Inland Fisheries

Responsible stocking and enhancement of inland waters in Asia

Rehabilitation & mitigation

This document provides an overview and guidance to inform responsible stocking and enhancement of inland waters in Asia. It comprises three technical papers prepared for and presented to the APFIC/FAO regional consultation “Improving the contribution of culture-based fisheries and fishery enhancements in inland waters to blue growth”, 25–27 May 2015, Jetwing Blue Hotel, Negombo, Sri Lanka.

The first paper in this review summarizes the main conclusions of various global reviews and research in stocking and develops guidance on fish species introductions and stocking. The purpose is to avoid the negative impacts and maximize the positive benefits of such activities. A decision framework for assessing the suitability of fishery enhancement in inland waters is proposed. This framework requires input and decisions at various steps to decide whether a new species introduction is acceptable and whether measures have to be taken to regulate such practices. This review provides support for these various steps for environmentally sound procedures for stocking activities and how these activities should be evaluated.

The second paper reflects on the competition for use of water and aquatic environments for human purposes other than fisheries. The cost-benefit resolutions to such conflicts are rarely explored, but are crucial to future management decisions regarding mitigation of environmental impacts and fisheries practices such as stocking. There are four main types of environmental interventions: protection; restoration/rehabilitation; mitigation and intensification, and some or all of these may involve the stocking of fish. The current trend in the stocking of open waters in Asia tends to be pursued uncritically with limited evaluation of its impact, both in terms of cost-effectiveness, environmental consequences and social impact. Although floodplain stocking has been credited with increasing fish production and fishers’ incomes, concerns have been raised about its implication for ecological and social equity, as well as its cost-effectiveness and sustainability. Even taking into account the costs of such enterprises, critical evaluation may well show that careful management of the natural environment through rehabilitation and mitigation techniques may be a more viable option in sustaining fish production from river and reservoir systems than stocking. This paper reviews some of the environmental and habitat actions that can deliver benefits to fisheries in lieu of, or alongside, stocking.

The third paper focuses on the form of stock enhancement most commonly used in Asia, namely stocking seed for the primary purpose of increasing yield. One of the most common stock enhancement practices in the region is culture-based fisheries. This is often conducted in small waterbodies to increase production. Some of these waterbodies are sometimes incapable of sustaining even a subsistence fishery through natural recruitment. In this paper, the benefits and constraints of culture-based fisheries practices in inland waters in Asia are considered. Details on species used, fish yields, income distribution patterns, and other community benefits such as improved nutrition are presented and discussed. The review highlights that the adoption of culture-based fisheries can result in significant increases in food fish production, especially in aquatic habitats that are limited in terms of natural recruitment (e.g. small seasonal reservoirs), but also including instances where there has been a shift from conventional capture fisheries to culture-based fisheries.