Publication Abstract

Migration

J.D. Metcalfe, G.D. Arnold and R. McDowall

Migration is a common feature of the life histories of many of the world's economically important species of fish. For many, these movements are extensive, and the regular seasonal changes in population distribution that result often have significant implications for commercial fisheries. Consequently, understanding migration is important to the cost-effective and sustainable exploitation of fish stocks.

'Understanding' in this context may simply involve an appreciation of the seasonal arrival and disappearance of a stock, allowing fishermen to target their activities effectively. Alternatively, it may involve a more detailed knowledge that allows the development of realistic models of population dynamics that can be used to assess the likely effects of different management strategies. However, fish migration is a very broad subject. At one end it involves the behavioural ecology of whole populations, at the other it focuses on the neurobiology of sensory systems that form the basis of the orientation and navigation abilities of individuals.

While the different aspects of migration fascinate the biologist, not all are directly relevant in a fisheries context, and some are beyond the limited scope of this chapter. Further, it is not our aim to give exhaustive accounts of the life-history strategies, or migration circuits, of all economically important migratory fish. For this the reader is directed to other, more extensive texts relating to migration (e.g. Harden Jones 1968; Baker 1978; McKeown 1984; McDowall 1988) or to individual species (e.g. Pickett and Pawson 1994). Our aim is to review the occurrence of migration in the life histories of commercial fish species and the ecological principles that drive migratory behaviour. We describe a number of different migratory strategies and attempt to explain how understanding migration is of value to fisheries management and conservation. Many species of fish live in environments that are hostile, at least to human observers, and their migrations are therefore particularly difficult to study, so finally we review the field techniques used to study fish migration and consider how these are likely to develop and improve our understanding in the future.

Reference:

J.D. Metcalfe, G.D. Arnold and R. McDowall, 2002. Migration. p. 175-199 In: Hart PJB; Reynolds JD (eds.). Handbook of Fish Biology and Fisheries, Volume 1. Oxford: Blackwell Publishing.