Vulnerability is expressed through people’s ability or inability to shift to other sources of income, such as livestock rearing or employment, and their opportunity to buy food if the subsistence fishery declines. Poor people are the most vulnerable as they lack the necessary resources and capacity to change occupations and would have difficulty earning the extra income to purchase more of the food they need. Even though fish and other aquatic animals may not form a large proportion of the daily calorie intake or income source, a small shift such as eliminating the contribution from fish and other aquatic animals, can push people below the poverty line. Poor people are therefore very vulnerable to changes in access to these resources.