INTRODUCTION

Sustainable management of a resource was the theme of Chapter 2, with specific reference to agriculture, but there is obviously much more to this topic. We specifically explored production as well as some of the underlying biological principles of relevance. Thus we looked at the link between the biodiversity of agricultural systems and output, including the importance of system resilience and what farmers are trying to achieve. Farmers in many countries look to crop diversity as an insurance policy against crop failure, especially as they may lack access to inputs such as fertiliser, pesticide and irrigation. Underlying this is the concept of the niche and compatibility of crops.

But agriculture is only one source of food, albeit the most important one on a global scale. In this chapter we will continue the production theme, but look instead at the management of a wild animal resource, notably fish stocks. Fish farming aside, people manage fish stocks primarily through the means by which they harvest them. Wild fish stocks are not directly replenished by people in the same way that farmers plant crops or breed farm animals. Instead, the management is by controlling the rate of extraction of the stock or by the size (equates to age) of the animals which are removed. Thus, the management regime is more one dimensional than that of the systems we discussed in Chapter 2.