Cooperative versus non-cooperative management of shared linefish stocks inSouth Africa: an assessment of alternative management strategies for geelbek (Atractoscion aequidens)

The South African boat-based linefishery is a multi-species fishery with pa rticipants broadly divided into commercial (approximately 3000 vessels) and recreational (at least 4000 vessels) components. Atractoscion aequidens is an important species which, owing to a migratory lifestyle, is targeted by commercial communities throughout its estimated 2000 km distribution along the eastern seaboard of southern Africa. The national government is respon sible for the management of South Africa's marine resources; in the case of the linefishery this is effort-based, with limits on minimum size, daily b ags, the number of commercial permits and to some extent operational area. Results from an age-structured model reveal that the South African geelbek stock is heavily depleted, and that long term biological sustainability wou ld require an increase in the current minimum size limit and/or a daily bag limit for commercial fishers. Compliance with regulations and thus coopera tion with the responsible management authority is also essential. Cooperati ve versus non-cooperative management of the South African A. aequidens stoc k is explored using game theoretic bio-economic modelling, which simulates the effects of alternative size limits and effort restrictions on two separ ate jurisdictions that compete for this common-pool resource. The large num ber of players (licensees) within the linefishery creates a costly situatio n in terms of facilitating cooperative management, in spite of the potentia l greater long term social and economic benefits that such management arran gements can yield. The distribution of the different life-history stages of geelbek among competing interests on the east coast of South Africa exacer bates the problem of facilitating cooperative management, because the short term private economic benefits of non-cooperation exceeds the long term ov erall economic benefits from cooperative management. (C) 2001 Elsevier Scie nce B.V. All rights reserved.