua New Guinea, and the Federated States of Micronesia.
In south-east Asia, the increase in marine and freshwater fish catch, and in the production from freshwater aquaculture and mariculture has enabled per capita fish consumption to increase from about 13 to 32 kg per year since 1961. As a result, present day fish consumption in the region is well above the per capita global average of about 19 kg per year. Nevertheless, many fish stocks have been over-exploited causing fish abundance at the end of the 20th century being 5-30% of the level in the 1950s. Marine fisheries in the South China Sea are characterized by high numbers of fishing vessels collectively employing millions of people.
Maintaining the significant contribution of marine fisheries and mariculture to livelihoods in south-east Asia will be a huge challenge as the ocean continues to warm. Under a business-as-usual emissions scenario, harvests from marine fisheries are projected to decrease by 20 to 30% by 2050 relative to 1970-2000. Overall, a loss of more than 20% of the original fish species richness in south-east Asia seas is projected by 2050 
In the western Indian Ocean, the high population density in small island developing states relative to coral reef area, coupled with poverty-driven dependence on fishing for food and cash has caused the deterioration of fish habitats through over-harvesting and destructive fishing. As a result, fisheries based on coral reefs now only make a modest contribution to per capita fish consumption, typically less than 5 kg/year for communities living within 25 km of the coast, although the Seychelles and Mayotte are the exception to this trend. By 2030, population growth coupled with the coral mortality linked to ocean warming is expected to reduce productivity even further 
For more information check out these sources ….
 See the FAO report : The state of food insecurity in the world. Available at : http://www.fao.org/publications/sofi/2014/en/
 See the FAO Statistical yearbook, available at : http://www.fao.org/3/a-i4691e.pdf
 See the report from the World Bank titled : Turning the tide: Saving fish and fishers, available at: http://documents.worldbank.org/curated/en/461681468181780318/pdf/831790WP0seawe00Box379886B00PUBLIC0.pdf
 See the FAO report: Building adaptive capacity to climate change: Policies to sustain livelihoods and fisheries. Available at: http://www.fao.org/docrep/010/a1115e/a1115e00.pdf
 World Bank: Turning the tide. Cited above
 See the IUCN report: Explaining ocean warming: Causes, scale, effects and consequences. Available at : https://portals.iucn.org/library/node/46254
 See the IUCN report cited above.