Livelihood sustainability is also affected by external factors; sometimes
referred to as the vulnerability context, comprising trends and shocks that are outside
the control of the household. Trends might include decreasing catch rates, increasing
prices for fish, and a number of non-fishing related trends that nevertheless impact on
fishing households, such as the degradation of critical coastal habitats, an increase in
the price of coastal property, or increased restrictions imposed by planning authorities
on coastal building and infrastructure developments. Shocks might include storm
events that damage shore facilities, an outbreak of paralytic shellfish poisoning or, at
a household level, the illness or death of a family member (Allison and Ellis 2001).