Stocking in inland food fisheries of South and Southeast Asia: issues, risks, and rewards

Abstract

Inland fisheries in South and Southeast Asia represent important sources of food, and many are extensively stocked. Stocking often catalyses wider changes in inland fisheries is considered in this context. Stocking can be beneficial, providing additional sources of food, incentives to manage, and income‐generating opportunities. However, there are also identifiable risks: stocking can be used to avoid or ignore addressing reasons underlying the degradation of inland fisheries and economic development, tenure arrangements, and culture technologies involved in stocking can combine to transform the very nature of inland fisheries. These transformations can degrade environments and alter the nature and distribution of benefits, potentially marginalising and impoverishing fishers. There is consequently a need to consider and assess more explicitly in advance the implications of stocking for the nature and distribution of social and environmental costs and benefits, and the risks related to access to, and availability of, food.

Stocking fish in inland waters: Opportunities and risks for sustainable food systems

“…Fisheries enhancements have the goal to supplement or sustain the recruitment of aquatic organisms, or compensate for lost recruitment due to environmental perturbation, or increasing the population or production of a fishery up to or beyond the naturally sustainable level (de Silva, 2015). Whilst stocking is a practice frequently used by states, fisheries owners, managers, and scientists (Klefoth et al, 2023), evidence is growing that stocking alone does not necessarily improve catches or harvest yields, even when well managed by accounting for wider issues that may impinge on the outcome of stock enhancement intervention (Arlinghaus et al, 2022; Arthur et al, 2023; Claussen & Philipp, 2023; Cowx et al, 2015). This is often because limitations to natural recruitment processes or over‐harvesting, especially of juvenile fish (or stocked individuals intended in the case of enhancement), are not addressed by stocking, and pressures persist on the sustainability of the target fish stock.…”

“…In such cases, stocking is implemented to exploit available ecosystem productivity to its full extent. Stocking can help establish culture‐based fisheries in both open and closed water bodies (Arthur et al, 2023; de Silva, 2015; Lorenzen, 2008, 2014), compensate for losses due to environmental perturbation and degradation, such as loss of connectivity and pollution, enhance fish yield in water bodies that have limited natural recruitment or poor species diversity (Arthur et al, 2023), or support aquaculture‐based activities (Fiorella, 2023). Food fish have also been introduced into water bodies to enhance biodiversity and establish successful fisheries (Brummett, 2023; Gozlan et al, 2010), such as introducing kapenta ( Limnothrissa moidon ) into Lake Kariba and Lake Itezhi‐tezhi in Zambia to exploit vacant pelagic niches in newly created impoundments that created successful and productive fisheries (Cowx, 1997).…”

“…Thus, the overall feasibility of an action can be assessed in terms of environmental and ecological risk, bio‐economic gain, and practicality. Explicit recognition of the implications of stocking in terms of social and environmental benefits and costs is also needed to assess the feasibility of any action (Arthur et al, 2023). Without such action, any benefits accruing from a stocking programme are likely to be dissipated quickly, and stocking will have to be continuous, as is commonly practiced in many stocked fisheries.…”

“…Such stocking should be undertaken in an environmentally and socially acceptable and economically viable way. Issues raised during the InFish seminars and reported in associated papers (Arthur et al, 2023; Brummett, 2023; Claussen & Philipp, 2023; Fiorella, 2023), coupled with a management framework illustrated herein, could all be considered before existing stocking programmes are continued or new programmes are promoted.…”

“…Stocking can help establish F I G U R E 1 Production from different capture and culture systems (modified from Welcomme & Bartley, 1998). (Arthur et al, 2023;de Silva, 2015;Lorenzen, 2008Lorenzen, , 2014, compensate for losses due to environmental perturbation and degradation, such as loss of connectivity and pollution, enhance fish yield in water bodies that have limited natural recruitment or poor species diversity (Arthur et al, 2023), or support aquaculture-based activities (Fiorella, 2023).…”