Uncertainty in Fishery Systems

Uncertainties are ubiquitous in fisheries. Stock sizes and fish prices are never known precisely within a given year, much less from one year to the next. Impacts of fishing methods, and fishing behaviour, on the resource or the environment cannot be predicted exactly. And there are many other uncertainties as well. A wide variety of uncertainties arise in fishery systems, on the natural, the human and the management sides. This chapter discusses how to categorise the various forms of uncertainty. This is illustrated by examining a crucial example where uncertainties arise in fishery systems, within fishery science and stock assessment, namely the stock–recruitment relationship, the manner by which the current fish stock can predict future stocks, by predicting the subsequent recruitment. A fundamental form of uncertainty arises as random fluctuations – in fish survival rates, fish prices, and many other quantities. Such fluctuations pose major challenges to fishery management.