Have Centuries of Inefficient Fishing Sustained a Wild Oyster Fishery: a Case Study

Stephen Long,Matthew J Witt,Richard Ffrench Constant

doi:10.4172/2150-3508.1000198

Abstract

The native European flat oyster (Ostrea edulis) has declined throughout its range, due to over-exploitation, a situation mirrored in oyster stocks globally. There are three remaining oyster fisheries in England (Fal, Solent, and Thames Estuary). The Fal oyster fishery though employs traditional methods, using hand-hauled dredges from rowing punts or under sail and is home to the last commercial sailing fleet in Europe. Against a backdrop of temporary closures to protect dwindling stocks in the Solent and Thames Estuary, this study considers whether the longevity of the Fal oyster fishery is linked to the traditional methods that have been employed for centuries. Using GPS tracking in combination with on board observers, we demonstrate that dredging under sail is inefficient compared to more modern mechanically powered methods that are utilised elsewhere. A review of historical landings suggests that both overall landings and fishing effort have declined. The fishery appears to have gone through cycles of over-exploitation and one closure due to disease. However, the key to the long-term survival of the Fal oyster fishery may be linked to the traditional method of dredging. It is estimated that a switch from traditional methods to modern techniques would result in a greater than 9 fold increase in effort per season. The data presented highlight this unique fishery as a counterfactual to the increases in power seen in commercial fisheries over the last century and serve as a reference point for future studies.

Highlights

Despite recognition that centuries of marine exploitation have drastically reduced stocks of formerly abundant marine species [1], unsustainable fishing continues on a global scale [2]
Oysters are environmentally and economically important; they act as ecosystem engineers producing biogenic reef habitat [6], as well as providing ecosystem services including water filtration, food provision, habitat and coastal defence [7]
The fishery offers a sharp contrast to the industrialisation and increased fishing power of almost all other fisheries throughout the North Atlantic Ocean over the last two centuries, which has been linked to stock declines and fishery collapse [26,27]. Set against this historic back-drop the current study aims to highlight the Fal as a fishery that has maintained traditional practices and not exhibited the increases in fishing power through technological advances

Summary

Introduction

Despite recognition that centuries of marine exploitation have drastically reduced stocks of formerly abundant marine species [1], unsustainable fishing continues on a global scale [2]. There is significant scientific and economic interest in rebuilding collapsed fisheries and ensuring marine resources are used sustainably [3,4]. Achieving such sustainability will be challenging given the wide range of fishing practices, their target stocks and host ecosystems. Oysters are of significant economic value to coastal communities, with global production from aggregated country level data of 5.3 million tonnes in 2014, of which the vast majority (5.1 million tonnes) was from aquaculture [8,9]. Long term exploitation has edged oyster reefs to extinction, with an estimated 85% of oyster reefs lost globally [10]

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