Useful Disasters: The Complexity of Response to Stress in a Tropical Lake Ecosystem [Introduction of Nile Perch to Lake Victoria]

Article excerpt

Abstract: The introduction of the Nile perch in the 1960s enhanced the economic value of the local fishery and encouraged women to become involved in fish processing and marketing. Over time, however, the predatory perch has severely reduced stocks of popular indigenous fishes. Currently, competition created by high foreign demand for the perch is forcing small-scale traders out of business and depriving local consumers of fish protein. Case studies reveal that the increased competition also has elicited various forms of production relations among men and women processors and traders. The complexities associated with the socio-ecology of this ecosystem hinder attempts to develop effective management policies.

Introduction

The introduction of the Nile perch (Lates niloticus) into Lake Victoria in the middle of this century has had far-reaching repercussions. To examine this phenomenon adequately requires a powerful analytical framework that combines both historical and processual ecological methods. Historical ecology as outlined by Schmidt (1994) seeks to identify ecological transformations induced by human cultural systems over time by analyzing the interplay of cultural systems with the physical environment. Processual ecological methods also serve to identify various mechanisms that link environment and behaviour by employing small and large units of analysis, dropping assumptions of equilibrium and balance and addressing processes of conflict and co-operation (Orlove 1980). Processual ecological anthropology examines the "interactions between the choices which actors make, behaviours on an individual or group level, and the biological and social systems which influence the distribution of resources, constrain the possible adaptive strategies and provide some of the goals which the actors attempt to meet" (Orlove 1980:257).

This article investigates a few of the complex relationships between the Lake Victoria ecosystem and the human populations that depend on its resources. It suggests that the development of useful resource management policies becomes problematic when the very patterns and dynamics of resource production and distribution are constantly undergoing changes that are incompletely understood and relatively unpredictable.

The Setting: Lake Victoria and Its Western Shore

Located mostly in the Kagera Region of Tanzania, the western shore of Lake Victoria consists of three main agro-ecological zones: a well-watered area stretching along the shore from Muleba and Biharamulo Districts north to the border with Uganda; a drier, flatter area located in Biharamulo District to the south; and a high plateau that stretches west toward the Ruwenzori mountains (see Figure 1). Seasonally heavy rainfall in the northwestern portion of the region has leached the soils of their nutrients over the millennia. Local farmers responded by painstakingly building up the land, using mulching techniques to nourish their plantations of plantains and coffee. The poor quality of the soil has also obliged many local women to look to off-farm activities for personal income generation.

The western shore is inhabited by Haya peoples in the north and Zinza -- mixed with other groups -- in the south. In pre-colonial and colonial times, the highly stratified, patriarchal Haya and Zinza societies were ruled by kings who maintained their control through a feudal, agropastoral system based on plantains and cattle. European colonization of East Africa at the turn of this century greatly diminished the power of these kings. The introduction of animal and human diseases, Western religions, new fish species and the cultivation of coffee for export during the German and British rule strongly influenced the social and physical environments of the west lake region.

Figure 1 The Western Shore of Lake Victoria [Map Not Transcribed]

Perched on a plateau about 1128 metres above the Indian Ocean, Lake Victoria is the largest tropical lake in the world, approximately the same size as Ireland [between 26 200 and 26 828 square kilometres (EAHC 1953; Ford 1955)]. …